Question

A lake with an area of 525 [acre] was monitored during a one-month period. The average inflow was 30 [cfs] for the month and the average outflow was 27 [cfs]. A 1.5 [inch] seepage loss was measured and there was 4.25 [inch] of rain. Evaporation was measured as 6 [inch]. Calculate the change in lake storage for the month.

Answer 1

`\Delta S = 1581663.5ft^3`

Step-by-step explanation:

We need to calculate the change in storage through the changes given,

That is,

`\Delta S = P+I-O-O_(seepage)-E`

Where the loss are representing by,

`P= Precipitation\\I= Inflow\\O= Outflow\\O_(Seepage)= Outflow by seepage\\E=Evaporation`

So calculating the values we have

`\Delta S = P+(I-0)-O_(seepage)-E`

`\Delta S = 4.25+ (30ft^3/s-27ft^3/s)-1.5in-6in`

The values inside the are parenthesis need to be konverted as I note here.

`(30days(24hr/1day)(3600s/1hr)(1acre.ft/43560ft^3)(1/525acres)(12in/1ft)`

That is,

`\Delta S = 0.83in\Delta S= (0.83in*1ft/12in)(525acres)\\\Delta S=36.31 acres.ft\\\Delta S=36.31acres.ft*(43560ft^3/acrees.ft)\\\Delta S = 1581663.5ft^3`