Eastmain-1 Fishway Optimization
Contributed by Jean-François Mercier, eng., Tecsult Inc., Montreal, Qc, Canada
A fishway was built in 2005-2006 by SEBJ on the Eastmain River in James Bay, Quebec, Canada. Follow-up studies conducted in 2006 and 2007 showed no successful use of the fishway by sturgeon, while other species of fish climbed the ladder.
Two problems were identified: the low attraction of fish to the fishway and high water velocities. Tecsult engineers decided to carry out a numerical modeling study with FLOW-3D in order to find solutions.
Three different meshes were developed:
- A regional model to evaluate the flow distribution between the river and the fishway that would maximize the attraction to the fishway;
- A local model to design the modifications to the slots and deflector addition;
- A fishway model to balance the water levels over the entire length of the work.
The results of the study lead to a major reduction in discharge through the fishway and the addition of concrete blocks and deflectors. Corrective works were undertaken during winter 2007-2008. The follow-up study conducted during spring 2008 indicated that the modifications were successful, since sturgeon passage was recorded in the fishway.