The average width of the Kishwaukee River is 80 feet with a gradient of 1.5 feet per mile. The river flows unimpeded from its source to the Rock River, except for a small dam at Belvidere. Since 1970 there has been a significant jump in the average annual flow in the Kishwaukee Basin, with more than a 50% increase over previous average flows.
This watershed covers an area of approximately 1,257 square miles.