GROUND WATER MODELLING FOR SALAWA AREA

Abstract

Mathematical models for simulation of groundwater flow are becoming increasingly popular over the past decade, as compared to other types of models. Ai mathematical model using "Integrated Finite Difference Method" is developed for the groundwater studies of Salawa area. The area is fed by Left Salawa distributary and it's branches, off-taking fra Upper Ganga Canal. The study area occupies 42,699 ha. and is divided into 54 polygons having an average area of 791 ha. ctual observation wells are located at only seven nodal. points. Historic water levels were adopted by linear interpolation at the locations of rest of the nodes. The model was calibrated against the historic levels over three year's period from 1977-78 to 1979-80. The average error in calibration for the seven nodes where observation wells are located comes to 0.077 m. and that considering all nodes to-gether works out to 0.137m, over the calibrated period of 3 years. The specific yield and transmissibility values as obtained from the calibrated model range from 0.03 to 0.22 and 1.50 ha./month to 6.50 ha month respectively. The model can be used for prediction of groundwater responses to any combinations of recharges/ abstractions over a significant period with fairly good accuracy. The prediction has been attempted for an annual increase of abstraction at 5%.