Construction and use of special drawdown scales for use in prediction of water-level changes throughout heavily pumped areas

Abstract

Problem and Proposed Method of Solution Frequently the Theis nonequilibrium formula is use din the quantitative analyses that are part of many-ground-water investigations. The computations associated therewith may become quite involved and tedious, especially when dealing with predictions of the decline of water levels throughout large areas in which there are many discharging wells. The process of predicting future water-level declines can be greatly simplified and shortened by preparing a special draw-down scale for given conditions. Through use of such a scale much of the computation can be reduced to scaling the values sought from a map, on which the pumped wells have been spotted. The net drawdown effect, which is the sum of the water-level declines caused by the many individual pumped wells, can be determined readily for any desired point in the area. If the net drawdown effect is desired, a summation of the effects of all the pumped wells can be repeated for each point. By determining the water-level change at a number of points, for a given period of time, a contour map of predicted water-level changes for the multiple-well system can be drawn.