CS(AR)-7/99-2000 : Seasonal mapping of water bodies along the Andhra coast using satellite data

Abstract

Before taking up any water resources project such as reservoir construction, anicut regulation or irrigation canal project to augment it's judicial management of water surrounding other waterbodies and its behavior in different seasons is required. Remote sensing methods admirably suits over conventional methods to collect such information because of its capability to provide broad synoptic and repetitive coverage of the area in multispectral mode. Andhra Pradesh coastal area has been selected to study the pre- and post-monsoon surface variations of the water bodies using 1:250,000 scale False Colour Composite (FCC). In this task a total of forty FCC's has been delineated for both the pre- and post-monsoon seasons. Along the coast twenty four medium to major reservoirs are identified and mapped including forty minor reservoirs/anicuts. Two major reservoirs Yeluru and Kanigiri are located in East Godavari and Nellore districts and the later district is commissioned with more number of reservoirs and tanks. The minimum area 0.25 sq.km which is measurable using the digital planimeter has been kept has the threshold to map the tanks/lakes. Kolleru a fresh water lake which serves as bird sanctuary covering an area of 853,8 sq.km and Pulicat Lake fully brackish waterbody measuring 508.1 sq.km are the special features among tanks and lakes. During monsoon season 904.8 sq.km coastal area get waterlogged which lies between West Godavari and Krishna districts'. Due to the involvement of small scale satellite data minor reservoir's/anicut's pre- and post-monsoon variations could not be analysed. Usage of 1:50,000 scale topographic and remote sensing data would give better results on the minor reservoirs and tanks.