Answer:
-0.1 inches
Explanation:
The net inflow is ...
36 cfs -30 cfs = 6 cfs
The number of seconds in 30 days is ...
(3600 s/h)(24 h/da)(30 da) = 2,592,000 . . . . seconds/(30 days)
Then the volume of inflow is ...
(6 ft^3/s)(2,592,000 s) = 15,552,000 ft^3
The number of square feet in 1260 acres is ...
(1260 ac)(43560 ft^/ac) = 54,885,600 ft^2
So, the increase in depth due to the inflow is ...
(15,552,000 ft^3)/(54,885,600 ft^2) ≈ 0.283353 ft ≈ 3.4002 in
__
The net change in water level is then ...
inflow - seepage + precipitation - evaporation
3.4 in -1.5 in +4.0 in -6.0 in = -0.1 in
The water level change in the period is -0.1 inch.
