Geoinformatics based groundwater potential assessment in hard rock terrain of Ranchi urban environment, Jharkhand state (India) using MCDM-AHP techniques

The study was conducted to delineate the groundwater potential (GWP) zones and to analyze groundwater trend in Ranchi Urban Agglomeration (RUA), Jharkhand. Groundwater level (GWL) and its fluctuations were analyzed estimated by using time series regression and employing sum of least square method. The groundwater potential (GWP) zones were delineated using various terrain characteristics and modeled using analytical hierarchical process (AHP) in geographic information system (GIS) environment. The high rate of built-up growth (39.0%) and population growth (32.6%) enhanced the pressure over existing groundwater resources during 2001-2010. The hard rock formations and increasing urbanization retarded groundwater recharge in the region. The study revealed that the central parts are largely covered by built-up land (7.35%) and have very low GWP and also faced severe water crisis. The northern (17%), south-western parts (13%), southern (8.07%) and eastern (9.61%) parts have high to very high GWP with less groundwater fluctuation and shallow GWL resembling suitable site for future built-up development in view of groundwater resource availability. The groundwater condition suggested site specific methods to recharge and replenish groundwater within the urban milieu.