Estimating water budget through water balance method in alluvial damodar fan-delta: a study in semi-critical pandua block of West Bengal

Abstract

The water balance method is a bookkeeping procedure which estimates the balance between the inflow and outflow of water of the system. This method was developed by Thornthwaite in 1948 and was revised by himself and Mather in 1955. This method helps in identifying and estimating the natural water surplus and water deficit months of an area. There are 38 semi-critical blocks in West Bengal where there has been either a pre- or postmonsoon fall of static water level with respect to every preceding year. The Pandua block of Hugli District in West Bengal is a semi-critical block according to the CGWB but the area entirely lies in the alluvial Damodar fan-delta which is generally considered as highly potential for recharge. Hence the present study aims at estimating the water budget of the semi-critical Pandua block through the Thornthwaite and Mather water balance method to infer whether the study area is naturally a water surplus or water deficit block. Water surplus and water deficit months have been found based on precipitation, potential evapotranspiration, and actual evapotranspiration.