5-Flow Towards Partially Panetrating Walls With Storage in Confined Aquifers.

Abstract

The formulation of strategy for the optimal management of the groundwater demands a knowledge of the relationship between the pumpage from the well to the drawdowns in the aquifers in spatial as well as temporal coordinates. The existing literature does not provide a suitable relationship for partially screened wells with storage. Most of the wells in India are dug wells of large diameter with huge amounts of storage in them. Use of tne existing relationships for the evaluation of aquifer parameters may yield erroneous values in such cases. Hence, a study of transient flow towards finite diameter wells with storage has been attempted with a view to develop type curves required for the proper estimation of aquifer param ters. In the present investigation, a digital model based o' finite element technique is developed and it is used to obtain the solutions for partially penetrating/screened wells with storage in confined aquifers. An attempt has been made to generalise these solutions and type curves at discrete distances from the dischargln„ wells have been presented. From the critical observation of these type curves ' storage affected zones' is demarcated in spatial and temporal coordinates. A simple method has been suggested to determine the transmissivity of the aquifer from the early time record of pumping.