Answer:
change in storage = -310,500 ft^3
intital storage= 3.67 acre ft
Explanation:
Given data:
Rate of inflow = 350 cfs
Rate of outflow = 285 cfs
After 90 min, rate of inflow = 250 cfs
Rate of outflow = 200 cfs
final storage = 10.8 acre-ft
calculating the average inflow and outflow
average inflow
average outlow
total amount of water drain during the period of one hour
= (average outflow - average inflow) *60*90
= (242.5 - 300)*60*90 = -310,500
change in storage is calculate as
= -310,500 ft^3
in cubic meter
= -310500/35.315 = 8792.30 cm^3
in acre-ft
= -310,500/43560 = 7.13 acre ft
initial storage = 10.8 - 7.13 = 3.67 acre ft