Homework 3
McKinney CE374L
Prob. 3.1.1. A 30m thick confined aquifer has a porosity of 0.15. The piezometric head
measured at two wells 1,000 m apart are 52.35 m and 56.90 m. If K = 25 m/day. Determine the
specific discharge (q), flow rate (Q) per unit width of the aquifer, and the average linear velocity
(v) of the flow. How long would it take for a tracer to travel the distance between the wells?
Prob. 3.1.3. A confined aquifer with a horizontal bed has a varying thickness as shown in the
figure. Assuming the flow in the aquifer is essentially horizontal, determine the flow rate if the
heads at sections (1) and (2) are 23.7 and 27.1 m, respectively.
Prob. 3.3.1. A constant head permeameter has a cross-sectional area of 175 cm2 and is used to
measure the hydraulic conductivity of a field sample 40 cm long. If the permeameter discharges
100 ml in 320 seconds under a head difference of 60 cm: (a) what is the hydraulic conductivity
as measured in the laboratory; (b) what is the intrinsic permeability of the sample given that
water at 20oC is used in the test? (c) is Darcy’s Law valid under the given conditions (D = 0.5
mm)?; and (d) what would be the in-situ hydraulic conductivity if the regional groundwater
temperature is 12oC?
Prob. 3.3.3. A 30-cm long field sample is tested in a falling head permeameter with at 10-cm
diameter cylinder. The diameter of the tube is 10-mm. The water level in the tube is 35 cm
above the outlet level after one hour of operation, while the level drops to 22 cm after 12 hours
of operation. Find the hydraulic conductivity of the sample.
Prob. 3.4.1. The stratification of the same aquifer at three locations is shown below. Calculate
the equivalent horizontal and vertical conductivities for each location. What happens to the
degree of anisotropy?