Assessment of Tank Water Spread Area in Cheyyar Sub Basin Using Sentinel 1A Data

A research study was conducted for estimating the water spread area of tanks in Cheyyar sub basin for the year 2022. Tanks are low-cost irrigation water source and play a key role in recharge of ground water. Mapping and regular monitoring of tanks plays an important role in water resource planning. Sentinel-1A SAR data has high potential in estimating water spread area as it is unaffected by cloud cover, light or weather conditions. After processing the obtained satellite data using SNAP software, the water spread area was obtained by threshold approach. The backscattering (dB) value ranged between -30.641 and 22.898 during the course of study. The total water spread area was noticed maximum and minimum during the month of January and July with 5728.20 ha and 1123.44 ha (21.88% and 4.29 % of total tank area) respectively. The total rainfall received in Cheyyar sub basin was about 1290 mm. The water spread area seems to be proportional to the rainfall of previous and current months.