Problem 6 Solution

Instructions: Draw the water table and draw the 80 m and 70 m equipotential contours. Estimate the flow direction.

Figure for Example Problem 6

Solution Step 1: Recognize that the water level in the shallow wells are in the screened interval. Therefore, these water levels define a water table of an unconfined aquifer. Accordingly, the water table can be interpolated based on these data and also considering the elevation of the nearby water body.

Figure for Example Problem 6 solution step 1

Solution Step 2: Define the hydraulic head at each measurement location, which includes the water table elevations and the water elevation in the wells screened at depth; the head is based on the points of measurement (the screen interval) and the corresponding water level elevations.

Figure for Example Problem 6 solution step 2

Solution Step 3: Using the resulting hydraulic head distribution, connect points of equal hydraulic head and/or approximate the location of equipotential contours by interpolating between values. Furthermore, consider the expected flow geometry given site features. In this case, we expect some convergence of flow towards the surface water body, so equipotential lines are curved rather than connected with a straight line. Draw flow lines perpendicular to the equipotential lines.

Figure for Example Problem 6 solution step 3

Return to Example Problem 6


Conceptual and Visual Understanding of Hydraulic Head and Groundwater Flow Copyright © 2020 by Andrew J.B. Cohen and John A. Cherry. All Rights Reserved.