Dams Report

The Impact of Dams on Life in Rivers A WWF Research Report

Submitted to the World Commission on Dams

Prepared by Biksham Gujja and Diwata Olalia Hunziker April 2000

The Impact of Dams on Life in Rivers

This document brings together information on the impact of dams on river ecosystems and species. This information was submitted by members of the WWF Network and its consultants with a view to contribute to the process of the World Commission on Dams. All scientific data mentioned herein were taken from factsheets, which can be obtained on request from WWF International. The views expressed in this document do not necessarily represent those of WWF International. The material and geographical designations in this report do not imply the expression of any opinion whatsoever on the aprt of WWF concerning the legal status of any country, territory, or area, or concerning the delimitation of its frontiers or boundaries. Published in April 2000 by WWF−World Wide Fund for Nature (formerly World Wildlife Fund), Gland, Switzerland. Any reproduction in full or in part of this publication must mentioned the title and credit the above-mentioned publisher as the copyright owner.

© WWF International, April 2000

2

The Impact of Dams on Life in Rivers

The Impact of Dams on Life in Rivers A WWF Research Report

Submitted to the World Commission on Dams

Prepared by Biksham Gujja and Diwata Olalia Hunziker

Copyright WWF International Gland, Switzerland April 2000

3

The Impact of Dams on Life in Rivers

Photo credits Cover: WWF China Page 8: © WWf/Sturre Karlsson Traneving Page 17: © WWF-Canon/Michel Gunther Page 27: © WWF Netherlands © WWF-Canon/Mike Baltzer/TNPCP (Javan Rhino/Rhinoceros sondaicus annamiticus) Page 25: © WWF-Canon/Paul Barruel Page 26: © WWF-Canon/Juan Pratginestos

4

The Impact of Dams on Life in Rivers

5

The Impact of Dams on life in Rivers A Research Report Submitted to the World Commission on Dams

CONTRIBUTIONS Our heartfelt thanks to the following colleagues and contributors without whom this paper would not have been possible, and to those who have chosen to remain anonymous. Robin Adell (WWF USA);Azwar (Indonesia); Arch. Guglielmo Blanzone (Italy); Alain Cassani (Switzerland); Monica Chundama (WWF Zambia); Alberto Fernandez (WWF Spain);

Michelle Handley (WWF Australia);

Kurshid (WWF Pakistan);

Roger Landivar (WWF Bolivia);

(Zambia); Daniel Ngantou (WWF Cameroon); Gert Polet (Vietnam);

Liang Haitang (WWF China);

Najam

Chiseche M. Mutale

Bernadete Ribas Lange (WWF Brazil);

Juan Carlos Riveros (WWF Peru);

David Claudio Antonio

Scarpinella (Brazil); P.A. Brasil; Joanna Tang (WWF Malaysia); Seng Teak, WWF Indochina (Cambodia);

Antonio Tricarico (Italy);

David Stone (Switzerland); Liang

Haitang (WWF China); Syed Najam Khurshid (Pakistan); Alexander Zinke (Austria)

Acknowledgements We wish to thank Musonda Mumba and Amalia Romeo (WWF Freshwater Programme) for their most valuable assistance in preparing this report.

The Impact of Dams on Life in Rivers

6

Contents I.

Introduction

II.

Methodology

III

Brief context of the study A. Dams 1. History of Dams 2. Functions of Dams B. Rivers and species

III.

Main findings

IV.

Summary & conclusions

Annexes Annex 1. Annex 2. Annex 3.

Fact sheets Synoptic table of dams and their impact on species and the ecosystem List of threatened species according to the findings of the study, the 1996 IUCN Red List of Threatened Plants and the 1997 IUCN Red List of Threatened Animals

References List of tables Table 1. Table 2. Table 3. Table 4. Table 5. Table 6.

Number of fact sheets received, by country Freshwater Ecosystems Index Number of fish species in the world's 11 most species-rich primary watersheds Some of the major impacts of dams on ecosystems and species Selection of species that have disappeared, become extinct or endangered by dam operations Samples of decline of species and how they are affected by dam operations

Boxes Box 1. Box 2. Box.3

Significance of major groups of organisms and their significance in freshwater Selected cases of how dams affect species Species indicated as NI (no information available)

The Impact of Dams on Life in Rivers

I.

5

Introduction

This report is a contribution of WWF World Wide Fund for Nature to the ongoing work of the World Commission on Dams (WCD). Prior to this study and as a member of its Consultative Forum, WWF had submitted a Discussion Paper, A place for dams in the 21st century, and a policy paper and recommendations. In the latter document, WWF states its commitment to the work of the WCD: WWF will play a role in influencing the agenda and implementation of the work programme of the World Commission on Dams. WWF will provide information, advice, recommendations, and funding for specific programmes that advance the conservation and protection of nature and wildlife affected by the construction of dams. In subsequent informal discussions, the lack of specific data on the impact of dams on biodiversity was mentioned. Indeed, there is an extensive documentation on the social and environmental impacts of dams, but specific information on the impact of dams on ecosystems and species seem to be insufficient. In response to this need, WWF initiated a brief study that would provide an overview of the impacts of dams on river ecosystems.

WWF is acutely aware of implications of the degradation of ecosystems and loss of species, on local peoples and communities and their livelihood and survival. While this question is recognized as a vital issue by WWF and since it is being addressed in another thematic review of the WCD, the data analysis was focused on loss of species and degradation of ecosystems. The primary objective of this study is to provide a factual snapshot of the impacts of dams on species and ecosystems by providing examples of specific species and habitats which have been lost and degraded due to construction of dams, regardless of their size. In view of the scope of the subject, the technical expertise required and the availability of scientific data, this report is focused on the information supplied by the WWF network. We hope that the findings would provide the WCD with useful tools and information necessary to accomplish its mission.

The Impact of Dams on Life in Rivers

II.

6

Methodology

A fact sheet (Annex 1) was developed and first sent to WWF's freshwater network, who had the technical expertise in providing the information needed. Some were able to provide information immediately, and others had to hire consultants for various reasons (work overload, need for additional research, etc.) or gave names of contact persons. Considerable follow-up was required to have the fact sheets submitted on time, and the deadline was extended many times in order to receive as many fact sheets as possible. The data received through the fact sheets can be considered as primary first-hand information. They came in four languages: English, French, Spanish and Italian. The majority was received from WWF network. As expected from primary sources, the information given revealed regional/cultural influences and different levels of understanding of the subject. These could be mainly attributed to inadequate and/or lack of scientific data. Nevertheless, the data gathered represents sufficient evidence and geographical representation (e.g., Bangladesh, Bolivia, Brazil, Cambodia, Cameroon, China, Namibia, Pakistan, Slovakia, and USA) to produce a synopsis of some of the major impacts of dam operations on ecosystems and

species. The impacts could be more significant than we could possibly substantiate through the data received. Information on a total of 91 dams representing 30 countries were received (Table 1). Pakistan provided data on 23 dams and barrages that constitute the water resources development of the Indus River and Spain enumerated information on specific species threatened or endangered in 19 dams. The information submitted by Pakistan and Spain underscores the degree of difficulty in obtaining data required on the dams. For dams in 1 Bangladesh, Brazil , Egypt and Namibia 2, the information (for which no fact sheets were written) given in Annex 2 was researched by the authors. Certain data given in the fact sheets mention only the number of endemic species that have become extinct or have disappeared, or endangered and threatened, without necessarily specifying the name of the species. Others contain information limited to the first part of the fact sheet (physical and geographical description, EIA that are not analyzed in this study). Altogether, the fact sheets are the product of the time and effort that the various offices and individuals, within the given technical capabilities and deadlines. 1 2

Tucurui Dam. Epupa Hydropower Dam.

The Impact of Dams on Life in Rivers

A synoptic table (Annex 2) has been drawn to show the country, name of dam, location, main purposes, status and the summary of impacts on the ecosystem and species. The original fact sheets will be reproduced in a separate annex to the report. Finally, for the purposes of the study, the species were classified according to IUCN's Red List categories (Annex 3) and the authors' own designation (NI-no information available). While most

Wattled crane (Grus carunculatus)

7

species are not listed in the IUCN Red List of Threatened Animals (1997) and Threatened Plants (1996), they are officially recognized in the country itself as extinct, rare, endangered, threatened or protected. This explains the number of species for which no information is available in IUCN's Red List. Moreover, considering that the IUCN Red List goes back to four/five years, it is highly probable that the species listed in the fact sheets would be appropriately indexed in the updated Red List currently being prepared.

The Impact of Dams on Life in Rivers

8

Table 1. Dams studied Country

No. of dams

Name of dams

Argentina, Bolivia, Brazil, Paraguay, Uruguay

1

Hidrovía Project

Australia

1

Lake Pedder (Serpentine Impoundment)

Bangladesh

10

Bank Protection and River Training Project, Brahmaputra River Bank Priority Works, Dhaleswari Closure Dam, Farakka Barrage, Jamalpur Priority Project, Jamuna River Project Embankment, Kalni-Kushiyara River Improvement Project, Kaptai Dam, Manu Barrage, Teesta Barrage

Bolivia

1

Bala Dam Project

Brazil

6

Balbina Dam, Curua Una Dam, Itaipú Binacional, Porto Primavera Dam, Serra da Mesa Mill Dam, Tucurui Dam

Cambodia

1

Prek Thnot Multipurpose Project

Cameroon

1

Barrage de Maga

Canada

1

Lake Winnipeg Churchill-Nelson River Diversion Project

Chile

1

Ralco Dam

China

2

Three Gorges Dam Project, Cascade Hydropower Projects

Colombia

1

Urra I Dam

Egypt

1

Aswan High Dam

Indonesia

2

Kedung Ombo Dam, Wadaslintang Dam

Italy

1

Diga di Genzano di Lucania Dam

Laos

1

Nam Theun-Hinboun Hydropower Project

Lesotho

1

Lesotho Highlands Water Project

Malaysia

1

Bakun Hydroelectric Project

Namibia

1

Hydropower Scheme on the Lower Cunene River (Epupa Hydropower Dam)

Nepal

1

Kaligandaki Hydroelectric Project

Nigeria

1

Tiga and Challawa Gorge Dams (Kano River Irrigation Project and Hadejia Valley Project)

Pakistan

23

Kalabagh Dam Project, Kalabagh Barrage, Khanki Barrage, Khanpur Dam, Kotri Barrage, Mangla Dam, Marala Barrage, Panjpad Barrage, Qadirabadballoki Link, Rasul Barrage, Rawal Dam, Sidhnai Barrage, Sukkur Barrage, Suleimanki Barrage, Tanda Dam, Tarbela Dam, Taunsa Barrage, Trimu Barrage, Warsak Dam

Peru

1

El Platanal Hydroelectric Project

Slovak Republic

1

Gabcikovo-Cunovo Dam

Spain

20

Enciso Dam, Rialp Dam, Itoiz Dam, Atance, Irueña Dam, Santa Liestra Dam, Navia Dam, Breña II, Melonares Dam, Andevalo Dam, Castrovido Dam, Biscarrues Dam, Janovas Dam, Sela Dam, Hozgarganta Dam, Venta del Obispo Dam, Pozo de los Ramos, Genal Dam, Ubeda La Vieja Dam

Tanzania

1

Lower Kihansi Hydropower Project

USA

5

Glen Canyon Dam, Elwha Dam and Glines Canyon Dam, Rodman Dam and Spillway (now Kirkpatrick Dam), Condit Dam, Ice Harbor Dam, Lower Monumental Dam, Little Goose Dam, and Lower Granite Dam

Vietnam

1

Dong Nai No. 3 and Dong Nai No. 4 Combined Hydropower Project

Yugoslavia/Romania

1

Iron Gate I and Iron Gate II

2

Itezhi-tezhi Hyropower Project, Kariba HydropowerDam

Zambia TOTAL

91

The Impact of Dams on Life in Rivers

9

III. Brief context of the study A.

Dams

1. History of dams 3 Civilizations have consistently walled, canalized and blocked river systems. The earliest remains of dams found were built around 3,000 BC as part of an elaborate water supply system for the town of Jawa in today's Jordan. The largest of the dams was more than four metres high and 80 metres long. Some 400 years later, around the time of the first pyramids, Egyptian masons constructed the Sadd elKafra, or 'Dam of the Pagans' across a seasonal stream near Cairo. By the late first millennium BC, stone and earth dams had been built around the Mediterranean, in the Middle East, China, and Central America. The Romans built some of the most impressive in Spain, which

continued to be preeminent in hydraulic engineering through the Moorish period and into modern times. A 46-metre-high stone dam near Alicante begun in 1580 and completed 14 years later was the highest in the world for the better part of three centuries. South Asia, too, has a long history of dam building. Long earthen embank-ments were built to store water for Sri Lankan cities from the 4th century BC. One of these early embank-ments was raised in 460 AD to a height of 34 metres and was the world's highest dam for more than a millennium later.

The Elwha and Glines Canyon during

construction early 20

th

century 4

Technologies to convert the energy of flowing water into mechanical energy have a history 3

McCully, Silenced Rivers, pp. 12-17.

4

http://www.nps.gov/olym/issues/isselwha2.htm

The Impact of Dams on Life in Rivers

almost as long as that of irrigation. A type of waterwheel known as the Noria which has buckets around its rim to scoop up water from a river or canal was used in Ancient Egypt and Sumeria. By the first century BC, watermills were used to grind corn in Rome. During the later Middle Ages, watermills performed numerous tasks in the industrial centres of Germany and northern Italy including pulping rags for paper, hammering iron, beating hides in tanneries, spinning silk, crushing ores and pumping water from mines. Ores from the famous "silver mountain" at Potos’ in Bolivia were ground in well over a hundred watermills. The industrializing world of the 19th century built increasingly large dams to store water for its expanding cities. These dams were mainly earth embankments designed largely on the basis of trial and error – until the 1930s there was little scientific understanding of how soil and rock behaved under pressure, leading to quite a few catastrophes of structures collapsing. Following the production of the first water turbines in 1832, advances in electrical engineering led to building of power stations and transmission lines. The world's first hydro plant, a run-ofriver dam in Appleton,

10

Wisconsin (USA), began producing power in 1882. The following year hydro dams were built in both Italy and Norway. Over the next few decades, small hydro dams proliferated on the swift-flowing rivers and streams of Europe, most notably in Scandinavia and the Alps. After the turn of the century, the size of the dams and power stations being built began rapidly to increase. Progress in turbine design increased the head at which turbines could operate from 30 metres in 1900 to more than 200 metres by the 1930s, and improvements in dam engineering allowed the high dams to be built to create this head. A recent WWF study on dams reports that worldwide, there are 41,413 operational dams shigher than 15m. 5.

2.

Functions of dams

Dams are constructed for many reasons: to protect land from floods, to store water, to generate power, to redirect river channels, to create artificial lakes (reservoirs), to transport, and to keep water levels high for the boats. All dams, no matter why they are built, must be strong enough to contain huge volumes of water without leaking or breaking.

5

WWF, A Place for Dams in the 20th Century, p. 4

The Impact of Dams on Life in Rivers

Dams have two main functions. The first is to store water to compensate for fluctuations in river flow or in demand for water and energy. Storing water requires raising the level of the water upstream to enable water to be diverted into a canal or to increase "hydraulic head" – the difference in height between the surface of a reservoir and the river downstream. The creation of storage and

Fishing at the Elwha River in the 1800s 6

6

http://www.nps.gov/olym/issues/isselwha2.htm

11

head allow dams to generate electricity (hydropower provides nearly a fifth of the world's electricity); to supply water for agriculture, industries and households; to control flooding; and to assist river navigation by providing regular flows and drowning rapids. Other reasons for building large dams include reservoir fisheries and leisure activities such as boating (cf. column 4, Annex 2).

The Impact of Dams on Life in Rivers

12

seeds of trees and emergent vegetation of the rivers, which in turn provide food to other species in the adjacent ecosystems.8

The Balui river and the surrounding forest, 7 where the Bakun dam is being built.

B.

Rivers and species

Flowing waters such as rivers are rich in species diversity. A river system represents a complex aggregation of physical and biological elements. In its downhill journey, rivers carry along water to refresh wells and springs and to provide communities, farms and factories. Rivers are responsible for meeting most of the water resources for human needs. A large river and its drainage basin are an ecosystem in itself, with both terrestrial and aquatic components. The amount of debris in the water – such as leaves and mud – also affect their existence. If the river environment changes, some its aquatic species may have to migrate elsewhere or perish.

Complex and dynamic, river systems can change course radically as a result of deposition and erosion of their channels and tributaries, and the uplift and erosion of watershed uplands. The different organisms living symbiotically in these river ecosystems are consequently threatened when their environment is disturbed. Box 1 outlines some of the major groups of organisms (listed in our findings) and their significance/role in the sustainability of freshwaters.

The project would involve clearing 69,640 ha of forest area, causing extensive destruction of habitats and loss of natural vegetation.... Dipterocarpus oblongifolius can only be found in the upstream part of most rivers in Sarawak .... The extensive formation of its root system effectively prevents erosion in areas where the river flows fast all the time. The fruits of this species provide nutritious food for aquatic life and wildlife. (Malaysia, Bakun Hydroelectric Project)

Fish and other species live and depend on rivers, adapting to its depth, flow and temperature of water. Some fish fight the fast currents of midstream, while others flock near rocks in calm, shallow waters. In addition, they serve as food to migratory birds and are known to disperse 7

http://www.foe.co.uk/camps/biohab/bakunhom.htm

8

WWF International, Changing Worlds, pp. 91-101.

The Impact of Dams on Life in Rivers

Box 1.

Some of the major groups of organisms and their significance in freshwaters

Plants Provide a substrate for other organisms and food for many. Trees are ecologically important in providing shade and organic debris (leaves, fruit), structural elements (fallen trunks) and branches) that enhance vertebrate diversity, in promoting bank stabilisation, and in restricting or modulating floodwaters. Invertebrates: protozoans Found in virtually all freshwater habitats. Most abundant in waters rich in organic matter, bacteria or algae. Feed on detritus, or consume other microscopic organisms; many are parasitic on algae, invertebrates or vertebrates. Invertebrates: crustaceans Include larger bottom-living species such as shrimps, crayfish and crabs of lake margins, streams, alluvial forests and estuaries. Invertebrates: insects In rivers, streams and lake communities, grazing and predatory aquatic insects dominate intermediate levels in food webs (between microscopic producers, mainly algae, and fishes). Vertebrates: fishes More than half of all vertebrate species is fishes. Fishes are the dominant organisms in terms of biomass, feeding ecology and significance to humans, in virtually all aquatic habitats, including freshwaters. Vertebrates: birds Top predators. Wetlands are often key feeding and staging areas for migratory birds. Vertebrates: mammals Top predators, and grazers. Large species widely impacted by habitat modification and hunting.

Source: WCMC/UNEP, 1998, pp. 18-20

13

Box 1 mentions organisms that inhabit rivers, lakes and wetlands, which are home for most of freshwater biodiversity. Representing only one percent, river water is therefore a small part of an equally small and vulnerable ecosystem containing a comparatively rich diversity of life. It is so complex that "unlike forest ecosystems, it is not possible to indicate biological trends". WWF's Living Planet Report 1999 on freshwater ecosystems index − based on 102 freshwater species (available data mostly North American and European) including "... every mammal, bird, reptile, amphibian, and fish species for which time-series population data could be obtained" − indicates that freshwater species have, on average, declined by about 45 percent over a period of 30 years (Table 2). 9 The downward trend of fish species represents both considerable biological and economic significance. Other species (birds and mammals) in the surrounding ecosystems depend on

The Impact of Dams on Life in Rivers

14

freshwater fishes and adjacent communities are sustained by them.

local

For example, inland wetlands of Africa are reported to produce 1.5 metric tonnes of fish annually and support one million fishermen and about five million ancillary fishery workers (Bernacsek, 1992). In Asia alone, more than two billion people depend on wetland crops and fish as their main staple and protein source (Ramsar, 1998). To illustrate further this richness, Table 3 summarizes information available provided on some of the world's major watersheds. The number of fish species indicated includes estimates of the total number of fish species present in each basin, excluding introduced species where relevant information was available. The data has a significant error margin, reflecting different survey and reporting methods, different taxonomies, date and completeness of surveys, etc. (WCMC, 1998).

Table 2. Freshwater Ecosystems Index Freshw ater Ecosystem s Index 12 0

10 0

80

60

40

20

0 19 70

19 75

19 80

19 85

19 90

19 95

Source: WWF International, Living Planet Report 1999, Gland, Switzerland.

9

WWF, Living Planet Report 1999, pp. 6-7.

The Impact of Dams on Life in Rivers

Rivers do not only provide "shelter" to fish species but are also essential grounds for waterbirds and other large aquatic species, providing nutrients and supplying them vital biological corridors. Notable wildlife species on the Kafue flats are the semi-aquatic Kafue lechwe (Kobus leche kafuensis) and the Wattled crane (Grus carunculatus), both of which have in the past been identified as endangered by dam operations. (Zambia, Itezhi-Itezhi Hydro-power Project)

15

Table 3. Number of fish species in the world's 11 most species-rich primary watersheds

Watershed/Continent

No. of fish species

Amazon Congo Nile & Lake Victoria Mississippi Parana Yangtze Kapus (Indonesia) Orinoco

2,500 700 432 375 355 322 320 318

Source: WCMC/UNEP, 1998, pp. 94-101.

Kafue Gorge Dam (Zambia) (Photo by Musonda Munda)

Lock gates and hydropower station at Gabcikovo (Romania/Yugoslavia)

IV.

MAIN FUNDINGS

The Impact of Dams on Life in Rivers

Every every river and the species it supports are both unique and complex at the same time. The same could be said of the effects every dam has on the river and its ecosystems. For the downstream section alone, some of the impacts the WWF discussion paper on dams outlined include the following: loss and damage to freshwater habitats and species, reduction in silt due to filters and the dam wall, changes in groundwater level, changes in flow, and waterlogging and salinity.10 The major impacts of dams on ecosystems and species considered in this report are outlined in Table 4 below. According to the submissions, the most significant consequence of dams is the degradation or the destruction of riverine ecosystems, isolating populations of species living up and downstream of the dam and cutting off migrations and other species' movements. Almost all dams reduce normal flooding, fragment ecosystems and isolate migratory species. The elimination of biological benefits to a chain of organisms may be the most damaging impact of dams.

species and ecosystems. Irrigation waters, for instance, whether from rivers or groundwater, contain dissolved salts washed out of rocks and soils. Evaporation from reservoirs, canals and fields increase the concentration of salts. When the water reaches crops, the roots absorb water but leave in the soil most of the toxic salts. This has obvious severe consequence on the fields of farmers whom, to prevent salinization, apply more water to wash salts from the roots. However, this procedure increases the salinity of groundwater and in the absence of good drainage, causes the water table to rise and through a chemical process, reaches the surface, eventually evaporating and leaving behind a crust of white crystals, thus waterlogging the roots of the crops. Finally, saline wastewater draining back into the river progressively reduces downstream water quality for all users of water.11 Notable wildlife species on the Kafue flats are the semi-aquatic Kafue lechwe (Kobus leche kafuensis) and the Wattled crane (Grus carunculatus), both of which have in the past been identified as endangered by dam operations. (Zambia, Itezhi-Itezhi Hydro-power Project)

Initial analysis of information reveals that dams built for irrigation, flood control and hydroelectric purposes are those that most endanger and threatens

10

WWF, A Place for Dams in the 20th Century, p.7-18.

16

11

McCully, Silenced Rivers, pp. 168-169.

The Impact of Dams on Life in Rivers

Table 4. Some of the major impacts of dams on ecosystems and species

Immediate impact Flooding and inundation

Water withdrawal

Long-term impact changes in water flows, levels and temperatures Sedimentation and erosion

Salinization, siltation, waterlogging, alkanization

Reduction of oxygen flow, loss of agricultural lands

Flooding and inundation of riparian communities and wetlands

Destruction of aquatic ecosystem, increase of pollutants discharge and other toxic gases

Destruction of river banks, lakes and delta soils

Destruction of wildlife and bird sanctuaries, Reduction of nutrients and other trace elements

Rise of groundwater levels

Drainage problems, blocking fish migration and reducing fish reproduction, water shortage

Increase in temperatures of fish ladders Proliferation of aquatic weeds

Source: Factsheets

Fish kills

Lower dissolved oxygen from decaying vegetation

17

The Impact of Dams on Life in Rivers

Examples of fishes which have adapted morphologically to changes in water 12 temperatures

Razorback sucker (Xyrauchen texanus)

Flannelmouth sucker (Catostomus latipinnis)

Colorado squawfish (Ptychocheilus lucius)

Humpback chub (Gila cypha)

12

Source: USA Fact sheets

18

Some of the impacts of dams can benefit certain species to the detriment of others. For example, impounding a reservoir will create habitat for lake fish, and warm water released from a reservoir can increase the abundance of those that failed to thrive in the cooler temperatures. The emergence of marsh plants and exotic species were mentioned as examples of the proliferation of species, which were before negligible in numbers or were not present at all (cf. Annex 2, Dam No. 83, col. 6). At the same time, morphological adaptation was observed in the following endemic fishes in the USA: humpback chub (Gila cypha), bonytail (G. elegans), Colorado squawfish (Ptychocheilus lucius), roundtail chub (G. robusta), razorback sucker (Xyrauchen texanus). The Colorado squawfish is the largest cyprinid in North America.

The Impact of Dams on Life in Rivers

Box 2.

Selected cases of how dams affect species

USA: Elwha Dam and Glines Canyon Dam – constructed in 1912 – the Glines Canyon Dam lies within Olympic National Park, a World Heritage Site – built without fish passage facilities Before the dam: an estimated 380,000 migrating salmon and trout spawned in the river, including all five species of Pacific salmon (chinook/Oncorrhynchus tschawytscha; coho/O. kisutch; sockeye/O. nerka; pink/O. gorbuscha; and chum/O. keta), and 3 species of anadromous trout (steelhead/O. mykiss; cutthroat/O. clarki; and Dolly Varden char/Salvelinus malma). After the dam: – eliminated 93 % of fish habitat – all 10 runs of Elwha salmon and sea-going trout have subsequently declined. – rare wildlife species other than fish were adversely affected: Northern spotted owl (Strix occidentalis caurina), Marbled murrelet (Brachyramphus marmoratus), Fisher (Martes pennantiI), Harlequin duck (Histrionicus histrionicus), Vaux's swift (Chaetura vauxi), Pileated woodpecker (Dryocopus pileatus), and several uncommon amphibian species –

Brazil − Porto Primavera Dam − construction started in 1979; operational in February 1999 − situated within two ecosystems: Atlantic Rainforest and Brazilian savannahs Impact: − endangers rare endemic species such as the wetland deer, giant anteater and freshwater otters − threatens thousands of rare monkeys, birds, vegetal species (câtinga and cerrado), and fishes China: Yangtze Three Gorges Dam – Construction started in December 1994; scheduled to finish in 17 years – The dam will control 56 % of the Yangtze catchment, or 1 million km2 of watershed area Impact: – modification of natural habitats of fish and birds that depend on the surrounding wetlands, which contains Ramsar-designated sites: Dongting Lake and Poyang Lake (two largest freshwater lakes in China), where more 200 migratory birds pass, including the endangered Siberian White Crane Tanzania – Lower Kihansi Hydropower Project Construction started in 1995; scheduled to be completed end-1999 The project area is located in the Uzungwa Mountains, a national park. Impacts: – destruction of evergreen forests and woody biomass (Parinari excelsa), endangering the biological corridors (gene exchange) between Kihansi Gorge and Uzungwa Scarpo forest communities – modification of ecosystems depending on moisture and spray due to change in water flows – inundation of riverbank forest and consequent extinction of epiphytic orchids and the possible extinction of the Sanja mangobey and Red colobus monkeys – –

Source: Factsheets

19

The Impact of Dams on Life in Rivers

Flooded forest along Rio Negro (Brazil) during rainy season

20

River and floodplain habitats are some of the world's most diverse ecosystems. The permanent inundation of riverine forests has the most obvious impact on the survival of species. Although it is difficult to ascertain in this study the direct correlation between flooding and inundation and the number of species of plants and animals that have become extinct, the study has revealed a total of 245 species of animals and plant species directly and indirectly affected by dam operations. Table 6 below summarizes the impact of dams on species using the IUCN Red List categories. There are, however, some of the species mentioned in the fact sheets as extinct or disappeared are not mentioned in the IUCN Red List categories (Table 6). More specifically, six species are believed to have disappeared or become extinct, and a few others need to be specified with the area concerned (e.g., extinction of two critically endangered fish species (Namibia); extinction of other aquatic species (Pakistan); loss and disappearance of migratory birds of Siberia and Kazakhstan (Pakistan), disappearance of protected, endangered, red-listed or endemic flora (Slovak Republic)). A dramatic example of the loss of species is the case of the Itaipú Binacional Mill Dam, where "all fauna classes [were] eliminated".13

13

Brazil, Itaipú

The Impact of Dams on Life in Rivers

21

The Gaur ( Bos gaurus ) inhabits evergreen and deciduous forested hills and associated grassy clearings up to 1,800m, eastwards from India, Nepal and Bhutan to Myanmar, Thailand, Laos, Cambodia, Vietnam, southern China and the Malay Peninsula. A large (650 to 1,000kg) and where undisturbed mainly diurnal animal, it lives in herds of from 2 to 40 individuals containing only one mature bull. (...) During the dry season, herds congregate and remain in small areas, dispersing into the hills with the arrival of the monsoon. While gaurs are dependent on water for drinking, they do not seem to bathe or wallow. When alarmed, gaurs crash into the jungle at a surprising speed. Gaurs live in herds led by a single adult male. [Gaurs] are declining drastically through over-hunting; intolerance of habitat 14 destruction and disturbance by people.

The species were grouped according to mammals, fish and amphibians, birds and plants. Although the majority of the names are in English with the equivalent scientific name, some data on species' names were given only in the local language. This is revealing of the fact that there is indeed inadequate data to effectively catalogue all species that have declined, disappeared or gone extinct.

14

http://www.wcmc.org.uk/infoserv/countryp/vietnam/app4.html #GAUR; http://www.ultimateungulate.com/gaur.html

The Impact of Dams on Life in Rivers

Table 5.

Selection of species that have disappeared, become extinct, or endangered by dam operations

Species Siberian Crane

Coho salmon (O. kisutch)

Cob defassa (Kobus cob); Hippopotamus (Hippopotamus equinus) Gaur (Bos gaurus)

Dam Yangtze Three Gorges Dam (China) Ice Harbor Dam, Lower Monumental Dam, Little Goose Dam, and Lower Granite Dam (Washington, USA) Barrage de Maga (Cameroon)

Dong Nai No. 3 and Dong Nai No. 4 Combined Hydropower Project

Atlantic sturgeon (Acipenser )

Lake Winnipeg ChurchillNelson River Diversion Project (Canada)

Javan rhino (Rhinoceros sondaicus annamiticus); Whitewinged wooden duck (Cairina scutulata)

Dong Nai No. 3 and Dong Nai No. 4 Combined Hydropower Project (Vietnam)

Sanja mangobey monkey Red colobus monkey (Colobus rufomitratus)

Lower Kihansi Hydropower Project (Tanzania)

Ganges river dolphin or susu (Platanista gangetica)

Jamuna River Project Embankment (Bangladesh)

Iberian lynx (Lynx pardinus)

Irueña Dam, Melonares Dam, Andevalo Dam (Spain)

Giant anteater (Myrmecophaga tridactyla)

Porto Primavera Dam (Brazil)

Ikan temoleh (Probarbus julleni)

Prek Thnot Multipurpose Project (Vietnam)

Amazon dolphin, or boto, tonina, or bufeo (Inia geoffrensis) Source: Factsheets

Balbina Dam (Brazil)

22

The Impact of Dams on Life in Rivers

23

Some of the most vulnerable and endangered 15 mammals due to dam operations

Hippo tamus (Trich echus manat us latiros tris)

15

cf. Annex 3

Ganges dolphin

(Platanista gangetica)

Javan rhino (Rhinoceros sondaicus annamiticus

The Impact of Dams on Life in Rivers

IV.

24

SUMMARY AND CONCLUSIONS

This study is intended to provide an overview of the current situation rather than suggest solutions to solve it. While it recognizes the complex issues involved, WWF hopes that these findings will be integrated in the final report and recommendations of the WCD. Dams are giant barriers that trap river water in reservoirs. They are known to generate electricity or to protect homes from disastrous floods. Yet, dams can also prevent floodwaters from replenishing the soil downstream and, in time, make the farmers' fields on the river's floodplain less fertile – even barren.

W hit e-winged wood duck (Cairina scutulata)

Table 6. Samples of species and how 16 they are affected by dam operations

Damming rivers have disastrous effects on the capability of most species to survive. Many rivers are no longer free flowing, reducing flows and nutrients to wetlands. Rivers have been blocked, diverted and so fragmented that ecosystems and species are threatened. The current study, undertaken within a limited time frame, has documented a total of total of 254 species. Of this number, 72 are registered and 182 are not in mentioned in the current IUCN Red Lists (cf. Boxes 3 and 4).

Species Pedder Galaxias (Galaxias pederensis) Wetland deer (Blastocerus dichotomus) Gato-maracaja (Leopardus wiendii)

16

Dam operation Impoundment filling Flooding of wetlands

Change in water quality of reservoir

Ganges river dolphin/susu (Platanista gangetica)

Reduction in the flow of freshwater, saline encroachment in delta habitat

Siberian White Crane

Fluctuation in water level, leading to flooding during dry season, blockage of sedimentation upstream, siltation, erosion

Source: Fact sheets

The Impact of Dams on Life in Rivers

The vulnerability of a small but rich and complex ecosystem such as rivers is heightened by the construction of dams. Primary analysis of the raw data received from WWF network submissions indicate that general dam operations lead to changes in water (e.g., see China, Yangtze Three Gorges, Annex 2) or could be long-term leading to the disappearance or extinction of species (cf. Annex 2, USA, coho salmon/ Oncorryncchus kisutch). The survival of river dolphins, for example, is by far the most graphic example of the impact of dams on river ecosystems. A number of potential problems caused by waterway obstruction has been identified: (a) fragmentation of populations into genetically isolated subpopulations; (b) reduction in fish prey due to blocked migratory routes; (c) less diversity and smaller biomass of prey in impoundments upstream of dams due to lowered nutrient availability; (d) downstream effects on prey caused by changes in flow rate, sediment transport, and estuarine salinity; (e) limited dispersal of dolphins between river systems due to saline encroachment in estuaries (Reeves and Leatherwood, 1994).

25

The destructive cycle not only affects aquatic species but also adjacent forest and wetland ecosystems on which migratory birds are dependent, (cf. Siberian White Crane, China, Annex 2) and other mammals (cf. Javan rhino/Rhinoceros sondaicus annamiticus, Vietnam, Annex 2). The task to determine the extent of the impact of dams on the species is made more difficult by the lack of any scientific study both before and after a dam is constructed. Some endemic fish species were observed to have developed morphological changes (e.g., see Colorado squawfish/ Ptychocheilulucius, Annex 2) or have increased and adapted to the changes in water flows and temperatures (e.g. see Piranha, Brazil, Annex 2). Other marsh plants species have also been observed to increase and develop following dam operations in the USA (e.g., netleaf hackberry/Celtic reticulata), honey mosquito/Prosopis glandulosa).

Photo: Ganges dolphin (Platanista gangetica)

The Impact of Dams on Life in Rivers

26

Some of the most vulnerable and endangered birds and fishes due to dam operations

Bald Ibis (Geronticus 17 calvus)

Siberian White Crane (Grus leucogeranus) 18

Atlantic Sturgeon 19 (Acipenser oxyrrhynchus)

Pedder Galaxias 20 (Galaxias pedderensis )

18

17 http://perso.club-internet.fr/alfosse/ Threskiornithid.html

Photo taken from Partnership for a living Yangtze: Joining hands for Better Future, WWF China. 19 http://www.dnr.cornell.edu/Sarep/fish/ Acipenseidae/atlsturg.html 20 http://www.parks.tas.gov.au/esl/pedder.html

The Impact of Dams on Life in Rivers

Box 3.

Summary of species listed in Annex 3 affected by dams, and classified according to IUCN Red Lists

IUCN Red List 21 Categories

Plants

22

Mammals

Fish and Amphibians

Birds

TOTAL

EX

-

-

-

-

EW

-

-

-

-

Ex/E

-

-

-

-

CR

-

1

1

1

3

EN

2

5

3

3

13

VU

3

11

3

7

24

23

-

2

3

-

5

LR cd

-

-

-

2

2

LR nt

1

10

3

9

23

DD

-

-

1

-

1

NE

-

1

-

-

1

I

-

-

-

-

-

6

30

14

22

72

R

TOTAL

21

27

Box 4.

NI − Summary of species not mentioned in the current IUCN Red Lists

Plants

Mammals

Fish and Amphibians

Birds

Insects

TOTAL

32

29

50

70

1

182

EX-extinct; EW-extinct in the wild; Ex/E-extinct/endangered; CR-critically endangered ; EN-endangered; VU-vulnerable; R-rare; LR-lower risk (nt-near threatened; cd-conservation dependent); DD-data deficient; NE-not evaluated; I-indeterminate 22 For plants, the pre-1994 IUCN Red List Categories was used. 23 Ibid.

The Impact of Dams on Life in Rivers

While the 91 dams studied produced concrete evidence of the impact of dams due to obstruction of rivers, the vulnerability of the surrounding ecosystems was established by the number of plants and wetlands animals affected (cf. Annex 3). But the extent of the loss of biodiversity and species caused by dams may perhaps never be known due to inadequate data.

28

Some species never before catalogued may have been lost forever, and the remaining need to be protected for the benefit of future generations. It is certain though that whatever the benefits damming rivers are (e.g., generation electrical power), they will never bring back a dead species.

Due to flood (...) forest, the fauna's element that suffered more and more into the list of animal extinction like Tapirus terrestris (anta), Ozothocerus bezoarticus (cervo), Mazama gouazombira (veado catingueiro), etc.((Brazil, Serra da Mesa Mill Dam)

Brazilian Tapir

Phot above: Giant Anteater

24 12

24

http://www.interlog.com/~insight/iwokrama/mammals/guides/ante0.html http://vivabrazil.com/images/anta.jpg

12

The Impact of Dams on Life in Rivers

29

REFERENCES Bernacsek, G.M. 1992. Research priorities in fisheries management as a tool for wetlands conservation and rural development in Africa in Conservation and Development: The Sustainable Use of Wetland Resources, IUCN, Switzerland, 131-144. Gujja, Biksham and Perrin, Mireille. 1999. A Place for Dams in the 21st Century? WWF International, Gland, Switzerland. Hertlein, Luke M.A. 1999. Lake Winnipeg Regulation Churchill-Nelson River Diversion Project and the Crees of Northern Manitoba, Canada. Prepared for the Forest Peoples Programme and the World Commission on Dams. Consultative Meeting on Dams, Indigenous Peoples and Ethnic Minorities, July 31 to August 1, 1999, Geneva. Switzerland. Legal Assistance Centre. 1998 and 1999. The Epupa Debate and Case study on the proposed Epupa Hydropower Dam in Namibia. Documentation presented at the Consultative Meeting on Dams, Indigenous Peoples and Ethnic Minorities, July 31 to August 1, 1999, Geneva. Switzerland. McAllister, Don. E. et al. 1999. Freshwater biodiversity. Impacts of large dams. IUCN/UNEP/WCD. Unpublished report. McCully, Patrick. 1996. Silenced Rivers. The Ecology and Politics of Large Dams. Zed Books, London, UK. Moore, Deborah. 1999. Speech given at the Seventh Conference of the Parties to the Ramsar Convention on Wetlands of International Importance, Costa Rica., May 1999. Ramsar, 1998. The Key Role of Wetlands in Addressing the Global Water Crisis. Paper prepared by the Bureau of the Convention on Wetlands, International Conference on Water & Sustainable Development, Paris, March 1998, 6 pages. Reeves, Randall R. and Leatherwood, Stephen. 1994. Dams and River Dolphins: Can They Co-exist? in Ambio, Vol. 23 No. 3, May 1994, Royal Swedish Academy of Sciences. Smith, Brian D. et al. 1998. Profile: River Dolphins in Bangladesh: Conservation and the Effects of Water Development in Environmental Management, Vol. 22, No. 3, SpringerVerlag, New York, USA, pp. 323-335. World Conservation Monitoring Centre. 1998. Freshwater Biodiversity: a preliminary global assessment. By Brian Broombridge and Martin Jenkins. WCMC-World Conservation Press, Cambridge, UK. WWF International. 1996. Changing Worlds. WWF International, Gland, Switzerland.

The Impact of Dams on Life in Rivers

WWF International, New Economics Foundation, and World Conservation Monitoring Centre. 1999. The Living Planet Report 1999. WWF International, Gland, Switzerland.

WEB sources http://natsafaris.com/beco2.htm http://www.southwest.com.au/~kirbyhs/pinkdolphins.html http://www.irn.org/pubs/wp/dolphin.html http://www.delm.tas.gov.au/esl/pedder.html http://www.mlists.net/sindh-intl/mail/mail_kalabagh.htm http://www.riogrande.com.br/turismo/riozinho_faunaflora.htm http://www.ucm.es/info/zoo/Vertebrados/papers.htm#Papers on Sturgeon

30

The Impact of Dams on Life in Rivers

31

WWF is the world's largest and most experienced independent conservation organization. It has 4.7 million regular supporters and a global network active in 96 countries. WWF's mission is to stop the degradation of the planet's natural environment and to build a future in which humans live in harmony with nature, by: • conserving the world's biological diversity • ensuring that the use of renewable natural resources is sustainable • promoting the reduction of pollution and waste consumption.

WWF International Avenue du Mont-Blanc 1196 Gland Switzerland Tel.: +41 22 364 91 11 Fax: +41 22 364 53 58 http://www.panda.org