calculate the depth of water in a stormwater pond resulting from a two hour rainfall event. the rainfall occurs over a 24-acre watershed at an average rate of 1 inch/hour. the runoff coefficient is 0.5. the average area of the pond is 2 acres and the depth at the beginning of the rainfall is 5 ft. the pond water exfiltates at a rate of 4 in./hr through the pond side walls ( area = 2100 ft^2) when the water is above 5 ft. what is the pond depth above the 5 ft. - level 8.2 hours after the rainfall ends?