How do they work?

Resistance board weirs function by directing adult fish through a special opening (the 'passage chute') and into a live trap. The weir 'floats' due to lift and tension created by the force of flow against the resistance boards which create a planing surface, elevating individual weir panels. Floatation can be supplemented by adding barrels to the downstream end of weir panels to increase operational tolerances. Tolerance limits are site specific and dependent on the overall size of the weir, channel and floodplain characteristics, and debris loads/type.

Click on each image to see a full-resolution version.