ESTIMATION OF HYDROGEOLOGICAL PARAMETERS (S,T) FROM PUMPING TESTS FOR UNSTEADY-STATE SOLVING A NONLINEAR SYSTEM EQUATIONS (SNE)

Abstract

The Pumping test is one of the most useful means for determining the hydraulic properties of aquifer and confning beds. Results can be obtained that, in general, are representative of an area larger than those obtained by means of point observations (Kruseman and de Ridder, 1990). Theis (1935) was the frst to develop a formula for unsteady-state fow that introduces the time factor and the storavity. The unsteady-state equation, wich was derived from analogy between the fow of groundwater and the conduction of heat introduced the expotential integral (Chiccoli et al., 1990) (which is written symbolically W(u)). Classical methods use approximations to ‘well function’, where you must fulfll conditions (constraints) on the physical variables for minimal error (Theis, 1935; Chow, 1952; Cooper and Jacob, 1946). This work proposes a method to estimate the transmisivity (T) and the storativity (S) for unsteady-state fow. Our proposed method generates more robust and accurate estimation leading to a more reliable characterization of the hydrogeological specifed area.