Simulation of the effects of hypothetical residential development on water levels in Graber Pond, Middleton, Wisconsin

An investigation of the effects of hypothetical residential development in the Graber Pond watershed was done by the U.S. Geological Survey in cooperation with the city of Middleton. The investigation entailed evaluation of the existing (1989) water budget and water-level conditions for the pond and the water-level conditions expected to result from the hypothetical development that may occur by the year 2000. A water-budget model was calibrated to closely match water levels observed from July 18-August 31, 1989. Water input to the pond during this period was computed to be about 2.58 feet. Of this, about 25 percent (0.65 foot) was from direct rainfall on the pond surface, about 19 percent (0.50 foot) was from storm runoff, and about 55 percent (1.43 feet) was discharge from a nearby manufacturing plant. Simulation of the hypothetical development conditions in the watershed predicts that the average late-summer pond level may rise about 0.7 foot.