TOOL FOR ESTIMATION OF ADDITIONAL DRAWDOWN DUE TO PARTIALLY PENETRATING WELLS IN CONFINED AND SEMI-CONFINED AQUIFERS

摘要

This paper presents a simplified approach for estimating the additional drawdown due topartially penetrating wells in confined and semi-confined aquifers. Hantush’s Equationusually provide s acceptable representation of the associated flow field, should thisequation be properly solved. An interactive MATLAB-based computational program hasbeen developed and verified to provide the analytical solution for the later equation.Results are projected as standard design curves which can be used to determine the totaland additional drawdown due to partial penetration for semi-confined and confinedaquifers , respectively. Empirical formulae, commonly used to calculate the additionaldrawdown in case of steady state flow for confined aquifers are also discussed, andcompared with the analytical solution, showing significant differences in many cases. Aproposed design chart for steady flow in confined aquifers, along with two families ofcurves; one for steady flow in leaky aquifers and the other for transient conditions , arethus recommended for well design purposes.