Wedge-shaped and sloping aquifers

Adam ForsbergJanuary 28, 2013

Until Now

• Thickness constant• Water table horizontal

3 Cases:

1. Wedge shaped confined aquifers at unsteady-state2. Sloping unconfined aquifers at steady-state3. Sloping unconfined aquifers at unsteady-state

Wedge-shaped confined at unsteady-state flow

• Assumptions– Thickness of aquifer

varies exponentially in direction of flow (x-direction)• 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