River Falls reservoir drawn down for good after dam damaged by flood City decides to end hydropower generation rather than perform costly repairs for a couple more years of service. Powell Dam (Photo courtesy Kinni Corridor Project Committee) When nearly seven inches of rain fell on the River Falls area last June, it caused a powerful flood in the Kinnickinnic River. The St. Croix River tributary is renowned for its trout fishing, and has also been the focus of debate in recent years over removing two dams owned by the city. The flash flood last summer was more than one of the dams could handle. The lower dam, Powell Dam, was significantly damaged. In October, the city drew down the reservoir behind the dam, called Lake Louise, so it could inspect the structure.