Determination of Areal Shrinkage of Sasthamkotta Freshwater Wetland a Ramsar Site in South India

摘要

Wetlands perform valuable functions such as recycling nutrients, purifying water, attenuating floods, maintaining stream flow, recharging ground water and also serve the water needs of the human populace. In this study, the shrinkage in aerial extent of Sasthamkotta lake, a freshwater wetland and a Ramsar site in the Southern part of India between 1973 and 2021 is determined using Remote Sensing data and Geographical Information System technology. The water spread area was delineated from the available cloud free satellite images and the same was computed using Normalised Difference Water Index. It was found that the water spread area of the lake has shrunk from 3.02 km~2 in the year 1973 to 2.55 km~2 in the year 2021 respectively. The percentage aerial reduction of the lake for the said period was found to be 15.56. Decrease in rainfall, increased rate of water withdrawal from the lake and land use land cover changes in the adjoining areas of the lake could be attributed to the reduction in the aerial spread.