Report

Wedge-shaped and sloping aquifers Adam Forsberg January 28, 2013 Until Now • Thickness constant • Water table horizontal 3 Cases: 1. Wedge shaped confined aquifers at unsteady-state 2. Sloping unconfined aquifers at steady-state 3. Sloping unconfined aquifers at unsteady-state Wedge-shaped confined at unsteady-state flow • Assumptions – Thickness of aquifer varies exponentially in direction of flow (xdirection) • Constant in y-direction – Homogeneous, isotropic – Rate of change in aquifer thickness < 0.20 in direction of flow Hantush’s inflection point method Sloping, unconfined aquifers steady-state • Culmination-point method – Slope of the water table = slope of impermeable basement • Assumptions – Unconfined Aquifer with constant saturated thickness – Slopes uniformly in the direction of flow Sloping, unconfined aquifers steady-state • Flow per unit width – F = width where water is drawn – α= slope of the impermeable base • At some distance from the well, the combined slopes for α and dh/dx will equal zero – Inflection or culmination point Sloping, unconfined aquifers unsteady-state • Assumptions – Unconfined – Seemingly infinite areal extent – Isotropic, homogeneous, and uniform thickness – Prior to pumping, the water table slopes in direction of flow with gradient < 0.2 – Unsteady-state Sloping, unconfined aquifers unsteady-state • Hantush’s method • i < 0.2