The Institution Of Surveyors

THE INSTITUTION OF SURVEYORS SUB DIVISION – I (b) HYDROGRAPHIC SURVEYING FINAL EXAMINATION - 2009

HYDROGRAPHIC SURVEY - OF KRISHNAPATNAM

Prepared by

:

S Sudhakar, LSSR-I Studentship No. S/10615/IS

Under the Guidance of

:

Lt Cdr RA Rahiman Grade II Surveyor

INDIA – EAST COAST

HYDROGRAPHIC SURVEY OF KRISHNAPATNAM SURVEYED BY: S Sudhakar, S/10615/IS (Project work for Institution of Surveyors Final Exams) 04th May to 08th May 2009 1 : 50000

REPORT OF SURVEY ROS-S/10615/S May 09

Prepared by:

S Sudhakar LSSR I

S/10615/IS

ACKNOWLEDGEMENT I express my sincere gratitude to The Commanding Officer INS Nirupak for the opportunity he provided to me for carrying out and completing this work.

I much indebted to Lt Cdr SE John, Senior Hrdrographic Surveyor and Lt Cdr RA Rahiman, INS Nirupak for their priceless guidance, encouragement and inspiration given to me throughout this project. I also express gratitude to AK Mallick, CPO SRI CHREC to his valuable assistance throughout the project.

I also thank the survey recorders of INS Nirupak for the necessary help they rendered tome during completion of the project

(S Sudhakar) LSSR I S/10615/IS Date:

Nov 09

REFERENCES 1.

Indian Navigational chart No. 3031 & 356

2.

Hydrographic quality assurance Instructions for Admiralty Surveys (HQAIs, NP 145 Edition 1/03)

3.

Professional Paper 20

4.

SOI Coastal Bench Mark Pamphlet (1958)

5.

IHO Publication S-57 (Edition 3.1)

6.

IHO Publication SP – 44 (4th Edition)

CONTENTS PART I - DESCRIPTIVE

Sl. No.

Section

1.

Introduction

2.

Geodetic Control

3.

Digital Surveying System

4.

Navaids

5.

Bathymetry

6.

Tides and Sounding Datum

7.

Seabed Topography

8.

Wrecks and Obstructions

9.

Lights and Buoys

10.

Miscellaneous

U

PART I

1.

Introduction.

1.1

The Hydrographic Survey of Krishnapatnam issued vide INS Nirupak

letter 738/IOS dated 28 Apr 08 was undertaken in accordance with partial fulfilment of the final examination of Institution of Surveyors, New Delhi. Copy of Hydrographic Instructions is placed at Annexure I to this report. The survey was commenced on 04 May 09 and completed 08 May 09. 1.2

Krishnapatnam, a small town under the District Nellore in southern

Andhra Pradesh is situated 260 Nm south of Visakhapatnam and 90 Nm North of Chennai. The nearest railhead is Nellore, which is 25 Km away. Being at the border of states of Andhra Pradesh and Tamilnadu, the local population is conversant with both Telegu and Tamil languages. The main occupation of people of this area is fishing and farming. 1.3

The survey was carried out at Scale 1: 50,000 for the area bounded by

the following limits:Of Krishnapatnam

1.4

Latitude

-

14° 08’ 00” N

to

14° 12’ 20” N

Longitude

-

80° 04’ 15” E

to

80° 12’ 10” E

Survey Programme.

A reccee of the survey area was undertaken

for finding out the suitable location for setting up of the tide pole. During the reccee facilities for accommodating the tide camp party was also checked. Thereafter, the tide pole was set up at selected location. Thereafter the survey of Krishnapatnam was undertaken by operating SMB. delineated by walking over.

Full coast was

1.5

Weather

The weather during the survey remained calm with

sea state below one. South/North Easterly winds of 06 to 08 knots were experienced. The sky remained clear throughout and the visibility was 10 to 12 nm. 2.

Geodetic Control.

2.1

The horizontal control of the survey was referred to WGS 84 Spheroid,

Transverse Mercator Projection on a scale of 1: 50,000 and Central Meridian 80°15’ 00” E. 2.2

The origin of survey is the geodetic station situated on the roof top of

the porch of Krishnapatnam light House. The station was established by INS Darshak by SPP solution in 2006. In order to confirm the accuracy of the station, it was decided to connect the station to IGS network. Six hourly GPS 1230 observations was carried out at the station on 05 Apr 08. The observed data was converted into Rinex format using Leica Geo software. The Rinex data was then uploaded through “Auspos” utility for post processing using the IGS Stations. The processed results were compared with the SPP solution established by INS Darshak and found to be in close agreement. However it was decided to accept the coordinates obtained through IGS network for the survey. The coordinates of the station thus established and used for the survey is as follows:-

Name Krishnapatnam Lt Ho Station

2.3.

Monitoring station.

Position in WGS 84 Latitude (N) Longitude (E) 14° 15’ 18”.2997 80° 07’ 33”.8852

Ell. Height -81.795 m

A new station was established on the front

yard of the Krishnapatnam light house to monitor the performance of DGPS corrections. The station was established by carrying out simultaneous GPS 1230 observations with the reference station. The data was processed using Leica Geo software in baseline mode keeping Krishnapatnam Lt Ho Station

as reference. The computated coordinates of the Monitoring Station is as follows:Name Monitoring Station

2.4.

Position in WGS 84 Latitude (N) Longitude (E) 14° 15’ 18”.11375 80° 07’ 33”.46389

Ell. Height -85.4310 m

The detailed descriptions of the geodetic stations are placed at

Annexure “C”. 2.5

The Differential position was obtained in real time using Sercel NR 203

differential receiver. The co-ordinates of the monitoring station were observed to be consistent and accurate. 2.6

Datum Shift Parameters.

Due to non-availability of sufficient

Everest stations, datum shift parameters for the survey area were not computed.

3.

Digital Surveying System.

3.1

Hypack Max Ver. 4.3 a Software were used for planning, execution and

collection of survey data. Bathymetric data and position data were simultaneously logged digitally on Laptop using Hypack Max ver. 4.3a Software. 3.2

The collected raw data was processed using Single Beam Max Editor

manually to remove any spurious data. Tidal correction was applied after obtaining the tidal value observed at Krishnapatnam Jetty. The collected bathymetric data was sorted in sort program available in HYPACK MAX ver 6.2 b. The sorting of the bathymetric data was carried out at 125 m radius in order to convert the sounding data into *.xyz format. Both the sorted data and the supressed data were saved in separate files and later imported to CARIS GIS Ver 4.4a for making the final fairsheet.

4. 4.1

Navaids. The medium range Thales Navigation Aquarius2 DGPS with reference

station consisting of NDS 200 system was used for positioning in conjunction with Aquarius2 DGPS receiver / Sercel NR 203 differential receiver configured in differential mode for sounding/coast lining. 4.2

The reference station NDS 200 was configured to transmit differential

data on frequency 1871 KHz and 3276 KHz. The origin of the survey is the station situated on roof top at the porch of Krishnapatnam light House. Six hourly GPS 1230 observations was carried out at this station and connected to IGS network. The position obtained by “Auspos” utility was accepted and used for the survey. 5.

Bathymetry.

5.1

Depths in the area varied from 0.3 m to 19.4m. The inbuilt dual

frequency Atlas DESO 25 was used for collection of bathymetric data by the SMB. The high frequency channel (210 Khz) was used for the entire duration of survey as the soundings were below 40 m in the entire survey area. 5.2

Sound velocity was determined using 2-DACM prior to commencement

of sounding for the day and set in Echo sounder. The average sound velocity of the water column computed from the results of morning cast was applied in the Echo sounder and was kept constant.

The difference in the sound

velocity due to spatial and temporal component of the sound velocity was considered negligible for the following reasons:(a)

The sound velocity observations in the morning, evening and at

different locations were found to varying between 1542 m/s to 1544 m/s only. (b)

No seasonal change was observed during the conduct of

survey.

(c)

No abnormal weather condition was experienced during the

period of the survey.

5.3

For greater accuracy, boat echo sounder was calibrated by bar check

daily twice before the commencement of sounding and after completion of sounding. The details of sound velocity observations are placed at Annexure 'E'. 5.4

The total errors in measurements of depths have not exceeded the

stipulated level of 2 σ accuracy. A detailed analysis of estimated and calculated errors likely to be present in the measured depths is placed at Annexure ‘G’ to this report. The survey is considered to be thorough and complete in all respects with regard to sounding density. 6.

Tides and Sounding Datum.

6.1

A flat tide pole was erected on the western side of existing export jetty

of Krishnapatnam Port Company Limited. The SOI BM which was situated in the old Port Office premises was destroyed during the ongoing construction works. However the BM was shifted to Krishnapatnam light house premises by INS Nirupak. 6.2

The tide pole was leveled to this Bench Mark, which is situated in the

premises of Krishnapatnam light house. The bench mark is situated on a concrete platform, one feet south of the steps leading to the entrance of the Krishnapatnam Light House. It consists of a brass circular disc inscribed with letters “NAVAL HYDROGRAPHIC SURVEY, INS NIRUPAK, LBM, 03-1206". The value of BM is 2.7822 m above the Chart Datum. The zero of the tide pole was found to be 1.084m below the Chart datum. 6.3

A Local Bench Mark was established close to the tide pole on the base

of bollard on the eastern side of export jetty. The LBM is engraved with a circle and dot with “LBM NPK-07-08” painted below. The value of LBM was found to be 3.037 mtr above Sounding Datum. Regular check leveling was

carried out in order to ascertain that the tide pole has not been disturbed at any time. The detailed description of SOI Bench Mark along with leveling data is placed at Annex ‘F’. 6.4

No difficulty was experienced during the tidal observations. Tide was

observed regularly at an interval of 15 min for the entire duration of survey. Levelling records, observed tides and the smoothened graphs of the reduced tide are placed at Annexure ‘F’ to this report. 7.

Seabed Topography and Textures.

7.1

The seabed was observed to be steeply shelving especially close to

the coast and breakers of about 0.5 m in height were observed all along the coast. However, the height of breakers increased to 1 – 1.5 m in strong wind conditions during the noontime. The bathymetry of the sounded area generally agrees with the existing small-scale chart of the area. 8.

Wrecks and Obstructions.

8.1

Neither any wrecks/obstructions were reported nor observed in

the survey area. 9.

Lights and Buoys.

9.1

No lights and buoys were present in the survey area.

10.

Miscellaneous

10.1

No abnormal bathymetry was observed in the area and clear of any

under water obstructions. 10.2

The survey has been carried out professionally with complete

emphasis on accuracy and the quality. The survey is considered complete in all respects

Acknowledgement 1.

This student expresses his gratitude to Lt Cdr RA Rahiman for his

kind consent to be the Guide for this Thesis. His vast experience as Grade II Surveyor and deep understanding of each and every aspect of a Hydrographic Survey had a humbling effect on this student.

(S Sudhakar) LSSR I Student No. S/10615/S Date: -

May 09