LABORATORY STUDIES ON VARIATION OF RADIUS OF INFLUENCE WITH DISCHARGE IN UNCONFINED TUBE WELL

Abstract

Ground water offers a reliable source of water supply for both domestic and agriculture needs. India. needs a lot of development of its ground water. Tapping ground water _will solve dual rpurpose of irrigation and minimising water logging. The extensive use of the water requires better methods of solving the problems of ground water flow through tubewells. Dupuit relation gives free surface curve, without seepage ;- face. With this limitation the work of Dupuit and the formulae. evolved from the same general concept based on assumed steady flow conditions have provided a valuable basis for well engin-eering and for field testing to determine the permeability of underground sediments.. With its limitations, Dupuit f. rmula is used for comput-ing discharge from a tubewell for which observations at a test bore dug within the radius of influence are necessary. Genera• ily test bore, data is not available. For predicting discharge in the absence of test bore data radius of influence is. assumed to vary linearly wit.hh--theedischarge. Present studies_ are aimed to check validity of this assumption with the help of hydraulic studies on a 30 degree angular sector laboratgry model of tubewell with unconfined- flow.