The Coyote Watershed has two large reservoirs built and operating on-stream to capture storm runoff in the upper watershed. They are named Coyote and Anderson Reservoirs. The capacities of these two reservoirs are 23,244 ac-ft and 90,373 ac-ft, respectively. Coyote Reservoir is approximately five miles upstream from the high water line of Anderson Reservoir and is regulated by releasing water downstream into Anderson Reservoir.
In January, 2017, storms added considerable volume of water to this set of reservoirs, approximately 20,000 ac-ft of runoff were captured. Assuming the upper watershed is 200 square miles and is saturated (100% runoff), calculate the total inches of rain needed to add this amount of runoff to yield this net increase in the two reservoirs combined. Hint: 1 sq. mi. = 640 acres 1 acre-ft= 12 acre inches