Damming the Invasive Carp Migration
Invasive Carp threaten Minnesota’s $2.6 billion recreational fishing and boating industry is at risk. The large fish threaten native fish populations by undercutting their ecosystem and can injure boaters and skiers by leaping into the air when startled.
Stanley Consultants was selected by the Minnesota Department of Natural Resources to rehabilitate the dam into a physical barrier that prevents fish from entering the upstream pool. Inflatable gates were replaced with a full-operation, top discharging crest gate system that maximizes the elevation difference between the upstream and downstream water levels.
The gates maintain precise upstream water levels while maximizing the height between upstream and downstream water levels. Nine gates installed along the length of the 1,000-foot-long dam allow more water to pass during high flows with minimal gate lowering. All construction took place without “drawing down” or lowering the upstream pool levels. This uncommon approach, which was carefully analyzed for safety and required continuous water level monitoring, sustained the physical Invasive Carp barrier during construction.
Coon Rapids Dam is now one of the State’s primary defenses against Invasive Carp. Stanley Consultants was the lead engineer for the all phases of the $16 million project, which also included a 450-foot-long energy dissipating/scour preventing stilling basin.