Fish counting weir: rigid weir and bulkhead

welding-rigid-weir rigid-weir-panels

Resistance board weir panels are designed for use in the main river channel and adjust to changing flow and debris conditions, but they are not intended for sloped river banks. Instead, rigid weir panels are used on either side of the resistance panels to extend the weir out to the bank. Rigid panels are simply galvanized steel pipes welded to iron cross members, held in place by A-frame supports. We usually make the panels 3 ft. wide and 5 to 10 ft. tall, depending on the expected range of channel depths. Large vertical panels (5 ft. x 20 ft.) called bulkheads serve as an interface between the stationary and movable parts of the weir, moving up and down with the resistance board panels. Bulkheads consist of a welded aluminum frame with PVC conduit pickets spaced 2 in. apart, and are fastened to long stakes driven into the substrate.

rigid-weir-bulkhead

Photo source: FISHBIO