“DELINEATION OF GROUND WATER RECHARGE POTENTIAL ZONES OF CHITWAN DISTRICT”

Abstract

This research analyzes the ground water recharge potential and identifies the high ground water recharge potential zones in Chitwan district. The calculation and estimation of groundwater recharge is the way to understand the groundwater reservoir and forecast its potential accessibility. The main objective of this study is to assess the groundwater recharge and its controlling factors at Chitwan District included as Rapti and Narayani catchment basin. Groundwater recharge process is crucial for maintaining the water balance in an area and securing sustainable water supply for drinking, agriculture and industrial purposes and it is also very necessary for the management of both surface and subsurface water resources. Our study uses the application of analytical hierarchical process (AHP) on geospatial analysis for the exploration of potential zones for artificial groundwater recharge. Various aspects of earth surface features such as geology, geomorphology, soil types, land use and land cover, slope, aspect, precipitation, population density, elevation etc. are taken in consideration that influence the groundwater recharge in either direct or indirect way. These thematic layers are prepared and extracted using population data, Landsat 8 image, topographical map, and various other data sources. Weighted analysis and union of data obtained is used for formation of recharge map in this study. A pair-wise matrix analytical method is used to calculate the geometric mean and normalized weight of individual parameters also known as AHP analysis. Further, the normalized weighted layers are mathematically overlaid for preparation of groundwater recharge potential zone map. The results reveals that around 133.17 sq. km (6%) of total area has been identified as high potential zone for groundwater recharge. The forest areas in central part and south western part have high potential for groundwater recharge. Hilly and mountain terrains in north Mahabharata range are considered as unsuitable zone with very low groundwater recharge potential.