UNSTEADY FLOW TO A LEAKY CONFINED AQUIFER WITH SOURCE BED DRAWDOWN CHANGES

Abstract

Using discrete kernel approach, unsteady flow to a weft to A.L. aiy confined aquifer considering the source bed drawdown changes, has, been analysed. For a given pumping rate and known aquifir parameters, the spatial and temporal distributions of drawdown in the source bed have ben found out. Results for recharge to the confined aquifer from the unconfined aquifer, for aquitard resistance ranging from 100 day to 10000 day are presented. The drawdownsin the unconfined aquifer even with Low resistance of aquitrad are small to be detected by observation well. Therefore, the assumption that the water table does not change with respect to time is a valid assumption for hç9s aquitrad resistance and when the source bed happens to be an unconfined, The drawdown in the unconfined aquifer is not an indication of the quantity of water the bad source is loosing. As a matter of fact, it is the aquitrad resistance which governs the recharge. For aquitrad resistance of 100 days, it is the unconfined aquifer which is virtually pumped. Influ,.nce coefficients for recharge have been calcu-lated, and by making use of them, temporal and spatial distri-bution of recharge, can be found out for a variable pumping rate in a Leaky confined aquifer.