Question

In a ground-water basin of 12 square miles, there are two aquifers: an upper unconfined aquifer 500 ft in thickness and a lower confined aquifer with an available hydraulic head drop of 150 ft. Hydraulic tests have determined that the specific yield of the upper unit is 0.12 and the storativity of the lower unit is 4x10-4. What is the amount of recoverable ground water in the basin

Answer 1

Answer:

0.1365 m^3

Explanation:

thickness of upper aquifer = 500 ft

lower aquifer head drop = 150 ft

area of ground water basin = 12 m^2

specific yield of upper unit = 0.12

Storativity of lower unit = 4 * 10^-4

determine the amount of recoverable ground water

first step : calculate volume of unconfined aquifer  

                = 12 * 500/5280   = 1.1364 miles^3

The recoverable volume of water from unconfined aquifer

= 1.1364 * 0.12  = 0.1364 miles^3

next : calculate volume of confined aquifer

       = 12 * 150/5250 = 0.341 miles^3

The recoverable volume of water from confined aquifer

     = 0.341 * ( 4 * 10^-4 )  = 1.364 * 10^-4 miles^3

Hence the amount of recoverable ground water in the basin

= ∑ recoverable ground water from both aquifer

 = 0.1365 m^3