Law
Calculate the speed at which polluted groundwater travels from the Weapons Center using Darcy's
Law, in which velocity (Q) is equal to a constant (in this case 100 feet/day) times the change in
water table elevation between two wells (Δh), divided by the distance between the wells (l).
a. Using Well Q1 in the path of the plume from the Weapons Center, subtract its water table
elevation from the water table elevation at the Weapons Center (show work):
Well Q
Δh = height at pollution source - height at polluted well
b. Measure and record the horizontal distance between the chosen well and the Weapons Center
(Map scale: 1 cm = 300 ft)
distance (l) = _ cm on map = _ ft on ground
c. Calculate groundwater velocity Q = 100 ft/day x Δh (in feet) / distance (l, in feet)
Show your work, including units
Sample Solution