Question

Three piezometers located 1000 m apart bottom in the same horizontal aquifer. Piezometer A is due south of piezometer B and piezometer C is to the east of the line AB. The surface elevations of A, B, and C are 95, 110, and 135 m, respectively. The depth to water in A is 5 m, in B is 30 m, and in C is 35 m. Determine the direction of ground-water flow through the triangle ABC and calculate the hydraulic gradient.

Answer 1

Answer:

Hydraulic gradient=0.0173

Explanation:

The hydraulic head at the points A, B and C will be as follows

A=95-5=90 m

B=110-30=80 m

C=135-35= 100 m

By drawing the equipotential lines, the direction of ground water can be seen as in the triangle

The length of flow will be

$L=\sqrt {1000^{2}-500^{2}}\approx 866.025 m$

The hydraulic gradient will be given by

$i=\frac {\triangle h}{L}=\frac {95-80}{866.025}\approx 0.0173$