Final Report Vol3-river Basin Study

NORTH WEST IRRIGATION SECTOR PROJECT ADB Loan No. 2035 - CAM (SF) AFD Grant No. CHK 3003.01

RIVER BASIN AND WATER USE STUDIES, PACKAGE 2 Boribo and Dauntri Sub-basins

Final Report Volume 3: Dauntri Sub-basin 5 December 2006

Prepared for MINISTRY OF WATER RESOURCES AND METEOROLOGY by PRD Water & Environment in association with DHI Water & Environment

Version 2

North West Irrigation Sector Project River basin and water use studies, Package 2

Revisions Version 1:

New section 4.4: Water availability Summary expanded Table 8.3 changed

Version 1a:

Section 4.4 expanded A large part of Section 6.3 (water quality) shifted to new Appendix 5

Version 2:

Section 3.5: Reference added to Appendix 3 Sections 4.3 and 4.4, new Table 4.14: Discussion of a further extension of the Damnak Ampil Canal all the way to St. Dauntri (to serve the Prek Chik candidate sub-project), with exemplification of achievable benefits New Section 4.5 (allocation of manageable flows), with explanation of manageable flows, and estimates of water availability downstream of candidate sub-projects Section 8.4: Livestock analysis revised

Acknowledgement The Package 2 Team expresses its sincere thanks to the staff members from the Provincial Departments, the district officers, and the many individual persons who have kindly taken time out to share their knowledge for the purpose of the present study. MOWRAM, the PMO, the PIUs and the TA Consultant have provided valuable guidance and shared data and knowledge, including results from monitoring programmes and previous related studies. MRC has kindly made data and GIS layers available for the purpose of the study.

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North West Irrigation Sector Project River basin and water use studies, Package 2

Summary The Northwest Irrigation Sector Project (NWISP) is being implemented by MOWRAM, with assistance from Asian Development Bank (ADB) and Agence Française de Développement (AFD). It has the overall objective of supporting the effort of the Royal Government of Cambodia to reduce poverty in rural areas of northwest Cambodia through enhanced agricultural production. The immediate objectives are to improve the use of water resources and to take advantage of the potential for irrigated agriculture. One activity of the NWISP is a series of river basin and water use studies, which have the over-all objective 'to provide a framework leading eventually to institutional means for installing a scientifically informed approach for management of water quantity and quality in the target river basins'. The river basin and water use studies will provide a part of the basis for subsequent master planning, and for design and feasibility studies of irrigation schemes to be conducted later on under the NWISP. Package 2 of these studies covers the Dauntri Sub-basin in Battambang and Pursat Provinces, and the Boribo Sub-basin in Pursat and Kg Chhnang Provinces (and with a small corner in Kg Speu Province). The present 'Final Report, volume 3' describes the water balance and water uses in Dauntri Sub-basin. The work has been based on data and information available from the Commune Database, MOWRAM, MRC and others, as well as comprehensive field surveys conducted under the present study. The analyses have been supported by numerical river basin modeling of water balance and water quality. A summary of the average water balance and the present water utilization is shown in the following table.

Dauntri Sub-basin (St. Kambot, St. Svay Donkeo and St. Dauntri) Area: 3,542 km2 (21 percent of which is more than 100 m above mean sea level) Cultivated area (rice and other crops) (2005): 1,623 km2, of which wet season irrigated: 17 km2 (actual), 447km2 (potential) dry season irrigated (2 crops per year): 5 km2 (actual), 3 km2 (potential) Population (2004): 233.509

Annual water balance, present conditions, 4 out of 5 years Rainfall

Evapo-ration

Storage and losses

Water availability

Domestic uses

Irrigation uses

Livestock uses

Outflow

m3/s

m3/s

m3/s

m3/s

m3/s

m3/s

m3/s

m3/s

119,9

81,0

0,1

38,8

0,1

6,5

0,4

31,8

l/s/km2

l/s/km2

l/s/km2

l/s/km2

l/s/km2

l/s/km2

l/s/km2

l/s/km2

33,3

22,5

-

10,8

-

1,8

0,1

8,8

'-' means 'less than 0.05'

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North West Irrigation Sector Project River basin and water use studies, Package 2

Dauntri Sub-basin has 2 schemes that have been identified as candidate sub-projects under the NWISP. The estimated manageable water availability is summarized below.

Water availability at candidate sub-projects Krouch Sauch

Anlong Svay

Anlong Svay and Roneam Prayol (to share)

Prek Chik

Low estimate

High estimate

Low estimate

High estimate

Low estimate

High estimate

(a)

(a)

(a)

(a)

(a), (b)

(a), (b)

(c)

m3/s

m3/s

m3/s

m3/s

m3/s

m3/s

m3/s

J

1,5

2,7

2,4

4,0

2,4

4,0

0,3

F

0,9

1,7

1,3

2,3

1,3

2,3

-0,1

M

0,9

1,7

1,3

2,3

1,3

2,3

-0,3

A

0,9

1,7

1,3

2,3

1,3

2,3

-0,3

M

1,5

2,7

2,2

3,8

2,2

3,8

-0,3

J

2,1

3,6

3,3

5,4

3,3

5,3

0,9

J

4,9

7,1

9,6

12,6

9,9

12,9

8,2

A

8,2

10,5

17,0

20,0

18,2

21,2

21,3

S

10,2

12,5

21,4

24,4

23,1

26,1

29,1

O

8,2

10,4

16,9

19,9

18.0

21,0

21,1

N

4,1

6,4

7,9

10,9

8,1

11,1

5,2

D

2,2

3,7

3,7

5,7

3,7

5,7

1,5

The water availability is the estimated availability in 4 out of 5 years under present conditions The estimate includes present withdrawals for irrigation; and present and future withdrawals for domestic and livestock The estimate excludes any future expansion of irrigation withdrawals (a) The water availability at Krouch Sauch, Anlong Svay and Roneam Prayol is influenced by the operation of the Damnak Ampil Canal. The low and high estimates are based on assumptions about the future operation. Please refer to text for details (b) The water availability at Roneam Prayol is influenced by the implementation of the Anlong Svay scheme (c) Negative values means that water is inadequate for the assumed future domestic and livestock demand No allocation has been made for in-stream demands

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Contents Acronyms and abbreviations..................................................................................................................vii Study tasks ........................................................................................................................................... viii Terminology............................................................................................................................................ix Names .....................................................................................................................................................ix Location map............................................................................................................................................x 1

Introduction .........................................................................................................................1

2

Geography ...........................................................................................................................2 2.1 Data ........................................................................................................................2 2.2 Population, administrative boundaries ...................................................................2 2.3 Elevations, land use, soils ......................................................................................4 2.4 Irrigation.................................................................................................................6

3

Hydrology..........................................................................................................................10 3.1 Data ......................................................................................................................10 3.2 River network and catchment delineation ............................................................10 3.3 Rainfall and evaporation ......................................................................................14 3.4 Streamflow ...........................................................................................................15 3.5 Regulation ............................................................................................................17

4

Water uses and water balance............................................................................................22 4.1 Water uses ............................................................................................................22 4.2 Water balance.......................................................................................................23 4.3 Candidate sub-projects .........................................................................................39 4.4 Water availability .................................................................................................41 4.5 Allocation of manageable flows...........................................................................45

5

Morphology, floods and drought .......................................................................................51 5.1 Data ......................................................................................................................51 5.2 Morphology..........................................................................................................51 5.3 Floods and drought...............................................................................................52

6

Aquatic environment .........................................................................................................55 6.1 Data ......................................................................................................................55 6.2 Pollution loads......................................................................................................55 6.3 Water quality........................................................................................................63 6.4 Implications of irrigation development ................................................................65

7

Fisheries.............................................................................................................................69 7.1 Dauntri River........................................................................................................69 7.2 Svay Don Keo River ............................................................................................69 7.3 St. Kambot............................................................................................................69

8

Socio-economics................................................................................................................71 8.1 Data ......................................................................................................................71

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8.2 8.3 8.4 8.5

ii

Socio-economic context .......................................................................................71 Water utilization...................................................................................................77 Economic analysis................................................................................................85 Water user groups ................................................................................................91

References..............................................................................................................................................92 Appendix 1: Thematic maps ..................................................................................................................93 Appendix 2: Data files ...........................................................................................................................98 Appendix 3: Water management structures .........................................................................................100 St. Dauntri (St. Moung) ...................................................................................................100 St. Svay Donkeo ..............................................................................................................101 St. Kambot (Preahmlu) ....................................................................................................102 Appendix 4: Water balance tables........................................................................................................103 Appendix 5: Water quality simulations................................................................................................133 A5.1 General ...............................................................................................................133 A5.2 Present conditions ..............................................................................................135 A5.3 Implications of irrigation development ..............................................................139

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North West Irrigation Sector Project River basin and water use studies, Package 2

Figures 2.1:

Communes in Dauntri Sub-basin

2.2:

Land elevations in Dauntri Sub-basin

2.3:

Land elevation distribution in Dauntri Sub-basin

2.4:

Land use in Dauntri Sub-basin

2.5:

Irrigation schemes in Dauntri Sub-basin

3.1:

River network, Dauntri Sub-basin (detailed and simplified)

3.2:

Comparison between sub-basin boundaries

3.3:

Ou Souphi Offtake

3.4:

Monthly average flow, St. Dauntri

3.5:

Structures along the Damnak-Ampil Canal

3.6:

The Damnak Ampil Canal and regulator under construction (6 July 06)

3.7:

The Damnak-Ampil Canal from Pursat River to Prek Chik

3.8:

Photos from the Damnak-Ampil Canal

4.1:

MIKE Basin model of the Dauntri Sub-basin

4.2:

Schematic representation of sub-catchments

4.3:

Rainfall-runoff simulation for the Dauntri catchment

4.4:

Simulated and observed discharge in Stung Sangker at Battambang

4.5:

Schematisation of the Damnak-Ampil irrigation canal

4.6:

Water availability, present conditions, April, m3/s

4.7:

Specific water availabilty, present conditions, April (l/s/km2)

4.8:

Water availability, present conditions, September (m3/s)

4.9:

Specific water availabilty, present conditions, September (l/s/km2)

4.10:

Specific water availabilty, present conditions, annual (l/s/km2)

4.11:

Ratio between groundwater flow and total runoff

4.12:

Schematization of St. Kambot

4.13:

Schematization of St. Svay Donkeo

4.14:

Schematization of St. Dauntri

5.1:

Erosion and accretion

6.1:

Amount of annual BOD load by sub-catchment

6.2:

Location of the sub-catchments

6.3:

Amount of annual Total Nitrogen load by sub-catchment

6.4:

Amount of annual Total Phosphorous load by sub-catchment

6.5:

Time series results for the outlet of St. Dauntri, present conditions

6.6:

Simulated discharge for reference scenario and the candidate sub-projects

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North West Irrigation Sector Project River basin and water use studies, Package 2

6.7:

Changes in water discharge from the present situation after irrigation development

6.8:

Time series results for the outlet of St. Dauntri after irrigation deveopment

8.1:

Household income structure

8.2:

Main sources of drinking water in Pursat and Battambang Provinces

8.3:

Irrigated cropping areas in Dauntri Sub-basin

8.4:

Present and future composition of major extractive water demands

8.5:

Value added by water to livelihoods in Dauntri Sub-basin

A5.1:

Average concentration of BOD for 2000 and 2001

A5.2:

Maximum concentration of BOD for 2000 and 2001

A5.3:

Average concentrations of NH4 for 2000 and 2001

A5.4:

Maximum concentrations of NH4 for 2000 and 2001

A5.5:

Average concentrations of NO3 for 2000 and 2001

A5.6:

Maximum concentrations of NO3 for 2000 and 2001

A5.7:

Average concentrations of Total-phosphorus for 2000 and 2001

A5.8:

Maximum concentrations of Total-phosphorus for 2000 and 2001

A5.3

Implications of irrigation development

A5.9:

Average concentration of BOD for the candidate sub-projects

iv

A5.10: Maximum concentration of BOD for the candidate sub-projects A5.11: Difference in BOD concentrations between the candidate sub-projects and the present situation A5.12: Average concentrations of NH4 for the candidate sub-projects A5.13: Maximum concentrations of NH4 for the candidate sub-projects A5.14: Difference in NH4 concentrations between the candidate sub-projects and the present situation A5.15: Average concentrations of NO3 for the candidate sub-projects A5.16: Maximum concentrations of NO3 for the candidate sub-projects A5.17: Difference in NO3 concentrations between the candidate sub-projects and the present situation A5.18: Average concentrations of total-phosphorus for the candidate sub-projects A5.19: Maximum concentrations of total-phosphorus for the candidate sub-projects A5.20: Difference in total-phosphorus concentrations between the candidate sub-projects and the present situation

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North West Irrigation Sector Project River basin and water use studies, Package 2

Tables 2.1:

Administrative units with area and population, Dauntri Sub-basin

2.2:

Land use

2.3:

Forest cover

2.4:

Irrigation schemes in Dauntri Sub-basin

3.1:

Distribution of annual rainfall

3.2:

Pan evaporation

3.3:

Assumed flow from Pursat River into the Damnak-Ampil Canal

4.1:

Estimate of future domestic demand, Dauntri Sub-basin

4.2:

Summary water balance, base situation, 4 out of 5 years

4.3:

Summary water balance with the Damnak Ampil Canal

4.4:

Monthy simulated ratio between groundwater flow and total runoff

4.5:

Summary water balance with Damnak Ampil Canal and candidate sub-projects

4.6:

Summary water balance with Damnak Ampil Canal, candidate sub-projects, and climate change

4.7:

Estimated water availability at Krouch Saeuch

4.8:

Estimated water availability at Anlong Svay

4.9:

Estimated water availability at Roneam Prayol

4.10:

Estimated water availability at Prek Chik

4.11:

Manageable flows downstream of candidate sub-projects

4.12:

Rainfall deficit

4.13:

Irrigable areas

4.14:

Irrigable area at Prek Chik assuming a supply from the Damnak Ampil Canal

5.1:

Cultivation areas affected by floods and drought

5.2:

Occurrence of floods and drought

6.1:

Distribution of areas for rice cultivation and estimated fertiliser application

6.2:

Overall generated load of BOD, nitrogen and phosphorus

6.3:

Estimated BOD load reaching the river in each subcatchment

6.4:

Estimated nitrogen load reaching the river in each subcatchment

6.5:

Estimated phosphorus load reaching the river in each subcatchment

8.1:

Sources of cash income in each sub-basin

8.2:

Summary socio-economic indicators

8.3:

Cultivated areas in Dauntri Sub-basin

8.4:

Irrigated crop areas

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North West Irrigation Sector Project River basin and water use studies, Package 2

8.5:

Future demands for irrigation in Dauntri Sub-basin

8.6:

Present livestock water demands in Dauntri Sub-basin (2005)

8.7:

Projected livestock water demands to 2030

8.8:

Projected domestic consumption demands

8.9:

Crop budget summary for Dauntri Sub-basin

8.10:

Livestock value in Dauntri Sub-basin

8.11:

Average tariff and unit production costs

8.12:

Net benefits of domestic water supply

8.13:

Value of the potential fish yield in Dauntri Sub-basin

8.14:

Water User Groups in Dauntri Sub-basin

A2.1:

Time series data

A2.2:

Data tables

A4.1:

Summary water balance, base situation

A4.2:

Summary water balance, base situation with Damnak Ampil Canal

A4.3:

Summary water balance with Damnak Ampil Canal and candidate sub-projects

A4.4:

Summary water balance with Damnak Ampil Canal, candidate sub-projects and climate change

A4.5:

Water balance, base situation

A4.6:

Water balance with Damnak Ampil Canal

A4.7:

Water balance with Damnak Ampil Canal and candidate sub-projects

A4.8:

Water balance with Damnak Ampil Canal, candidate sub-projects and climate change

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North West Irrigation Sector Project River basin and water use studies, Package 2

Acronyms and abbreviations ADB

: Asian Development Bank

AFD

: Agence Française de Développement

CNMC

: Cambodia National Mekong Committee

DoE

: (Provincial) Department of Environment

EIA

: environmental impact assessment

FWUC

: farmer's water user community

GW

: groundwater

IWRM

: integrated water resources management

MAFF

: Ministry of Agriculture, Forestry and Fisheries

MCM

: million cubic metres

MoE

: Ministry of Environment

MOWRAM

: Ministry of Water Resources and Meteorology

MRC

: Mekong River Commission

NWISP

: North West Sector Irrigation Project

PDAFF

: Provincial Department of Agriculture, Forestry and Fisheries

PDWRAM

: Provincial Department of Water Resources and Meteorology

PIU

: Project Implementation Unit (of the NWISP)

PMO

: Project Management Office (of the NWISP)

PRA

: participatory rural appraisal

RGC

: Royal Government of Cambodia

ToR

: terms of reference

WQ

: water quality

WUC, WUG

: water user community, water user group

WUP-FIN

: Finnish component of MRC's Water Utilization Programme

WUP-JICA

: Japanese component of MRC's Water Utilization Programme

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North West Irrigation Sector Project River basin and water use studies, Package 2

viii

Study tasks No.

Item

Reference

Inception phase – Collection of information 1

Collection of general data and information

(cross-cutting)

2

Collection of hydro-meteorological and hydraulic data and information

Vol1 Sect 4.1

3

Field surveys, inspection of monitoring stations, flood damage assessment

(cross-cutting)

4

Consultation meetings at province, commune and village level

(cross-cutting)

5

Basic thematic maps

Vol2&3 App 1

6

Approach to hydrological analysis

Vol1 Sect 5.3, Vol1 App 2

7

Technical workshop with MOWRAM/PDWRAM

(reported separately)

Hydrological studies and modelling 8

Review of river monitoring network

Vol1 Sect 9.1

9

Hydrological analysis

Vol2&3 Ch 4

10

Morphological analysis

Vol1 6.2, Vol2&3 Sect 5.2

11

Flood characteristics

Vol1 Sect 6.3, Vol2&3 Sect 5.3

12

Fish, fish habitats and fish migration

Vol1 Sect 7.2, Vol2&3 Ch 7

13

Support to selecting candidate NWISP subprojects

Vol1 Sect 9.2, Vol2&3 Sect 4.3

Analysis of water uses 14

Remote sensing analysis and field survey

(cross-cutting)

15

Forestry and land use survey

Vol1 Sect 2.3, Vol2&3 Sect 2.3

16

Field surveys of water uses

Vol1 Sect 5.2, Vol2&3 Sect 4.1

17

Inventory of water users committees

18

Quantification of consumptive and non-consumptive water uses

Vol1 Sect 5.2, Vol2&3 Sect 4.1

19

Economic analysis of water utilization

Vol1 Ch 8, Vol2&3 Ch 8

20

Economic analysis of long-term development opportunities

Vol1 Sect 8.4

Water balance 21

Water balance for the sub-basins

Vol2&3 Sect 4.2, Vol2&3 App 4

22

Assessment of trends in water availability and demand

(same)

23

Assessment of impacts of each subproject on downstream water uses

Vol2&3 Sect 4.3, Vol2&3 App 4

NWISP candidate sub-projects

Vol2&3 Sect 4.4

24

Environmental aspects 25

Existing WQ data and classification

Vol1 Sect 7.3

26

Point and non-point sources

Vol1 Sect 7.4, Vol2&3 Sect 6.2

27

Aquatic environment in representative reaches

Vol2&3 Sect 6.3

28

Environmental flows in representative reaches, and assessment of enforcement

Section 9.6

29

Evaluation of fish passages

Vol2&3 Ch 7

30

Inception report

(reported separately)

31

Sub-basin reports

(reported separately)

32

Surface water and groundwater maps

Vol2&3 Sect 4.2 (no GW maps)

33

Response to data shortcomings

(cross-cutting)

34

Project completion report

(reported separately)

35

Project completion workshops

(reported separately)

36

Weekly progress statements

(reported separately)

37

Liaison with RGC and provincial agencies and community representatives

(cross-cutting)

38

Knowledge-sharing with designated counterpart staff

(cross-cutting)

Reports – progress meetings - workshops

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ix

Terminology Following a discussion at the Inception Workshop in Pursat on 11 July 2006, and with a view to the terminology applied in the Terms of Reference, the following suggestions are made: Terms used in the present study: Catchment: The general term for an area from where the surface flow proceeds towards a specific location (like a cross-section of a river or canal, or a lake or reservoir). A catchment is delineated by a catchment boundary. It can be a river basin or a part of a river basin. Same as drainage area Catchment boundary: The boundary of a catchment (or a river basin or a sub-catchment). The surface flow of rain falling on each side of the boundary will proceed towards different locations. A review of catchment boundaries is a part of the present study River basin: The catchment of a whole river (with its tributaries). In the present study, this term is used both for the Mekong Basin and the Tonle Sap Basin. (In some other studies, the Tonle Sap Basin is referred to as a sub-basin of the Mekong Basin) Study area (Package 2): The Dauntri/Svay Don Keo and the Boribo/Thlea Maam Sub-basins Sub-area: An area that is a part of another area Sub-basin: The catchment of a tributary, and hereby a part of river basin. The present study deals with the Dauntri/Svay Don Keo Sub-basin and the Boribo/Thlea Maam Sub-basin Sub-catchment: A catchment that is explicitly a part of a larger catchment. In the present study, an irrigation scheme will receive water from a sub-catchment, and sub-catchments are used as units for the river basin modelling of water balance and water quality Terms not used in the present study: Drainage area or drainage basin: Same as a catchment (or a sub-catchment) Watershed: (1) in English, same as a catchment boundary; (2) In American English, same as a catchment. Watershed management can cover different aspects of water-related management within a watershed, depending on the circumstances

Names Most rivers change their names along their course, often within short distances. Different spellings are used for many rivers, streams and locations, for example Pursat/Pouthisat, Dauntri/Dauntry /Daun Try, etc. St. Dauntri is also named St. Muong, and St. Kambot is also named St. Preahmlu.

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x

Location map 300 000

350 000

400 000

450 000

500 000

300 000

350 000

400 000

450 000

500 000

1 500 000

1 450 000

1 400 000

1 350 000

1 500 000

1 450 000

1 400 000

1 350 000

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North West Irrigation Sector Project River basin and water use studies, Package 2

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1

Introduction The Northwest Irrigation Sector Project (NWISP) is being implemented by MOWRAM, with assistance from Asian Development Bank (ADB) and Agence Française de Développement (AFD). It has the overall objective of supporting the effort of the Royal Government of Cambodia to reduce poverty in rural areas of northwest Cambodia through enhanced agricultural production. The immediate objectives are to improve the use of water resources and to take advantage of the potential for irrigated agriculture. It is intended to establish ten to twelve rehabilitated and sustainably operational small to medium-scale irrigation systems and other water control infrastructure. The NWISP is managed by a Project Management Office (PMO) within MOWRAM, assisted by a TA Consultant (BCEOM/ACIL/SAWAC). The assistance by the TA Consultant includes guidance and supervision of the studies outlined in the present report. One activity under the NWSIP is the 'River Basin and Water Use Studies, Package 2', covering Dauntri Sub-basin in Battambang and Pursat Provinces, and Boribo Sub-basin in Pursat and Kg Chhnang Province. This work is being carried out by PRD Water & Environment in association with DHI Water & Environment. The scope of the river basin and water use studies is specified in the Terms of Reference prepared by MOWRAM. The overall objective is 'to provide a framework leading eventually to institutional means for installing a scientifically informed approach for management of water quantity and quality in the target river sub-basins'. The aim is not a master plan nor a set of feasibility studies for selected subprojects. Rather, the work will serve as a part of the basis for subsequent master planning and preparations for individual projects. The Final Report comes in 3 volumes: 1

Methodology and general findings

2

Boribo Sub-basin

3

Dauntri Sub-basin

Data tables and thematic maps are submitted separately. Basic documentation has been indexed and compiled on a CD. A report about Dauntri Sub-basin was discussed at a workshop in Battambang on 27 October 2006. The present revised report is based on guidance received at the workshop as well as from the TA Consultant.

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Geography

2.1

Data

2

This section relates to ToR, Task 1: Collection of general data and information

The physical geopgraphic description has been based on •

Land cover maps 1992/93, 1996/97 and 2002

•

Satellite images (RADARSAT-1) 1998, 2000, 2002 and 2005 (showing topographical features and land use)

•

Aerial photos (available for a part of the area only)

•

Administrative boundaries: Country, province, district, commune and village (villages as point coverage)

•

Topographical maps 1:50,000 and 1:100,000

•

Digital Elevation Model with 50 m resolution

•

Soil coverage digitized from 1,000,000 scale map

Various demographic information origins from the 2004 Commune Database. The commune is the basic unit for a substantial part of the geographic, agricultural and socio-economic data.

2.2

Population, administrative boundaries This section relates to ToR, Task 1: Collection of general data and information Related data

(submitted electronically)

Area-population.xls

Area and population (2002-04) within the study area; buffaloes, cows, horses, goats, pigs, and poultry; families using fertilizer; by province, district and commune

In Dauntri-Svay Don Keo Sub-basin, the population density was 56 persons/km2 in 2004and the population growth was 1.5 percent/year from 2002 to 2004. The Tonle Sap Basin in general witnesses the highest population growth within the Lower Mekong Basin, with 4.8 % per year as compared with Cambodia's average rate of 2.2/2.5 % per year (CNMC October 04, p. 30). The difference is partly related to migration. There are no major urban settlements (such as provincial towns) in the study area. This influences the future population growth, which is expected to be much higher in urban areas than in rural areas. District and commune boundaries, areas and population are shown in the following figure and table.

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Figure 2.1: Communes in Dauntri Sub-basin

Table 2.1: Administrative units with area and population, Dauntri Sub-basin Province

District

Commune

Battambang

Moung Ruessei

Koas Krala Pursat

Bakan

Phnum Kravanh

Area (km2)

Area within subbasin (km2)

Population within sub-basin (2004)

Moung

50.9

38.9

12,672

Kear

96.2

96.2

15,941

Prey Svay

143.6

143.6

13,114

Ruessei Krang

163.1

163.1

14,251

Chrey

491.7

280.3

6,478

Ta Loas

135.9

73.9

4,288

Kakaoh

85.6

36.2

4,904

Robas Mongkol

128.8

104.3

9,228

Prek Chik

139.2

139.2

12,544

Prey Tralach

273.6

273.6

20,663

Doun Ba

199.2

39.8

620

Chhnal Moan

624.5

218.6

992

Boeng Bat Kandaol

194.9

25.3

1,276

Boeng Khnar

56.6

56.6

12,188

Khnar Totueng

53.7

53.7

7,734

Me Tuek

265.0

262.3

14,429

Ou Ta Paong

292.0

292.0

15,674

Rumlech

52.9

52.9

8,154

Snam Preah

228.9

13.7

984

Svay Doun Kaev

29.9

29.9

5,978

Ta Lou

305.0

305.0

15,354

Trapeang Chong

83.0

69.5

16,119

Bak Chenhchien

40.7

14.7

2,543

Phteah Rung

156.1

143.6

14,396

Samraong

546.6

36.0

634

Sampov Meas

Lolok Sa

42.7

7.7

1,700

Veal Veaeng

Krapeu Pir

705.6

535.5

532

Pramaoy

865.9

Total Data: Commune Database 2004 and GIS analysis

Version 2

35.7

118

3,541.9

233,509

North West Irrigation Sector Project River basin and water use studies, Package 2

2.3

4

Elevations, land use, soils This section relates to ToR, Task 1: Collection of general data and information Related data

(submitted electronically)

Landuse.xls

Land use within each sub-basin (2005), and forest cover within each sub-basin (1993, 1997, 2002, 2005), and rate of change

Geology.xls

Geological classification of each sub-basin

Protectedareas.xls

Protected areas in each sub-basin

The land elevation in the sub-basin is illustrated below. The highest elevation in Dauntri-Svay Don Keo Sub-basin is around 1,273 m (according to the 50 x 50 m resolution DEM). Figure 2.2: Land elevations in Dauntri Sub-basin

Figure 2.3: Land elevation distribution in Dauntri Sub-basin > 500 m (2.3 pct) 200-500 m (8.4 pct) 100-200 m (10.0 pct) 50-100 m (4.4 pct)

20-50 m (19.5 pct)

Version 2

0-20 m (55.4 pct)

North West Irrigation Sector Project River basin and water use studies, Package 2

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Land use and soils The present land use (2005) is shown in the following figure, which provides an important characterization of the sub-basin: The major part is forest - evergreen, semi-evergreen or deciduous (shedding the leaves annually). There is some rainfed paddy area, and only small parts of other land use. Additional information is given in Tables 2.2 and 2.3. Figure 2.4: Land use in Dauntri Sub-basin

Data: Interpretation from Landsat ETM (2005)

Table 2.2: Land use (2005) Land use

386

Semi-evergreen forest

182

Deciduous forest

543

Other forest

552

Grassland

181

Dry season rice Rain fed rice

Version 2

Area (km2)

Evergreen forest

6 1,538

Other crop

85

Village

60

Water

10

Total

3,542

North West Irrigation Sector Project River basin and water use studies, Package 2

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Table 2.3: Forest cover (1993-2005) Forest cover

Evergreen forest

Rate of change

1993

1997

2002

2005

1993-97

1993-2002

1993-2005

km2

km2

km2

km2

percent

percent

percent

224

224

395

386

0,0

4,8

4,6 -3,3

Semi-evergreen forest

298

298

186

181

0,0

-3,2

Deciduous forest

427

427

549

543

0,0

3,5

3,3

Other forest

996

973

516

552

-0,6

-13,5

-12,5

Non-forest

1.598

1.621

1.895

1.879

0,6

8,4

7,9

Total

3.542

3.542

3.542

3.542

0,0

0,0

0,0

'0,0' means 'less than 0,005'

2.4

Irrigation This section relates to ToR, Task 1: Collection of general data and information Related data

(submitted electronically)

Irrigation.xls

Wet and dry season irrigated areas (actual and potential)

Many of the schemes were registered and evaluated under the so-called Halcrow study in 1994, conducted for the Mekong Committee (today's MRC). Some of them, including most candidate sub-projects, were re-visited and evaluated under NWISP in 2003. These studies are still relevant. When using them, however, it is noted that in some cases, both the scheme and the commune(s) have changed their names. The UTM coordinates provide the best identification. Irrigation schemes are shown in the following table and figure. Additional information (including coordinates and water source) are included in the corresponding electronic file. An overview of water management structures is given in Appendix 3.

Version 2

North West Irrigation Sector Project River basin and water use studies, Package 2

Figure 2.5: Irrigation schemes in Dauntri Sub-basin

Version 2

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Table 2.4: Irrigation schemes in Dauntri Sub-basin District

Name

Commune

Existing

Potential

Status

Wet (ha)

Dry (ha)

Wet (ha)

Dry (ha)

Moung R.

Po Canal, Ream Kun

Chrey, Ta Lass

400

0

2.500

0

2

Moung R.

Don Try

Chrey, Ta Lass

70

20

1.550

0

1

Moung R.

Ta Nak

Kear

8

0

65

0

2

Moung R.

Our Beng

Kear

20

0

20

0

2

Moung R.

Our Veng

Kear

0

0

50

0

1

Moung R.

Ream Koun

Kear, Chrey, Prey Svay

190

0

4.700

0

2

Moung R.

Kbal Mus

Moung

0

0

300

0

1

Moung R.

Prek Ta Am

Moung

400

0

1.000

0

3

Moung R.

Anglong Koub

Muong Reusei

0

450

1.350

0

2

Moung R.

Basac Reservoir

Prek Chik

0

0

3.500

0

1

Moung R.

Or Rum Chek

Prek Chik

0

0

0

30

1

Moung R.

Tracheak Chett

Prek Chik, Prek Talach

0

0

1.900

0

1

Moung R.

Srer Sdao

Prek Chik, Robas Mongko

0

0

500

0

1

Moung R.

Prek Chik

Prek Chik, Ruessei Kran

490

0

18.470

0

CS, 2

Moung R.

Chhouk

Prey Svay

0

0

240

0

1

Moung R.

Tum Leng

Prey Svay

0

0

100

0

1

Moung R.

Rum Chek

Prey Svay

0

0

90

0

1

Moung R.

Chay Vay

Prey Svay

0

0

90

0

1

Moung R.

Taserk

Prey Tralach

0

0

900

0

1

Moung R.

Prey Tralach

Prey Tralach

0

0

2.700

0

1

Moung R.

Cheang Chaot

Prey Tralach

0

0

40

0

1

Moung R.

Pov Eang

Prey Tralach

0

0

100

0

1

Moung R.

Mokh Rea

Prey Tralach

0

0

100

0

1

Moung R.

Prey Klot

Prey Tralach

0

0

100

0

1

Moung R.

Tramkong

Reusei Krang

0

0

740

0

1

Moung R.

Nikom Le

Reusei Krang

0

0

330

0

1

Moung R.

Dai Ta Chan, Kampang Reusei Krang

50

0

300

0

2

Moung R.

Dam Nak Angkrong

Rubos Mungkoul

40

0

550

0

2

Moung R.

Beung Ktum

Rubos Mungkoul

0

0

25

0

1

Moung R.

Sdei

Ta Lass

0

0

400

0

1

Moung R.

Brour Lay Sdao

Ta Lass

50

0

95

0

2

Bakan

Kroch Seuch

Boeng Bat Kandaol

Unknown

Unknown

132

0

CS

Bakan

Vaot Chre

Boeng Khnar

Unknown

Bakan

Boeng Khnar

Boeng Khnar

Unknown

Unknown

0

0

Bakan

Koah Khsach

Me Toek

0

0

100

30

400

1

3

Bakan

Vaot Leab

Me Toek

0

0

335

170

3

Bakan

Boeng Kanthor

Me Toek

0

0

382

73

3

Bakan

Roneam Prayol

O Ta Paong

Unknown

Unknown

300

0

CS

Bakan

Anlong Svay

Rom Leach

Unknown

Unknown

220

0

CS

1.718++

470++

44.674

303

Total (ha) ++: Figure may be higher, but data coverage is incomplete

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Speech by the PM visiting the Damnak Ampil irrigation system on 5 October 2006 Today I have a great pleasure to be with you all to inspect an irrigation system at Damnak Ampil that is very important for the irrigation of three districts of Sampeo Meas, Ba Kaan and Phnom Kravanh of Pursat, covering a total area of about 27467 hectares of rainy season rice and another 1500 hectares of dry season rice. ... I first came to this place 21 years ago and again in June, 2005. I remember seeing a bad road condition and dilapidated irrigation system in those days ... As time has come, ... the system has now been almost completed. ... Rice cultivation this year in this area as well as throughout the country seems to be better in general. HE Chhay Saret reported just now that the area of cultivation this year is 7488 hectares or 93.90% of the total cultivation land. This is great news. As far as the irrigation system is concerned, we are happy because of the fact that the system serves not only as water channel but also road access. Take for instance we used to have a ferry boat to cross the river here and now we have a bridge. Since the area is quite granted with natural availability, perhaps there would be room for development that might attract tourists to this area in the near future. This proves that we have put our country on a correct path of development ... According to HE Chan Sarun, Minister for Agriculture, Forestry and Fisheries, last year we have collected about six million tons of paddy rice or two million tons more than local consumption demand. This amounts to 1.3 million tons of milled rice in conversion. This was the result of rice cultivation on 1.8 million hectares of land. But this year we have increased the area of cultivation to 2.13 million hectares or about 30,000 hectares more than last year. The state of the rice is in good prospect. Therefore it is worth mentioning with confidence that the rice harvest this year would also be increasing. I would take this opportunity to share with you that agriculture in the last few years has played a very important role in the country's economic development. Land for cultivation has increased from 70,000 hectares to 900,000 hectares. We should try to enlarge land for cultivation in area with irrigation coverage and also deal with areas where irrigation is still a problem so that the total area of agricultural production will play an increasingly important economic role. Irrigation is important for agriculture and we have to do everything we can to get the irrigation in place. I have come frequently to this place and once I said to the people from Satre commune about the possibility of swapping their long-term rice cultivation to that of short-term rice cultivation. According to statistics I wish to share with you that the area of cultivation under short-term rice species has increased, though we maintain to grow long-term rice in high-level of water fields. Area where level of water accessibility is low, the Royal Government has advised our people to opt for short-term rice cultivation. What remains to be our focus has been to guarantee food security level in the country and we have made a great achievement in this endeavor because we were able to have a surplus even in the worst year of 2000, 2002 or even in 2004.

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Hydrology

3.1

Data

10

This section relates to ToR, Task 2: Collection of hydro-meteorological and hydraulic data and information

3.2

Related data

(submitted electronically)

[email protected]

Daily, monthly and annual rainfall at Battambang (8 years), Kg Chhnang (55 years), Pursat (60 years), Krakor (36 years), Kravanh (10 years), Svay Donkeo (6 years), Talo (6 years), Bamnak (15 years) and Boeung Khnar (7 years)

R@Pursat-12-05

Daily and monthly rainfall data from Pursat 1912-2005 (53 years), with summary statistics

[email protected]

Monthly rainfall data from 16 stations from 2001-2004 (4 years), with summary statistics

[email protected]

Monthly rainfall data from Battambang, Pursat and Kg Chhnang, from 1939, 1996, and 2001-05 (7 years)

[email protected]

Daily and monthly evaporation at Pochentong 2000-04 and Siem Reap 1996-2000

[email protected]

Daily water level at Kg Chhnang 1995-2004 (10 years)

[email protected]

Daily water level at Prek Kdam 1995-2004 (10 years)

[email protected]

Daily and monthly flow at Prek Kdam 1964-73 (10 years)

[email protected]

Daily water level and calulated flow at Boribo (St. 590101) Jun 98 Dec 05 (7.5 years)

[email protected]

Daily water level and calulated flow at Maung Russey (St. Dauntri) (St. 5501101) Jun 01 - Dec 02 (1.5 years)

[email protected]

Flow records from St. Boribo (91 months), St. Dauntri (19 months), and St. Pursat (72 and 58 months)

River network and catchment delineation This section relates to ToR, Task 9: Hydrological analysis

The river network has been established on the basis of satellite (RADARSAT-1) images; aerial photos (where available); and topographical maps 1:50,000 and 1:100,000. In addition, several reconnaissance visits have been made to locations where there was doubt about the network. In addition to the detailed network, which forms the basis for the catchment delineation, a simplified network (of main rivers and streams) has been derived as a basis for the hydrological analysis. Results are shown below.

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Figure 3.1: River network, Dauntri Sub-basin (detailed and simplified)

St Svay Don Keo

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In connection with the present study, the catchment boundary has been revised as follows: 1.

Southern part of the Stung Dauntri Basin: The revision is based on the DTM model and check with contour lines. From the contour lines, the water at the revised area is drained to Stung Pursat Basin and not to Stung Dauntri Basin.

2.

Eastern part of the Stung Dauntri Basin: The revision is based on the DTM model and check with the satellite images, aerial photographs, river network and field check. Some part of the basin boundary followed along the roads and some other parts follows the levee of the rivers. The water at the revised area is drained to Stung Pursat Basin and not to Stung Dauntri Basin.

3.

Western part of the Stung Dauntri Basin: The revision is based on the DTM model and check with the satellite images, aerial photographs, river network and field check. Some part of the basin boundary follows the levee of the rivers. The water at the revised area is drained to Stung Sangke Basin through O Say river.

4.

North-western part of the Stung Dauntri Basin: The revision is based on the DTM model and check with the satellite images and aerial photographs. The revised basin boundary follows the levee of the rivers. The water at the revised area is drained to Stung Dauntri Basin.

The picture below illustrates the revised area. The red color boundary is the new boundary and the black color is the old one (taken from MRC). The difference between the areas is as follows: Old Sub-basin boundary (MRC):

3,695.97 km2

New Sub-basin boundary (present study):

3,541.91 km2

Figure 3.2: Comparison between sub-basin boundaries

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The sub-basin receives water from the adjacent Pursat Sub-basin via the Damnak Ampil Canal (please refer to section 4.6, regulation), and also via a natural offtake located downstream of this canal. During high stages, this offtake diverts water from St. Pursat across the catchment boundary and into Ou Souphi (in the Dauntri Sub-basin), and further to Ou Bakan and St. Kambot. This offtake is shown in the figure below.

Figure 3.3: Ou Souphi Offtake

National Road 5

Sub-basin boundary Ou Souphi

Railway Damnak Ampil Canal St. Pursat

1 km

Version 2

North West Irrigation Sector Project River basin and water use studies, Package 2

3.3

14

Rainfall and evaporation This section relates to ToR, Task 9: Hydrological analysis Related data

(submitted electronically)

[email protected]

Daily, monthly and annual rainfall at Battambang (8 years), Kg Chhnang (55 years), Pursat (60 years), Krakor (36 years), Kravanh (10 years), Svay Donkeo (6 years), Talo (6 years), Bamnak (15 years) and Boeung Khnar (7 years)

R@Pursat-12-05

Daily and monthly rainfall data from Pursat 1912-2005 (53 years), with summary statistics

[email protected]

Monthly rainfall data from 16 stations from 2001-2004 (4 years), with summary statistics

[email protected]

Monthly rainfall data from Battambang, Pursat and Kg Chhnang, from 1939, 1996, and 2001-05 (7 years)

[email protected]

Daily and monthly evaporation at Pochentong 2000-04 and Siem Reap 1996-2000

Rainfall The long-term record from Pursat has been chosen as the basis for the water balance analysis presented in this study. The rainfall in Dauntri Sub-basin can be estimated as the rainfall in Pursat minus 6 percent. Hereby, the analysis builds on (i) 53 years of 'good' data (which is fully acceptable); (ii) a relatively safe estimate of the 4-out-of-5 years rainfall; (iii) another relatively safe estimate of the variation along the Great Lake; and (iv) a less safe assumption that the rainfall is homogenous within the sub-basin. The resulting estimate of rainfall in the study area is shown below.

Table 3.1: Distribution of annual rainfall, Dauntri Sub-basin (mm) 1986

4 of 5 yrs

Average

1995

Year

819

1.055

1.241

1.956

Jan

0

3

3

0

Feb

0

4

5

23

Mar

5

33

39

33

Apr

18

62

73

67

May

77

120

141

224

Jun

119

105

124

161

Jul

88

111

131

268

Aug

188

145

170

210

Sep

142

189

222

398

Oct

101

181

212

369

Nov

44

88

104

173

Dec

36

14

17

30

Data: Estimated as Pursat minus 6 percent

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Evaporation Evaporation data are sparse. The following figure and related table are based on 9 station-years of 'accepted' data from two different stations - Battambang and Pochentong, which are located on each side of the study area. There was no overlap between the 'accepted' records, but the difference between the stations remained within 5 percent on an over-all average basis. The average variation from one year to another on a monthly basis was +/- 24 percent. Table 3.2: Pan evaporation (mm) J

F

M

A

M

J

J

A

S

O

Lowest

112

110

114

137

120

115

116

Average

130

135

167

163

154

143

151

Highest

156

184

217

203

200

167

167

171

N

D

Year

83

97

105

139

128

124

83

93

1,543

125

133

155

147

150

1,691

183

2,000

Data: Battambang (1996-2000) and Pochentong (2001-04) (9 years)

The actual evaporation will be less than the pan evaluation values, depending on the so-called pan coefficient and also on the vegetation cover (that varies very much over the year in the study area). In view of the uncertainties, a conservative estimate of 0.7 times the pan evaporation has been applied.

3.4

Streamflow This section relates to ToR, Task 9: Hydrological analysis Related data

(submitted electronically)

[email protected]

Daily water level and calulated flow at Boribo (St. 590101) Jun 98 Dec 05 (7.5 years)

[email protected]

Daily water level and calulated flow at Maung Russey (St. Dauntri) (St. 5501101) Jun 01 - Dec 02 (1.5 years)

Rating curves from St. Pursat and St. Dauntri have been considered. St. Pursat There is no indication that Bac Trakoun station is subject to back water effects. Further Carbonnel and Guiscafre suggest that the rating curve is of the type Q=f(H), where H is the water level at Bac Trakoun. The correlation coefficient is very good, 0.99. The formula reads (JICA 2004): Q = 25 .5 ⋅ (H BakTrakoun − 0.0856 )

Version 2

Rating curve Stung Pursat at Bak Trakoun Q=f(H), data from 1998,1999, 2001 6.00

Gauge height [m]

5.00 4.00 3.00 2.00 1.00 0.00

2

0.00

100.00

200.00

300.00 Q [m3/s]

400.00

500.00

600.00

North West Irrigation Sector Project River basin and water use studies, Package 2

16

St. Dauntri

(

Q = 12.4 ⋅ H Maung − 1.2439

Rating curve Stung Dauntri at Maung, Q=f(H) 3.

2.5

Gauge height [m]

The rating curve at Maung is suggested to be of the type Q=f(H) (Carbonnel and Guiscafre). It means that there are no back water effects at the station. Despite very few data from year 2001, a rating curve has been established (JICA 2004). The rating curve has the formula:

2.

1.5

1.

0.5

)2

0. 0

5

10

15

20

Q [m3/s]

At the gauging location, the flow in St. Dauntri appears to be highly variable, with a peak of 323 m3/s (on 27 Oct 02), as compared with an average flow of 7,87 m3/s and a median flow of 2,36 m3/s. The corresponding specific yield is 6,5 l/s/km2 or 169 mm/year (average) and 1,9 l/s/km2 (median). The variation of the monthly average flow is shown in the Figure below.

Figure 3.4: Monthly average flow, St. Dauntri

50 40 30 20 10 0 J

F

M

A

M

J

J

A

S

O

N

D

Data: Maung (St. 5501101), catchment area 1214 km2, June 01-Dec 02

Rainfall versus discharge The runoff in a catchment is clearly a result of the amount of rainfall. However, in terms of establishment of a relation between the rainfall and runoff, the outcome may be more of less successful. The reasons are several: The selected rainfall station(s) may not be representing the entire catchment, the infiltration rate may be unevenly distributed throughout the catchment, and there may be flow regulation and storage occurring, just to mention a few.

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The relation between the rainfall and runoff is likely to be better on bi-weekly or monthly time scale rather on a daily scale. One source of uncertainty in the present study is that the discharges are mostly rated and that the number of rainfall stations are few and of different quality.

3.5

Regulation This section relates to ToR, Task 9: Hydrological analysis

The Damnak Ampil Canal The Damnak Ampil Canal was built under Khmer Rouge between Maung and St. Pursat. Part of it has been restored, and a diversion weir is in an advanced stage of completion across St. Pursat to feed the canal (where the flow went in the opposite direction in the past). The structure will also provide water to irrigation systems on the right bank of St. Pursat. The project is a government project implemented by MOWRAM. So far, 7.7 km of the canal has been restored from Damnak Ampil and towards Svay Don Keo. Later on, it will be restored further all the way to Svay Don Keo. The width of the canal is app. 10 m, and the slope is 0.0002 m/m. Water is distributed by a network of new and old 2nd order gates and canals.

Figure 3.5: Structures along the Damnak-Ampil Canal

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Figure 3.6: The Damnak Ampil Canal and regulator under construction (6 July 06)

No data for the canal or its diversion structure on the Pursat river was available to the consultant. However, upon physical inspection of the canal and intake site, as well as with the available flow data from the Pursat river, it was possible to provide an estimate of the flow in the irrigation canal. The subsequent diversion of the canal flow into the catchment has been assumed. The extent of the Damnak-Ampil canal (in its full extent during KR times) is seen in the figure below. The length the canal that has been restored as per 2006 is also indicated. It is seen that the canal is going to influence the water availability in the upstream catchments in the Kreuch Sauch and Anlong Svay areas. The photos show the conditions of the canal during the field visit in June 2006.

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Along the restored reach, 3 pairs (one on each side of embankment) of secondary gates were observed. The purpose of these gates is to convey flows into the paddy field areas on both sides of the canal. A typical layout of one of these gates is seen in the bottom-left photo. At some reaches flooding outside the laft embankment could be observed. The water level in this areas was significantly higher than in the canal. As mentioned, no data of flow capacity were available to the consultant. Hence the canal capacity was estimated using Manning’s formula and the observed cross section geometry. The canal is approximately 10 m wide. The water depth at the time of visit was app. 1.75 m. Information from the provincial department in Pursat reveals that the slope of the canal is 0.0002. Assuming a roughness coefficient of n=0.02, the canal flow capacity can be computed as follows : Q = 1/n * A * R2/3 * S1/2 where n: is Manning’s roughness coefficient A: is cross section area R: is hydraulic radius (~D*W/(2D+W), where D is depth and W is width ) S: is canal slope (m/m) Using the Manning’s formula with the above assumptions gives a flow of app. 15 m3/s.

Figure 3.7: The Damnak-Ampil Canal from Pursat River to Prek Chik

Dark dots are candidate sub-projects

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Obviously the canal can not carry this flow at all times, as it will be dependent on the flows in the Pursat river. An attempt to derive a monthly variation of the irrigation canal flow has been made. First, the discharge rating curve for Pursat river at Pursat as derived by the WUP-JICA study was used to produce a daily rated discharge for three years, 2001-2003. Then the daily discharge on monthly basis was derived for each of these years, and finally the average daily discharge on monthly basis was derived, see the table below. A sound judgement of a possible water intake into the canal for each month was hereafter applied.

Figure 3.8: Photos from the Damnak-Ampil Canal

Damnak-Ampil canal near Pursat River

Gates on Damnak-Ampil Canal

Section of the restored canal

Flooding outside of the embankment

Gates towards paddy fields

Un-excavated part of the canal

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Table 3.3: Assumed flow from Pursat River into the Damnak-Ampil Canal

Month January February March April May June July August September October November December

Average daily flows, based on Average of Assumed abstracted rated discharge [m3/s] years 01-03 flow from Pursat river Year [m3/s] [m3/s] 2001 2002 2003 20.8 9.5 8.7 13.0 8 9.6 6.2 16.0 10.6 5 51.7 3.8 11.3 22.2 5 13.2 8.2 16.5 12.6 5 17.2 13.9 23.0 18.0 8 37.6 13.0 12.9 21.2 10 64.7 17.4 104.4 62.2 15 75.6 54.4 86.6 72.2 15 88.2 79.0 104.6 90.6 15 279.1 99.4 424.9 267.8 15 60.1 65.9 35.3 53.8 15 16.4 23.3 18.3 19.3 10

The geographical position of the pairs of secondary gates along the Damnak-Ampil canal were recorded during the field trip in June 2006. Please refer to Appendix 3 for an overview of regulation in each of the catchments of the sub-basin. Details are provided in the thematic 'Sub-basin map', submitted separately.

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4

Water uses and water balance

4.1

Water uses This section relates to ToR, Task 18: Quantification of consumptive and non-consumptive water uses Related data

(submitted electronically)

Area-population.xls

Area and population (2002-04) within the study area; buffaloes, cows, horses, goats, pigs, and poultry; families using fertilizer; by province, district and commune

Agriculture-2006.xls

PRD survey Jul-Aug 2006: Cultivation practices; cropping cycles; labour input; livestock; use of fertilizers and pesticides; farmgate prices; obstacles to cultivation

Domesticdemand.xls

Present and projected domestic water demand in each sub-basin

Domestic water uses An attempt has been made to illustrate the possible development of domestic demand. The following assumptions have been made: •

The actual long-term population growth within the sub-basin, including the effect of migration, will be between nil and 2 percent per year

•

The unit demand will increase by between 1 and 2 l/p/d per year

If so, as seen in the table below, the future domestic demand will be somewhere between 3 and 6 times the present demand. This is still a small part of the available water in the area, but the increase must be kept in mind in connection with the predicted increased demand for other purposes, particularly irrigation. For long-term planning, a 'strategic priority allocation' could be considered, perhaps of 60-80 l/p/d. This is believed to be a realistic level, although it cannot be safely predicted when it will be reached.

Table 4.1: Estimate of future domestic demand, Dauntri Sub-basin Year

Population High estimate

Unit demand Low estimate

High estimate

Total demand Low estimate

High estimate

Low estimate

2 pct/yr

nil

l/p/d

l/p/d

Mm3/year

Mm3/year

2004

233.509

233.509

23

23

2,0

2,0

2009

257.813

233.509

33

28

3,1

2,4

2014

284.646

233.509

43

33

4,5

2,8

2019

314.272

233.509

53

38

6,1

3,2

2024

346.982

233.509

63

43

8,0

3,7

2029

383.096

233.509

73

48

10,2

4,1

2034

422.969

233.509

83

53

12,8

4,5

Data: The present unit demand of 23 l/d is from TSBMO (Mar 03); the present pupolation is from the Commune Database; other values are estimates

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Agricultural water uses Agricultural water uses are by far the largest in terms of volume, and play an important role in terms of social and economic value, including livelihoods. Today, the agricultural water uses are limited both by the raw water availability and by infrastructural constraints. In the course of time, however, as the infrastructural constraints are gradually removed, the raw water availability will become the sole limiting factor. Distribution of water uses Spatial and monthly distributions of present and future domestic demand, livestock demand and irrigation demand are inlcluded in Appendix 2.

4.2

Water balance This section relates to ToR, Task 21: water balance for the sub-basins Related data

(submitted electronically)

D-W-balance-4of5yrs.xls

Dauntri Sub-basin, calculated water balance, present conditions, with water uses and availability, in 4 out of 5 years, whole sub-basin and details

D-W-balance-scenarios.xls

Dauntri Sub-basin, calculated water balance, alternative scenarios: Damnak Ampil Canal, candidate sub-projects, and impact of climate change

MIKE Basin set-up Water balances have been calculated using the MIKE Basin modeling system. Please refer to Appendix 3 for a general description. The set-up for the present study is shown in the following figure.

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Figure 4.1: MIKE Basin model of the Dauntri Sub-basin

The MIKE Basin model is divided into 21 sub-catchments with associated river network as well as water uses. The sub-catchments follow largely internal catchments divides, and are thus derived on basis of physical boundaries. In some cases the topographical information was insufficient for a sub-catchment delineation, instead the average distance to tributaries has been used. During the field visits it was observed that the Damnak Ampil irrigation canal was restored for a distance of about 7 km from Pursat river and into the catchment. The water intake structure on the Pursat river was almost completed, and it is anticipated that this canal will be in operation in year sometime in 2007. The Damnak Ampil Canal is going to have a major impact on the available water in the catchment. Although not confirmed, this canal is likely to be extended further to the Svay Don Keo river. Since the is almost in operation, its presence and function as a water supply source appears in all simulations except the first, which is considered a base condition. The figure below shows in schematic form the connection between the subcatchments and their areas.

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Figure 4.2: Schematic representation of sub-catchments

C21 413

C26 155

C20 45

C22 186

C7 331

C12 74

C24 6

C18 28

C19 122

C14 27

C17 504

C15 24

C6 104

C25 216

C23 196

C8 156

C16 191

C10 95

C2 367

C1 184

C4 121

Sub-catchments are given by a number (eg. C21) and an area in km2 (eg. 413). Grey: St. Kambot; yellow: Flow directly to the Great Lake; green: St. Svay Donkeo; red: St. Dauntri. The Damnak Ampil irrigation canal and its entry points in the catchments are shown with red arrows

The calibration is made in two steps: First the NAM model is calibrated for the Stung Sangker (the results from WUP-JICA is used). Then the calibrated parameters were applied for the Dauntri catchment, and a comparison made between the observed (only few measurements) and the simulated discharge, as it was not possible to establish a rated discharge due to lack of water level data.

Rainfall-runoff model calibration In the Dauntri – Svay Don Keo catchment there is only one station in which discharges have been observed in recent times, namely at Prek Chik. This station is located somewhat upstream in the catchment, and catches mainly flows from the hilly areas. Further the station represents only approximately 20% of th entire Dauntri – Svay Don Keo catchment. However, since this is the onle station within the catchment which has flow measurements, this information should be used to support the calibration of the model. The discharge measurements are few, altogether 11 measurements measured in year 2001. This is hardly enough to base a model calibration upon. An attempt to match the observed discharge with the NAM model has been made, as illustrated in the figure below.

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In order to get in the order of the observed discharge, a very low runoff coefficient had to be used (= 0.05). This value is questionable in itself, and it is not physically justifiable to bring this value further down. It is seen from the figure that the model predicts a discharge which is twice the recorded one. The explanation for this ambiguity is likely to be found in the data basis, both the rainfall, and possibly the observed discharge as well. There are no rainfall stations in the mountain areas which could possibly improve the model prediction. Also there are no further of water levels at Prek Chik made available to the consultant to derive a rated discharge which could improve the data basis for model calibration. Therefore, instead of attempting a further improvement of the calibration on the sparse data basis described above, it was decided to apply the calibrated NAM model parameters from the Stung Sangker catchment, which were derived through the WUP-JICA study. This catchment is neighbouring to the north of the Dauntri catchment. It was concluded in the WUP-JICA study that the NAM parameters from the Stung Sangker calibration could be transferred to the Stung Dauntri catchment. For illustration of the NAM calibration of the Stung Sangker, please refer to Figure 5.6. The NAM parameters from the Stung Sangker calibration are listed in Appendix 3. The calibrated NAM parameters from Stung Sangker have been applied for the entire Dauntri – Svay Don Keo catchment in the MIKE Basin model together with the various water uses.

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Figure 4.3: Rainfall-runoff simulation for the Dauntri catchment 140.0

120.0 Simulated Observed

Discharge [m3/s]

100.0

80.0

60.0

40.0

20.0

0.0 01-01-98

01-01-99

01-01-00

01-01-01

01-01-02

Figure 4.4: Simulated and observed discharge in Stung Sangker at Battambang 600.0

500.0

Observed Simulated

Discharge [m3/s]

400.0

300.0

200.0

100.0

0.0 01-01-98

Version 2

01-01-99

01-01-00

01-01-01

01-01-02

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Water uses The water uses that have been accounted for in the model are domestic, irrigation and livestock water uses. The data from the commune data base have been used to derive the above uses. The principle in the MIKE Basin model is that the water uses in a given subcatchment draws water from a particular node, in this case the catchment nodes. Hence all the water uses in a sub-catchment takes water from the same subcatcment node, which is always located in the downstream end of the subcatchment. Since the sub-catcments are based on physical boundaries and the water uses are based on commune data, it has been necessary to calculate the fractional contribution of each commune to each of the sub-catchments. The commune data (eg. number of persons) are then assumed to be evenly distributed in the communes. Domestic water uses: It is assumed that each person presently consumes 23 l/d in the catchment. On basis of the results from the Boribo – Thlea Maam catchment modelling, which showed that future increase in domestic water use has only minor effect on the water balance, it was decided not to make a scenario simulation with inceased domestic water use. Irrigation water use: Data for rainfed irrigation area, wet season irrigation area, dry recession irrigation area and dry season irrigation area are available in the commune data base. These data have been used for the estimation of the irrigation areas in each of the sub-catchments. The present state of the irrigation systems suggest that there are no return flows from the paddy fields. Hence the rain fed irrigation areas can simply be taken out of the calculations, as the water use in there areas does not affect and is not affected by the river flows. In the present MIKE Basin model, the wet season irrigation, the dry recession irrigation and the dry season irrigation areas have been included. It is assumed that the wet season irrigation takes place between July and November, the dry recession irrigation between December and February, and the dry season irrigation between March and June. It is assumed for all categories that the water demand for irrigation is 2 l/s/ha, and that the paddy fields are evenly distributed in the communes. It is further assumed that there are no return flows from the paddy fields. Livestock water use: In the MIKE Basin model it is assumed that the major water consuming livestock are cows, buffalos, pigs and poultry.

The Damnak Ampil Canal The Damnak-Ampil irrigation canal is likely to convey flows from the Pursat into the Dauntri - Svay-Don Keo catchment some time in year 2007. It is therefore considered important to include the function of this canal into the model analysis. A short description of the canal is provided in Section 4.6. The schematisation of the Damnak-Ampil irrigation canal is made by defining a river branch which at the upstream end starts outside the Dauntri catchment, i.e. in

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the Pursat river. The river branch is then extended into the Dauntri catchment for app. 7.5 km. The location of the 3 pairs of gates is used to determine which subcatchments will receive water from the canal. There is no distinction between gates located on the left or right side of the canal. Hence, altogether three abstraction points have ben defined along the river branch representing the Damnak-Ampil Canal. The flow abstracted from the Pursat river is assumed as indicated in Table 3.3 (Section 3.5). However, it is based on an assessment of both the capacity of the channel (using Manning’s formula) and the water availability in the Pursat river. The latter is derived using the extended flow record at Pursat. An underlying assumption is that the the amount of water available at Pursat is likewise available at the Damnak Ampil water intake. The time-series of assumed abstracted flow from the Pursat river is fed into the canal at its upstream (sutheastern) end. A total of three abstraction points along he Ampil canal has been assumed. This has been done in order to provide each of the three subcatchments which the canal traverses with irrigation water. This corresponds approximately to the observations made in the field, where sets of gates were observed along the channel. Since the flow in the Ampil canal is assumed, it is subject to uncertainty. Therefore the flow at the three abstractions points has been assumed to be equal. The schematisation is shown in the figure below. The water diverted from the irrigation canal is used for irrigation of paddy fields in a reasonable vicinity of the canal. It is assumed that 30% of the abstracted flow is returned to the local river systems. This additional water in the rivers will be available for water use, for example for the proposed candidate sub-projects. If return flows were neglected, the effect of the canal would be neutral in the simulations.

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Figure 4.5: Schematisation of the Damnak-Ampil irrigation canal

Location of abstraction points for irrigation

Water balance, present conditions The MIKE Basin model has been used to compute a water balance for the subbasin on a monthly and annual basis, considering the rainfall, evaporation, inflow, outflow, storage/losses and water uses. The following table shows the summary of the water balance for the Dauntri – Svay Don Keo catchment under the existing conditions. The conditions imply that all existing water uses have been included. However, the Damnak – Ampil canal is not included in this simulation. It is seen from the table that the water uses in general constitute a small fraction of the available water, at least on a yearly basis and during the wet season. In the dry season – January to May, the water uses are of the same magnitude as the available water. In March to May there are no outflows from the catchment. Both presently (in some years) and in the future there is therefore competition for water in the driest months of the year, as not all demands can be met. Proper planning of the water allocation is therefore inevitable, if the situation is to be improved. Conversely, as seen in table, in the period of June to November, that is in the wet season, as well as a part of the recession period (December), there is plenty of available water for irrigation water use or other uses. Presently most water in this period flows into the Tonle Sap Lake, were it naturally serves other purposes. The numbers in the table are based on precipitation data that represent a ‘4 out of 5 years’ situation, or 80 % reliability. This means that in 1 out of 5 years the water availability may be less.

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Table 4.2: Summary water balance, base situation, 4 out of 5 years Rainfall

Evaporation

Storage and losses

Water availability

Domestic uses

Irrigation uses

Livestock uses

Outflow

m3/s

m3/s

m3/s

m3/s

m3/s

m3/s

m3/s

m3/s

January

3,9

19,6

-19,2

3,6

0,1

1,5

0,4

1,7

February

4,9

7,1

-4,4

2,2

0,1

1,5

0,4

0,3

March

45,2

45,2

-3,4

3,4

0,1

2,9

0,4

0,0

April

84,6

84,6

-3,4

3,4

0,1

2,9

0,4

0,0

May

163,2

135,7

24,2

3,4

0,1

2,9

0,4

0,0

June

143,6

126,9

10,3

6,4

0,1

2,9

0,4

3,0

July

151,4

111,1

-7,7

48,0

0,1

12,5

0,4

35,1

August

197,7

98,3

-12,3

111,6

0,1

12,5

0,4

98,7

September

256,7

77,7

29,4

149,6

0,1

12,5

0,4

136,7

October

246,8

85,6

50,6

110,6

0,1

12,5

0,4

97,7

November

121,0

102,3

-15,3

34,0

0,1

12,5

0,4

21,0

December

19,7

78,3

-67,5

8,8

0,1

1,5

0,4

6,9

Year

119,9

81,0

0,1

38,8

0,1

6,5

0,4

31,8

l/s/km2

l/s/km2

l/s/km2

l/s/km2

l/s/km2

l/s/km2

l/s/km2

l/s/km2

January

1,1

5,4

-5,3

1,0

0,0

0,4

0,1

0,5

February

1,4

2,0

-1,2

0,6

0,0

0,4

0,1

0,1

March

12,6

12,6

-0,9

0,9

0,0

0,8

0,1

0,0

April

23,5

23,5

-0,9

0,9

0,0

0,8

0,1

0,0

May

45,3

37,7

6,7

0,9

0,0

0,8

0,1

0,0

June

39,9

35,2

2,9

1,8

0,0

0,8

0,1

0,8

July

42,0

30,8

-2,1

13,3

0,0

3,5

0,1

9,7

August

54,9

27,3

-3,4

31,0

0,0

3,5

0,1

27,4

September

71,2

21,6

8,2

41,5

0,0

3,5

0,1

37,9

October

68,5

23,7

14,1

30,7

0,0

3,5

0,1

27,1

November

33,6

28,4

-4,2

9,4

0,0

3,5

0,1

5,8

December

5,5

21,7

-18,7

2,4

0,0

0,4

0,1

1,9

Year

33,3

22,5

0,0

10,8

0,0

1,8

0,1

8,8

mm

mm

mm

mm

mm

mm

mm

mm

3

15

-14

3

0

1

0

1

January February

3

5

-3

1

0

1

0

0

March

34

34

-2

2

0

2

0

0

April

61

61

-2

2

0

2

0

0

May

121

101

18

2

0

2

0

0

June

103

91

7

5

0

2

0

2

July

113

83

-6

36

0

9

0

26

August

147

73

-9

83

0

9

0

73

September

185

56

21

108

0

9

0

98

October

184

64

38

82

0

9

0

73

November

87

74

-11

24

0

9

0

15

December

15

58

-50

7

0

1

0

5

1055

713

-14

356

1

58

3

294

Year

The detailed water balance assessment for each individual sub-catchment is presented in Appendix 4.

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Figure 4.6: Water availability, present conditions, April, m3/s

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Figure 4.7: Specific water availabilty, present conditions, April (l/s/km2)

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North West Irrigation Sector Project River basin and water use studies, Package 2

Figure 4.8: Water availability, present conditions, September (m3/s)

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North West Irrigation Sector Project River basin and water use studies, Package 2

Figure 4.9: Specific water availabilty, present conditions, September (l/s/km2)

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Figure 4.10: Specific water availabilty, present conditions, annual (l/s/km2)

Water balance, future conditions Apart from the implications of irrigation development (which is described in a separate section below), water balances have been calculated for three development scenarios:

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•

Implementation of the Damnak Ampil Canal;

•

Implementation of the Damnak Ampil Canal and the canidate sub-projects; and

North West Irrigation Sector Project River basin and water use studies, Package 2

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37

Implementation of the Damnak Ampil Canal and the canidate sub-projects in connection with climate change - illustrated by tentative (and quite uncertain) assumptions as described in Section 4.8.

Base situation with Damnak-Ampil Canal included: In this scenario, the DamnakAmpil irrigation canal has been incorporated in the model setup, to study the influence of abstracting water from the Pursat river. The assumptons and technical specifications for the canal are described in Section 4.6. A summary of the water balance for this scenario is seen in the following table. Detailed water balances for each sub-catchment are presented in Appendix 4. The general conclusion when comparing to the base situation is that the canal conveys sufficient water to the Dauntri – Svay Don Keo catchment, that there will always be an outflow from the catchment as a whole. The outflow from the catchment is increased in all months of the year, including the dry months. This means that all present water demands can be met. Table 4.3: Summary water balance with the Damnak Ampil Canal Rainfall

Evaporation

Storage and losses

Water availability

Domestic uses

Irrigation uses

Livestock uses

Outflow

[m3/s]

[m3/s]

[m3/s]

[m3/s]

[m3/s]

[m3/s]

[m3/s]

[m3/s]

January

3,9

19,6

-24,2

8,6

0,1

1,5

0,4

6,7

February

4,9

7,1

-8,6

6,4

0,1

1,5

0,4

4,5

March

45,2

45,2

-6,6

6,6

0,1

2,9

0,4

3,2

April

84,6

84,6

-7,5

7,5

0,1

2,9

0,4

4,2

May

163,2

135,7

17,3

10,2

0,1

2,9

0,4

6,9

June

143,6

126,9

-1,5

18,2

0,1

2,9

0,4

14,8

July

151,4

111,1

-22,7

63,0

0,1

12,5

0,4

50,1

August

197,7

98,3

-27,3

126,6

0,1

12,5

0,4

113,7

September

256,7

77,7

14,4

164,6

0,1

12,5

0,4

151,7

October

246,8

85,6

35,6

125,6

0,1

12,5

0,4

112,7

November

121,0

102,3

-25,9

44,6

0,1

12,5

0,4

31,7

December

19,7

78,3

-75,7

17,1

0,1

1,5

0,4

15,2

Year

119,9

81,0

-11,1

49,9

0,1

6,5

0,4

42,9

It is important to emphasize that while this holds true for the catchment as a whole, it does not apply to the Dauntri river itself, which does not receive additional water from the Pursat river. This is clearly seen in the tables of each individual subcatchment in Appendix 4. Groundwater No groundwater data has been available for the study wherefore a direct assessment of this resource could not be made. Instead, the groundwater flow has been determined indirectly through calibration of the NAM model. Practically this is obtained by adjusting the various parameters until a reasonable fit exist between observed total runoff and simulated total runoff. Through the various exchange functions in the model (threshold values for overland flow, interflow and groundwater flow) the groundwater flow (or base flow) comes implicitly as a result.

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The figure below shows the simulated relative contribution of the groundwater flow to the total runoff for Dauntri Sub-basin. The base case is shown. The table below contains average monthly values of the ration between the groundwater flow and the total runoff. Figure 4.11: Ratio between groundwater flow and total runoff

Table 4.4: Monthy simulated ratio between groundwater flow and total runoff Month J F M A M J J A S O N D

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Groundwater flow : total runoff 1 1 1 1 1 0.37 0.01 0.11 0.28 0.39 0.52 0.90

North West Irrigation Sector Project River basin and water use studies, Package 2

4.3

39

Candidate sub-projects This section relates to ToR, Task 23: Assessment of impacts of each sub-projects on downstream water uses; and Task 24: NWISP candidate sub-projects Related data

(submitted electronically)

D-W-balance-4of5yrs.xls

Dauntri Sub-basin, calculated water balance, present conditions, with water uses and availability, in 4 out of 5 years, whole sub-basin and details

D-W-balance-scenarios.xls

Dauntri Sub-basin, calculated water balance, alternative scenarios: Damnak-Ampil Canal, candidate sub-projects, and and impact of climate change

There are four proposed candidate sub-projects in the catchment, namely Kreuch Sauch, Anlong Svay, Roneam Prayol and Prek Chik. Two sets of water balances have been calculated: One without an ssumed climate change, and one including the (uncertain) effects of a climate change. Both sets include the Damnak Ampil Canal. Damnak-Ampil Canal and candidate sub-projects included: This scenario incorporates the Damnak Ampil Canal as well as the proposed candidate subprojects in the model. The candidate sub-projects are simply treated as the present irrigation systems, namely with a demand of 2 l/s/ha and no return flows. Return flows may occur in the future, but disregarding them is on the conservative side with regards to water availability. The following table gives a summary of the water balance for this scenario. For details, please refer to Appendix 4.

Table 4.5: Summary water balance with Damnak Ampil Canal and candidate sub-projects Rainfall

Evaporation

Storage and losses

Water availability

Domestic uses

Irrigation uses

Livestock uses

Outflow

[m3/s]

[m3/s]

[m3/s]

[m3/s]

[m3/s]

[m3/s]

[m3/s]

[m3/s]

January

3,9

19,6

-24,2

8,6

0,1

1,9

0,4

6,3

February

4,9

7,1

-8,8

6,6

0,1

1,9

0,4

4,3

March

45,2

45,2

-7,0

7,0

0,1

3,3

0,4

3,2

April

84,6

84,6

-7,9

7,9

0,1

3,3

0,4

4,2

May

163,2

135,7

16,9

10,6

0,1

3,3

0,4

6,9

June

143,6

126,9

-1,5

18,2

0,1

3,3

0,4

14,4

July

151,4

111,1

-22,7

63,0

0,1

23,7

0,4

38,9

August

197,7

98,3

-27,3

126,6

0,1

23,7

0,4

102,5

September

256,7

77,7

14,4

164,6

0,1

23,7

0,4

140,5

October

246,8

85,6

35,6

125,6

0,1

23,7

0,4

101,5

November

121,0

102,3

-26,4

45,1

0,1

23,7

0,4

20,9

December

19,7

78,3

-75,7

17,1

0,1

1,9

0,4

14,8

Year

119,9

81,0

-11,2

50,1

0,1

11,4

0,4

38,2

The main conclusion for the catchment as a whole, in comparison with the previous simulation described, is that the catchment outflows are reduced in the wet season, whereas it is unchanged in the dry season. The reason for this is that there are no dry season irrigation in the proposed candidate sub-projects, except at Prek Chik.

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North West Irrigation Sector Project River basin and water use studies, Package 2

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However, looking at the detailed results for Stung Dauntri river, it can be concluded that the Prek Chik candidate sub-projects will not be able to receive all of its water demand. The insufficient amounts of water held back for the Prek Chik candidate sub-project, has further as a consequence that downstream flows are further reduced, extending the period with zero or near zero aoutflows from the catchment. The remaining candidate sub-projects Krouch Saeuch, Anlong Svay and Roneam Mneash have sufficient water when combined with the Damnak-Ampil irrigation Canal. Without the canal, the Anlong Svay candidate sub-projects will be short of water in periods, whereas the demands from Krouch Saeuch and Roneam Mneash are just fulfilled. However, the fulfilment for the latter two are on the expense of flows downstream from these projects. A detailed analysis can therefore be carried out in which the optimal allocation of water at the three abstraction points along the Damnak-Ampil Canal is determined. Damnak-Ampil Canal, candidate sub-projects, and climate change: The assumed changes are a decrease of 2 % in the rainfall and and an increase in evaporation of 2%. These changes have been imposed on the rainfall and evaporation series that were used for the base situation simulation. No other changes have been considered as compared with the previous scenario. Results are shown in the table below. Detailed water balances for each subcatchment are presented in Appendix 2. The climate change mainly involves a change in the catchment outflow during the wet season, and to a lesser degree during the dry season. Table 4.6: Summary water balance with Damnak Ampil Canal, candidate sub-projects, and climate change Rainfall

January

Evaporation

Storage and losses

Water availability

Domestic uses

Irrigation uses

Livestock uses

Outflow

[m3/s]

[m3/s]

[m3/s]

[m3/s]

[m3/s]

[m3/s]

[m3/s]

[m3/s]

3,9

19,6

-24,0

8,4

0,1

1,9

0,4

6,1

February

4,9

7,1

-8,8

6,6

0,1

1,9

0,4

4,3

March

45,2

45,2

-6,9

6,9

0,1

3,3

0,4

3,2

April

84,6

84,6

-7,9

7,9

0,1

3,3

0,4

4,2

May

163,2

135,7

17,0

10,5

0,1

3,3

0,4

6,8

June

143,6

126,9

2,3

14,5

0,1

3,3

0,4

10,7

July

151,4

111,1

-11,5

51,8

0,1

23,7

0,4

27,7

August

197,7

98,3

-20,1

119,4

0,1

23,7

0,4

95,3

September

256,7

77,7

21,3

157,7

0,1

23,7

0,4

133,6

October

246,8

85,6

41,2

120,1

0,1

23,7

0,4

96,0

November

121,0

102,3

-22,8

41,5

0,1

23,7

0,4

17,4

December

19,7

78,3

-75,2

16,5

0,1

1,9

0,4

14,2

Year

119,9

81,0

-8,0

46,8

0,1

11,4

0,4

34,9

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4.4

41

Water availability This section relates to ToR, Task 24: NWISP candidate sub-projects Related data

(submitted electronically)

Subprojects.xls

Water availability for candidate sub-projects, and irrigable areas

On the basis of the analyses described above, the present section elaborates on the water availability for candidate sub-projects in the sub-basin. St. Kambot There is one candidate sub-project on this river: Krouch Saeuch. It is located within the command area of the Damnak Ampil Canal. Figure 4.12: Schematization of St. Kambot Flow from Damnak Ampil Canal

Krouch Saeuch scheme

Flow to the Great Lake

Not all the water available at each location should be used for irrigation. As estimated in Section 4.1, the domestic demand may increase by a factor 3-6 within a period of 30 years. Also, livestock breeding may increase. However, these demands are small in comparion with the over-all water availability. Today, between them, they are estimated at around 0,43 m3/s for the entire sub-basin. A 5fold increase would amount to 2.1 m3/s. They have been included in the availability estimates in proportion to the catchment area of each scheme, not because they are significant but in order not to forget about them. The estimated, manageable water availability is shown in the following table.

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Table 4.7: Estimated water availability at Krouch Saeuch Inflow

From Damnak Ampil

Other uses

Manageable

m3/s (1)

low estimate m3/s (2)

high estimate m3/s (3)

m3/s (4)

low estimate m3/s (5) = (1) + (2) - (4)

high estimate m3/s (6) = (1) + (3) - (4)

J

0,0

1,6

2,8

0,09

1,5

2,7

F

0,0

1

1,8

0,09

0,9

1,7

M

0,0

1

1,8

0,09

0,9

1,7

A

0,0

1

1,8

0,09

0,9

1,7

M

0,0

1,6

2,8

0,09

1,5

2,7

J

0,1

2

3,5

0,09

2,1

3,6

J

2,0

3

5,3

0,09

4,9

7,1

A

5,3

3

5,3

0,09

8,2

10,5

S

7,3

3

5,3

0,09

10,2

12,5

O

5,3

3

5,3

0,09

8,2

10,4

N

1,2

3

5,3

0,09

4,1

6,4

D

0,3

2

3,5

0,09

2,2

3,7

Catchment area: 186km2 (St. Kambot) (2): Assuming that 20 percent of the flow is directed to St. Kambot (could be more or less) (3): Assuming that 35 percent of the flow is directed to St. Kambot (could be more or less) The water availability is the estimated availability in 4 out of 5 years under present conditions, including present withdrawals for irrigation; present and future withdrawals for domestic and livestock; and excluding any future expansion of irrigation withdrawals

St. Svay Donkeo The two candidate sub-projects are located upstream and downstream of each other, as shown in the figure below. The water availability for the downstream one, Roneam Prayol, is influenced by the implementation of the upstream one, Anlong Svay. In consequence, the water availability can conveniently be presented as 1

Water available for the Anlong Svay scheme; and

2

water available to share between this scheme and the Roneam Prayol scheme.

Hereby, the water available for Anlong Svay is included in the water available to share between the schemes. The two schemes are within the command area of the Damnak Ampil Canal, which is manageable to within its capacity, subject to water being available at its intake. The estimated water availability is shown in the following tables.

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Figure 4.13: Schematization of St. Svay Donkeo Flow from Damnak Ampil Canal

Anlong Svay scheme Roneam Prayol scheme

Flow to the Great Lake

Table 4.8: Estimated water availability at Anlong Svay Inflow

From Damnak Ampil

Other uses

Manageable

m3/s (1)

low estimate m3/s (2)

high estimate m3/s (3)

m3/s (4)

low estimate m3/s (5) = (1) + (2) - (4)

high estimate m3/s (6) = (1) + (3) - (4)

J

0,2

2,4

4,0

0,19

2,4

4,0

F

0,0

1,5

2,5

0,19

1,3

2,3

M

0,0

1,5

2,5

0,19

1,3

2,3

A

0,0

1,5

2,5

0,19

1,3

2,3

M

0,0

2,4

4,0

0,19

2,2

3,8

J

0,6

3

5,0

0,19

3,3

5,4

J

5,3

4,5

7,5

0,19

9,6

12,6

A

12,7

4,5

7,5

0,19

17,0

20,0

S

17,1

4,5

7,5

0,19

21,4

24,4

O

12,6

4,5

7,5

0,19

16,9

19,9

N

3,6

4,5

7,5

0,19

7,9

10,9

D

0,9

3

5,0

0,19

3,7

5,7

Catchment area: 413km2 (St. Svay Donkeo) (2), (5): Assuming that 30 percent of the flow is directed to St. Svay Donkeo (could be more or less) (3), (6): Assuming that 50 percent of the flow is directed to St. Svay Donkeo (could be more or less) The water availability is the estimated availability in 4 out of 5 years under present conditions, including present withdrawals for irrigation; present and future withdrawals for domestic and livestock; and excluding any future expansion of irrigation withdrawals

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Table 4.9: Estimated water availability at Roneam Prayol Inflow

From Damnak Ampil

Other uses

To share

m3/s (1)

low estimate m3/s (2)

high estimate m3/s (3)

m3/s (4)

low estimate m3/s (5) = (1) + (2) - (4)

high estimate m3/s (6) = (1) + (3) - (4)

J

0,2

2,4

4,0

0,21

2,4

4,0

F

0,0

1,5

2,5

0,21

1,3

2,3

M

0,0

1,5

2,5

0,21

1,3

2,3

A

0,0

1,5

2,5

0,21

1,3

2,3

M

0,0

2,4

4,0

0,21

2,2

3,8

J

0,6

3

5,0

0,21

3,3

5,3

J

5,7

4,5

7,5

0,21

9,9

12,9

A

13,9

4,5

7,5

0,21

18,2

21,2

S

18,8

4,5

7,5

0,21

23,1

26,1

O

13,7

4,5

7,5

0,21

18,0

21,0

N

3,8

4,5

7,5

0,21

8,1

11,1

D

0,9

3

5,0

0,21

3,7

5,7

Catchment area: 458km2 (entire upstream area) (St. Svay Donkeo) (2), (5): Assuming that 30 percent of the flow is directed to St. Svay Donkeo (could be more or less) (3), (6): Assuming that 50 percent of the flow is directed to St. Svay Donkeo (could be more or less) (5), (6): Water available to share between Anlong Svay and Roneam Prayol The water availability is the estimated availability in 4 out of 5 years under present conditions, including present withdrawals for irrigation; present and future withdrawals for domestic and livestock; and excluding any future expansion of irrigation withdrawals

St. Dauntri There is one candidate sub-project on this river: Prek Chik. The estimated water availability is shown in the following table.

Figure 4.14: Schematization of St. Dauntri

Prek Chik scheme

Flow to the Great Lake

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Table 4.10: Estimated water availability at Prek Chik Inflow

Other uses

Manageable

m3/s (1)

m3/s (2)

m3/s (3) = (1) - (2)

J

0,6

0,33

0,3

F

0,2

0,33

-0,1

M

0,1

0,33

-0,3

A

0,0

0,33

-0,3

M

0,0

0,33

-0,3

J

1,2

0,33

0,9

J

8,6

0,33

8,2

A

21,6

0,33

21,3

S

29,4

0,33

29,1

O

21,4

0,33

21,1

N

5,6

0,33

5,2

D

1,8

0,33

1,5

Catchment area: 728 km2 (entire upstream area) (St. Svay Dauntri) The water availability is the estimated availability in 4 out of 5 years under present conditions, including present withdrawals for irrigation; present and future withdrawals for domestic and livestock; and excluding any future expansion of irrigation withdrawals

Table 4.10 indicates a visible water shortage in February through April. In this connection, the thought has been raised whether the shortage can be mitigated by extending the Damnak Ampil Canal all the way to St. Dauntri 1. Technically, this may or may not be feasible, as far as in the past, the canal linked with St. Dauntri although with a flow direction that was the opposite of today's, so that the canal drew water from St. Dauntri, rather than supplying water to it. If it is possible to augment the flow in this way, it will obviously make a significant difference to the benefit of the Prek Chik scheme. This is illustrated in Table 4.14 at the end of the following section.

4.5

Allocation of manageable flows Manageable flow (or water availability) The manageable flow is the water that can technically be withdrawn for off-stream uses at a given river section. The manageable flow is determined as the upstream generation of water (by net rainfall and storage exchange) minus upstream off-stream uses. The manageable flow is available to share between • off-stream uses at the given river section • off-stream uses downstream; and • in-stream (non-consumptive) uses downstream. The allocation can depend on the value generated, observation of exsiting water uses, and other aspects.

1

Version 2

Please refer to Section 3.5 for a description of the canal

North West Irrigation Sector Project River basin and water use studies, Package 2

46

Downstream water uses The following table lists the estimated manageable flows downstream of each candidate sub-project. The table indicates that consumption exceeds the availability in the following periods: •

St. Kambot: January through March;

•

St. Svay Donkeo: January through June, and November; and

•

St. Dauntri: February/March to May.

In these periods, the areas in question rely on inflow from upstream to serve their demands. In the rest of the year, the water availability exceeds the consumption, even in the absence of inflow from upstream (in case that all water were diverted to the candidate sub-projects). St. Kambot and St. Svay Donkeo (with 3 of the candidate sub-projects) are within the command area of the Damnak Ampil Canal. As illustrated in the previous section, this canal makes quite a difference to the water availability. Table 4.11: Manageable flows downstream of candidate sub-projects Kr Saeurch St. Kambot

AnlongSvay

R Prayol

St. Svay Donkeo

Prek Chik St. Dauntri

m3/s

m3/s

m3/s

m3/s

J

-0,35

-0,04

-0,05

0,28

F

-0,52

-0,20

-0,18

0,00

M

-0,41

-0,85

-0,77

-0,34

A

-0,44

-0,88

-0,79

-0,39

M

-0,43

-0,87

-0,79

-0,37

J

0,12

-0,35

-0,34

0,54

J

3,45

0,93

0,53

5,13

A

9,38

6,55

5,34

15,03

S

12,93

9,91

8,21

20,94

O

9,29

6,46

5,27

14,88

N

2,10

-0,35

-0,56

2,88

D

0,19

0,47

0,39

1,18

Values are water generated in 4 out of 5 years minus present off-stream uses, extracted from MIKE Basin baseline simulation (Appendix 4, Table A4.5) Inflow from upstream not included Negative values indicate that inflows from upstream are relied upon to serve present demand Values include present estimated withdrawals for irrigation, domestic use and livestock Contributions from the Damnak Ampil Canal are not included

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In-stream water uses Environmental flows (and other in-stream demands) have not been included in the analysis. An allocation of (for example) 2 l/s/km2 (or 3.0 m3/s for the entire subbasin) would exceed the present water availability from December through June and is simply not possible to achieve. On the other hand, 2 l/s/km2 is around the flow required on the average for the entire Mekong Basin to keep the saline sea water out of the Mekong Delta. It is an open question, however, how the contributions to this flow should be functionally allocated within the Mekong Basin, considering that much more water is available elsewhere. Areas that can be irrigated with the available water The area that can be irrigated with the available water will change from one month to another, and will depend on the withdrawal demand. The withdrawal demand, in turn, depends on the crops, the cultivation routines, the direct rainfall, and the water losses in the irrigation system (conveyance losses, seepage and infiltration). Today, during an average rainy season, the farmers can raise one purely rainfed crop, although the yield is affected by water stress (which means that the water availability is less than ideal). This indicates a present withdrawal demand of somewhere around 0,5 l/s/ha minus direct rainfall - which would allow the farmers to cultivate their present wet season rice crops, with the present yield, in years with rainfall less than average. Short- and medium-term rice varieties require more water than long-term varieties, and dry season paddy cultivation requires more water that wet season cultivation, whereas many crops other than rice require less water. Withdrawal demands According to MOWRAM's design manual for irrigation schemes (draft, Dec 03) Crop water requirement: 1,700 m3/mth (December) to 2,300 m3/month (April), or 0.6-0,9 l/s/ha, assuming a crop factor 1.1 for paddy and including percolation 2 mm/day Over-all system efficiency: Varying between 60 percent to schemes up to 50 ha and 51 percent for schemes above 400 ha This gives a withdrawal demand of between 1.1 and 1.7 l/s/ha in December to April The MOWRAM Manual notes that 'experience in other countries has indicated that crop yields are not significantly reduced if water supplied is within 85-90% of optimum'.

The area that can be irrigated with a given amount of water can be calculated as the rainfall deficit divided by the flow that is available. The rainfall deficit is the difference between the irrigation demand and the direct rainfall. It is shown in the following table for assumed withdrawal demands of 0.5, 1 and 2 l/s/ha. The former value is an indication of present practices in the wet season, while the latter value indicates possible future practices in the dry season. Table 4.12: Rainfall deficit, Dauntri sub-basin Withdrawal demand

0.5 l/s/ha

Rainfall

Demand

(1)

(2)

1 l/s/ha Deficit

Demand

(3) =

(4)

(2) - (1) J

Version 2

2 l/s/ha Deficit

Demand

(5) =

(6)

(4) - (1)

Deficit (7) = (6) - (1)

mm

mm

mm

mm

mm

mm

mm

3

134

131

268

265

536

533

North West Irrigation Sector Project River basin and water use studies, Package 2

F

4

48

122

118

244

240

488

484

M

33

134

101

268

235

536

503

A

62

130

68

259

197

518

456

M

120

134

14

268

148

536

416

J

105

130

25

259

154

518

413

J

111

134

23

268

157

536

425

A

145

134

0

268

123

536

391

S

189

130

0

259

70

518

329 355

O

181

134

0

268

87

536

N

88

130

42

259

171

518

430

D

14

134

120

268

254

536

522

Note: Values are for 4 out of 5 years

The corresponding irrigable areas are shown in the following tables. Table 4.13a: Irrigable areas (a), withdrawal demand 0.5 l/s/ha Krouch Sauch

Anlong Svay

Roneam Prayol

Prek Chik

to share Low estimate J

High estimate

Low estimate

High estimate

Low estimate

High estimate

ha

ha

ha

ha

ha

ha

ha

3.097

5.552

4.917

8.191

4.888

8.162

561 0

F

1.890

3.441

2.706

4.774

2.663

4.731

M

2.426

4.416

3.473

6.127

3.418

6.072

0

A

3.504

6.380

5.018

8.853

4.938

8.772

0

M

29.130

52.220

42.500

73.286

42.096

72.882

0

J

21.699

37.504

35.507

56.580

35.224

56.297

9.500

J

57.213

83.507

111.771

146.828

116.140

151.198

96.064

A

n/a

n/a

n/a

n/a

n/a

n/a

n/a n/a

S

n/a

n/a

n/a

n/a

n/a

n/a

O

n/a

n/a

n/a

n/a

n/a

n/a

n/a

N

25.783

39.803

49.103

67.795

50.281

68.973

32.698

D

4.908

8.258

8.214

12.681

8.348

12.815

3.271

n/a: Cultivation not limited by water availability (irrigation supplies not required)

Table 4.13b: Irrigable areas (b), withdrawal demand 1 l/s/ha Krouch Sauch

Anlong Svay

Roneam Prayol

Prek Chik

to share Low estimate J

High estimate

Low estimate

High estimate

Low estimate

High estimate

ha

ha

ha

ha

ha

ha

ha

1.531

2.745

2.431

4.049

2.417

4.035

277

F

929

1.692

1.331

2.347

1.309

2.326

0

M

1.042

1.898

1.493

2.633

1.469

2.609

0

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North West Irrigation Sector Project River basin and water use studies, Package 2

A

1.201

2.187

49

1.720

3.035

1.693

3.007

0

M

2.743

4.917

4.002

6.900

3.964

6.862

0

J

3.462

5.983

5.665

9.026

5.619

8.981

1.516

J

8.361

12.203

16.334

21.457

16.972

22.095

14.038

A

17.941

22.846

36.998

43.539

39.584

46.125

46.422

S

37.736

46.044

78.995

90.072

85.168

96.245

107.463

O

25.226

32.166

51.998

61.251

55.620

64.873

65.072

N

6.265

9.672

11.931

16.474

12.218

16.760

7.945

D

2.319

3.901

3.881

5.991

3.944

6.054

1.545

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50

Table 4.13c: Irrigable areas (c), withdrawal demand 2 l/s/ha Krouch Sauch

Anlong Svay

Roneam Prayol

Prek Chik

to share Low estimate J

High estimate

Low estimate

High estimate

Low estimate

High estimate

ha

ha

ha

ha

ha

ha

ha

761

1.365

1.209

2.013

1.201

2.006

138 0

F

461

839

660

1.164

649

1.153

M

487

887

697

1.230

686

1.219

0

A

519

945

743

1.311

731

1.299

0

M

975

1.749

1.423

2.454

1.410

2.441

0

J

1.291

2.232

2.113

3.367

2.096

3.350

565

J

3.088

4.507

6.032

7.924

6.268

8.160

5.185

A

5.641

7.184

11.633

13.690

12.446

14.503

14.596

S

8.042

9.813

16.835

19.196

18.151

20.511

22.902

O

6.176

7.876

12.731

14.997

13.618

15.883

15.932

N

2.492

3.847

4.746

6.553

4.860

6.667

3.160

D

1.128

1.898

1.888

2.915

1.919

2.946

752

As mentioned in Section 4.4, the possibility exists to increase the inflow to the Prek Chik scheme by extending the Damnak Ampil Canal all the way to St. Dauntri. As an illustration of the effect, an estimate has been made based on the tentative assumption that Prek Chik receives an amount of 20 percent of the flow that is diverted from St. Pursat for distribution via the Damnak Ampil Canal. (In rality, a lower or a higher flow rate could equally well be assumed, since the system is highly manageable). Table 4.14: Irrigable area at Prek Chik assuming a supply from the Damnak Ampil Canal Inflow (1)

From Damn. Ampil Canal (2)

Other uses (3)

Manageable (4) =

Irrigable area 0,5 l/s/ha

1 l/s/ha

2 l/s/ha ha

(1) + (2) - (3) m3/s

m3/s

m3/s

m3/s

ha

ha

J

0,6

1,6

0,3

1,9

3.835

1.896

942

F

0,2

1,0

0,3

0,9

1.866

918

455

M

0,1

1,0

0,3

0,7

1.944

835

390

A

0,0

1,0

0,3

0,7

2.579

884

382

M

0,0

1,6

0,3

1,3

24.942

2.348

835

J

1,2

2,0

0,3

2,9

30.573

4.877

1.819

J

8,6

3,0

0,3

11,2

131.121

19.162

7.077

A

21,6

3,0

0,3

24,3

n/a

52.963

16.653

S

29,4

3,0

0,3

32,1

n/a

118.540

25.263

O

21,4

3,0

0,3

24,1

n/a

74.325

18.198

N

5,6

3,0

0,3

8,2

51.390

12.487

4.967

D

1,8

2,0

0,3

3,5

7.738

3.655

1.779

Example: If the withdrawal demand is 1 l/s/ha, the manageable flow in January is equivalent with an area of 1,896 ha (2): Taken as 20 percent of the monthly withdrawal from St. Pursat. (This is an assumption rather than a recommendation) n/a: Cultivation not limited by water availability (irrigation supplies not required)

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Morphology, floods and drought

5.1

Data

51

This section relates to ToR, Task 2: Collection of hydro-meteorological and hydraulic data and information

Information about morphological processes was collected in July-August 2006 in connection with the present study.

5.2

Morphology Bank erosion and accretion takes place along the alluvial reaches of rivers and streams, sometimes as a gradual process that proceeds for years in a predictable way, and sometimes rather abruptly. In the present study area, the erosion rate is generally slow to moderate. Bank erosion can cause damage to property, buildings and infrastructure (including irrigation infrastructure), while accretion can increase the flood risk and affect fish habitats and mish migration. Locations of particular erosion and accretion are shown in the figure below.

Figure 5.1: Erosion and accretion

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52

Floods and drought This section relates to ToR, Task 23: Assessment of impacts of each sub-project on downstream water uses; and Task 24: NWISP candidate sub-projects Related data

(submitted electronically)

Agriculture-2006.xls

PRD survey (Jul-Aug 06): Cultivation practices; cultivation areas; cropping cycles; labour input; livestock; use of fertilizers and pesticides; farm gate prices; obstacles to cultivation

Flooded areas in 1999, 2000, 2001 and 2002 are shown in a thematic map (submitted separately). Effects of floods and drought exist over most of the sub-basin, to an extent that depends on the cultivation cycle. Normally, a drought is regarded as a drought only if it occurs during cultivation. The effects vary from one village to another, over short distances, often within each commune. In general, drought problems are much more widespread and more frequent. The following tables show drought-affected areas and the general occurrence of floods and drought in the sub-basin.

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Table 5.1: Cultivation areas affected by floods and drought Province

District

Commune

2005, flood

Pursat

Krokor

AnsaChambak

15

ha

Battambang

Maung Reusey

Drought

2004, flood

ha

ha

Drought ha 66

Kbal Trach

20

Anlung Tnoat

28

25

137 92

Snar Ansar

24

8

270

Ou Sandann

18

164

Boeng Kantout

…

250

Tnoat Chum

…

Kampung Po

20

265 12

46

Cheu Tom

45

285

Svay Sor

20

251

Maung

5622

Kear

3112

Prey Svay

5354

Reusey Krang

320

1987

Chrey

61

1629

Taloas

115

3180

Kokoah

2230

Robos Mongkol

2430

Prek Chik

2564

Prey Tralach

1200

Prey Toch

7798

Total:

496

190

45

38932

Data: District Agriculture Offices

Table 5.2: Occurrence of floods and drought Province

District

Commune

Village

Flood

Pousat

Bakan

Boeng Khnar

Chamkar Leu

1994,96,97,2000

Drought Usally

Pousat

Bakan

Boeng Khnar

Chamkar Leu

1996 and 2000

Usally

Pousat

Bakan

Boeng Khnar

Ma

1997 and 2000

Usally

Pousat

Bakan

Boeng Khnar

Rung

1996,97,2000

Usally

Pousat

Bakan

Boeng Khnar

Rung

1996 and 2000

Usally

Pousat

Bakan

Boeng Khnar

Sakor

1996 and 2000

Usally

Pousat

Bakan

Boeng Khnar

Sakor

1997 and 2000

Usally

Pousat

Bakan

Khnar Totueng

Doem Roka

1996 and 2000

Usally

Pousat

Bakan

Khnar Totueng

Doem Roka

1995,96,2000

Usally

Pousat

Bakan

Khnar Totueng

Phtek Sla

1996, 2000

Usally

Pousat

Bakan

Khnar Totueng

Phtek Sla

1996,97,2000

Usally

Pousat

Bakan

Meteuk

Ma

1996 and 2000

Usally

Pousat

Bakan

Meteuk

Meteuk

2000

Every year

Pousat

Bakan

Meteuk

Oupreal

2000

Every year

Pousat

Bakan

Meteuk

Trang

2000

Every year

Pousat

Bakan

Outapoang

Sdock Khlock

2000

Every year

Pousat

Bakan

Outapoang

Tanai

2000

Usally

Pousat

Bakan

Phtek Rong

Thlok Donkor

0

Usally

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Province

District

Commune

54

Village

Flood

Drought

Pousat

Bakan

Phtek Rung

Prey Kanlong

0

Usally

Pousat

Bakan

Svaydaunkeo

Chrab

1997 and 2000

Usally

Pousat

Bakan

Svaydaunkeo

Chrab

2000

Usally

Pousat

Bakan

Svaydaunkeo

Kampang

2000

Every year

Pousat

Bakan

Svaydaunkeo

Nikumkrom

2000

Every year

Pousat

Bakan

Talor

Burchres

0

Usally

Pousat

Bakan

Talor

Prey Rong

0

Usally

Pousat

Bakan

Talor

Prey Toa

0

Usally

Pousat

Bakan

Talor

Prey Veang

0

Usally

Pousat

Bakan

Talor

Thmey

0

Usally

Pousat

Bakan

Trapeang Chong

Bakan

2000

Every year

Pousat

Bakan

Trapeang Chong

Kroal Krobei

0

Usally

Pousat

Bakan

Trapeang Chong

Pit Trang

0

Usally

Pousat

Bakan

Trapeang Chong

Snai Tol

0

Usally

Pousat

Bakan

Trapeang Chong

Thmey

0

Usally

Pousat

Bakan

Trapeang Chong

Thmey

Usally

Usally

B.Bang

Moung Russey

Kear

Kear Mouy

2000

Every year

B.Bang

Moung Russey

Kear

Kear Mouy

0

2006

B.Bang

Moung Russey

Moung

Pen

0

Every year

B.Bang

Moung Russey

Moung

Russey Mouy

2000

Every year

B.Bang

Moung Russey

Moung

Russey Mouy

0

Every year

B.Bang

Moung Russey

Prek Chik

Chke Kham Prus

2000

Every year

B.Bang

Moung Russey

Prek Chik

Chke Kham Prus

2004

Every year

B.Bang

Moung Russey

Prek Chik

Prek Chik

0

Every year

B.Bang

Moung Russey

Prek Chik

Prek Taven

0

Every year

B.Bang

Moung Russey

Robos Monkol

Boeng Bei

0

2004

B.Bang

Moung Russey

Robos Monkol

Boeng Bei

0

Every year

B.Bang

Moung Russey

Robos Monkol

Prek Am

2000

2004

Data: 68 household surveys in Dauntri Sub-basin 2006 Flood damage: Damage to crops, livestock and infrastructure Drought damage: Damage to crops and livestock disease For details, please refer to data table Agriculture-2006.xls

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6

Aquatic environment

6.1

Data This section relates to ToR, Task 25: Exisiting WQ data and classification

Data used in the evaluation and assessment of the aquatic environment is mainly from the commune database 2004 as presented in the previous chapters regarding population and livestock estimates. Besides this also satellite images from LandSat 2005 have been used in the analysis including data on landuse from 1993, 1997 and 2002. No water quality data have been available for the studied sub-catchments. Only data from Tonle Sap Lake have been available to a limited extent. The work has included: •

compilation and processing of input data for pollution load estimation;

•

compilation and processing of input data for MIKE Basin Water Quality model; and

•

post-processing of simulation results.

The output of the MIKE Basin WQ model presented below is only covers the Dauntri study area. The water balance used is based on the preceding water balance calculations. No monitoring data on water quality has been available for the study areas. Thus, the results presented in the chapter do not reflect calibrated concentration level. Instead pollution loads and water quality parameters have been adjusted to reach expected concentrations levels based on measurements available from rivers in the coastal area of Cambodia.

6.2

Pollution loads This section relates to ToR, Task 26: Point and non-point sources Related data

(submitted electronically)

Area-population.xls

Area and population (2002-04) within the study area; buffaloes, cows, horses, goats, pigs, and poultry; families using fertilizer; by province, district and commune

Agriculture-2006.xls

PRD survey Jul-Aug 2006: Cultivation practices; cropping cycles; labour input; livestock; use of fertilizers and pesticides; farmgate prices; obstacles to cultivation

Cultivation areas The available information for this project states that on average 1 crop is cultivated per year. The areas and the corresponding estimates of fertilizer utilization are listed below.

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Table 6.1: Distribution of areas for rice cultivation and estimated fertiliser application, per commune in Dauntri catchment

Dauntri

ID 20601 20602 20603 20604 20605 20606 20607 20609 20610 20611 21304 21306 150101 150102 150103 150104 150105 150106 150107 150108 150109 150110 150401 150403 150407 150503 150602 150604

PROVINCE Battambang Battambang Battambang Battambang Battambang Battambang Battambang Battambang Battambang Battambang Battambang Battambang Pursat Pursat Pursat Pursat Pursat Pursat Pursat Pursat Pursat Pursat Pursat Pursat Pursat Pursat Pursat Pursat

DISTRICT Moung Ruessei Moung Ruessei Moung Ruessei Moung Ruessei Moung Ruessei Moung Ruessei Moung Ruessei Moung Ruessei Moung Ruessei Moung Ruessei Koas Krala Koas Krala Bakan Bakan Bakan Bakan Bakan Bakan Bakan Bakan Bakan Bakan Phnum Kravanh Phnum Kravanh Phnum Kravanh Sampov Meas Veal Veaeng Veal Veaeng

COMMUNE Moung Kear Prey Svay Ruessei Krang Chrey Ta Loas Kakaoh Robas Mongkol Prek Chik Prey Tralach Doun Ba Chhnal Moan Boeng Bat Kandaol Boeng Khnar Khnar Totueng Me Tuek Ou Ta Paong Rumlech Snam Preah Svay Doun Kaev Ta Lou Trapeang Chong Bak Chenhchien Phteah Rung Samraong Lolok Sa Krapeu Pir Pramaoy

Area km2 39 96 144 163 288 52 47 124 139 274 151 241 10 57 54 262 292 53 12 30 305 70 15 150 36 7 536 36

Rice Rice Fertiliser P Fertiliser N ha pct kg/year kg/year 43811 125592 6964 179 3549 37 92053 263886 7577 53 172360 494099 9337 57 188680 540882 2538 9 64288 184292 1878 36 47334 135690 2823 61 71139 203932 5129 41 117087 335650 3719 27 83680 239883 4102 15 117883 337932 10711 71 241004 690879 736 3 16571 47504 203 21 6856 19654 4122 73 76539 219412 3711 69 86400 247681 4856 19 97993 280914 5812 20 142730 409158 4470 84 104624 299921 121 10 6870 19693 33594 96302 6043 202 3332 11 144621 414580 5576 80 79171 226958 594 40 13376 38345 4007 27 90165 258474 68 2 1538 4410 174 24 3920 11237 115 0 2579 7392 10 0 230 659

Data on rice cultivation are (i) from the commune database and (ii) collected from local agricultural authorities. Statistics refer to the proportion of each commune that lies within the study area. Numbers for Moung and Svay Don Kaeo commune were not correct since total cultivated area exceeded total commune area. Instead a cultivation percentage of 50 % pct have been assumed for both communes

Pollutant loads The pollution load calculated and load reaching the water bodies in the different subcatchments are discussed in more detail in the following section. To establish a priority programme of potential actions it is important to know the main sources of pollution and the pollution load from these. It is especially important to know the role and amount of the different sources of pollution for determining priorities. Based on the estimations above and use of the Load Module of the Mike Basin model the overall load of BOD, Total-nitrogen and Totalphosphorus in the two sub-catchments have been estimated for the major pollution sources. Furthermore, it has been used to calculate the amount of the separate pollutants that ends up in the rivers and also for quantification of the pressure of human activities for each of the sub-catchments. For each of the catchments also a calculation has been made on the distribution of the calculated load between point and non-point sources.

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Table 6.2: Overall generated load of BOD, nitrogen and phosphorus (t/year) in the Dauntri catchment Source

BOD (T/y)

Total-Nitrogen (T/y)

TotalPhosphorus (T/y)

NS

NS

NS

Non-sewered population

2850

520

170

Live stock (generated)

24150

3300

1060

-

6480

2260

1850

1850

190

Point sources

Fertiliser (used) Background load incl. precipitation

A short discussion of the different potential sources and their significance is given below considering the categories: point sources, non-sewered population, background load including precipitation, livestock and fertiliser use. Point sources The present load from point sources is very low or non-existent for the moment but potential point sources in the future could be wastewater treatment plants, industries, and hotels giving rise to significant load to certain stretches of the rivers. Non-sewered population The population today is not connected to a wastewater system and the pollution load from this source will also end up in the river system after different forms of reduction and decay which is considered as described above. The generated load from this source of BOD, nitrogen and phosphorus can be estimated to 2850, 520 and 170 tons/year, respectively for the Dauntri Sub-basin. Background load As the nutrients are naturally occurring in the nature, the natural processes and cycling of elements will contribute to the overall load of the catchments. These estimations are based on findings from other areas. Livestock The livestock on the farms in the catchment areas contributes significantly to the overall generated load of the river system. Based on the statistics described above on livestock numbers in the households it can be estimated that approximately 24150, 3300 and 1060 tons/year of BOD, nitrogen and phosphorus, respectively, are produced in the Dauntri Sub-basin. Mineral fertiliser Based on the received information regarding fertiliser use the amount applied make up a significant proportion of the estimated generated load in each of the catchment areas. Based on the area of agricultural land and the use of unit figures of nitrogen and phosphorus application a total amount of 6480 and 2260 tons/year are used in the Dauntri Sub-basin.

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Using the Load Module of Mike Basin the load of BOD, nitrogen and phosphorus for the different sub-catchments in the two catchments have been calculated. The figures also indicate in which sub-catchments the pressure from human activities are most significant. BOD In the figure below the load of BOD is shown for each sub-catchment.

Figure 6.1: Amount of annual BOD load by sub-catchment

From this figure it can be seen that the BOD load reaching the receiving waters will be biggest in sub-catchments covering the mid-stretches of the Dauntri catchment and especially in the districts of Bakan and Moung Russei. The figure also show the distribution of receiving water load between domestic and non-point load. This shows clearly that in all sub-catchments the non-point load is the highest. In Table 6.3 below the estimated pollution load of BOD to each subcatchment of the river is presented. The total load, the load for non-point pollution sources and domestic load has been calculated.

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Table 6.3: Estimated BOD load reaching the river in each subcatchment ID

Name

Area

BODTotal

BODNonPoint

BODDomestic

km2

kg

kg

kg

1

Catchment1

185

78476

74802

3673

2

Catchment2

367

212861

184276

28586

3

Catchment4

121

77069

72782

4287

4

Catchment6

104

71841

66891

4950

5

Catchment7

331

217344

197220

20124

6

Catchment8

156

64560

60614

3945

7

Catchment10

95

57074

52473

4602

8

Catchment12

74

54663

50720

3943

9

Catchment14

27

21594

20266

1328

10

Catchment15

24

25852

23128

2724

11

Catchment16

191

133281

117050

16231

12

Catchment17

504

188462

169487

18975

13

Catchment18

28

28003

24927

3077

14

Catchment19

122

119405

108092

11313

15

Catchment20

45

37794

34255

3539

16

Catchment21

413

119111

106338

12773

17

Catchment22

186

157131

139879

17252

18

Catchment23

196

61865

61192

673

19

Catchment24

6

2102

2097

5

20

Catchment25

216

42833

42637

196

21

Catchment26

155

23074

22993

82

Figure 6.2: Map showing the location of the different sub-catchments of the Dauntri catchment

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Nitrogen The highest contribution of nitrogen to the receiving waters originates in the subcatchments covering the districts of Moung Russei and Bakan. Substantial differences in the receiving water load between the upper and some of the mid-stretches of the Dauntri Sub-basin can be seen. Compared to the BOD load there is indications that the proportion of nitrogen load from non-point sources might be even more pronounced.

Figure 6.3: Amount of annual Total Nitrogen load by sub-catchment

In Table 6.4 below the estimated pollution load of total-nitrogen to each subcatchment of the river is presented. The total load, the load for non-point pollution sources and domestic load has been calculated.

Table 6.4. Estimated nitrogen load reaching the river in each subcatchment ID

Version 2

Name

Area

N_Total

N_Nonpoint

N_Domestic

km2

kg

kg

kg

1

Catchment1

185

74001

73603

397

2

Catchment2

367

152864

149499

3365

3

Catchment4

121

57414

56945

469

4

Catchment6

104

46215

45714

501

5

Catchment7

331

145750

143431

2319

6

Catchment8

156

70179

69727

453

7

Catchment10

95

45184

44646

538

8

Catchment12

74

36852

36410

441

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61

ID

Name

Area

N_Total

N_Nonpoint

N_Domestic

km2

kg

kg

kg

9

Catchment14

27

14444

14298

146

10

Catchment15

24

16887

16567

320

11

Catchment16

191

102936

101008

1928

12

Catchment17

504

154872

152591

2281

13

Catchment18

28

18069

17705

363

14

Catchment19

122

73364

72014

1350

15

Catchment20

45

25411

24996

415

16

Catchment21

413

89829

88192

1638

17

Catchment22

186

79691

77551

2140

18

Catchment23

196

67394

67322

72

19

Catchment24

6

2353

2353

1

20

Catchment25

216

51698

51676

22

21

Catchment26

155

29653

29643

10

Phosphorus The phosphorus load shows a similar pattern as for nitrogen when indicating the pressure of human impact. Again the highest overall phosphorus load to the river system is generated in Moung Russei and Bakan districts.

Figure 6.4: Amount of annual Total Phosphorous load by sub-catchment

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In Table 6.5 below the estimated pollution load of total-phosphorus to each subcatchment of the river is presented. The total load, the load for non-point pollution sources and domestic load has been calculated.

Table 6.5: Estimated phosphorus load reaching the river in each subcatchment ID

Name

Area

PtotTotal

PtotNonPoint

PtotDomestic

km2

kg

kg

kg

1

Catchment1

185

7176

6993

183

2

Catchment2

367

15857

14831

1026

3

Catchment4

121

7152

6925

227

4

Catchment6

104

5359

5145

214

5

Catchment7

331

18839

17896

943

6

Catchment8

156

8556

8347

209

7

Catchment10

95

5636

5428

208

8

Catchment12

74

4753

4566

187

9

Catchment14

27

2165

2090

74

10

Catchment15

24

3044

2898

146

11

Catchment16

191

13966

13262

704

12

Catchment17

504

16225

15448

778

13

Catchment18

28

3032

2873

159

14

Catchment19

122

11004

10503

501

15

Catchment20

45

3775

3606

170

16

Catchment21

413

6596

6235

362

17

Catchment22

186

10998

10338

660

18

Catchment23

196

4901

4869

32

19

Catchment24

6

205

204

0

20

Catchment25

216

2347

2341

6

21

Catchment26

155

1274

1271

3

The results above are estimates on pollutant loads entering the river. The results give an indication on how the relative differences in concentration may look like and which catchments may contribute relatively more than others to pollution levels expected in the river system. The plan plot showing pollutant loads entering the river system discriminates between non-point and point types of sources. In general the plots indicate that non-point sources in general are far more important than point sources (e.g. domestic sources from population). However this cannot be verified but compared to the above load amount generated it seems reasonably. However, a number of local conditions may affect the transport and retention of different source types and it is important to obtain monitoring data covering both low flow and high flow periods in order to verify that this is also actually the case.

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63

Water quality This section relates to ToR, Task 27: Aqautic environment in representative reaches

The different water uses require a raw water quality that is adequate for the particular use, whether domestic, fisheries, industrial, or for agriculture. And most water uses generate a return flow, the water being released as sewage from households, businesses and industries, or as tailwater from irrigation systems and mines. A MIKE Basin Water Quality model was setup for the Dauntri study area based on the water balance. The water balance is based on down stream discharges calculated from the water level measurements and Q/h relations which are available for 1998 – 2005. Calculated discharges have been translated into area specific runoffs as input for the MIKE Basin model. Results are summarised below and are elaborated in Appendix 5. Water quality simulations This section presents the results from the water quality simulations. Two types of simulation results are presented. •

Time series plot for a selected location in the river

•

Plan plot showing average and maximum concentrations

Below is shown the simulated concentrations of BOD, total-nitrogen and total phosphorus. The time series plot shown below indicated relative high concentrations of all the simulated compounds in the dry season and reaching maximum concentrations in May in the period with very low flow in the catchment. BOD The simulated average concentration of BOD during the present conditions show that the concentration levels will increase in the lower reaches of the Dauntri catchment and especially a small stretch in the mid-reaches will show relatively high concentrations. The calculations indicate that an up to two to three times increase might occur in the lower reaches of the catchment However the calculation indicate using the assumptions given above that the present quality conditions should be good in most of the catchment. During periods with low flow the simulations indicate more or less the same pattern but higher concentration levels. Ammonia The average annual concentrations of ammonia in the main part of the catchment in general meets the requirements for good quality except some short stretches in some of the branches where the quality might reach fair qulity. However, the calculations indicate that in periods with low flow during the dry season the quality conditions regarding ammonia might be poor as the levels found in the lower reaches might be five to six times higher than the upper reaches

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Figure 6.5: Time series simulation results for the outlet of St. Dauntri. Results for BOD, ammonia, nitrate and total phosphorous

N3|BOD [mg/l]

25 20 15 10 5 2000

2001

2000

2001

2000

2001

2000

2001

N3|NH4 [mg/l]

4.0 3.0 2.0 1.0

N3|NO3 [mg/l]

1.5

1.0

0.5

N3|P_tot [mg/l]

1.0

0.5

Nitrate Regarding nitrate the average concentrations indicates that good quality conditions might occur in all river stretches except a small stretch on Svay Don Keo, where the quality might be poor to bad.. The calculations indicate however that during the dry season the quality conditions in the lower reaches will be decreasing showing concentration levels higher than in the wet season.

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Total-phosphorus

The total-phosphorus concentrations in the upper parts of Dauntri show levels up to approx. 2 times the less affected parts. However, it looks like good quality conditions occur in most of the catchment. During the dry season an increase in concentration level occurs in all the lower reaches of the catchment.

6.4

Implications of irrigation development This section relates to ToR, Task 23: Assessment of impacts of each sub-projects on downstream water uses

The impact of the candidate scheme on the water quality conditions will be evaluated in the following. The candidate scheme evaluated includes all candidate irrigation projects and allocation of water from Pursat River. The comparison have been made under the assumption that all pollution loads and retention in the system will be similar to the present situation, so that the only change that will occur will be the changed water flow due to the irrigation schemes. The calculated changes in water discharge are shown in the figures below. The figures show clearly that the discharge through the northern most branch of the Dauntri catchment will be reduced during the rainy season for the candidate subprojects and also that the discharge in the dry season will be very low. In some river stretches the water flow in the dry season increases compared to the present situation due to the potential contribution from Pursat River. The difference in water discharge in this area is indicated in the figure below for the present situation and for the candidate sub-projects.

Figure 6.6: Simulated discharge for reference scenario (black) and the candidate sub-projects (blue) at node 3 at the outlet of St. Dauntri N3|Net flow to node - Candidate project [m^3/s] N3|Net flow to node - reference [m^3/s]

50 40 30 20 10

2000

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Figure 6.7: Changes in water discharge at Node 185 from the present situation and the candidate scheme including the irrigation schemes and allocation of water from Pursat River

The simulations indicate that relative small changes will take place in the concentrations of BOD, ammonium, nitrate and total phosphorus in the northern branch in the catchment area. The biggest changes will for all compounds be in the end of the dry season and slightly later than in the present situation. In the early part of the dry season even lower concentrations than at present might occur according to the simulated results.

BOD

The simulated average concentration of BOD for the candidate sub-projects including the irrigation schemes and water allocation from Pursat River have been calculated. The concentration show a similar situation as for the present situation but with slightly lower values in some of the mid reaches and significantly lower concentration in the mid part of Svay Don Keo. Figure 6.24 show the simulated differences in concentration levels between the candidate sub-projects and the present situation. These calculations indicate that the levels in the lower reaches will be at the same level or slightly lower in the average situation.

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Figure 6.8: Time series simulation results for the outlet of St. Dauntri after irrigation development. Results for BOD, ammonia, nitrate and total phosphorous N3|NH4 - Candidate project [mg/l] N3|NH4 - reference [mg/l]

4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 2000

2001

N3|P_tot - Canditate project [mg/l] N3|P_tot - reference [mg/l]

1.4 1.2 1.0 0.8 0.6 0.4 0.2 2000

2001

Ammonium

The simulated concentrations of ammonium show almost no changes in the most part of the catchment. In the Dauntri part the simulations indicate a slight increase in the upper reaches and a slight decrease in the mid-reaches. The biggest change can be found in Svay Don Keo where the allocation of water will increase the amount of water in the dry season leading to lower concentrations of ammonium in this part. Nitrate

The simulated concentrations of nitrate for the candidate sub-projects show that the concentrations in most of the Dauntri catchment will change very little, with an increase between 0 and 0.07 mg/l. The biggest changes will occur in the mid parts of Svay Don Keo. Total Phosphorus

The simulated concentrations of total-phosphorus show a similar pattern as the other compounds and indicates a slight reduction of total-phosphorus concentrations in the mid parts of Dauntri river and significant reductions at a small stretch in the mid parts of Svay Don Keo. Conclusion

The simulations indicate that the quality conditions for the compounds could be good and this seems to be in accordance with recent water quality monitoring programs, undertaken by MOWRAM, MRC and WUP-FIN, that the general

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pollution level is fairly low at present. The simulations conducted for the candidate sub-projects indicate very limited changes in the quality conditions in the Dauntri catchment except for in a small stretch of the Svay Don Keo where water transferred from the Pursat river provides more water in the dry season compared to the present situation. The proposed irrigation schemes will generally result in a reduction in water quality as less water will be available for dilution of the pollutants but the allocation of water from Pursat river will compensate for this. It should be pointed out that in the future, in case of crop diversification and related increased use of pesticides and fertiliser, it is important to consider and prevent serious environmental impacts in general, and contamination of edible fish in particular in the catchment.

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Fisheries The fishery in this sub-basin is associated with its three main rivers: Dauntri (Muong), Svay Don Keo and St. Kambot (Preah Mlou) 2.

7.1

Dauntri River The river seems to have been completely blocked at the site of the Chong Sanay barrage structures. However, the flood in 2000 has cut through the dam and created a new by-pass for migrating fishes. The fish migration is no longer denied. Fishing activities have been observed in both upstream and downstream of the structures. Further upstream, the river is blocked by a structure of Prekchik 17April. Under the current situation, this structure without gate regulators still allows a possible fish migration during the rainy season, when water level raises up. Fishing was observed during consultant visit and reported by local communities at upstream of this structure. Although the fishing practice here is only for family purpose, the rehabilitation of this irrigation scheme should include fishways to avoid possible negative impacts on the aquatic diversities including the family type fishery that still remains commonly in this area.

7.2

Svay Don Keo River The fishing activities are observed, during the consultant visit, significant along this river. Fishing is seen in the river, irrigation canals and in the rice fields. Kampang irrigation scheme is the only irrigation structure across the river downstream of National Road No. 5, but without blocking the river (no gate regulator). The passage between different parts of the river and the rice fields or flood plain is observed in a good favourable condition for fish migration both locally and laterally. This favourable condition could explained the more active fishing practice in this river sub-basin observed by the consultant comparing to other sub-basins of the two studied basins. Further upstream, at Roneam Proyol irrigation scheme, the fish migration remains also possible during rainy season, when the water level raises, due to present absence of gates of this irrigation scheme. The rehabilitation of this irrigation scheme in the future should include fishways to avoid possible negative impacts on the aquatic diversities in this river sub-basin.

7.3

St. Kambot Along its course, the river is cut into several segments by irrigation strucutres such as: Koas Khsach, Voat Leab, Preah Mlu, etc. These irrigation schemes are located downstream of the National Road No. 5. However, during the high water level, the regulator s seem not to be a barrier to the fish migration, because of a general flood over the area. Therefore fishes are able to bypass the structures during the upstream

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migration. This phenomenon could also help enriching rice field fishery, which is commonly observed by the consultant in this area. Further upstream, the Krouch Sach irrigation is the only irrigation structure with fishway found by the consultant in the studied areas. This fishway seems to be very effective, as local communities around this structure reported high fish yield at up stream of this structure. This high yield is reported un-declined up to now. Based on consultant observation, the design of this scheme seems very helpful for fishery in the area. The fishway makes fish migration possible, while the structure increase more permanent water body, thus gives some additional benefit for fish refuge in dry season as well as to the local people, who usually fully exploit the impoundment for fishing. It is recommended that similar type of fishway should be installed in every irrigation structure that involve with blocking the river.

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8

Socio-economics

8.1

Data This section relates to ToR, Task 1: Collection of general data and information Related data

(submitted electronically)

Area-population.xls

Area and population (2002-04) within the study area; buffaloes, cows, horses, goats, pigs, and poultry; families using fertilizer; by province, district and commune

Cultivation-livestock.xls

Cultivation areas and livestock (2005), by province, district and commune

Agriculture-2006.xls

PRD survey Jul-Aug 2006: Cultivation practices; cropping cycles; labour input; livestock; use of fertilizers and pesticides; farmgate prices; obstacles to cultivation

Data and information is available from

8.2

•

government reports, official publications by various ministries, consultant reports, and other relevant available literature

•

previous studies carried out by ADB and WUP-FIN;

•

secondary data from a variety of sources including the National Institute of Statistics and the Ministry of Agriculture, Forestry, and Fisheries (MAFF), commune databases and various projects; and

•

surveys conducted under the present study in July-August 2006.

Socio-economic context This section relates to ToR, Task 19: Economic analysis of water utilization

The Dauntri Sub-basin covers an area of 3,680km2 in Battambang and Pursat Provinces. Around 45% of this area is in Battambang. Prevailing socio-economic conditions are described briefly below. Population and population growth rates

The Dauntri Sub-basin has an estimated population of around 237,013 (considerably larger than that of the Boribo basin) and is growing at a rate of around 1.5% (compared with the national rate of 2.5%) Migration rates vary from 2-3% in Pursat to 3-5% in Battambang. Income and poverty

Battambang is one of the least poor provinces bordering The Great Lake. It is estimated that around 40% of the population lives below the consumption-based poverty line (MRC, 2003) in Pursat, while the population of Battambang is relatively better off with around 26% of the population living in poverty. The difference in poverty levels between the provinces may be attributed to the proximity of Battambang to important trade posts and employment opportunities along the Thai border.

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Average gross household cash income among households surveyed in the Dauntri Sub-basin is US$666 per year (or US$128 per person) compared to average national GDP per capita in 2004 of around US$363 (ADB, 2006). The difference in cash income between the two basins is due to (i) much lower off-farm income and (ii) lower income from livestock sales in Dauntri basin. This figure also assumes that 40% of the total annual rice yield is sold. Table 8.1: Sources of cash income in each sub-basin Income source

Boribo

Dauntri

US$ per household per year

US$ per household per year

Paddy cultivation

14

242

Livestock

308

147

Fish sales

1

27

6

21

301

75

Poultry sales Other sources of on-farm income Off-farm income

53

153

Total:

682

666

Source: Data from household surveys

The table clearly shows the dependency of households in the sub-basin on their land as their main source of wealth 3 and highlights their vulnerability to the impacts of drought and severe floods. Note again that the income levels shown in Figure 8.1 do not account for the costs associated with undertaking these incomegenerating activities. Unlike the Boribo Sub-basin, however, crop production is the largest contributor to household income in the Dauntri basin, providing around 40% of total household income from paddy cultivation alone. The sale of supplementary crops such as pineapples and vegetables is an important source of cash income. Figure 8.1: Household income structure

Average household cash income (2005)

23% 37%

Paddy cultivation Livestock Poultry Fisheries

11%

Paid work 4%

Off-farm 3%

22%

Source: project survey data

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Employment

All the households surveyed are engaged in agriculture as the main source of employment. However, there are more possibilities for employment outside of agriculture in Battambang as evidenced by the fact that around 25% of the provincial population is employed in the services sector and 4% in the industrial sector (MRC, 2003). In Pursat, only 17% of the labour force is employed outside of agriculture. As in the Boribo Sub-basin, seasonal migration is a common phenomenon with around 30-40% of households in the study area having at least one member employed in either Phnom Penh or market towns along the Thai border for up to 8 months of the year. Women working in garment factories in Phnom Penh are able to earn US$30 per month while men working in the Thai border areas earn up to US$60 per month, providing an important source of supplementary cash income to households. Access to water and sanitation

The Dauntri Sub-basin population has poor access to safe water and sanitation facilities. At the time of the last census in 1998, it was estimated that only around 12% of the population in Pursat had access to safe water and sanitation (MRC, 2003). Households in Battambang province are twice as likely to have access to safe water supplies and three times as likely to have access to sanitation facilities, but it is believed that among rural households, these percentages are much lower. None of the households interviewed had piped water supplies, for example. The majority of the sub-basin population harvests rainwater during the wet season which is stored in large jars. This is supplemented with water collected from nearby rivers and streams. Water quality has not been reported as a problem but with growing populations of both humans and livestock, and increasing applications of chemical fertilizers and pesticides in agriculture, poor water quality may become an issue, especially in the dry season.

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Figure 8.2: Main sources of drinking water in Pursat and Battambang Provinces Main source of drinking water - Pursat Province

4% 0% 1% 5%

Piped

2%

Tube / piped w ell Protected dug w ell Unprotected dug w ell 40%

48%

Spring / river / stream Bought Other

Main sources of drinking water - Battambang Province

11%

1%

4%

Piped

19%

Tube / piped w ell 1%

Protected dug w ell Unprotected dug w ell Spring / river / stream

12% 52%

Bought Other

Data: UNDP (2006)

Health

The health of people living in the Dauntri Sub-basin is generally poor due to low levels of access to clean water and sanitation. Diarrhea related to poor water quality is common among children. Some households were reporting up to 10 incidences per child during the dry season. Child malnutrition is a major problem in Pursat where around half the child population is undernourished, and is significant in Battambang where around 38% of the child population suffers from the condition (MRC, 2003). Again, it is believed that poor diet, rather than food or rice shortages, is the main cause of malnutrition among children. Based on information provided by farmers during the field surveys, average annual rice yields are more than sufficient to meet family needs. On average, paddy farmers in the Dauntri Sub-basin have the potential to sell almost 8 tonnes per year.

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Land holdings

Findings from village surveys reveal that the average cultivated area per household is around 3 hectares (double that of Boribo). The relatively larger size of land holdings allows farmers to benefit more from economies of scale although the problems of poor soils and dry season water shortages restrict the types of crops that can be grown and the amount of land that can be put into production at any one time. Generally, households devote most of their cultivated area to wet season paddy as wet season yields tend to be higher than dry season yields. Literacy

Education and training standards are extremely low by developing country standards. Literacy in Pursat and Battambang provinces is around 80% for men but much lower (60%) for women. Less than 20% of the population complete primary school and less than 10% are educated to a secondary school level (MRC, 2003). Low levels of education limit the options available to households to diversify their livelihoods away from subsistence farming, again making them extremely vulnerable to factors affecting agricultural productivity. Physical infrastructure

National Road 5 between Pursat and Battambang bisects the sub-basin but otherwise the physical infrastructure serving villages in the Dauntri Sub-basin is relatively undeveloped and roads are poorly maintained. Most of the roads and cart tracks become impassable during the wet season, isolating many rural communities and limiting opportunities to market surplus agricultural produce. Rivers and streams are thus important transport conduits in the wet season, allowing people to travel between villages located near waterways. The proposed upgrade of the railway between Phnom Penh and Poipet may facilitate access by local farmers to markets in Battambang and along the Thai border, but only if the railway proves to be a more cost-effective means of transportation than road. Summary

The residents of Dauntri Sub-basin are predominantly poor rice farmers, but are relatively better off than those living in the Boribo Sub-basin. Not only are the soils here more suitable for agricultural production, resulting in higher yields, but average landholdings are also larger, which means that households are often able to sell up to 8 tonnes of rice per year. Supplementary crops are also easier to grow and nearly all production of such crops is for sale. Rural households do not have access to safe water supplies and consequently suffer poor health which also affects their agricultural productivity. Like the Boribo Subbasin, livestock raising is an important source of wealth but livestock health depends on the availability of sufficient water for drinking and fodder. Summary socio-economic indicators for Dauntri Sub-basin are presented in Table 8.2 below.

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Table 8.2: Summary socio-economic indicators for Pursat, Battambang and the study area Indicator

Daun Try / Svay Don Keo

Pursat Province#

Battambang Province#

Demographics Population Population growth rate (% p.a.) Population density (persons/km2) Migrant population (%) Health & welfare Infant mortality rate (per 1,000 live births) Proportion of population aged 014 (%) Child malnutrition (%) Ave household size GDP per capita (US$)

237,013

360,400

793,100

28.4

67.8

2.8

3.6

104

80

47.2

44.4

48.6

38.7

5.2

5.3

40.7

26.4

12.3

21.6

11.7

36.9

1.5 56

Ave household landholdings (ha) % of population living below consumption-based poverty line % of population with access to safe water supply % of population with access to sanitation Ave household livestock holdings (cows, buffaloes, pigs) Education Literacy rate (%) Primary attainment rate (%) Lower secondary attainment rate (%)

82.5 (male) 82.1 (male) 59.5 (female) 60.7 (female) 16.7 19.4 8

7.9

Labour force participation rate (%)

74.2

66.2

Agricultural Employment (%) Industrial Employment (%) Services Employment (%) Unemployment (%)

82.6 2.1 15.3 3.5

71 4.1 25 8

Employment

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Water utilization This section relates to ToR, Task 19: Economic analysis of water utilization

This section provides a snapshot of knowledge about current water use in the Dauntri Sub-basin. It identifies and quantifies (as far as possible) the water uses and services by socio-economic sector thereby providing some insight into the relative socio-economic importance of water uses to the sub-basin residents. The economic importance of each water use is analysed in Section 8.3. Irrigated agriculture and forestry

Water is essential to the agricultural sector for irrigation, drinking water for livestock and cleaning. It is estimated that around 46% of the total sub-basin area is under cultivation (Table 8.3), but only a small fraction of the cultivated area receives any form of irrigation. Table 8.3: Cultivated areas in Dauntri Sub-basin Total

Wet paddy

Dry paddy

Other crops

Basin area (ha)

354,190

Cultivated area (ha)

162,300

153,800

600

8,500

Percent of basin area

46

43

0.2

2.4

Irrigated area (ha)

2,320

1,720

600

Percent of total cultivated area

1.4

1.1

0.4

Source: Cultivated area by land use analysis (2005) (Table 2.2); distribution of cultivated area estimated from data contained in the commune database and collected from local authorities; irrigation areas according to Table 2.4

In the Dauntri Sub-basin, 10 to 50% of the commune areas are used for rice production. Wet season paddy is by far the predominant crop (see Figure 8.3) with la very small part of the cultivated area devoted to dry season paddy and other supplementary crops (Table 8.3) such as beans, pineapples, potatoes and other vegetables. Unlike the Boribo Sub-basin where supplementary crops are grown primarily for subsistence use, in the Dauntri Sub-basin they are grown primarily for sale. All the households interviewed reported experiencing drought for at least one month of the year, during which time both animal health and crop productivity suffer. Severe flooding appears to be less of an issue with only 20% of households reporting damages to crops and livestock during the floods of 2000. However, the impacts of flooding can be devastating. One household in Rung village (Boeng Khnar district) estimated its losses as 90% of crop value and 30% of livestock value during the floods of 2000. Irrigated agriculture is the largest user of water in the Dauntri basin, presently consuming around 204 million m3 per annum, compared to domestic and livestock uses which use 2 and 11 million m3 respectively. Most agriculture is rainfed with only around 2% of the total land area receiving any form of irrigation. However, where irrigation is possible, the benefits are substantial. The total potential irrigable area is estimated to be around 44,674 ha in the wet season and 303 ha in the dry season. This implies a reduction of dry season irrigation by around 55% from 470

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ha today while only 4% of the irrigation potential is being exploited in the wet season. Figure 8.3: Irrigated cropping areas in Dauntri Sub-basin Irrigation areas in Dauntry Basin (2005) 1%

1%

Wet paddy Dry paddy Supplementary crops

98%

Data from commune database and district authorities

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Table 8.4: Irrigated crop areas District

Commune

Paddy (ha) Wet paddy

Maung Reusey Maung Reusey Maung Reusey Maung Reusey Maung Reusey Maung Reusey Maung Reusey Maung Reusey Maung Reusey Maung Reusey Koas Krala Koas Krala Bakan Bakan Bakan Bakan Bakan Bakan Bakan Bakan Bakan Bakan Phnum Kravanh Phnum Kravanh Phnum Kravanh Sampov Meas Veal Veaeng Veal Veaeng

Maung Kear Prey Svay Reusey Krang Chrey Taloas Kokoah Robos Mongkol Prek Chik Prey Tralach Doun Ba Chhnal Moan Snam Preach Trapeangchong Boengbatkandol Boeng Khnar Metuek Outapoang Svaydaunkeo Khnar Totueng Rumlech Talor Bak Chenhchien Phteah Rung Samraong Lolok Sa Krapeu Pir Pramaoy

Total

Other Irrigation Crops (Ha)

Dry paddy

Corn

Potato

Bean

Sugar Cane

Pineapple Vegetable

9,009 3,500 7,562 8,650 4,019 4,830 5,180 5,340 4,000 3,500

4 3 .... 339 152 16 .... .... 3 ....

12 8 6 1 ….. ….. ….. ….. 6 132

10 6 2 ….. ….. ….. ….. ….. ….. 37

15 6 2 2 8 2 1 2 20 6

7 4 ….. ….. ….. ….. ….. ….. 6 4

7 4 ….. ….. ….. ….. ….. ….. 40 15

34 14 7 5 7 3 2 1 25 25

5,647 3,905 6,015 3,300 4,369 6,300 2,097 3,670 4,052 4,691

22 12 24 13 80 310 280 5 4 5

19 24 2 2 1 2 1 2 4 24

4 6 4 3 2 6 3 6 7 24

10 10 3 4 4 6 4 6 8 40

100 139 ….. ….. ….. ….. 1 1 1 49

4 8 3 10 12 22 16 10 36 65

6 10 ….. ….. 2 9 …. 11 9 8

99,636

1,272

246

120

159

312

252

178

*Note that these irrigation areas refer to the total commune area

Demands for irrigation water can be expected to increase over time as more food is required to support a growing population. It is difficult to predict exactly how much additional water will be required as much depends on the mix of crops grown, technological uptake and water-use efficiency. Access to markets, agricultural extension and the terms of trade offered to farmers will also impact agricultural productivity. Future demands for irrigation water (Table 8.5) are estimated based on the following assumptions: •

The full development of potential irrigation areas such that water utilization is limited by the water availability rather than by distribution capacity

•

Improvements in water and land-use efficiencies

•

A partial shift towards crops that are less water-consuming and more valuable than rice

During the course of the household surveys, all farmers interviewed noted water as a main constraint to cultivation while half said that lack of appropriate technology was an issue.

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Table 8.5: Future demands for irrigation in Dauntri basin

Irrigation demands

Present

Future

204 Mm3/year

356 Mm3/year

Forestry

47 percent of the Dauntri Sub-basin is covered by evergreen, semi-evergreen or deciduous forest (PRD Interpretation from Landsat ETM (2005). Agronomically, natural forest may be the largest consumer of water in the basin. The forest receives all of its required water from annual rainfall and by tapping residual soil moisture plus water from shallow aquifers during the dry season. Overall water consumption decreases in land denuded of forest and cultivated with annuals, but there will be an accompanying change in seasonal flows into the mainstream and possible long-term climate change effects (Nesbitt, 2005). Livestock

As noted earlier, livestock is regarded as both a source of income and as a livelihood safety net to be sold in response to shocks such as illness or expenses associated with marriage or death. Animal sales are a major source of income for subsistence farmers who see them as ‘banks’ for accumulation of wealth. Based on information from project surveys, around 89% of all households in the study area raise cows, and around 69% of all households raise pigs. Most households also raise chickens and/or ducks, with an average stock of 9 per household. However, there are 10-14 households in Svay Don Keo and Russey Krang communes who raise poultry on a commercial basis. Estimates of water consumption by large animals range from 50 to 120 litres of water per animal per day. Table 8.6 shows present livestock water demands based on both low and high estimates of daily water consumption.

Table 8.6: Present livestock water demands in Dauntri Sub-basin (2005)

Head

Buffalo Cows Pigs Poultry Total

20,057 64,297 40,333 386,026 510,713

Total Total annual Daily water Daily water Water annual water demand per demand per Water demands demands water animal (m3) - demands (m3) - (m3/s) - LOW animal (m3/s) demands HIGH (m3) - LOW HIGH HIGH (m3) - LOW 0.05 366,040 0.12 878,497 0.948 10.168 0.05 1,173,420 0.10 2,346,841 3.040 27.163 0.03 441,646 0.05 736,077 1.144 8.519 0.01 1,408,995 0.02 2,817,990 3.650 32.616 3,390,102 6,779,404

* Livestock numbers are based on a combination of project surveys and information contained in commune databases

Based on recent over-all changes in livestock population for Cambodia as a whole, it is possible to project future livestock demands, assuming that: •

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Animal population growth rates will remain more or less stable over the next 10 years

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•

Livestock productivity among subsistence farmers will not be heavily impacted by the spread of animal diseases such as avian influenza

•

Possible changes in market prices will not influence the holding patterns of subsistence farmers in Boribo Sub-basin

The figures in Table 8.7 are based on conservative (low) estimates of daily livestock water demands.

Table 8.7: Projected livestock water demands to 2030

2005 population Buffalo Cows Pigs Poultry Total

20,057 64,297 40,333 386,026 510,713

2030 population 8,023 99,660 57,475 916,812 1,081,969

2030 water 2030 annual water demand demands (m3) (m3/s) 146,416 0.005 1,818,801 0.058 629,346 0.020 3,346,363 0.106 5,940,926

Domestic consumption

Today, in the project area, with its large rural population, domestic water uses are limited by the infrastructure (withdrawal capacity and distribution capacity), and also, in some places and in part of the year, by the immediate raw water availability. Information from the household surveys revealed the following: •

Most households in the study area collect and store rainwater in large 225 litre jars during the wet season. Each household will have between 3 and 5 jars. The harvested rainwater is used for drinking and cooking only and will last until around Feb/March.

•

Bathing and washing is done in nearby rivers and ponds.

•

Those households living within 100 metres of rivers and streams tend to fetch drinking water from the nearest source. Households who have to collect water from streams or rivers generally spend about 1 hour per week doing so.

•

During the dry season households will either purchase water from delivery trucks (around 10,000 riel per load = 1,250 litres) in more built up areas, or fetch water from rivers in rural areas. Those households who cannot afford to pay for water are able obtain it from the nearest pagoda or community well.

Estimated daily water consumption in the Dauntri Sub-basin is around 50 litres per person, or a total of 11.5 million litres per day. This is high in comparison with estimates of per capita consumption for Cambodia as a whole – 20.7 litres per person per day in rural areas and 65.1 litres per person per day in urban areas (MRC Jun 03).

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Demands for domestic water are expected to increase over the coming years as a result of: •

Population growth, including the impacts of migration. Net migration may be negative, since there are no significant urban centres (such as provincial towns) in the study area. The possibility exists that at a certain stage, the population of the study area will stagnate, and, later on, decrease, reflecting an anticipated shift of livelihood opportunities from rural to urban areas, as well as new agricultural technologies with a much higher labour efficiency.

•

Increased per capita demand because of better education about the benefits of water for good hygiene

•

Improved lifestyles with more widespread use of water-using technologies and an expanded coverage of piped water supplies direct to each household

Assuming a conservative population growth rate of 0% per annum (low) and a more typical one of 2% (high) as well as an increase in per capita demands of between 1 and 2 litres per day per year until 2015, consumption levels are projected to be around the levels shown in Table 8.8. Based on these assumptions, domestic demand in 25 years’ time will be somewhere between 2 and 5 times the present demand. This is still a small part of the available water in the area, but the increase must be kept in mind in connection with the predicted increased demand for other purposes, particularly irrigation.

Table 8.8: Projected domestic consumption demands

Population Daily per capita consumption (litres)* Total annual demand (m m3)

2004

2030 (low)

2030 (high)

237,013

270,245

439,108

23

49

75

1.99

4.24

10.86

* assumes an increase of 1 litre per capita per day under the low growth scenario and 2 litres per capita per day under the high growth scenario. The present unit demand of 23 l/d is from TSBMO (Mar 03); the present population is from the Commune Database; other values are estimates

Fisheries

Fisheries in the Dauntri Sub-basin (like elsewhere in the Mekong basin) is enormously important both commercially and for subsistence livelihoods. Fish provide a vital source of nutrients to the people of the Tonle Sap and the surrounding area (Ahmed et. al., 1998) and are also an important component of households’ cash economy. Fish provide self-employment, wage employment (for men and women in the fishing lots on Tonle Sap Lake), direct nutrition, indirect nutrition, and other livelihood needs (by cash sale or barter for other produce). Both subsistence and commercial fishing takes place in the Dauntri Sub-basin. While most households are involved in subsistence fishing in the wet season (10 days per month in the wet season), only a very small number of villagers do any kind of commercial fishing. Around 30% of total fish catch is either sold or exchanged for rice.

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No data on fisheries productivity in the basin was collected for the purposes of this study, but based on studies by the MRC Fisheries Program, it is estimated that average consumption of fish and other aquatic products (OAP) in the Lower Mekong Basin as a whole is about 36 kg/person/year. Applying this figure to the population of Dauntri implies a present annual demand of around 8,500 tonnes.With a growing population (and assuming no change in diet), future demands are expected to rise to around 11,600 tonnes per year by 2030 (under a conservative population growth rate of 1.2%). Actual production estimates vary widely, and are subject to a number of methodological debates centred around whether catch or consumption should be used as the basis for measuring yield. The estimated fish yield of the Great Lake and the Tonle Sap river itself is as high as 139-190 kg/ha/year (by Van Zalinge et al 2001). Annual fish productivity in the Cambodian floodplains is estimated to be around 243kg/ha. This is a high-end estimate based on work near Phnom Penh by Dubeau et al 4 (see Beecham and Cross, 2005). The productivity and sustainability of fisheries – and hence their ability to meet rising demands - depends on a number of factors including: •

fishing practices

•

total fishing effort

•

river flows

•

barriers to migration

•

access to, and from floodplain habitats; and

•

the floodplain area that is inundated in the wet season, which in turn depends on the annual maximum flood height.

There is, as yet, no standard functional form for evaluating the impact of changes in river flow levels to changes in fisheries productivity but recent advances have, however, been made in modelling how fisheries productivity may be affected by changes in hydrological flow levels using indicators relating to habitat availability and migration (Beecham & Cross, 2005). Preserving the Mekong fishery is central to food security in the region. The wild fishery is particularly important for the poorest rural households, making significant contributions to their nutrition, food security and income (MRC, 2003). Industry

There are no significant industrial activities in the Dauntri Sub-basin at present. Future industrial development in the area is limited by the poor infrastructure network and generally low levels of education among sub-basin residents. It is not therefore expected to impact, or be impacted upon by, water availability.

4

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Dubeau, P., Poeu, O. and Sjorslev, J. (2001) Estimating fish and aquatic animal productivity /yield per area in Kampong Tralach: An integrated approach. http://www.mekonginfo.org/

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Navigation

The roads and tracks in the study area are generally very poor and virtually impassible during the wet season. Many villagers thus rely on waterborne transport when they need to travel beyond their own village in the wet season. Irrigation development in the sub-basin is not expected to impact upon river navigability during the wet season. Tourism and recreation

As mentioned in regard to the Boribo basin, Pursat province is the gateway to the Cardamom mountains and, together with its location not far from Phnom Penh, offers significant tourism potential. However, the poor condition of the access road (impassable during the wet season) and extremely limited tourist facilities are reflected in the low number of visitors to the region. Furthermore, access to the mountains is more likely to be developed further south of the Dauntri Sub-basin (i.e. through the Boribo Sub-basin) to minimise the distance between the mountainous area and National Road No. 5. Micro-hydropower

There are no known active or planned micro-hydropower schemes in the Dauntri basin. The scale of such schemes is such that, if implemented, they would have no impact upon water availability. Maintenance of aquatic ecosystems for livelihood support and environmental sustainability

Apart from the direct use value that rivers provide in the form of water for irrigation, livestock, domestic and industrial consumption and fisheries production, they are also important for the maintenance of aquatic ecosystems. Riverine ecosystems in Cambodia support a highly diverse aquatic animal and plant community, many of which are valuable foods and medicines for rural households. Summary

As is the case with the Boribo basin, agriculture is also the biggest user of water in the Dauntri Sub-basin and is likely to expand its share of water demand significantly if the basin’s irrigation potential is fully exploited (Figure 8.4). Domestic demands are almost insignificant by comparison (in terms of volume), although they are important in value. With the available data, it is not possible to quantify industrial demands but these are negligible at present and expected to continue to be so. Instream demands (such as fisheries and ecology) are also difficult to quantify, not least of all because the relationships between productivity and water flows are generally not yet well understood. Note how the profile of demand is almost identical to that of Boribo, the scale of total demand is up to three times greater even though the per capita and per unit area demands are the same.

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Figure 8.4: Present and future composition of major extractive water demands

Present and future composition of extractive water demands in the Dauntry Basin

Million cubic metres

400 350 300 250

Present

200

Future

150 100 50 0 Livestock

8.4

Irrigation

Domestic

Economic analysis This section relates to ToR, Task 19: Economic analysis of water utilization

This section attempts to quantify, in monetary terms, the value of water uses in the Dauntri Sub-basin. Irrigated agriculture

The value of water used for irrigation can be broadly estimated by determining the net value of irrigated crop harvests. Wet season paddy is the principal crop. with only relatively small areas of dry season paddy and other supplementary crops receiving any form of irrigation. Supplementary crops are, however, more widely grown in Dauntri than in Boribo, and all output is sold. The valuation approach can be summarised as follows:

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•

Although a large share of production is for subsistence, using economic prices for all irrigated crops is justified on the basis that farmers would otherwise need to acquire these products in the market.

•

Values are calculated per hectare and per household on the basis of the net profits to farmers once production costs have been accounted for.

•

Crop production costs were not widely available for supplementary crops and thus estimates of the approximate returns to production were based on limited information from reports containing farm production budgets. Using this information, production costs are estimated at around 75% for fruit and vegetables. This takes into account both the direct costs of crop production and the opportunity cost of family labour and land.

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Table 8.9: Crop budget summary for Dauntri Sub-basin Unit Irrigated area ha Yield t/ha Price US$/kg Gross value US$/ha Production costs Seed US$/ha Labour US$/ha Fertiliser US$/ha Pesticide US$/ha Water US$/ha Pumping costs US$/ha US$/ha Net crop income Cultivated area per househo ha Ave h/hold income US$

1/ 2/ 3/ 4/ 5/ 6/ 7/

WS rice DS Rice Corn Potatoes Beans Sugarcane Pineapple Vegetables 99,636.00 1,272.00 246.00 120.00 159.00 312.00 252.00 178.00 2.20 3.70 2.00 2.00 2.00 16.40 10.00 2.00 0.12 0.12 0.09 0.27 0.69 0.11 0.24 0.19 264.00 444.00 185.06 546.01 1,378.67 1,818.18 2,355.89 372.16 139.09 87.38 138.80 409.50 1,034.00 1,363.64 1,766.92 279.12 12.00 12.00 97.50 45.00 17.81 17.81 0.00 0.79 11.78 11.78 124.91 2.25 280.88

356.62 0.03 10.24

46.27 0.01 0.26

136.50 0.00 0.37

344.67 0.00 1.24

454.55 0.01 3.20

588.97 0.01 3.35

93.04 0.00 0.37

Assumptions: Labour is valued at US$1.50 per day (both hired and family); wet season rice requires around 65 days of labour per ha Seed costs US$0.12 per kg. To cultivate 1 ha of rice requires approx 100kg of seed Fertiliser is applied at a rate of around 60kg/ha. One kg costs 1,232 riel Pesticides are applied at a rate of around 0.4 bottles per ha. One bottle costs 8.166 riel Yields for supplementary crops are based on MAFF (2004-5) statistics for Pursat Producer prices for supplementary crops are based on FAOStat database for Cambodia (2003) In the absence of detailed data, production costs for supplementary costs are assumed to be 75% of farmgate prices. This is consistent with values obtained from individual farm budget studies

Despite the low profitability of agriculture, it employs more than 80% of the workforce (in terms of person-days) and accounts for around 70% of total household income. In Dauntri district, the production and sale of supplementary crops provides a valuable source of income to households. Improving the irrigation system would allow more farmers to engage in dry season paddy production but is unlikely to have the desired effect on poverty unless irrigation improvements are accompanied by: •

investments in appropriate technologies (including higher yield varieties, more water efficient crops and cropping techniques, a shift to higher value crops)

•

agricultural extension (including marketing and value-adding), access to markets (including storage, transport infrastructure and the terms of trade offered to farmers)

•

some form of agricultural insurance for farmers who are prepared to diversify against the risks of external shocks and stresses such as drought and severe flooding

Livestock

As mentioned earlier, livestock is regarded as both a source of income and as a livelihood safety net. Animal sales are a major source of income for subsistence farmers who see them as ‘banks’ for accumulation of wealth. However, in most cases, livestock are only sold in times of need, for instance in response to shocks such as illness or expenses associated with marriage or death. The value added by water to livestock is estimated as follows: •

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value is not known, the net benefit values in Table 23 reflect the total value of livestock that water availability supports. They do not reflect the valueadded by water alone. •

The gross value of livestock to individual households is equivalent to the market value of total stock holdings (and not simply cash sales) at any given time

•

The net value of livestock includes the cost of purchase and raising

Table 8.10: Livestock value in Dauntri Sub-basin

Number of head in Dauntry basin

Cows Buffalo Pigs Poultry Total

1/ 2/ 3/ 4/ 5/ 6/ 7/ 8/

64,297 20,050 40,333 386,026 510,706

Raising Gross costs from Gross Net value to Net value value to Purchase time of Sales value value to the the basin to each each costs purchase (US$/head) basin (US$ (US$ household household (US$/head) to time of millions) millions) (US$) (US$) sale (US$/head) 289 289 108 3

19 6 4 1 30

420 131 99 25 674

169 169 24 0

0 0 36 0

7.75 2.42 1.94 1.12 13

175 55 44 25 298

Assumptions: Market price of chicken is 8000 riel/kg. Each head of chicken produces 1.5kg of meat Households purchase young cows and buffaloes (<3 years) at a cost of 600,000 - 800,000 riel. Households are able to sell mature cows and buffaloes (>3 years) at a price of 1,200, 000 riel. Costs of raising cows and buffalo are minimal (but not zero) Each household spends 2,000 riel per day on pig feed (for 2-3 pigs) or 1,000 riel per day per pig Replacement/purchase costs of poultry are zero. The poultry population regenerates itself. Households sell cows and buffalo on average once every 3 years Pigs are sold every 4-6 months

Information from the household surveys shows that on average, households earn around US$150 per year from the sale of livestock, but the net value of total holdings (shown in Table 8.10) is up to two times higher and provides an important safety net to these households in times of need. It is important to note that the water-related benefits presented above are believed to be overstated for the following reasons: •

They do not reflect the value-added by water alone, but rather the total net benefits of livestock, where water is just one of a number of inputs.

•

The full economic costs of livestock husbandry have not been considered. In practice, there are real costs associated with the feeding and care of animals, including provision of shelter, medication, etc.

During times of drought and severe flood, livestock productivity is adversely affected. Farmers interviewed in Psar and Melum communes reported losses of between 20-40% of their livestock during the floods of 2000. Livestock reportedly suffer ill-health during times of drought, which are an annual occurrence in Boribo Sub-basin. Although the diseases may not be fatal, they require expensive treatment which lowers the total net benefits that households are able to obtain from their livestock holdings.

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Domestic consumption

The value of water for household consumption is based on estimates of household willingness-to-pay (WTP). Most households in the study area collect and store rainwater in large 225 litre jars during the wet season. Each household will have between 3 and 5 jars. The harvested rainwater is used for drinking and cooking only and will last until around Feb/March, where after households either purchase water from vendors (in urban areas) or fetch it from rivers in rural areas. Those households who purchase water from vendors spend up to US$2 per m3 (information from household surveys). Those households who cannot afford to pay for water are able obtain it from the nearest pagoda or community well. Assuming that all households hold the same value for a reliable source of clean drinking water (regardless of ability to pay), the value of the benefits derived from drinking water can be set equivalent to the willingness-to-pay for water from vendors. Water also has significant real costs of supply. Various kinds of costs are involved (Briscoe, 1996; Cotton et al, 1991; Winpenny, 1994; Herrington, 1987; Rogers, Bhatia and Huber, 1997; Webster, 1998): •

Supply costs (the capital and recurrent costs associated with the installation of the necessary infrastructure required to treat, transport and provide service levels, operation and maintenance costs of this infrastructure and the depreciation costs which accrue over the life of the project as parts need to be repaired or upgraded).

•

Opportunity costs (the value of water in its next best alternative use). The size of the opportunity cost depends on the value of the water in its highest alternative current-use value.

•

Environmental costs (both direct and indirect, relating to the abstraction, distribution and use of the resource)

Together, the opportunity and supply or use costs make up what is commonly referred to as the ‘economic cost’ of water. Table 8.10 shows average tariffs and unit production costs for the Phnom Penh water supply authority. It is assumed that district authorities will face similar, if not higher unit production costs. Table 8.11: Average tariff and unit production costs Average tariff

Phnom Penh

Unit production cost

USD/m3

USD/m3

0.244

0.082

Source: ADB (2004): Water in Asian cities

Based on this information, the annual net benefits of domestic water supplies are estimated to be in the region of US$81 per household (Table 8.11).

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Table 8.12: Net benefits of domestic water supply

WTP Cost of provision Net benefit Net benefit per household

1/ 2/

Unit US$/m3 US$/m3 US$/m3

1.927711 0.082 1.845711

US$

80.57144

Assumptions: Vendors sell water for 10,000 riel per truck load (1,250 litres) The unit costs of production are based on data from Phnom Penh Water Supply Authority (ADB, 2004)

Fisheries

Net fishery values can be estimated as the yield, times average farm-gate price less the cost of harvesting or production. A very simplistic analysis of the potential gross value of fish in the Dauntri Subbasin is shown in the table below.

Table 8.13: Value of the potential fish yield in Dauntri Sub-basin

Area of water (ha) Fish productivity (kg/ha) Fish yield (kg) Fish value (US$) Fish value per ha (US$)

408 150 61,200 41,616 102

Assumptions: 1/ 2/ 3/

Ave fish density is uniform across all water bodies in the Boribo sub-basin Fish productivity is based on work by Van Zalinge et al (2001) Fish value is based on farmgate prices for capture fisheries (MRC, 2006)

To estimate the net value (i.e. sales value less costs of raising and production), the production costs are estimated to be around 30% of gross (or sales) value (MRC, 2006). This works out to approximately US$21,000. Standard functional forms for the evaluation of the relationship between water flows and the value of fish production (necessary to calculate the value added by water to the value of fisheries) are not readily available. However, productivity is known to be a function of multiple factors including:

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•

fishing practices

•

total fishing effort

•

river flows

•

barriers to river migration

•

access to and from floodplain habitats and habitat changes

Recent advances have, however, been made in modelling how fisheries productivity may be affected by changes in hydrological flow levels (MRC, 2005) using indicators relating to habitat availability and migration. However, the parameters required to calculate the productivity changes were not available for the project area at the time of this study. From a household perspective, the value of the fishery can be simply estimated on the basis of the value of household consumption and sales. If each household in Boribo Sub-basin is assumed to consume around 100kg per year, then the value of fish to each household is around US$70 per annum. Summary

The findings of the analysis above, suggest that – from a household perspective – agriculture is indeed the most valuable use of water (see Fig. 8.5). The net benefits per household are still low (< US$1 per day) but are significantly higher than in Boribo basin, owing primarily to higher yields and diversification beyond rice to cash crops. Livestock raising provides equivalent net worth in terms of the average value of livestock held by each household.

Figure 8.5: Value added by water to livelihoods in Dauntri Sub-basin

Net benefits (US$/household)

Value added by water to livelihoods in Dauntry/Svay Don Keo sub-basin

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350 300 250 200 150 100 50 0 Irrigated agriculture

Livestock

Domestic consumption

Fisheries

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Water user groups This section provides background information for ToR Task 17: Inventory of water users committees

Information on Water User Groups (WUGs) was collected from the PDWRAMs. The WUGs were established with support from the SEILA Program and PDWRAM. There are four WUGs in Daunti Sub-basin: 1

Kampang Water User Group. This Water User Group is already registered with MOWRAM. The WUG uses the water from Kampang irrigation system.

2

Boeng Kanthor Water User Group. This WUG is already registered with MOWRAM. The WUG uses the water from Boeng Kanthor reservoir.

3

Boeng Kan Seng WUG. This WUG is not yet registered. The WUG plans to use the water from Boeng Kanseng reservoir.

4

Prek Am WUG. This WUG is already registered with PDWRAM. The WUG uses the water from Prek Am irrigation system

Based on the field survey and interview, we found out that those WUGs do not work at all because: -

The irrigation scheme are not yet complete, it has only the main canal and the tributaries are not yet rehabilitated. So the supply of water for farmers are not efficient.

-

The water regulation does not work well

-

The capacity of the Water User Group Committee is limited

-

Lack of budget for O&M of the irrigation system because the community members are not willing to pay because of inefficient service of water supply.

For example in Prek Am WUG, the people said that they do not get any benefit from the irrigation scheme because in the wet season the cultivated areas mostly flooded and in the dry season this irrigation scheme is also dry up no water for irrigation. This is the main reason that people do not to participate in the Water User Group.

Table 8.14: Water User Groups in Dauntri Sub-basin No

Community

Province

District

Commune

Registered

1

Kampang

Pursat

Bakan

Svaydaunkeo

yes

2

Boeng Kanthor

Pursat

Bakan

Metoek

yes

3

Boeng Kanseng

Pursat

Bakan

Otapourng

Not yet

4

Prek Am

Battambang

Moung Reiseiy

Robas Monkul

yes

Data: PDWRAM in Pursat and Battambang province

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References (References marked 'EL' are available in the Electronic Library) CTI and DHI (Aug 03): Consolidation of hydro-meteorological data and multi-functional hydrological roles of Tonle Sap Lake and its vicinities, Phase II. Final reports. CTI Engineering International Co., Ltd. and DHI – Water & Environment. Client: Mekong River Commission (EL) CTI (May 04): Consolidation of hydro-meteorological data and multi-functional hydrological roles of Tonle Sap Lake and its vicinities, Phase III. Final report. CTI Engineering International Co., Ltd. And DHI – Water & Environment. Client: Mekong River Commission (EL) Halcrow (Dec 03): Ranking criteria report. Irrigation Rehabilitation Study in Cambodia, prepared for the Mekong Secretariat by Sir William Halcrow and Partners Ltd. in association with Mandala Agricultural Development Corporation. Contract CAM.IRS 238.93, UNDP Grant 3.3.37/92/UNP, B/L 21 Halcrow (Apr 04): Inventory & analysis of existing systems. Volume 1: Main report; Volume 2: Banteay Meanchey, Battambang, Kampot, Kandal; and Volume 6: Pursat, Siem Reap, Svay Rieng, Takeo. Irrigation Rehabilitation Study in Cambodia, prepared for the Mekong Secretariat by Sir William Halcrow and Partners Ltd. in association with Mandala Agricultural Development Corporation. Contract CAM.IRS 238.93, UNDP Grant 3.3.37/92/UNP, B/L 21 Halcrow (Jun 04): Final report: Main report; Annex A: Hydrology; Annex B: Agronomy; Annex C: Lowland rice soils of Cambodia; Annex D: Socio-economics; and Annex F: Environmental assessment. Irrigation Rehabilitation Study in Cambodia, prepared for the Mekong Secretariat by Sir William Halcrow and Partners Ltd. in association with Mandala Agricultural Development Corporation. Contract CAM.IRS 238.93, UNDP Grant 3.3.37/92/UNP, B/L 21 JICA and MRD (May 02): The study on groundwater development in Central Cambodia. Final report prepared for Japan International Cooperation Agency and Ministry of Rural Development, Cambodia, by Kokusai Kogyo Co. Ltd. MOWRAM (March 2002): Smallholder water and land management in Cambodia. Prepared for Ministry of Water Resources and Meteorology with the assistance of M. P. Mosley as Project Report 5 under the North West Irrigation Sector Project, Part A: Capacity-building in Ministry of Water Resources and Meteorology, Cambodia, funded by ADB (TA 3758-CAM) MRC-BDP (Nov 05): National Sector Reviews. BDP Library Volume 13, October 2004, revised November 2005. Mekong River Commission MRC-WUP-JICA (Mar 04a): The study on hydro-meteorological monitoring for water quantity rules in Mekong River Basin. Final report, Volume I (Main report), prepared by CTI and Nippon Koei (EL) MRC-WUP-JICA (Mar 04b): The study on hydro-meteorological monitoring for water quantity rules in Mekong River Basin. Final report, Volume 2a (supporting documents 1: Improvement of hydrological stations; 2: Gap filling of rainfall data; 3: Hydrological monitoring; 4: Development of hydro-hydraulic model for the Cambodian floodplains; 5: Application of hydro-hydraulic model; and 6: Water use in the Lower Mekong Basin), prepared by CTI and Nippon Koei (EL) MRC-WUP-JICA (Mar 04c): The study on hydro-meteorological monitoring for water quantity rules in Mekong River Basin. Final report, Volume 2b (supporting documents 7: Maintenance of flows on the Mekong mainstream; 8: institutional strengthening; and 9: Water use management), prepared by CTI and Nippon Koei (EL) MRC-WUP-JICA (Mar 04d): The study on hydro-meteorological monitoring for water quantity rules in Mekong River Basin. Final report, Volume III (Summary), prepared by CTI and Nippon Koei (EL) Le van Sanh (June 02): Mission Report, Analysis of Hydrological Data at Stations around the Great Lake and on Mekong, Bassac Rivers in 1960s and from 1998 to 2001. Phnom Penh Nanni, Marcella (April 2001): End of assignment report, submitted to MOWRAM (Cambodia) by SMEC International Pty. Ltd. under the Agricultural Hydraulics Component of the Agricultural Productivity Improvement Project Nhim Sophea (Mar 06): Water quality data assessment 2005, MRC water quality monitoring network. Water Quality Office, Department of Hydrology and River Works, MOWRAM OADA (Mar 03): Study report on Kamping Puoy Irrigation Scheme Rehabilitation project in Battambang Province, the Kingdom of Cambodia. Overseas Agricultural Development Association WUP-FIN (Aug 02b): Data report. MRC Water Utilization Program, WUP-FIN component - Modelling of the flow regime and water quality of the Tonle Sap Karri Eloheimo, Seppo Hellsten, Teemu Jantunen, Janos Jozsa, Mikko Kiirikki, Hannu Lauri, Jorma Koponen, Juha Sarkkula, Olli Varis, and Markku Virtanen (EL)

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Appendix 2: Data files Note: The data files are submitted separately

Table A2.1: Time series data File name

Contents

[email protected]

Daily, monthly and annual rainfall at Battambang (8 years), Kg Chhnang (55 years), Pursat (60 years), Krakor (36 years), Kravanh (10 years), Svay Donkeo (6 years), Talo (6 years), Bamnak (15 years) and Boeung Khnar (7 years)

R@Pursat-12-05

Daily and monthly rainfall data from Pursat 1912-2005 (53 years), with summary statistics

[email protected]

Monthly rainfall data from 16 stations from 2001-2004 (4 years), with summary statistics

[email protected]

Monthly rainfall data from Battambang, Pursat and Kg Chhnang, from 1939, 1996, and 2001-05 (7 years)

[email protected]

Daily and monthly evaporation at Pochentong 2000-04 and Siem Reap 1996-2000

[email protected]

Daily water level at Kg Chhnang 1995-2004 (10 years)

[email protected]

Daily water level at Prek Kdam 1995-2004 (10 years)

[email protected]

Daily and monthly flow at Prek Kdam 1964-73 (10 years)

[email protected]

Daily water level and calulated flow at Boribo (St. 590101) Jun 98 - Dec 05 (7.5 years)

[email protected]

Daily water level and calulated flow at Maung Russey (St. Dauntri) (St. 5501101) Jun 01 - Dec 02 (1.5 years)

[email protected]

Flow records from St. Boribo (91 months), St. Dauntri (19 months), and St. Pursat (72 and 58 months)

Table A2.2a: Data tables: Geography. livelihoods File name

Contents

Area-population.xls

Area and population (2002-04) within the study area; buffaloes, cows, horses, goats, pigs, and poultry; families using fertilizer; by province, district and commune

Communes-catchments.xls

Commune areas within each sub-catchment

Elevations.xls

Distribution of land elevation within each sub-basin

Forestcover.xls

Forest cover within each sub-basin (1993, 1997, 2002, 2005), and rate of change

Soils.xls

Soil classification in each sub-basin

Geology.xls

Geological classification of each sub-basin

Protectedareas.xls

Protected areas in each sub-basin

Agriculture-2006.xls

PRD survey Jul-Aug 2006: Cultivation practices; cropping cycles; labour input; livestock; use of fertilizers and pesticides; farmgate prices; obstacles to cultivation

B-farming-econ-03-05.xls

Boribo sub-basin, PRD survey Jul-Aug 2006: Economy of farming households (2003-05)

Table A2.2b: Data tables: Water uses File name

Contents

Domesticdemand.xls

Present and projected domestic water demand in each sub-basin

Irrigation.xls

Wet and dry season irrigated areas, actual and potential, in each sub-basin

Subprojects.xls

Water availability for candidate sub-projects, and irrigable areas

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Table A2.2c: Data tables: Water balance File name

Contents

Monitoringstations.xls

Rainfall, water level and flow monitoring stations inside or near the study area

B-W-balance-4of5yrs.xls

Boribo Sub-basin, calculated water balance, present conditions, with water uses and availability, in 4 out of 5 years, whole sub-basin and details

B-W-balance-scenarios.xls

Boribo Sub-basin, calculated water balance, alternative scenarios: Increased domestic consumption, 50-50 and 100-0 diversion at Bamnak, and impact of climate change

D-W-balance-4of5yrs.xls

Dauntri Sub-basin, calculated water balance, present conditions, with water uses and availability, in 4 out of 5 years, whole sub-basin and details

D-W-balance-scenarios.xls

Dauntri Sub-basin, calculated water balance, alternative scenarios: Damnak Ampil Canal, candidate sub-projects, and impact of climate change

Wells.xls

Inventory of groundwater wells and yield

Wells-KgChhnang.xls

Inventory of groundwater wells in Kg Chhnang, with yield and geological layers

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Appendix 3: Water management structures St. Dauntri (St. Moung)

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St. Svay Donkeo

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St. Kambot (Preahmlu)

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Appendix 4: Water balance tables Note: The water balance tables are also submitted as electronic data files

Table A4.1: Summary water balance, base situation Base situation Rainfall [m3/s]

3.9 4.9 45.2 84.6 163.2 143.6 151.4 197.7 256.7 246.8 121.0 19.7 119.9

January February March April May June July August September October November December Yearly

Evaporation Storage and Water losses availability [m3/s] [m3/s] [m3/s]

19.6 7.1 45.2 84.6 135.7 126.9 111.1 98.3 77.7 85.6 102.3 78.3 81.0

-19.2 -4.4 -3.4 -3.4 24.2 10.3 -7.7 -12.3 29.4 50.6 -15.3 -67.5 0.1

3.6 2.2 3.4 3.4 3.4 6.4 48.0 111.6 149.6 110.6 34.0 8.8 38.8

Domestic uses [m3/s]

0.066 0.066 0.066 0.066 0.066 0.066 0.066 0.066 0.066 0.066 0.066 0.066 0.066

Irrigation uses [m3/s]

1.466 1.466 2.933 2.933 2.933 2.933 12.489 12.489 12.489 12.489 12.489 1.466 6.548

Livestock Outflow uses from catchment [m3/s] [m3/s]

0.360 0.360 0.360 0.360 0.360 0.360 0.360 0.360 0.360 0.360 0.360 0.360 0.360

1.7 0.3 0.0 0.0 0.0 3.0 35.1 98.7 136.7 97.7 21.0 6.9 31.8

Table A4.2: Summary water balance, base situation with Damnak Ampil Canal Scenario with Damnak Ampil channel included Rainfall [m3/s] January February March April May June July August September October November December Yearly

Version 2

3.9 4.9 45.2 84.6 163.2 143.6 151.4 197.7 256.7 246.8 121.0 19.7 119.9

Evaporation Storage and Water losses availability [m3/s] [m3/s] [m3/s]

19.6 7.1 45.2 84.6 135.7 126.9 111.1 98.3 77.7 85.6 102.3 78.3 81.0

-24.2 -8.6 -6.6 -7.5 17.3 -1.5 -22.7 -27.3 14.4 35.6 -25.9 -75.7 -11.1

8.6 6.4 6.6 7.5 10.2 18.2 63.0 126.6 164.6 125.6 44.6 17.1 49.9

Domestic uses [m3/s]

0.066 0.066 0.066 0.066 0.066 0.066 0.066 0.066 0.066 0.066 0.066 0.066 0.066

Irrigation uses [m3/s]

1.466 1.466 2.933 2.933 2.933 2.933 12.489 12.489 12.489 12.489 12.489 1.466 6.548

Livestock Outflow uses from catchment [m3/s] [m3/s]

0.360 0.360 0.360 0.360 0.360 0.360 0.360 0.360 0.360 0.360 0.360 0.360 0.360

6.7 4.5 3.2 4.2 6.9 14.8 50.1 113.7 151.7 112.7 31.7 15.2 42.9

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Table A4.3: Summary water balance with Damnak Ampil Canal and candidate sub-projects Scenario with Damnak Ampil Channel and Candidate projects included Rainfall [m3/s]

3.9 4.9 45.2 84.6 163.2 143.6 151.4 197.7 256.7 246.8 121.0 19.7 119.9

January February March April May June July August September October November December Yearly

Evaporation Storage and Water losses availability [m3/s] [m3/s] [m3/s]

19.6 7.1 45.2 84.6 135.7 126.9 111.1 98.3 77.7 85.6 102.3 78.3 81.0

-24.2 -8.8 -7.0 -7.9 16.9 -1.5 -22.7 -27.3 14.4 35.6 -26.4 -75.7 -11.2

8.6 6.6 7.0 7.9 10.6 18.2 63.0 126.6 164.6 125.6 45.1 17.1 50.1

Domestic uses [m3/s]

0.066 0.066 0.066 0.066 0.066 0.066 0.066 0.066 0.066 0.066 0.066 0.066 0.066

Irrigation uses [m3/s]

Livestock Outflow uses from catchment [m3/s] [m3/s]

1.866 1.866 3.333 3.333 3.333 3.333 23.689 23.689 23.689 23.689 23.689 1.866 11.448

0.360 0.360 0.360 0.360 0.360 0.360 0.360 0.360 0.360 0.360 0.360 0.360 0.360

6.3 4.3 3.2 4.2 6.9 14.4 38.9 102.5 140.5 101.5 20.9 14.8 38.2

Table A4.4: Summary water balance with Damnak Ampil Canal, candidate sub-projects and climate change Scenario with Damnak Ampil Channel and Candidate projects and climate change included Rainfall [m3/s] January February March April May June July August September October November December Yearly

Version 2

3.9 4.9 45.2 84.6 163.2 143.6 151.4 197.7 256.7 246.8 121.0 19.7 119.9

Evaporation Storage and Water losses availability [m3/s] [m3/s] [m3/s]

19.6 7.1 45.2 84.6 135.7 126.9 111.1 98.3 77.7 85.6 102.3 78.3 81.0

-24.0 -8.8 -6.9 -7.9 17.0 2.3 -11.5 -20.1 21.3 41.2 -22.8 -75.2 -8.0

8.4 6.6 6.9 7.9 10.5 14.5 51.8 119.4 157.7 120.1 41.5 16.5 46.8

Domestic uses [m3/s]

0.066 0.066 0.066 0.066 0.066 0.066 0.066 0.066 0.066 0.066 0.066 0.066 0.066

Irrigation uses [m3/s]

1.866 1.866 3.333 3.333 3.333 3.333 23.689 23.689 23.689 23.689 23.689 1.866 11.448

Livestock Outflow uses from catchment [m3/s] [m3/s]

0.360 0.360 0.360 0.360 0.360 0.360 0.360 0.360 0.360 0.360 0.360 0.360 0.360

6.1 4.3 3.2 4.2 6.8 10.7 27.7 95.3 133.6 96.0 17.4 14.2 34.9

North West Irrigation Sector Project River basin and water use studies, Package 2

Table A4.5a: Water balance, base situation. Catchments 23, 25 and 26.

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 23 Base situation Area (km2): 196.3 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.17 0.21 0.00 0.0002 0.0000 0.0014 0.17 0.07 0.28 0.00 0.0002 0.0000 0.0014 0.07 0.03 2.49 0.00 0.0002 0.0000 0.0014 0.03 0.01 4.70 0.00 0.0002 0.0000 0.0014 0.01 0.02 9.04 0.00 0.0002 0.0000 0.0014 0.02 0.34 7.97 0.00 0.0002 0.0000 0.0014 0.34 2.66 8.40 0.00 0.0002 0.0000 0.0014 2.66 6.18 10.96 0.00 0.0002 0.0000 0.0014 6.18 8.29 14.24 0.00 0.0002 0.0000 0.0014 8.29 6.13 13.67 0.00 0.0002 0.0000 0.0014 6.13 1.86 6.69 0.00 0.0002 0.0000 0.0014 1.86 0.49 1.07 0.00 0.0002 0.0000 0.0014 0.49

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 25 Base situation Area (km2): 215.52 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.18 0.23 0.00 0.0001 0.0000 0.0003 0.18 0.07 0.31 0.00 0.0001 0.0000 0.0003 0.07 0.03 2.74 0.00 0.0001 0.0000 0.0003 0.03 0.01 5.16 0.00 0.0001 0.0000 0.0003 0.01 0.02 9.93 0.00 0.0001 0.0000 0.0003 0.02 0.38 8.75 0.00 0.0001 0.0000 0.0003 0.38 2.92 9.22 0.00 0.0001 0.0000 0.0003 2.92 6.79 12.04 0.00 0.0001 0.0000 0.0003 6.79 9.10 15.63 0.00 0.0001 0.0000 0.0003 9.10 6.73 15.01 0.00 0.0001 0.0000 0.0003 6.73 2.04 7.35 0.00 0.0001 0.0000 0.0003 2.04 0.54 1.17 0.00 0.0001 0.0000 0.0003 0.54

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 26 Base situation Area (km2): 154.5 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.13 0.17 0.00 0.0000 0.0000 0.0002 0.13 0.05 0.22 0.00 0.0000 0.0000 0.0002 0.05 0.02 1.96 0.00 0.0000 0.0000 0.0002 0.02 0.01 3.70 0.00 0.0000 0.0000 0.0002 0.01 0.01 7.12 0.00 0.0000 0.0000 0.0002 0.01 0.27 6.28 0.00 0.0000 0.0000 0.0002 0.27 2.09 6.61 0.00 0.0000 0.0000 0.0002 2.09 4.87 8.63 0.00 0.0000 0.0000 0.0002 4.87 6.52 11.21 0.00 0.0000 0.0000 0.0002 6.52 4.83 10.76 0.00 0.0000 0.0000 0.0002 4.83 1.46 5.27 0.00 0.0000 0.0000 0.0002 1.46 0.38 0.84 0.00 0.0000 0.0000 0.0002 0.38

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Table A4.5b: Water balance, base situation. Catchments 24, 8 and 2

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 24 Base situation Area (km2): 6.16 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.01 0.01 0.31 0.0000 0.0000 0.0000 0.32 0.00 0.01 0.13 0.0000 0.0000 0.0000 0.13 0.00 0.08 0.05 0.0000 0.0000 0.0000 0.05 0.00 0.15 0.02 0.0000 0.0000 0.0000 0.02 0.00 0.28 0.03 0.0000 0.0000 0.0000 0.03 0.01 0.25 0.64 0.0000 0.0000 0.0000 0.65 0.08 0.26 5.02 0.0000 0.0000 0.0000 5.10 0.19 0.34 11.66 0.0000 0.0000 0.0000 11.85 0.26 0.45 15.63 0.0000 0.0000 0.0000 15.89 0.19 0.43 11.56 0.0000 0.0000 0.0000 11.75 0.06 0.21 3.51 0.0000 0.0000 0.0000 3.56 0.02 0.03 0.92 0.0000 0.0000 0.0000 0.93

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 8 Base situation Area (km2): 155.8 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.13 0.17 0.49 0.0019 0.0000 0.0098 0.61 0.05 0.23 0.19 0.0019 0.0000 0.0098 0.24 0.02 1.98 0.08 0.0019 0.0210 0.0098 0.06 0.01 3.73 0.03 0.0019 0.0210 0.0098 0.01 0.01 7.18 0.05 0.0019 0.0210 0.0098 0.03 0.27 6.33 1.00 0.0019 0.0210 0.0098 1.23 2.11 6.67 7.76 0.0019 1.3060 0.0098 8.55 4.91 8.70 18.03 0.0019 1.3060 0.0098 21.62 6.58 11.30 24.18 0.0019 1.3060 0.0098 29.44 4.87 10.85 17.88 0.0019 1.3060 0.0098 21.43 1.48 5.31 5.42 0.0019 1.3060 0.0098 5.58 0.39 0.85 1.42 0.0019 0.0000 0.0098 1.80

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 2 Base situation Area (km2): 366.54 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.31 0.40 0.61 0.0137 0.1100 0.0603 0.74 0.13 0.53 0.24 0.0137 0.1100 0.0603 0.18 0.05 4.65 0.06 0.0137 0.2300 0.0603 0.00 0.02 8.77 0.01 0.0137 0.2300 0.0603 0.00 0.03 16.88 0.03 0.0137 0.2300 0.0603 0.00 0.64 14.89 1.23 0.0137 0.2300 0.0603 1.57 4.97 15.69 8.55 0.0137 1.3900 0.0603 12.06 11.55 20.47 21.62 0.0137 1.3900 0.0603 31.71 15.48 26.59 29.44 0.0137 1.3900 0.0603 43.45 11.45 25.52 21.43 0.0137 1.3900 0.0603 31.42 3.47 12.50 5.58 0.0137 1.3900 0.0603 7.59 0.91 1.99 1.80 0.0137 0.1100 0.0603 2.52

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Table A4.5c: Water balance, base situation. Catchments 1, 17 and 21

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 1 Base situation Area (km2): 184.8 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.16 0.20 0.74 0.0012 0.0000 0.0047 0.89 0.06 0.27 0.18 0.0012 0.0000 0.0047 0.23 0.03 2.35 0.00 0.0012 0.1100 0.0047 0.00 0.01 4.42 0.00 0.0012 0.1100 0.0047 0.00 0.02 8.51 0.00 0.0012 0.1100 0.0047 0.00 0.32 7.51 1.57 0.0012 0.1100 0.0047 1.77 2.51 7.91 12.06 0.0012 0.8700 0.0047 13.69 5.82 10.32 31.71 0.0012 0.8700 0.0047 36.65 7.80 13.40 43.45 0.0012 0.8700 0.0047 50.38 5.77 12.87 31.42 0.0012 0.8700 0.0047 36.31 1.75 6.30 7.59 0.0012 0.8700 0.0047 8.46 0.46 1.01 2.52 0.0012 0.0000 0.0047 2.98

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 17 Base situation Area (km2): 503.89 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.43 0.55 0.00 0.0036 0.0300 0.0199 0.38 0.17 0.73 0.00 0.0036 0.0300 0.0199 0.12 0.07 6.40 0.00 0.0036 0.2840 0.0199 0.00 0.03 12.06 0.00 0.0036 0.2840 0.0199 0.00 0.04 23.21 0.00 0.0036 0.2840 0.0199 0.00 0.88 20.47 0.00 0.0036 0.2840 0.0199 0.57 6.83 21.56 0.00 0.0036 0.5070 0.0199 6.30 15.87 28.14 0.00 0.0036 0.5070 0.0199 15.34 21.28 36.55 0.00 0.0036 0.5070 0.0199 20.75 15.74 35.09 0.00 0.0036 0.5070 0.0199 15.21 4.77 17.18 0.00 0.0036 0.5070 0.0199 4.24 1.25 2.74 0.00 0.0036 0.0300 0.0199 1.20

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 21 Base situation Area (km2): 412.57 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.35 0.45 0.00 0.0063 0.1110 0.0394 0.19 0.14 0.60 0.00 0.0063 0.1110 0.0394 0.00 0.06 5.24 0.00 0.0063 0.1120 0.0394 0.00 0.02 9.87 0.00 0.0063 0.1120 0.0394 0.00 0.04 19.00 0.00 0.0063 0.1120 0.0394 0.00 0.72 16.76 0.00 0.0063 0.1120 0.0394 0.56 5.59 17.66 0.00 0.0063 0.2910 0.0394 5.26 13.00 23.04 0.00 0.0063 0.2910 0.0394 12.66 17.42 29.92 0.00 0.0063 0.2910 0.0394 17.09 12.89 28.73 0.00 0.0063 0.2910 0.0394 12.55 3.91 14.06 0.00 0.0063 0.2910 0.0394 3.57 1.03 2.24 0.00 0.0063 0.1110 0.0394 0.87

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Table A4.5d: Water balance, base situation. Catchments 20, 18 and 15

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 20 Base situation Area (km2): 45.26 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.04 0.05 0.19 0.0008 0.0260 0.0049 0.20 0.02 0.07 0.00 0.0008 0.0260 0.0049 0.00 0.01 0.57 0.00 0.0008 0.0790 0.0049 0.00 0.00 1.08 0.00 0.0008 0.0790 0.0049 0.00 0.00 2.08 0.00 0.0008 0.0790 0.0049 0.00 0.08 1.84 0.56 0.0008 0.0790 0.0049 0.56 0.61 1.94 5.26 0.0008 0.2130 0.0049 5.65 1.43 2.53 12.66 0.0008 0.2130 0.0049 13.87 1.91 3.28 17.09 0.0008 0.2130 0.0049 18.78 1.41 3.15 12.55 0.0008 0.2130 0.0049 13.75 0.43 1.54 3.57 0.0008 0.2130 0.0049 3.78 0.11 0.25 0.87 0.0008 0.0260 0.0049 0.95

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 18 Base situation Area (km2): 27.52 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.02 0.03 0.20 0.0010 0.1230 0.0045 0.10 0.01 0.04 0.00 0.0010 0.1230 0.0045 0.00 0.00 0.35 0.00 0.0010 0.1910 0.0045 0.00 0.00 0.66 0.00 0.0010 0.1910 0.0045 0.00 0.00 1.27 0.00 0.0010 0.1910 0.0045 0.00 0.05 1.12 0.56 0.0010 0.1910 0.0045 0.41 0.37 1.18 5.65 0.0010 0.5940 0.0045 5.42 0.87 1.54 13.87 0.0010 0.5940 0.0045 14.13 1.16 2.00 18.78 0.0010 0.5940 0.0045 19.34 0.86 1.92 13.75 0.0010 0.5940 0.0045 14.01 0.26 0.94 3.78 0.0010 0.5940 0.0045 3.44 0.07 0.15 0.95 0.0010 0.1230 0.0045 0.89

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 15 Base situation Area (km2): 24.32 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.02 0.03 0.47 0.0008 0.1030 0.0039 0.39 0.01 0.04 0.12 0.0008 0.1030 0.0039 0.02 0.00 0.31 0.00 0.0008 0.1640 0.0039 0.00 0.00 0.58 0.00 0.0008 0.1640 0.0039 0.00 0.00 1.12 0.00 0.0008 0.1640 0.0039 0.00 0.04 0.99 0.98 0.0008 0.1640 0.0039 0.85 0.33 1.04 11.72 0.0008 0.5100 0.0039 11.54 0.77 1.36 29.48 0.0008 0.5100 0.0039 29.73 1.03 1.76 40.09 0.0008 0.5100 0.0039 40.60 0.76 1.69 29.22 0.0008 0.5100 0.0039 29.46 0.23 0.83 7.69 0.0008 0.5100 0.0039 7.40 0.06 0.13 2.09 0.0008 0.1030 0.0039 2.04

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Table A4.5e: Water balance, base situation, catchments 16, 19 and 14

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 16 Base situation Area (km2): 190.51 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.16 0.21 0.00 0.0058 0.0060 0.0316 0.12 0.07 0.28 0.00 0.0058 0.0060 0.0316 0.02 0.03 2.42 0.00 0.0058 0.1770 0.0316 0.00 0.01 4.56 0.00 0.0058 0.1770 0.0316 0.00 0.02 8.77 0.00 0.0058 0.1770 0.0316 0.00 0.33 7.74 0.00 0.0058 0.1770 0.0316 0.12 2.58 8.15 0.00 0.0058 0.2890 0.0316 2.26 6.00 10.64 0.00 0.0058 0.2890 0.0316 5.68 8.05 13.82 0.00 0.0058 0.2890 0.0316 7.72 5.95 13.27 0.00 0.0058 0.2890 0.0316 5.62 1.80 6.49 0.00 0.0058 0.2890 0.0316 1.48 0.47 1.04 0.00 0.0058 0.0060 0.0316 0.43

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 19 Base situation Area (km2): 121.68 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.10 0.13 0.00 0.0040 0.0070 0.0264 0.07 0.04 0.18 0.00 0.0040 0.0070 0.0264 0.00 0.02 1.54 0.00 0.0040 0.0760 0.0264 0.00 0.01 2.91 0.00 0.0040 0.0760 0.0264 0.00 0.01 5.60 0.00 0.0040 0.0760 0.0264 0.00 0.21 4.94 0.00 0.0040 0.0760 0.0264 0.11 1.65 5.21 0.00 0.0040 0.5030 0.0264 1.12 3.83 6.80 0.00 0.0040 0.5030 0.0264 3.30 5.14 8.83 0.00 0.0040 0.5030 0.0264 4.60 3.80 8.47 0.00 0.0040 0.5030 0.0264 3.27 1.15 4.15 0.00 0.0040 0.5030 0.0264 0.62 0.30 0.66 0.00 0.0040 0.0070 0.0264 0.27

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 14 Base situation Area (km2): 26.53 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.02 0.03 0.03 0.0004 0.0000 0.0023 0.05 0.01 0.04 0.00 0.0004 0.0000 0.0023 0.01 0.00 0.34 0.00 0.0004 0.0560 0.0023 0.00 0.00 0.64 0.00 0.0004 0.0560 0.0023 0.00 0.00 1.22 0.00 0.0004 0.0560 0.0023 0.00 0.05 1.08 0.05 0.0004 0.0560 0.0023 0.04 0.36 1.14 0.56 0.0004 0.3540 0.0023 0.56 0.84 1.48 1.65 0.0004 0.3540 0.0023 2.13 1.12 1.92 2.30 0.0004 0.3540 0.0023 3.07 0.83 1.85 1.63 0.0004 0.3540 0.0023 2.11 0.25 0.90 0.31 0.0004 0.3540 0.0023 0.20 0.07 0.14 0.13 0.0004 0.0000 0.0023 0.20

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Table A4.5f: Water balance, base situation. Catchments 10, 12 and 4

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 10 Base situation Area (km2): 95.48 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.08 0.10 0.56 0.0016 0.0190 0.0091 0.61 0.03 0.14 0.05 0.0016 0.0190 0.0091 0.05 0.01 1.21 0.00 0.0016 0.2330 0.0091 0.00 0.01 2.29 0.00 0.0016 0.2330 0.0091 0.00 0.01 4.40 0.00 0.0016 0.2330 0.0091 0.00 0.17 3.88 1.01 0.0016 0.2330 0.0091 0.93 1.29 4.09 14.36 0.0016 0.7040 0.0091 14.94 3.01 5.33 37.53 0.0016 0.7040 0.0091 39.83 4.03 6.93 51.39 0.0016 0.7040 0.0091 54.71 2.98 6.65 37.19 0.0016 0.7040 0.0091 39.46 0.90 3.25 9.09 0.0016 0.7040 0.0091 9.28 0.24 0.52 2.67 0.0016 0.0190 0.0091 2.88

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 12 Base situation Area (km2): 7397 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.06 8.05 0.03 0.0014 0.0130 0.0075 0.07 0.03 10.73 0.00 0.0014 0.0130 0.0075 0.01 0.01 93.89 0.00 0.0014 0.1420 0.0075 0.00 0.00 177.05 0.00 0.0014 0.1420 0.0075 0.00 0.01 340.68 0.00 0.0014 0.1420 0.0075 0.00 0.13 300.45 0.05 0.0014 0.1420 0.0075 0.03 1.00 316.54 0.56 0.0014 0.8880 0.0075 0.66 2.33 413.11 1.65 0.0014 0.8880 0.0075 3.08 3.12 536.51 2.30 0.0014 0.8880 0.0075 4.53 2.31 515.05 1.63 0.0014 0.8880 0.0075 3.05 0.70 252.16 0.31 0.0014 0.8880 0.0075 0.11 0.18 40.24 0.13 0.0014 0.0130 0.0075 0.29

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 4 Base situation Area (km2): 120.54 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.10 0.13 0.68 0.0014 0.0000 0.0073 0.78 0.04 0.17 0.06 0.0014 0.0000 0.0073 0.09 0.02 1.53 0.00 0.0014 0.1910 0.0073 0.00 0.01 2.89 0.00 0.0014 0.1910 0.0073 0.00 0.01 5.55 0.00 0.0014 0.1910 0.0073 0.00 0.21 4.90 0.96 0.0014 0.1910 0.0073 0.97 1.63 5.16 15.60 0.0014 1.2600 0.0073 15.97 3.80 6.73 42.91 0.0014 1.2600 0.0073 45.44 5.09 8.74 59.23 0.0014 1.2600 0.0073 63.06 3.77 8.39 42.51 0.0014 1.2600 0.0073 45.00 1.14 4.11 9.39 0.0014 1.2600 0.0073 9.26 0.30 0.66 3.17 0.0014 0.0000 0.0073 3.46

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Table A4.5g: Water balance, base situation. Catchments 6, 22 and 7

jan feb . mar apr may jun jul aug sep oct nov dec

Catchment 6 Base situation Area (km2): 103.63 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.09 0.11 0.00 0.0078 0.2010 0.0473 0.00 0.04 0.15 0.00 0.0078 0.2010 0.0473 0.00 0.01 1.32 0.00 0.0078 0.3240 0.0473 0.00 0.01 2.48 0.00 0.0078 0.3240 0.0473 0.00 0.01 4.77 0.00 0.0078 0.3240 0.0473 0.00 0.18 4.21 0.00 0.0078 0.3240 0.0473 0.00 1.40 4.43 0.00 0.0078 1.3360 0.0473 0.01 3.26 5.79 0.00 0.0078 1.3360 0.0473 1.87 4.38 7.52 0.00 0.0078 1.3360 0.0473 2.99 3.24 7.22 0.00 0.0078 1.3360 0.0473 1.85 0.98 3.53 0.00 0.0078 1.3360 0.0473 0.00 0.26 0.56 0.00 0.0078 0.2010 0.0473 0.00

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 22 Base situation Area (km2): 185.68 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.16 0.20 0.00 0.0074 0.1270 0.0436 0.00 0.06 0.27 0.00 0.0074 0.1270 0.0436 0.00 0.03 2.36 0.00 0.0074 0.1270 0.0436 0.00 0.01 4.44 0.00 0.0074 0.1270 0.0436 0.00 0.02 8.55 0.00 0.0074 0.1270 0.0436 0.00 0.32 7.54 0.00 0.0074 0.1270 0.0436 0.15 2.52 7.95 0.00 0.0074 0.4840 0.0436 1.98 5.85 10.37 0.00 0.0074 0.4840 0.0436 5.31 7.84 13.47 0.00 0.0074 0.4840 0.0436 7.31 5.80 12.93 0.00 0.0074 0.4840 0.0436 5.27 1.76 6.33 0.00 0.0074 0.4840 0.0436 1.22 0.46 1.01 0.00 0.0074 0.1270 0.0436 0.28

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 7 Base situation Area (km2): 330.56 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.28 0.36 0.00 0.0068 0.5900 0.0359 0.00 0.11 0.48 0.00 0.0068 0.5900 0.0359 0.00 0.05 4.20 0.00 0.0068 0.4160 0.0359 0.00 0.02 7.91 0.00 0.0068 0.4160 0.0359 0.00 0.03 15.22 0.00 0.0068 0.4160 0.0359 0.00 0.58 13.43 0.15 0.0068 0.4160 0.0359 0.26 4.48 14.15 1.98 0.0068 0.9900 0.0359 5.43 10.41 18.46 5.31 0.0068 0.9900 0.0359 14.69 13.96 23.98 7.31 0.0068 0.9900 0.0359 20.23 10.33 23.02 5.27 0.0068 0.9900 0.0359 14.56 3.13 11.27 1.22 0.0068 0.9900 0.0359 3.32 0.82 1.80 0.28 0.0068 0.5900 0.0359 0.47

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Table A4.6a: Water balance with Damnak Ampil Canal, catchments 23, 25 and 26

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 23 Scenario with Damnak Ampil channel included Area (km2): 196.3 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.17 0.21 0.00 0.0002 0.0000 0.0014 0.17 . 0.07 0.28 0.00 0.0002 0.0000 0.0014 0.07 0.03 2.49 0.00 0.0002 0.0000 0.0014 0.03 0.01 4.70 0.00 0.0002 0.0000 0.0014 0.01 0.02 9.04 0.00 0.0002 0.0000 0.0014 0.02 0.34 7.97 0.00 0.0002 0.0000 0.0014 0.34 2.66 8.40 0.00 0.0002 0.0000 0.0014 2.66 6.18 10.96 0.00 0.0002 0.0000 0.0014 6.18 8.29 14.24 0.00 0.0002 0.0000 0.0014 8.29 6.13 13.67 0.00 0.0002 0.0000 0.0014 6.13 1.86 6.69 0.00 0.0002 0.0000 0.0014 1.86 0.49 1.07 0.00 0.0002 0.0000 0.0014 0.49

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 25 Scenario with Damnak Ampil channel included Area (km2): 215.52 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.18 0.23 0.00 0.0001 0.0000 0.0003 0.18 0.07 0.31 0.00 0.0001 0.0000 0.0003 0.07 0.03 2.74 0.00 0.0001 0.0000 0.0003 0.03 0.01 5.16 0.00 0.0001 0.0000 0.0003 0.01 0.02 9.93 0.00 0.0001 0.0000 0.0003 0.02 0.38 8.75 0.00 0.0001 0.0000 0.0003 0.38 2.92 9.22 0.00 0.0001 0.0000 0.0003 2.92 6.79 12.04 0.00 0.0001 0.0000 0.0003 6.79 9.10 15.63 0.00 0.0001 0.0000 0.0003 9.10 6.73 15.01 0.00 0.0001 0.0000 0.0003 6.73 2.04 7.35 0.00 0.0001 0.0000 0.0003 2.04 0.54 1.17 0.00 0.0001 0.0000 0.0003 0.54

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 26 Scenario with Damnak Ampil channel included Area (km2): 154.5 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.13 0.17 0.00 0.0000 0.0000 0.0002 0.13 0.05 0.22 0.00 0.0000 0.0000 0.0002 0.05 0.02 1.96 0.00 0.0000 0.0000 0.0002 0.02 0.01 3.70 0.00 0.0000 0.0000 0.0002 0.01 0.01 7.12 0.00 0.0000 0.0000 0.0002 0.01 0.27 6.28 0.00 0.0000 0.0000 0.0002 0.27 2.09 6.61 0.00 0.0000 0.0000 0.0002 2.09 4.87 8.63 0.00 0.0000 0.0000 0.0002 4.87 6.52 11.21 0.00 0.0000 0.0000 0.0002 6.52 4.83 10.76 0.00 0.0000 0.0000 0.0002 4.83 1.46 5.27 0.00 0.0000 0.0000 0.0002 1.46 0.38 0.84 0.00 0.0000 0.0000 0.0002 0.38

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Table A4.6b: Water balance with Damnak Ampil Canal, catchments 24, 8 and 2

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 24 Scenario with Damnak Ampil channel included Area (km2): 6.16 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.01 0.01 0.31 0.0000 0.0000 0.0000 0.32 0.00 0.01 0.13 0.0000 0.0000 0.0000 0.13 0.00 0.08 0.05 0.0000 0.0000 0.0000 0.05 0.00 0.15 0.02 0.0000 0.0000 0.0000 0.02 0.00 0.28 0.03 0.0000 0.0000 0.0000 0.03 0.01 0.25 0.64 0.0000 0.0000 0.0000 0.65 0.08 0.26 5.02 0.0000 0.0000 0.0000 5.10 0.19 0.34 11.66 0.0000 0.0000 0.0000 11.85 0.26 0.45 15.63 0.0000 0.0000 0.0000 15.89 0.19 0.43 11.56 0.0000 0.0000 0.0000 11.75 0.06 0.21 3.51 0.0000 0.0000 0.0000 3.56 0.02 0.03 0.92 0.0000 0.0000 0.0000 0.93

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 8 Scenario with Damnak Ampil channel included Area (km2): 155.8 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.13 0.17 0.49 0.0019 0.0000 0.0098 0.61 0.05 0.23 0.19 0.0019 0.0000 0.0098 0.24 0.02 1.98 0.08 0.0019 0.0210 0.0098 0.06 0.01 3.73 0.03 0.0019 0.0210 0.0098 0.01 0.01 7.18 0.05 0.0019 0.0210 0.0098 0.03 0.27 6.33 1.00 0.0019 0.0210 0.0098 1.23 2.11 6.67 7.76 0.0019 1.3060 0.0098 8.55 4.91 8.70 18.03 0.0019 1.3060 0.0098 21.62 6.58 11.30 24.18 0.0019 1.3060 0.0098 29.44 4.87 10.85 17.88 0.0019 1.3060 0.0098 21.43 1.48 5.31 5.42 0.0019 1.3060 0.0098 5.58 0.39 0.85 1.42 0.0019 0.0000 0.0098 1.80

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 2 Scenario with Damnak Ampil channel included Area (km2): 366.54 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.31 0.40 0.61 0.0137 0.1100 0.0603 0.74 0.13 0.53 0.24 0.0137 0.1100 0.0603 0.18 0.05 4.65 0.06 0.0137 0.2300 0.0603 0.00 0.02 8.77 0.01 0.0137 0.2300 0.0603 0.00 0.03 16.88 0.03 0.0137 0.2300 0.0603 0.00 0.64 14.89 1.23 0.0137 0.2300 0.0603 1.57 4.97 15.69 8.55 0.0137 1.3900 0.0603 12.06 11.55 20.47 21.62 0.0137 1.3900 0.0603 31.71 15.48 26.59 29.44 0.0137 1.3900 0.0603 43.45 11.45 25.52 21.43 0.0137 1.3900 0.0603 31.42 3.47 12.50 5.58 0.0137 1.3900 0.0603 7.59 0.91 1.99 1.80 0.0137 0.1100 0.0603 2.52

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Table A4.6c: Water balance with Damnak Ampil Canal, catchments 1, 17 and 21

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 1 Scenario with Damnak Ampil channel included Area (km2): 184.8 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.16 0.20 0.74 0.0012 0.0000 0.0047 0.89 0.06 0.27 0.18 0.0012 0.0000 0.0047 0.23 0.03 2.35 0.00 0.0012 0.1100 0.0047 0.00 0.01 4.42 0.00 0.0012 0.1100 0.0047 0.00 0.02 8.51 0.00 0.0012 0.1100 0.0047 0.00 0.32 7.51 1.57 0.0012 0.1100 0.0047 1.77 2.51 7.91 12.06 0.0012 0.8700 0.0047 13.69 5.82 10.32 31.71 0.0012 0.8700 0.0047 36.65 7.80 13.40 43.45 0.0012 0.8700 0.0047 50.38 5.77 12.87 31.42 0.0012 0.8700 0.0047 36.31 1.75 6.30 7.59 0.0012 0.8700 0.0047 8.46 0.46 1.01 2.52 0.0012 0.0000 0.0047 2.98

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 17 Scenario with Damnak Ampil channel included Area (km2): 503.89 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.43 0.55 0.00 0.0036 0.0300 0.0199 0.38 0.17 0.73 0.00 0.0036 0.0300 0.0199 0.12 0.07 6.40 0.00 0.0036 0.2840 0.0199 0.00 0.03 12.06 0.00 0.0036 0.2840 0.0199 0.00 0.04 23.21 0.00 0.0036 0.2840 0.0199 0.00 0.88 20.47 0.00 0.0036 0.2840 0.0199 0.57 6.83 21.56 0.00 0.0036 0.5070 0.0199 6.30 15.87 28.14 0.00 0.0036 0.5070 0.0199 15.34 21.28 36.55 0.00 0.0036 0.5070 0.0199 20.75 15.74 35.09 0.00 0.0036 0.5070 0.0199 15.21 4.77 17.18 0.00 0.0036 0.5070 0.0199 4.24 1.25 2.74 0.00 0.0036 0.0300 0.0199 1.20

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 21 Scenario with Damnak Ampil channel included Area (km2): 412.57 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.35 0.45 0.80 0.0063 0.1110 0.0394 0.99 0.14 0.60 1.67 0.0063 0.1110 0.0394 1.65 0.06 5.24 1.67 0.0063 0.1120 0.0394 1.57 0.02 9.87 2.03 0.0063 0.1120 0.0394 1.90 0.04 19.00 2.91 0.0063 0.1120 0.0394 2.79 0.72 16.76 3.94 0.0063 0.1120 0.0394 4.51 5.59 17.66 5.00 0.0063 0.2910 0.0394 10.26 13.00 23.04 5.00 0.0063 0.2910 0.0394 17.66 17.42 29.92 5.00 0.0063 0.2910 0.0394 22.09 12.89 28.73 5.00 0.0063 0.2910 0.0394 17.55 3.91 14.06 1.89 0.0063 0.2910 0.0394 5.46 1.03 2.24 2.09 0.0063 0.1110 0.0394 2.96

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Table A4.6d: Water balance with Damnak Ampil Canal, catchments 20, 18 and 15

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 20 Scenario with Damnak Ampil channel included Area (km2): 45.26 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.04 0.05 0.99 0.0008 0.0260 0.0049 1.00 0.02 0.07 1.65 0.0008 0.0260 0.0049 1.63 0.01 0.57 1.57 0.0008 0.0790 0.0049 1.49 0.00 1.08 1.90 0.0008 0.0790 0.0049 1.82 0.00 2.08 2.79 0.0008 0.0790 0.0049 2.71 0.08 1.84 4.51 0.0008 0.0790 0.0049 4.50 0.61 1.94 10.26 0.0008 0.2130 0.0049 10.65 1.43 2.53 17.66 0.0008 0.2130 0.0049 18.87 1.91 3.28 22.09 0.0008 0.2130 0.0049 23.78 1.41 3.15 17.55 0.0008 0.2130 0.0049 18.75 0.43 1.54 5.46 0.0008 0.2130 0.0049 5.67 0.11 0.25 2.96 0.0008 0.0260 0.0049 3.04

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 18 Scenario with Damnak Ampil channel included Area (km2): 27.52 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.02 0.03 1.00 0.0010 0.1230 0.0045 0.90 0.01 0.04 1.63 0.0010 0.1230 0.0045 1.52 0.00 0.35 1.49 0.0010 0.1910 0.0045 1.29 0.00 0.66 1.82 0.0010 0.1910 0.0045 1.62 0.00 1.27 2.71 0.0010 0.1910 0.0045 2.51 0.05 1.12 4.50 0.0010 0.1910 0.0045 4.35 0.37 1.18 10.65 0.0010 0.5940 0.0045 10.42 0.87 1.54 18.87 0.0010 0.5940 0.0045 19.13 1.16 2.00 23.78 0.0010 0.5940 0.0045 24.34 0.86 1.92 18.75 0.0010 0.5940 0.0045 19.01 0.26 0.94 5.67 0.0010 0.5940 0.0045 5.33 0.07 0.15 3.04 0.0010 0.1230 0.0045 2.98

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 15 Scenario with Damnak Ampil channel included Area (km2): 24.32 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.02 0.03 1.27 0.0008 0.1030 0.0039 1.19 0.01 0.04 1.63 0.0008 0.1030 0.0039 1.53 0.00 0.31 1.29 0.0008 0.1640 0.0039 1.13 0.00 0.58 1.62 0.0008 0.1640 0.0039 1.45 0.00 1.12 2.51 0.0008 0.1640 0.0039 2.35 0.04 0.99 4.92 0.0008 0.1640 0.0039 4.80 0.33 1.04 16.72 0.0008 0.5100 0.0039 16.54 0.77 1.36 34.48 0.0008 0.5100 0.0039 34.73 1.03 1.76 45.09 0.0008 0.5100 0.0039 45.60 0.76 1.69 34.22 0.0008 0.5100 0.0039 34.46 0.23 0.83 9.58 0.0008 0.5100 0.0039 9.29 0.06 0.13 4.18 0.0008 0.1030 0.0039 4.13

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Table A4.6e: Water balance with Damnak Ampil Canal, catchments 16,19 and 14.

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 16 Scenario with Damnak Ampil channel included Area (km2): 190.51 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.16 0.21 0.00 0.0058 0.0060 0.0316 0.12 0.07 0.28 0.00 0.0058 0.0060 0.0316 0.02 0.03 2.42 0.00 0.0058 0.1770 0.0316 0.00 0.01 4.56 0.00 0.0058 0.1770 0.0316 0.00 0.02 8.77 0.00 0.0058 0.1770 0.0316 0.00 0.33 7.74 0.00 0.0058 0.1770 0.0316 0.12 2.58 8.15 0.00 0.0058 0.2890 0.0316 2.26 6.00 10.64 0.00 0.0058 0.2890 0.0316 5.68 8.05 13.82 0.00 0.0058 0.2890 0.0316 7.72 5.95 13.27 0.00 0.0058 0.2890 0.0316 5.62 1.80 6.49 0.00 0.0058 0.2890 0.0316 1.48 0.47 1.04 0.00 0.0058 0.0060 0.0316 0.43

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 19 Scenario with Damnak Ampil channel included Area (km2): 121.68 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.10 0.13 2.30 0.0040 0.0070 0.0264 2.37 0.04 0.18 1.67 0.0040 0.0070 0.0264 1.67 0.02 1.54 1.67 0.0040 0.0760 0.0264 1.58 0.01 2.91 2.03 0.0040 0.0760 0.0264 1.93 0.01 5.60 2.91 0.0040 0.0760 0.0264 2.82 0.21 4.94 3.94 0.0040 0.0760 0.0264 4.05 1.65 5.21 5.00 0.0040 0.5030 0.0264 6.12 3.83 6.80 5.00 0.0040 0.5030 0.0264 8.30 5.14 8.83 5.00 0.0040 0.5030 0.0264 9.60 3.80 8.47 5.00 0.0040 0.5030 0.0264 8.27 1.15 4.15 4.39 0.0040 0.5030 0.0264 5.01 0.30 0.66 3.09 0.0040 0.0070 0.0264 3.35

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 14 Scenario with Damnak Ampil channel included Area (km2): 26.53 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.02 0.03 1.18 0.0004 0.0000 0.0023 1.20 0.01 0.04 0.84 0.0004 0.0000 0.0023 0.84 0.00 0.34 0.79 0.0004 0.0560 0.0023 0.73 0.00 0.64 0.97 0.0004 0.0560 0.0023 0.91 0.00 1.22 1.41 0.0004 0.0560 0.0023 1.35 0.05 1.08 2.03 0.0004 0.0560 0.0023 2.01 0.36 1.14 3.06 0.0004 0.3540 0.0023 3.06 0.84 1.48 4.15 0.0004 0.3540 0.0023 4.63 1.12 1.92 4.80 0.0004 0.3540 0.0023 5.57 0.83 1.85 4.13 0.0004 0.3540 0.0023 4.61 0.25 0.90 2.50 0.0004 0.3540 0.0023 2.40 0.07 0.14 1.68 0.0004 0.0000 0.0023 1.74

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Table A4.6f: Water balance with Damnak Ampil Canal, catchments 10,12 and 4

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 10 Scenario with Damnak Ampil channel included Area (km2): 95.48 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.08 0.10 2.51 0.0016 0.0190 0.0091 2.56 0.03 0.14 2.40 0.0016 0.0190 0.0091 2.40 0.01 1.21 1.86 0.0016 0.2330 0.0091 1.63 0.01 2.29 2.36 0.0016 0.2330 0.0091 2.12 0.01 4.40 3.70 0.0016 0.2330 0.0091 3.46 0.17 3.88 6.93 0.0016 0.2330 0.0091 6.85 1.29 4.09 21.86 0.0016 0.7040 0.0091 22.44 3.01 5.33 45.03 0.0016 0.7040 0.0091 47.33 4.03 6.93 58.89 0.0016 0.7040 0.0091 62.21 2.98 6.65 44.69 0.0016 0.7040 0.0091 46.96 0.90 3.25 13.17 0.0016 0.7040 0.0091 13.36 0.24 0.52 6.30 0.0016 0.0190 0.0091 6.51

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 12 Scenario with Damnak Ampil channel included Area (km2): 7397 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.06 8.05 1.18 0.0014 0.0130 0.0075 1.22 0.03 10.73 0.84 0.0014 0.0130 0.0075 0.84 0.01 93.89 0.79 0.0014 0.1420 0.0075 0.65 0.00 177.05 0.97 0.0014 0.1420 0.0075 0.82 0.01 340.68 1.41 0.0014 0.1420 0.0075 1.26 0.13 300.45 2.03 0.0014 0.1420 0.0075 2.00 1.00 316.54 3.06 0.0014 0.8880 0.0075 3.16 2.33 413.11 4.15 0.0014 0.8880 0.0075 5.58 3.12 536.51 4.80 0.0014 0.8880 0.0075 7.03 2.31 515.05 4.13 0.0014 0.8880 0.0075 5.55 0.70 252.16 2.50 0.0014 0.8880 0.0075 2.31 0.18 40.24 1.68 0.0014 0.0130 0.0075 1.84

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 4 Scenario with Damnak Ampil channel included Area (km2): 120.54 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.10 0.13 3.78 0.0014 0.0000 0.0073 3.88 0.04 0.17 3.24 0.0014 0.0000 0.0073 3.27 0.02 1.53 2.28 0.0014 0.1910 0.0073 2.10 0.01 2.89 2.94 0.0014 0.1910 0.0073 2.75 0.01 5.55 4.73 0.0014 0.1910 0.0073 4.54 0.21 4.90 8.85 0.0014 0.1910 0.0073 8.86 1.63 5.16 25.60 0.0014 1.2600 0.0073 25.97 3.80 6.73 52.91 0.0014 1.2600 0.0073 55.44 5.09 8.74 69.23 0.0014 1.2600 0.0073 73.06 3.77 8.39 52.51 0.0014 1.2600 0.0073 55.00 1.14 4.11 15.67 0.0014 1.2600 0.0073 15.54 0.30 0.66 8.35 0.0014 0.0000 0.0073 8.64

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Table A4.6g: Water balance with Damnak Ampil Canal, catchments 6, 22 and 7

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 6 Scenario with Damnak Ampil channel included Area (km2): 103.63 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.09 0.11 0.00 0.0078 0.2010 0.0473 0.00 0.04 0.15 0.00 0.0078 0.2010 0.0473 0.00 0.01 1.32 0.00 0.0078 0.3240 0.0473 0.00 0.01 2.48 0.00 0.0078 0.3240 0.0473 0.00 0.01 4.77 0.00 0.0078 0.3240 0.0473 0.00 0.18 4.21 0.00 0.0078 0.3240 0.0473 0.00 1.40 4.43 0.00 0.0078 1.3360 0.0473 0.01 3.26 5.79 0.00 0.0078 1.3360 0.0473 1.87 4.38 7.52 0.00 0.0078 1.3360 0.0473 2.99 3.24 7.22 0.00 0.0078 1.3360 0.0473 1.85 0.98 3.53 0.00 0.0078 1.3360 0.0473 0.00 0.26 0.56 0.00 0.0078 0.2010 0.0473 0.00

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 22 Scenario with Damnak Ampil channel included Area (km2): 185.68 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.16 0.20 2.30 0.0074 0.1270 0.0436 2.28 0.06 0.27 1.67 0.0074 0.1270 0.0436 1.55 0.03 2.36 1.67 0.0074 0.1270 0.0436 1.51 0.01 4.44 2.03 0.0074 0.1270 0.0436 1.87 0.02 8.55 2.91 0.0074 0.1270 0.0436 2.75 0.32 7.54 3.94 0.0074 0.1270 0.0436 4.09 2.52 7.95 5.00 0.0074 0.4840 0.0436 6.98 5.85 10.37 5.00 0.0074 0.4840 0.0436 10.31 7.84 13.47 5.00 0.0074 0.4840 0.0436 12.31 5.80 12.93 5.00 0.0074 0.4840 0.0436 10.27 1.76 6.33 4.39 0.0074 0.4840 0.0436 5.61 0.46 1.01 3.09 0.0074 0.1270 0.0436 3.37

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 7 Scenario with Damnak Ampil channel included Area (km2): 330.56 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.28 0.36 2.28 0.0068 0.5900 0.0359 1.93 0.11 0.48 1.55 0.0068 0.5900 0.0359 1.03 0.05 4.20 1.51 0.0068 0.4160 0.0359 1.10 0.02 7.91 1.87 0.0068 0.4160 0.0359 1.42 0.03 15.22 2.75 0.0068 0.4160 0.0359 2.32 0.58 13.43 4.09 0.0068 0.4160 0.0359 4.21 4.48 14.15 6.98 0.0068 0.9900 0.0359 10.43 10.41 18.46 10.31 0.0068 0.9900 0.0359 19.69 13.96 23.98 12.31 0.0068 0.9900 0.0359 25.23 10.33 23.02 10.27 0.0068 0.9900 0.0359 19.56 3.13 11.27 5.61 0.0068 0.9900 0.0359 7.71 0.82 1.80 3.37 0.0068 0.5900 0.0359 3.56

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Table A4.7a: Water balance with Damnak Ampil Canal and candidate sub-projects, catchments 23, 25 and 26

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 23 Damnak Ampil/Candidate projects channel included Area (km2): 196.3 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.17 0.21 0.00 0.0002 0.0000 0.0014 0.17 0.07 0.28 0.00 0.0002 0.0000 0.0014 0.07 0.03 2.49 0.00 0.0002 0.0000 0.0014 0.03 0.01 4.70 0.00 0.0002 0.0000 0.0014 0.01 0.02 9.04 0.00 0.0002 0.0000 0.0014 0.02 0.34 7.97 0.00 0.0002 0.0000 0.0014 0.34 2.66 8.40 0.00 0.0002 0.0000 0.0014 2.66 6.18 10.96 0.00 0.0002 0.0000 0.0014 6.18 8.29 14.24 0.00 0.0002 0.0000 0.0014 8.29 6.13 13.67 0.00 0.0002 0.0000 0.0014 6.13 1.86 6.69 0.00 0.0002 0.0000 0.0014 1.86 0.49 1.07 0.00 0.0002 0.0000 0.0014 0.49

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 25 Damnak Ampil/Candidate projects channel included Area (km2): 215.52 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.18 0.23 0.00 0.0001 0.0000 0.0003 0.18 0.07 0.31 0.00 0.0001 0.0000 0.0003 0.07 0.03 2.74 0.00 0.0001 0.0000 0.0003 0.03 0.01 5.16 0.00 0.0001 0.0000 0.0003 0.01 0.02 9.93 0.00 0.0001 0.0000 0.0003 0.02 0.38 8.75 0.00 0.0001 0.0000 0.0003 0.38 2.92 9.22 0.00 0.0001 0.0000 0.0003 2.92 6.79 12.04 0.00 0.0001 0.0000 0.0003 6.79 9.10 15.63 0.00 0.0001 0.0000 0.0003 9.10 6.73 15.01 0.00 0.0001 0.0000 0.0003 6.73 2.04 7.35 0.00 0.0001 0.0000 0.0003 2.04 0.54 1.17 0.00 0.0001 0.0000 0.0003 0.54

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 26 Damnak Ampil/Candidate projects channel included Area (km2): 154.5 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.13 0.17 0.00 0.0000 0.0000 0.0002 0.13 0.05 0.22 0.00 0.0000 0.0000 0.0002 0.05 0.02 1.96 0.00 0.0000 0.0000 0.0002 0.02 0.01 3.70 0.00 0.0000 0.0000 0.0002 0.01 0.01 7.12 0.00 0.0000 0.0000 0.0002 0.01 0.27 6.28 0.00 0.0000 0.0000 0.0002 0.27 2.09 6.61 0.00 0.0000 0.0000 0.0002 2.09 4.87 8.63 0.00 0.0000 0.0000 0.0002 4.87 6.52 11.21 0.00 0.0000 0.0000 0.0002 6.52 4.83 10.76 0.00 0.0000 0.0000 0.0002 4.83 1.46 5.27 0.00 0.0000 0.0000 0.0002 1.46 0.38 0.84 0.00 0.0000 0.0000 0.0002 0.38

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Table A4.7b: Water balance with Damnak Ampil Canal and candidate sub-projects, catchments 24, 8 and 2

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 24 Damnak Ampil/Candidate projects channel included Area (km2): 6.16 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.01 0.01 0.31 0.0000 0.0000 0.0000 0.32 0.00 0.01 0.13 0.0000 0.0000 0.0000 0.13 0.00 0.08 0.05 0.0000 0.0000 0.0000 0.05 0.00 0.15 0.02 0.0000 0.0000 0.0000 0.02 0.00 0.28 0.03 0.0000 0.0000 0.0000 0.03 0.01 0.25 0.64 0.0000 0.0000 0.0000 0.65 0.08 0.26 5.02 0.0000 0.0000 0.0000 5.10 0.19 0.34 11.66 0.0000 0.0000 0.0000 11.85 0.26 0.45 15.63 0.0000 0.0000 0.0000 15.89 0.19 0.43 11.56 0.0000 0.0000 0.0000 11.75 0.06 0.21 3.51 0.0000 0.0000 0.0000 3.56 0.02 0.03 0.92 0.0000 0.0000 0.0000 0.93

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 8 Damnak Ampil/Candidate projects channel included Area (km2): 155.8 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.13 0.17 0.49 0.0019 0.4000 0.0098 0.21 0.05 0.23 0.19 0.0019 0.4000 0.0098 0.00 0.02 1.98 0.08 0.0019 0.4210 0.0098 0.00 0.01 3.73 0.03 0.0019 0.4210 0.0098 0.00 0.01 7.18 0.05 0.0019 0.4210 0.0098 0.00 0.27 6.33 1.00 0.0019 0.4210 0.0098 0.83 2.11 6.67 7.76 0.0019 7.3060 0.0098 2.55 4.91 8.70 18.03 0.0019 7.3060 0.0098 15.62 6.58 11.30 24.18 0.0019 7.3060 0.0098 23.44 4.87 10.85 17.88 0.0019 7.3060 0.0098 15.43 1.48 5.31 5.42 0.0019 7.3060 0.0098 0.00 0.39 0.85 1.42 0.0019 0.4000 0.0098 1.40

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 2 Damnak Ampil/Candidate projects channel included Area (km2): 366.54 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.31 0.40 0.21 0.0137 0.1100 0.0603 0.34 0.13 0.53 0.00 0.0137 0.1100 0.0603 0.00 0.05 4.65 0.00 0.0137 0.2300 0.0603 0.00 0.02 8.77 0.00 0.0137 0.2300 0.0603 0.00 0.03 16.88 0.00 0.0137 0.2300 0.0603 0.00 0.64 14.89 0.83 0.0137 0.2300 0.0603 1.17 4.97 15.69 2.55 0.0137 1.3900 0.0603 6.06 11.55 20.47 15.62 0.0137 1.3900 0.0603 25.71 15.48 26.59 23.44 0.0137 1.3900 0.0603 37.45 11.45 25.52 15.43 0.0137 1.3900 0.0603 25.42 3.47 12.50 0.00 0.0137 1.3900 0.0603 2.01 0.91 1.99 1.40 0.0137 0.1100 0.0603 2.12

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Table A4.7c: Water balance with Damnak Ampil Canal and candidate sub-projects, catchments 1, 17 and 21

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 1 Damnak Ampil/Candidate projects channel included Area (km2): 184.8 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.16 0.20 0.34 0.0012 0.0000 0.0047 0.49 0.06 0.27 0.00 0.0012 0.0000 0.0047 0.00 0.03 2.35 0.00 0.0012 0.1100 0.0047 0.00 0.01 4.42 0.00 0.0012 0.1100 0.0047 0.00 0.02 8.51 0.00 0.0012 0.1100 0.0047 0.00 0.32 7.51 1.17 0.0012 0.1100 0.0047 1.37 2.51 7.91 6.06 0.0012 0.8700 0.0047 7.69 5.82 10.32 25.71 0.0012 0.8700 0.0047 30.65 7.80 13.40 37.45 0.0012 0.8700 0.0047 44.38 5.77 12.87 25.42 0.0012 0.8700 0.0047 30.31 1.75 6.30 2.01 0.0012 0.8700 0.0047 2.88 0.46 1.01 2.12 0.0012 0.0000 0.0047 2.58

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 17 Damnak Ampil/Candidate projects channel included Area (km2): 503.89 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.43 0.55 0.00 0.0036 0.0300 0.0199 0.38 0.17 0.73 0.00 0.0036 0.0300 0.0199 0.12 0.07 6.40 0.00 0.0036 0.2840 0.0199 0.00 0.03 12.06 0.00 0.0036 0.2840 0.0199 0.00 0.04 23.21 0.00 0.0036 0.2840 0.0199 0.00 0.88 20.47 0.00 0.0036 0.2840 0.0199 0.57 6.83 21.56 0.00 0.0036 0.5070 0.0199 6.30 15.87 28.14 0.00 0.0036 0.5070 0.0199 15.34 21.28 36.55 0.00 0.0036 0.5070 0.0199 20.75 15.74 35.09 0.00 0.0036 0.5070 0.0199 15.21 4.77 17.18 0.00 0.0036 0.5070 0.0199 4.24 1.25 2.74 0.00 0.0036 0.0300 0.0199 1.20

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 21 Damnak Ampil/Candidate projects channel included Area (km2): 412.57 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.35 0.45 0.80 0.0063 0.1110 0.0394 0.99 0.14 0.60 1.67 0.0063 0.1110 0.0394 1.65 0.06 5.24 1.67 0.0063 0.1120 0.0394 1.57 0.02 9.87 2.03 0.0063 0.1120 0.0394 1.90 0.04 19.00 2.91 0.0063 0.1120 0.0394 2.79 0.72 16.76 3.94 0.0063 0.1120 0.0394 4.51 5.59 17.66 5.00 0.0063 4.2910 0.0394 6.26 13.00 23.04 5.00 0.0063 4.2910 0.0394 13.66 17.42 29.92 5.00 0.0063 4.2910 0.0394 18.09 12.89 28.73 5.00 0.0063 4.2910 0.0394 13.55 3.91 14.06 1.89 0.0063 4.2910 0.0394 1.46 1.03 2.24 2.09 0.0063 0.1110 0.0394 2.96

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Table A4.7d: Water balance with Damnak Ampil Canal and candidate sub-projects, catchments 20, 18 and 15

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 20 Damnak Ampil/Candidate projects channel included Area (km2): 45.26 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.04 0.05 0.99 0.0008 0.0260 0.0049 1.00 0.02 0.07 1.65 0.0008 0.0260 0.0049 1.63 0.01 0.57 1.57 0.0008 0.0790 0.0049 1.49 0.00 1.08 1.90 0.0008 0.0790 0.0049 1.82 0.00 2.08 2.79 0.0008 0.0790 0.0049 2.71 0.08 1.84 4.51 0.0008 0.0790 0.0049 4.50 0.61 1.94 6.26 0.0008 0.8130 0.0049 6.05 1.43 2.53 13.66 0.0008 0.8130 0.0049 14.27 1.91 3.28 18.09 0.0008 0.8130 0.0049 19.18 1.41 3.15 13.55 0.0008 0.8130 0.0049 14.15 0.43 1.54 1.46 0.0008 0.8130 0.0049 1.07 0.11 0.25 2.96 0.0008 0.0260 0.0049 3.04

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 18 Damnak Ampil/Candidate projects channel included Area (km2): 27.52 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.02 0.03 1.00 0.0010 0.1230 0.0045 0.90 0.01 0.04 1.63 0.0010 0.1230 0.0045 1.52 0.00 0.35 1.49 0.0010 0.1910 0.0045 1.29 0.00 0.66 1.82 0.0010 0.1910 0.0045 1.62 0.00 1.27 2.71 0.0010 0.1910 0.0045 2.51 0.05 1.12 4.50 0.0010 0.1910 0.0045 4.35 0.37 1.18 6.05 0.0010 0.5940 0.0045 5.82 0.87 1.54 14.27 0.0010 0.5940 0.0045 14.53 1.16 2.00 19.18 0.0010 0.5940 0.0045 19.74 0.86 1.92 14.15 0.0010 0.5940 0.0045 14.41 0.26 0.94 1.07 0.0010 0.5940 0.0045 0.73 0.07 0.15 3.04 0.0010 0.1230 0.0045 2.98

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 15 Damnak Ampil/Candidate projects channel included Area (km2): 24.32 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.02 0.03 1.27 0.0008 0.1030 0.0039 1.19 0.01 0.04 1.63 0.0008 0.1030 0.0039 1.53 0.00 0.31 1.29 0.0008 0.1640 0.0039 1.13 0.00 0.58 1.62 0.0008 0.1640 0.0039 1.45 0.00 1.12 2.51 0.0008 0.1640 0.0039 2.35 0.04 0.99 4.92 0.0008 0.1640 0.0039 4.80 0.33 1.04 12.12 0.0008 0.5100 0.0039 11.94 0.77 1.36 29.88 0.0008 0.5100 0.0039 30.13 1.03 1.76 40.49 0.0008 0.5100 0.0039 41.00 0.76 1.69 29.62 0.0008 0.5100 0.0039 29.86 0.23 0.83 4.98 0.0008 0.5100 0.0039 4.69 0.06 0.13 4.18 0.0008 0.1030 0.0039 4.13

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Table A4.7e: Water balance with Damnak Ampil Canal and candidate sub-projects, catchments 16, 19 and 14

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 16 Damnak Ampil/Candidate projects channel included Area (km2): 190.51 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.16 0.21 0.00 0.0058 0.0060 0.0316 0.12 0.07 0.28 0.00 0.0058 0.0060 0.0316 0.02 0.03 2.42 0.00 0.0058 0.1770 0.0316 0.00 0.01 4.56 0.00 0.0058 0.1770 0.0316 0.00 0.02 8.77 0.00 0.0058 0.1770 0.0316 0.00 0.33 7.74 0.00 0.0058 0.1770 0.0316 0.12 2.58 8.15 0.00 0.0058 0.2890 0.0316 2.26 6.00 10.64 0.00 0.0058 0.2890 0.0316 5.68 8.05 13.82 0.00 0.0058 0.2890 0.0316 7.72 5.95 13.27 0.00 0.0058 0.2890 0.0316 5.62 1.80 6.49 0.00 0.0058 0.2890 0.0316 1.48 0.47 1.04 0.00 0.0058 0.0060 0.0316 0.43

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 19 Damnak Ampil/Candidate projects channel included Area (km2): 121.68 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.10 0.13 2.30 0.0040 0.0070 0.0264 2.37 0.04 0.18 1.67 0.0040 0.0070 0.0264 1.67 0.02 1.54 1.67 0.0040 0.0760 0.0264 1.58 0.01 2.91 2.03 0.0040 0.0760 0.0264 1.93 0.01 5.60 2.91 0.0040 0.0760 0.0264 2.82 0.21 4.94 3.94 0.0040 0.0760 0.0264 4.05 1.65 5.21 5.00 0.0040 0.5030 0.0264 6.12 3.83 6.80 5.00 0.0040 0.5030 0.0264 8.30 5.14 8.83 5.00 0.0040 0.5030 0.0264 9.60 3.80 8.47 5.00 0.0040 0.5030 0.0264 8.27 1.15 4.15 4.39 0.0040 0.5030 0.0264 5.01 0.30 0.66 3.09 0.0040 0.0070 0.0264 3.35

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 14 Damnak Ampil/Candidate projects channel included Area (km2): 26.53 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.02 0.03 1.18 0.0004 0.0000 0.0023 1.20 0.01 0.04 0.84 0.0004 0.0000 0.0023 0.84 0.00 0.34 0.79 0.0004 0.0560 0.0023 0.73 0.00 0.64 0.97 0.0004 0.0560 0.0023 0.91 0.00 1.22 1.41 0.0004 0.0560 0.0023 1.35 0.05 1.08 2.03 0.0004 0.0560 0.0023 2.01 0.36 1.14 3.06 0.0004 0.3540 0.0023 3.06 0.84 1.48 4.15 0.0004 0.3540 0.0023 4.63 1.12 1.92 4.80 0.0004 0.3540 0.0023 5.57 0.83 1.85 4.13 0.0004 0.3540 0.0023 4.61 0.25 0.90 2.50 0.0004 0.3540 0.0023 2.40 0.07 0.14 1.68 0.0004 0.0000 0.0023 1.74

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Table A4.7f: Water balance with Damnak Ampil Canal and candidate sub-projects, catchments 10, 12 and 4

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 10 Damnak Ampil/Candidate projects channel included Area (km2): 95.48 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.08 0.10 2.51 0.0016 0.0190 0.0091 2.56 0.03 0.14 2.40 0.0016 0.0190 0.0091 2.40 0.01 1.21 1.86 0.0016 0.2330 0.0091 1.63 0.01 2.29 2.36 0.0016 0.2330 0.0091 2.12 0.01 4.40 3.70 0.0016 0.2330 0.0091 3.46 0.17 3.88 6.93 0.0016 0.2330 0.0091 6.85 1.29 4.09 17.26 0.0016 0.7040 0.0091 17.84 3.01 5.33 40.43 0.0016 0.7040 0.0091 42.73 4.03 6.93 54.29 0.0016 0.7040 0.0091 57.61 2.98 6.65 40.09 0.0016 0.7040 0.0091 42.36 0.90 3.25 8.57 0.0016 0.7040 0.0091 8.76 0.24 0.52 6.30 0.0016 0.0190 0.0091 6.51

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 12 Damnak Ampil/Candidate projects channel included Area (km2): 7397 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.06 8.05 1.18 0.0014 0.0130 0.0075 1.22 0.03 10.73 0.84 0.0014 0.0130 0.0075 0.84 0.01 93.89 0.79 0.0014 0.1420 0.0075 0.65 0.00 177.05 0.97 0.0014 0.1420 0.0075 0.82 0.01 340.68 1.41 0.0014 0.1420 0.0075 1.26 0.13 300.45 2.03 0.0014 0.1420 0.0075 2.00 1.00 316.54 3.06 0.0014 0.8880 0.0075 3.16 2.33 413.11 4.15 0.0014 0.8880 0.0075 5.58 3.12 536.51 4.80 0.0014 0.8880 0.0075 7.03 2.31 515.05 4.13 0.0014 0.8880 0.0075 5.55 0.70 252.16 2.50 0.0014 0.8880 0.0075 2.31 0.18 40.24 1.68 0.0014 0.0130 0.0075 1.84

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 4 Damnak Ampil/Candidate projects channel included Area (km2): 120.54 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.10 0.13 3.78 0.0014 0.0000 0.0073 3.88 0.04 0.17 3.24 0.0014 0.0000 0.0073 3.27 0.02 1.53 2.28 0.0014 0.1910 0.0073 2.10 0.01 2.89 2.94 0.0014 0.1910 0.0073 2.75 0.01 5.55 4.73 0.0014 0.1910 0.0073 4.54 0.21 4.90 8.85 0.0014 0.1910 0.0073 8.86 1.63 5.16 21.00 0.0014 1.2600 0.0073 21.37 3.80 6.73 48.31 0.0014 1.2600 0.0073 50.84 5.09 8.74 64.63 0.0014 1.2600 0.0073 68.46 3.77 8.39 47.91 0.0014 1.2600 0.0073 50.40 1.14 4.11 11.07 0.0014 1.2600 0.0073 10.94 0.30 0.66 8.35 0.0014 0.0000 0.0073 8.64

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Table A4.7g: Water balance with Damnak Ampil Canal and candidate sub-projects, catchments 6, 22 and 7

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 6 Damnak Ampil/Candidate projects channel included Area (km2): 103.63 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.09 0.11 0.00 0.0078 0.2010 0.0473 0.00 0.04 0.15 0.00 0.0078 0.2010 0.0473 0.00 0.01 1.32 0.00 0.0078 0.3240 0.0473 0.00 0.01 2.48 0.00 0.0078 0.3240 0.0473 0.00 0.01 4.77 0.00 0.0078 0.3240 0.0473 0.00 0.18 4.21 0.00 0.0078 0.3240 0.0473 0.00 1.40 4.43 0.00 0.0078 1.3360 0.0473 0.01 3.26 5.79 0.00 0.0078 1.3360 0.0473 1.87 4.38 7.52 0.00 0.0078 1.3360 0.0473 2.99 3.24 7.22 0.00 0.0078 1.3360 0.0473 1.85 0.98 3.53 0.00 0.0078 1.3360 0.0473 0.00 0.26 0.56 0.00 0.0078 0.2010 0.0473 0.00

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 22 Damnak Ampil/Candidate projects channel included Area (km2): 185.68 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.16 0.20 2.30 0.0074 0.1270 0.0436 2.28 0.06 0.27 1.67 0.0074 0.1270 0.0436 1.55 0.03 2.36 1.67 0.0074 0.1270 0.0436 1.51 0.01 4.44 2.03 0.0074 0.1270 0.0436 1.87 0.02 8.55 2.91 0.0074 0.1270 0.0436 2.75 0.32 7.54 3.94 0.0074 0.1270 0.0436 4.09 2.52 7.95 5.00 0.0074 1.0840 0.0436 6.38 5.85 10.37 5.00 0.0074 1.0840 0.0436 9.71 7.84 13.47 5.00 0.0074 1.0840 0.0436 11.71 5.80 12.93 5.00 0.0074 1.0840 0.0436 9.67 1.76 6.33 4.39 0.0074 1.0840 0.0436 5.01 0.46 1.01 3.09 0.0074 0.1270 0.0436 3.37

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 7 Damnak Ampil/Candidate projects channel included Area (km2): 330.56 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.28 0.36 2.28 0.0068 0.5900 0.0359 1.93 0.11 0.48 1.55 0.0068 0.5900 0.0359 1.03 0.05 4.20 1.51 0.0068 0.4160 0.0359 1.10 0.02 7.91 1.87 0.0068 0.4160 0.0359 1.42 0.03 15.22 2.75 0.0068 0.4160 0.0359 2.32 0.58 13.43 4.09 0.0068 0.4160 0.0359 4.21 4.48 14.15 6.38 0.0068 0.9900 0.0359 9.83 10.41 18.46 9.71 0.0068 0.9900 0.0359 19.09 13.96 23.98 11.71 0.0068 0.9900 0.0359 24.63 10.33 23.02 9.67 0.0068 0.9900 0.0359 18.96 3.13 11.27 5.01 0.0068 0.9900 0.0359 7.11 0.82 1.80 3.37 0.0068 0.5900 0.0359 3.56

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Table A4.8a: Water balance with Damnak Ampil Canal, candidate sub-projects and climate change, catchments 23, 25 and 26

.

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 23 Damnak Ampil/Candidate projects and climate change Area (km2): 196.3 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.16 0.21 0.00 0.0002 0.0000 0.0014 0.15 0.06 0.28 0.00 0.0002 0.0000 0.0014 0.06 0.03 2.49 0.00 0.0002 0.0000 0.0014 0.02 0.01 4.70 0.00 0.0002 0.0000 0.0014 0.01 0.00 9.04 0.00 0.0002 0.0000 0.0014 0.00 0.12 7.97 0.00 0.0002 0.0000 0.0014 0.12 2.02 8.40 0.00 0.0002 0.0000 0.0014 2.02 5.79 10.96 0.00 0.0002 0.0000 0.0014 5.78 7.91 14.24 0.00 0.0002 0.0000 0.0014 7.91 5.83 13.67 0.00 0.0002 0.0000 0.0014 5.82 1.68 6.69 0.00 0.0002 0.0000 0.0014 1.68 0.46 1.07 0.00 0.0002 0.0000 0.0014 0.46

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 25 Damnak Ampil/Candidate projects and climate change Area (km2): 215.52 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.17 0.23 0.00 0.0001 0.0000 0.0003 0.17 0.07 0.31 0.00 0.0001 0.0000 0.0003 0.07 0.03 2.74 0.00 0.0001 0.0000 0.0003 0.03 0.01 5.16 0.00 0.0001 0.0000 0.0003 0.01 0.00 9.93 0.00 0.0001 0.0000 0.0003 0.00 0.13 8.75 0.00 0.0001 0.0000 0.0003 0.13 2.22 9.22 0.00 0.0001 0.0000 0.0003 2.22 6.35 12.04 0.00 0.0001 0.0000 0.0003 6.35 8.68 15.63 0.00 0.0001 0.0000 0.0003 8.68 6.40 15.01 0.00 0.0001 0.0000 0.0003 6.40 1.85 7.35 0.00 0.0001 0.0000 0.0003 1.85 0.50 1.17 0.00 0.0001 0.0000 0.0003 0.50

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 26 Damnak Ampil/Candidate projects and climate change Area (km2): 154.5 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.12 0.17 0.00 0.0000 0.0000 0.0002 0.12 0.05 0.22 0.00 0.0000 0.0000 0.0002 0.05 0.02 1.96 0.00 0.0000 0.0000 0.0002 0.02 0.01 3.70 0.00 0.0000 0.0000 0.0002 0.01 0.00 7.12 0.00 0.0000 0.0000 0.0002 0.00 0.09 6.28 0.00 0.0000 0.0000 0.0002 0.09 1.59 6.61 0.00 0.0000 0.0000 0.0002 1.59 4.55 8.63 0.00 0.0000 0.0000 0.0002 4.55 6.23 11.21 0.00 0.0000 0.0000 0.0002 6.23 4.58 10.76 0.00 0.0000 0.0000 0.0002 4.58 1.32 5.27 0.00 0.0000 0.0000 0.0002 1.32 0.36 0.84 0.00 0.0000 0.0000 0.0002 0.36

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Table A4.8b: Water balance with Damnak Ampil Canal, candidate sub-projects and climate change, catchments 24, 8 and 2

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 24 Damnak Ampil/Candidate projects and climate change Area (km2): 6.16 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.00 0.01 0.29 0.0000 0.0000 0.0000 0.30 0.00 0.01 0.12 0.0000 0.0000 0.0000 0.12 0.00 0.08 0.05 0.0000 0.0000 0.0000 0.05 0.00 0.15 0.02 0.0000 0.0000 0.0000 0.02 0.00 0.28 0.01 0.0000 0.0000 0.0000 0.01 0.00 0.25 0.22 0.0000 0.0000 0.0000 0.23 0.06 0.26 3.81 0.0000 0.0000 0.0000 3.87 0.18 0.34 10.91 0.0000 0.0000 0.0000 11.09 0.25 0.45 14.91 0.0000 0.0000 0.0000 15.16 0.18 0.43 10.98 0.0000 0.0000 0.0000 11.16 0.05 0.21 3.17 0.0000 0.0000 0.0000 3.22 0.01 0.03 0.86 0.0000 0.0000 0.0000 0.87

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 8 Damnak Ampil/Candidate projects and climate change Area (km2): 155.8 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.12 0.17 0.45 0.0019 0.4000 0.0098 0.17 0.05 0.23 0.18 0.0019 0.4000 0.0098 0.00 0.02 1.98 0.07 0.0019 0.4210 0.0098 0.00 0.01 3.73 0.03 0.0019 0.4210 0.0098 0.00 0.00 7.18 0.01 0.0019 0.4210 0.0098 0.00 0.09 6.33 0.34 0.0019 0.4210 0.0098 0.00 1.60 6.67 5.89 0.0019 7.3060 0.0098 0.18 4.59 8.70 16.87 0.0019 7.3060 0.0098 14.15 6.28 11.30 23.07 0.0019 7.3060 0.0098 22.03 4.62 10.85 16.99 0.0019 7.3060 0.0098 14.29 1.34 5.31 4.91 0.0019 7.3060 0.0098 -1.08 0.36 0.85 1.33 0.0019 0.4000 0.0098 1.28

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 2 Damnak Ampil/Candidate projects and climate change Area (km2): 366.54 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.29 0.40 0.17 0.0137 0.1100 0.0603 0.27 0.12 0.53 0.00 0.0137 0.1100 0.0603 0.00 0.05 4.65 0.00 0.0137 0.2300 0.0603 0.00 0.02 8.77 0.00 0.0137 0.2300 0.0603 0.00 0.01 16.88 0.00 0.0137 0.2300 0.0603 0.00 0.22 14.89 0.00 0.0137 0.2300 0.0603 0.00 3.77 15.69 0.18 0.0137 1.3900 0.0603 2.49 10.80 20.47 14.15 0.0137 1.3900 0.0603 23.49 14.77 26.59 22.03 0.0137 1.3900 0.0603 35.33 10.88 25.52 14.29 0.0137 1.3900 0.0603 23.71 3.14 12.50 -1.08 0.0137 1.3900 0.0603 0.60 0.85 1.99 1.28 0.0137 0.1100 0.0603 1.95

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Table A4.8c: Water balance with Damnak Ampil Canal, candidate sub-projects and climate change, catchments 1, 17 and 21

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 1 Damnak Ampil/Candidate projects and climate change Area (km2): 184.8 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.15 0.20 0.27 0.0012 0.0000 0.0047 0.42 0.06 0.27 0.00 0.0012 0.0000 0.0047 0.05 0.02 2.35 0.00 0.0012 0.1100 0.0047 0.00 0.01 4.42 0.00 0.0012 0.1100 0.0047 0.00 0.00 8.51 0.00 0.0012 0.1100 0.0047 0.00 0.11 7.51 0.00 0.0012 0.1100 0.0047 0.00 1.90 7.91 2.49 0.0012 0.8700 0.0047 3.51 5.45 10.32 23.49 0.0012 0.8700 0.0047 28.06 7.45 13.40 35.33 0.0012 0.8700 0.0047 41.90 5.48 12.87 23.71 0.0012 0.8700 0.0047 28.31 1.58 6.30 0.60 0.0012 0.8700 0.0047 1.31 0.43 1.01 1.95 0.0012 0.0000 0.0047 2.37

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 17 Damnak Ampil/Candidate projects and climate change Area (km2): 503.89 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.40 0.55 0.00 0.0036 0.0300 0.0199 0.35 0.16 0.73 0.00 0.0036 0.0300 0.0199 0.11 0.06 6.40 0.00 0.0036 0.2840 0.0199 0.00 0.03 12.06 0.00 0.0036 0.2840 0.0199 0.00 0.01 23.21 0.00 0.0036 0.2840 0.0199 0.00 0.30 20.47 0.00 0.0036 0.2840 0.0199 0.00 5.19 21.56 0.00 0.0036 0.5070 0.0199 4.66 14.85 28.14 0.00 0.0036 0.5070 0.0199 14.32 20.30 36.55 0.00 0.0036 0.5070 0.0199 19.77 14.95 35.09 0.00 0.0036 0.5070 0.0199 14.42 4.32 17.18 0.00 0.0036 0.5070 0.0199 3.79 1.17 2.74 0.00 0.0036 0.0300 0.0199 1.12

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 21 Damnak Ampil/Candidate projects and climate change Area (km2): 412.57 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.33 0.45 0.80 0.0063 0.1110 0.0394 0.97 0.13 0.60 1.67 0.0063 0.1110 0.0394 1.64 0.05 5.24 1.67 0.0063 0.1120 0.0394 1.56 0.02 9.87 2.03 0.0063 0.1120 0.0394 1.90 0.01 19.00 2.91 0.0063 0.1120 0.0394 2.76 0.25 16.76 3.94 0.0063 0.1120 0.0394 4.04 4.25 17.66 5.00 0.0063 4.2910 0.0394 4.91 12.16 23.04 5.00 0.0063 4.2910 0.0394 12.82 16.62 29.92 5.00 0.0063 4.2910 0.0394 17.29 12.24 28.73 5.00 0.0063 4.2910 0.0394 12.91 3.54 14.06 1.89 0.0063 4.2910 0.0394 1.09 0.96 2.24 2.09 0.0063 0.1110 0.0394 2.89

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Table A4.8d: Water balance with Damnak Ampil Canal, candidate sub-projects and climate change, catchments 20, 18 and 15

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 20 Damnak Ampil/Candidate projects and climate change Area (km2): 45.26 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.04 0.05 0.97 0.0008 0.0260 0.0049 0.98 0.01 0.07 1.64 0.0008 0.0260 0.0049 1.62 0.01 0.57 1.56 0.0008 0.0790 0.0049 1.48 0.00 1.08 1.90 0.0008 0.0790 0.0049 1.81 0.00 2.08 2.76 0.0008 0.0790 0.0049 2.68 0.03 1.84 4.04 0.0008 0.0790 0.0049 3.98 0.47 1.94 4.91 0.0008 0.8130 0.0049 4.56 1.33 2.53 12.82 0.0008 0.8130 0.0049 13.34 1.82 3.28 17.29 0.0008 0.8130 0.0049 18.29 1.34 3.15 12.91 0.0008 0.8130 0.0049 13.43 0.39 1.54 1.09 0.0008 0.8130 0.0049 0.66 0.11 0.25 2.89 0.0008 0.0260 0.0049 2.97

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 18 Damnak Ampil/Candidate projects and climate change Area (km2): 27.52 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.02 0.03 0.98 0.0010 0.1230 0.0045 0.87 0.01 0.04 1.62 0.0010 0.1230 0.0045 1.50 0.00 0.35 1.48 0.0010 0.1910 0.0045 1.29 0.00 0.66 1.81 0.0010 0.1910 0.0045 1.62 0.00 1.27 2.68 0.0010 0.1910 0.0045 2.48 0.02 1.12 3.98 0.0010 0.1910 0.0045 3.80 0.28 1.18 4.56 0.0010 0.5940 0.0045 4.24 0.81 1.54 13.34 0.0010 0.5940 0.0045 13.55 1.11 2.00 18.29 0.0010 0.5940 0.0045 18.80 0.82 1.92 13.43 0.0010 0.5940 0.0045 13.65 0.24 0.94 0.66 0.0010 0.5940 0.0045 0.29 0.06 0.15 2.97 0.0010 0.1230 0.0045 2.90

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 15 Damnak Ampil/Candidate projects and climate change Area (km2): 24.32 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.02 0.03 1.22 0.0008 0.1030 0.0039 1.13 0.01 0.04 1.61 0.0008 0.1030 0.0039 1.51 0.00 0.31 1.29 0.0008 0.1640 0.0039 1.12 0.00 0.58 1.62 0.0008 0.1640 0.0039 1.45 0.00 1.12 2.48 0.0008 0.1640 0.0039 2.31 0.01 0.99 3.79 0.0008 0.1640 0.0039 3.64 0.25 1.04 8.90 0.0008 0.5100 0.0039 8.63 0.72 1.36 27.87 0.0008 0.5100 0.0039 28.07 0.98 1.76 38.57 0.0008 0.5100 0.0039 39.04 0.72 1.69 28.07 0.0008 0.5100 0.0039 28.28 0.21 0.83 4.08 0.0008 0.5100 0.0039 3.78 0.06 0.13 4.02 0.0008 0.1030 0.0039 3.97

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Table A4.8e: Water balance with Damnak Ampil Canal, candidate sub-projects and climate change, catchments 16,19 and 14

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 16 Damnak Ampil/Candidate projects and climate change Area (km2): 190.51 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.15 0.21 0.00 0.0058 0.0060 0.0316 0.11 0.06 0.28 0.00 0.0058 0.0060 0.0316 0.02 0.02 2.42 0.00 0.0058 0.1770 0.0316 0.00 0.01 4.56 0.00 0.0058 0.1770 0.0316 0.00 0.00 8.77 0.00 0.0058 0.1770 0.0316 0.00 0.11 7.74 0.00 0.0058 0.1770 0.0316 0.00 1.96 8.15 0.00 0.0058 0.2890 0.0316 1.63 5.62 10.64 0.00 0.0058 0.2890 0.0316 5.29 7.68 13.82 0.00 0.0058 0.2890 0.0316 7.35 5.65 13.27 0.00 0.0058 0.2890 0.0316 5.33 1.63 6.49 0.00 0.0058 0.2890 0.0316 1.31 0.44 1.04 0.00 0.0058 0.0060 0.0316 0.40

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 19 Damnak Ampil/Candidate projects and climate change Area (km2): 121.68 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.10 0.13 2.30 0.0040 0.0070 0.0264 2.36 0.04 0.18 1.67 0.0040 0.0070 0.0264 1.67 0.02 1.54 1.67 0.0040 0.0760 0.0264 1.58 0.01 2.91 2.03 0.0040 0.0760 0.0264 1.93 0.00 5.60 2.91 0.0040 0.0760 0.0264 2.81 0.07 4.94 3.94 0.0040 0.0760 0.0264 3.91 1.25 5.21 5.00 0.0040 0.5030 0.0264 5.72 3.59 6.80 5.00 0.0040 0.5030 0.0264 8.05 4.90 8.83 5.00 0.0040 0.5030 0.0264 9.37 3.61 8.47 5.00 0.0040 0.5030 0.0264 8.08 1.04 4.15 4.39 0.0040 0.5030 0.0264 4.90 0.28 0.66 3.09 0.0040 0.0070 0.0264 3.33

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 14 Damnak Ampil/Candidate projects and climate change Area (km2): 26.53 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.02 0.03 1.18 0.0004 0.0000 0.0023 1.20 0.01 0.04 0.83 0.0004 0.0000 0.0023 0.84 0.00 0.34 0.79 0.0004 0.0560 0.0023 0.73 0.00 0.64 0.97 0.0004 0.0560 0.0023 0.91 0.00 1.22 1.40 0.0004 0.0560 0.0023 1.35 0.02 1.08 1.96 0.0004 0.0560 0.0023 1.91 0.27 1.14 2.86 0.0004 0.3540 0.0023 2.78 0.78 1.48 4.03 0.0004 0.3540 0.0023 4.45 1.07 1.92 4.68 0.0004 0.3540 0.0023 5.40 0.79 1.85 4.04 0.0004 0.3540 0.0023 4.47 0.23 0.90 2.45 0.0004 0.3540 0.0023 2.32 0.06 0.14 1.67 0.0004 0.0000 0.0023 1.73

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Table A4.8f: Water balance with Damnak Ampil Canal, candidate sub-projects and climate change, catchments 10, 12 and 4

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 10 Damnak Ampil/Candidate projects and climate change Area (km2): 95.48 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.08 0.10 2.44 0.0016 0.0190 0.0091 2.48 0.03 0.14 2.37 0.0016 0.0190 0.0091 2.37 0.01 1.21 1.86 0.0016 0.2330 0.0091 1.63 0.00 2.29 2.36 0.0016 0.2330 0.0091 2.12 0.00 4.40 3.66 0.0016 0.2330 0.0091 3.42 0.06 3.88 5.55 0.0016 0.2330 0.0091 5.37 0.98 4.09 13.05 0.0016 0.7040 0.0091 13.31 2.81 5.33 37.81 0.0016 0.7040 0.0091 39.91 3.85 6.93 51.78 0.0016 0.7040 0.0091 54.92 2.83 6.65 38.07 0.0016 0.7040 0.0091 40.19 0.82 3.25 7.40 0.0016 0.7040 0.0091 7.51 0.22 0.52 6.09 0.0016 0.0190 0.0091 6.29

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 12 Damnak Ampil/Candidate projects and climate change Area (km2): 7397 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.06 8.05 1.18 0.0014 0.0130 0.0075 1.22 0.02 10.73 0.83 0.0014 0.0130 0.0075 0.84 0.01 93.89 0.79 0.0014 0.1420 0.0075 0.65 0.00 177.05 0.97 0.0014 0.1420 0.0075 0.82 0.00 340.68 1.40 0.0014 0.1420 0.0075 1.25 0.04 300.45 1.96 0.0014 0.1420 0.0075 1.85 0.76 316.54 2.86 0.0014 0.8880 0.0075 2.72 2.18 413.11 4.03 0.0014 0.8880 0.0075 5.31 2.98 536.51 4.68 0.0014 0.8880 0.0075 6.77 2.20 515.05 4.04 0.0014 0.8880 0.0075 5.34 0.63 252.16 2.45 0.0014 0.8880 0.0075 2.19 0.17 40.24 1.67 0.0014 0.0130 0.0075 1.82

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Catchment 4 Damnak Ampil/Candidate projects and climate change Area (km2): 120.54 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.10 0.13 3.70 0.0014 0.0000 0.0073 3.79 0.04 0.17 3.21 0.0014 0.0000 0.0073 3.24 0.02 1.53 2.27 0.0014 0.1910 0.0073 2.09 0.01 2.89 2.94 0.0014 0.1910 0.0073 2.75 0.00 5.55 4.67 0.0014 0.1910 0.0073 4.47 0.07 4.90 7.22 0.0014 0.1910 0.0073 7.09 1.24 5.16 16.04 0.0014 1.2600 0.0073 16.01 3.55 6.73 45.22 0.0014 1.2600 0.0073 47.51 4.86 8.74 61.69 0.0014 1.2600 0.0073 65.27 3.58 8.39 45.53 0.0014 1.2600 0.0073 47.84 1.03 4.11 9.69 0.0014 1.2600 0.0073 9.46 0.28 0.66 8.10 0.0014 0.0000 0.0073 8.38

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Table A4.8g: Water balance with Damnak Ampil Canal, candidate subprojects and climate change, catchments 6, 22 and 7

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Catchment 6 Damnak Ampil/Candidate projects and climate change Area (km2): 103.63 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.08 0.11 0.00 0.0078 0.2010 0.0473 0.00 0.03 0.15 0.00 0.0078 0.2010 0.0473 0.00 0.01 1.32 0.00 0.0078 0.3240 0.0473 0.00 0.01 2.48 0.00 0.0078 0.3240 0.0473 0.00 0.00 4.77 0.00 0.0078 0.3240 0.0473 0.00 0.06 4.21 0.00 0.0078 0.3240 0.0473 0.00 1.07 4.43 0.00 0.0078 1.3360 0.0473 0.00 3.05 5.79 0.00 0.0078 1.3360 0.0473 1.66 4.18 7.52 0.00 0.0078 1.3360 0.0473 2.78 3.08 7.22 0.00 0.0078 1.3360 0.0473 1.68 0.89 3.53 0.00 0.0078 1.3360 0.0473 0.00 0.24 0.56 0.00 0.0078 0.2010 0.0473 0.00

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Catchment 22 Damnak Ampil/Candidate projects and climate change Area (km2): 185.68 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.15 0.20 2.30 0.0074 0.1270 0.0436 2.27 0.06 0.27 1.67 0.0074 0.1270 0.0436 1.55 0.02 2.36 1.67 0.0074 0.1270 0.0436 1.51 0.01 4.44 2.03 0.0074 0.1270 0.0436 1.86 0.00 8.55 2.91 0.0074 0.1270 0.0436 2.74 0.11 7.54 3.94 0.0074 0.1270 0.0436 3.88 1.91 7.95 5.00 0.0074 1.0840 0.0436 5.78 5.47 10.37 5.00 0.0074 1.0840 0.0436 9.34 7.48 13.47 5.00 0.0074 1.0840 0.0436 11.35 5.51 12.93 5.00 0.0074 1.0840 0.0436 9.37 1.59 6.33 4.39 0.0074 1.0840 0.0436 4.85 0.43 1.01 3.09 0.0074 0.1270 0.0436 3.34

jan feb mar apr may jun jul aug sep oct nov dec

Catchment 7 Damnak Ampil/Candidate projects and climate change Area (km2): 330.56 Water use Runoff Rainfall Inflow from Domestic Irrigation Livestock Outflow m3/s m3/s upstream m3/s m3/s m3/s m3/s 0.26 0.36 2.27 0.0068 0.5900 0.0359 1.90 0.11 0.48 1.55 0.0068 0.5900 0.0359 1.02 0.04 4.20 1.51 0.0068 0.4160 0.0359 1.10 0.02 7.91 1.86 0.0068 0.4160 0.0359 1.42 0.01 15.22 2.74 0.0068 0.4160 0.0359 2.28 0.20 13.43 3.88 0.0068 0.4160 0.0359 3.62 3.40 14.15 5.78 0.0068 0.9900 0.0359 8.15 9.74 18.46 9.34 0.0068 0.9900 0.0359 18.05 13.32 23.98 11.35 0.0068 0.9900 0.0359 23.63 9.81 23.02 9.37 0.0068 0.9900 0.0359 18.15 2.83 11.27 4.85 0.0068 0.9900 0.0359 6.65 0.77 1.80 3.34 0.0068 0.5900 0.0359 3.48

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Appendix 5: Water quality simulations A5.1

General

MIKE Basin set-up

A MIKE Basin Water Quality model was setup for the Dauntri study area based on the water balance. The water balance is based on down stream discharges calculated from the water level measurements and Q/h relations which are available for 1998 – 2005. Calculated discharges have been translated into area specific runoffs as input for the MIKE Basin model. Water quality settings

For water quality simulations the following input is needed apart from catchment associated pollutant sources described earlier: •

Pollutant residence time in river reaches calculated using Mannings equation

•

Water quality rate constants

•

Temperature in river water

•

Concentration of pollutants in base-flow

•

Pollutant residence time

•

Pollutant residence time in river reaches is calculated as a function of river discharge using Mannings equation:

•

River width: 10 m - applied for all branches

•

River Slope: calculated average from digital elevation model

•

Manning number: 25

•

River discharge: from MIKE Basin water balance calculation

Water quality rate constants

The following standard decay process rates were applied: BOD decay

0.1 day-1

Denitrification 0.2 day-1 Nitrification

0.2 day-1

P retention

0.1 day-1

N/BOD

0.1

A constant water temperature of 27 degrees Celsius was applied to correct for temperature dependent processes.

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Base-flow concentrations

Base-flow concentrations are most often significanty lower than concentration of pollutants in surface or drainage runoff due to much longer residence time in the groundwater and a significant retention of pollutants. The base-flow concentrations applied were: BOD:

0.1 mg/l

NO3:

0.5 mg/l

NH4

0.05 mg/l

TP:

0.01 mg/l

Ecoli:

0

Preliminary calibration

Targets (= average concentration levels) for simulated concentrations of water quality components: BOD

1 mg/l

NO3

0.5 – 1 mg/l

NH4

0.1 – 0.5 mg/l

TP

0.01-0.05

Ecoli

(no target available)

Results are shown below before and after the planned irrigation development.

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A5.2

Present conditions Figure A5.1: Average concentration of BOD for 2000 and 2001

Figure A5.2: Maximum concentration of BOD for 2000 and 2001

Please note: Not same scale as the above figure

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Figure A5.3: Average concentrations of NH4 for 2000 and 2001

Figure A5.4: Maximum concentrations of NH4 for 2000 and 2001

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Figure A5.5: Average concentrations of NO3 for 2000 and 2001

Figure A5.6: Maximum concentrations of NO3 for 2000 and 2001

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Figure A5.7: Average concentrations of Total-phosphorus for 2000 and 2001

Figure A5.8: Maximum concentrations of Total-phosphorus for 2000 and 2001

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A5.3

139

Implications of irrigation development Below is shown the simulated concentrations of BOD, ammonium, nitrate and total phosphorus in the different stretches of the rivers in the catchment.

Figure A5.9: Average concentration of BOD for the candidate sub-projects

Figure A5.10: Maximum concentration of BOD for the candidate sub-projects

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Please note: Not same scale as the above figure

Figure A5.11: Difference in BOD concentrations between the candidate sub-projects and the present situation

Figure A5.12: Average concentrations of NH4 for the candidate sub-projects

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Figure A5.13: Maximum concentrations of NH4 for the candidate sub-projects

Figure A5.14: Difference in NH4 concentrations between the candidate sub-projects and the present situation

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Figure A5.15: Average concentrations of NO3 for the candidate sub-projects

Figure A5.16: Maximum concentrations of NO3 for the candidate sub-projects

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Figure A5.17: Difference in NO3 concentrations between the candidate sub-projects and the present situation

Figure A5.18: Average concentrations of total-phosphorus for the candidate subprojects

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Figure A5.19: Maximum concentrations of total-phosphorus for the candidate subprojects

Figure A5.20: Difference in total-phosphorus concentrations between the candidate sub-projects and the present situation

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Project Working Team of River Basin Study-Package 2 Dr. Tue Kell Nielsen Mr. Toch Sophon Mr. Henrik Garsdal Mr. Jens Erik Lyngby Mr. Teang Sokhom Mr. Prum Peurn Ms. Petrina Rowcroft Ms. Sorn Somoline Mr. Nay Sophon

Team Leader Co Team Leader Hydrology Expert Water Quality Expert GIS and Remote Sensing Specialist Water Use and Water Balance Specialist Environmental Economic Expert Socio-Economic Specialist Community Development Specialist