TRANSIENT DUPUIT INTERFACE FLOW WITH PARTIALLY PENETRATING FEATURES

A comprehensive potential is presented for Dupuit interface flow in co astal aquifers where both the fresh water and salt water are moving. T he resulting potential flow problem may be solved, for incompressible confined aquifers, using analytic functions. The vertical velocity of the interface may then be computed analytically and the change of the position of the interface may be simulated by numerical integration th rough time, starting with a known (or estimated) initial position. The upconing of the interface below a partially penetrating ditch or well may be studied if Dupuit solutions for such features are available. A new Dupuit solution is derived for a ditch that penetrates the aquife r partially from above; a Dupuit solution for a partially penetrating well may be obtained following a similar derivation. The new Dupuit so lution is combined with the interface solution to simulate the upcomin g of an initially horizontal interface below a series of partially pen etrating ditches; the interface converges to the known steady state po sition.