ASBOG Hydrogeology 5

Question 1

Which of the following conditions will cause the water table to decline even in the absence of pumping wells?

Accepted Answer

Both B and C

Answer

Both high ET losses from the capillary fringe and reduction in recharge due to impervious cover can cause the water table to decline without pumping.

Question 2

A well installed in a leaky (semi-confined) aquifer is pumped. Compared to the Theis solution for a confined aquifer, drawdown in the leaky aquifer will:

Accepted Answer

Reach a steady state at smaller drawdown due to vertical leakage from the aquitard

Answer

Leakage from an overlying or underlying aquitard provides additional water, limiting drawdown and allowing a steady state to be reached at a shallower level than Theis predicts.

Question 3

The specific capacity of a well is defined as:

Accepted Answer

Pumping rate divided by drawdown in the pumped well

Answer

Specific capacity (Q/s) is pumping rate divided by the drawdown in the well; it is a practical field measure of well performance.

Question 4

Darcy's Law becomes invalid at high groundwater velocities primarily because:

Accepted Answer

Turbulent flow develops, violating the linear relationship between flux and gradient

Answer

At high velocities (Reynolds number > ~1–10 in porous media), inertial forces cause turbulence and the flux-gradient relationship becomes nonlinear, invalidating Darcy's Law.

Question 5

Which map product is used to show the configuration of the potentiometric surface of a confined aquifer and delineate groundwater flow directions?

Accepted Answer

Potentiometric surface map based on piezometric levels in the confined aquifer

Answer

A potentiometric surface map contours the static water levels in wells completed in a confined aquifer, with flow directed perpendicular to contours from high to low head.

ASBOG - Association of State Boards of Geology Practice Test

ASBOG - Association of State Boards of Geology Practice Test

ASBOG Hydrogeology 5