DISTRIBUTED. AQUIFER RESPONSE MODELLING e FOR SHEDI-SABARMATI INTER BASIN (GUJURAT)

Abstract

With the stress being laid on integrated use of surface and sub surface water resources to meet the growing need of the country, planned and economical utilization of ground water resources has assumed added importance. The ground water in a basin is not at rest, but is in a state of continuous movement, maintaining a hydrological equilibrium. Mans interference in this hydrologic equilibrium like; unrestricted ground water abstraction, introduction of artificial recharge through dams, barrages and a network of irrigation canals etc., may create undesirable side effects for the ground water basin. Ground water models can be used for quantitative assessment of such effects. Owing to the difficulties of obtaining analytical solutions to the complex ground water problems, numerical distributed ground water modelling is resorted to. In the present study, a distributed numerical model of unconfined-leaky-confined aquifer system was updated. Subsequently it was calibrated for Shedi-Sabarmati Inter Basin (Gujurat) using the data of May 1985-May 1938. The calibration was carried by a subjective minimization the sum of square of differences between the observed to the computed watertable/piezometric elevations. The subjective minimization was carried out by simulating the watertable/piezometric elevations for various parameter values and computing the corresponding sum of squares of the differences The aquifer parameters estimated are specific yield ,recharge cofficient, & transmissivity of unconfined aqifer, hydraulic resistance of agitard, and transmissivity of leaky-confined aquifer. The model, calibrated/validated for basin can be used in forecasting the response of the unconfined-leaky-confined aquifer to various pumping/recharge strategies.