Solve by spreadsheet, and turn in a copy of the first page of your spreadsheet: A new reservoir (lake) is being dug that will have a surface area of 2.5 square miles, and an average depth of 15 feet. If the empty lake starts receiving inflow on Jan. 1, in what month will it fill? Evaporation from the lake is constant at 0.1 inches per day, and the outflow seepage rate in cubic feet/day is given by 2500 H0.5 (where H is height of water above the bottom, in ft). The monthly average rainfall data (assumed to fall evenly over the whole watershed of 18 square miles) is as given below. The rainfall pattern repeats every year. The runoff from the land area of the watershed into the lake is 45% of the precipitation.
Jan 2.0 inches/month May 4.5 inches/month Sept 7.0 inches/month
Feb 1.5 inches/month June 6.5 inches/month Oct 5.0 inches/month
Mar 2.0 inches/month July 9.0 inches/month Nov 3.5 inches/month
Apr 3.0 inches/month Aug 8.0 inches/month Dec 1.5 inches/month