The size of Sunfish Lake depends on precipitation, because there are no significant streams or springs to feed it. About 525 acres of residential and agricultural land drain into the lake, which has averaged about 50 acres in extent. It is quite susceptible to pollution from this runoff. Over the past 70 years, the maximum depth of Sunfish Lake has ranged from “completely dry” to about 20 feet. The level is relatively high right now (May 2020)
The water level has also been changed artificially, raised by the Valley Branch Watershed District in the early 1980’s when water was pumped into Sunfish to minimize the flooding of homes around Lake Olson
So how can there be fish in the lake after it had gone dry? Oral history tells us that a local resident transplanted some sunfish into the lake several years ago, when the water had accumulated during a wet spell that followed some particularly dry years. Think about how the situation would be different if walleye, bass, yellow perch, or bullheads had been added!
From a Valley Branch Watershed District publication, here are the observations of the surface level of Sunfish Lake, listed in feet above mean sea level from 1972 to 2012. Do you wonder how this data compares to the annual precipitation levels?