The water in a soil flows from Point K to Point L, a distance of 250 ft. Point K is at elevation 543 ft and Point L is at elevation 461 ft. Piezometers have been installed at both points, and their water levels are 23 ft and 74 ft, respectively, above the points. Compute the average hydraulic gradient between these two points.

0.124

Explanation:

We calculate the hydraulic gradient by the formulas below.

I = (change in h)/(change in l)eqn 1

I = (hk-hl)/change in L equation 2

At k the headloss = hk,

At L the headloss = hL

The distance of water travel is change in I

Total head at k

hk = 543+23

= 566 ft

Total head at L

hL = 461+74

= 535 ft

Change in L = 250

When we substitute these values in equation 2

566-535/250

= 0.124

The hydraulic gradient is 0.124