Lake Delton is a man-made freshwater lake in Sauk County in central Wisconsin . For much of 2008 , it was a mostly empty lake basin after a portion of a county highway that forms part of the dike wall eroded on June 9 , 2008 , under the pressure of floods in the area . The resulting washout caused the lake to empty , leaving behind only rainwater pools and the flow from Dell Creek . By March 2009 , major repairs to correct the problem were completed , and the lake was allowed to refill . Minor repairs were expected to continue after that time , but the lake is now completely refilled and has been usable since Memorial Day weekend of 2009
floods in the area
June 2008 Midwest floods
Lake Delton