The purpose of this project is primarily to develop an equation to estimate the time that it will take for the water surface to decrease to another depth in an inverted conical-shaped reservoir behind an earth dam by means of the falling head permeability concept. This equation can be applied to the earth embankment either with or without underdrain. Since the derived equation for time span is a complicated and tedious matter, a computer program has been developed for solving this equation.
The computer program is written in BASIC language and executed on a Tektronix 4051 microcomputer. Primary effort has been used to set up the program in a universal BASIC so that it can be easily executed on any microcomputer with the BASIC language. This program also has been tested on an IBM P.C
