Fish Pass Fabrication and Installation
We are able to fabricate a wide range of passes, including Larinier passes, Alaskan A passes, Denils passes and low-cost easements such as recycled plastic baffles. All baffle passes can be fabricated in aluminium, stainless or galvanised steel.
Larinier passes can be fabricated in widths from 450mm to 3600mm+, with baffle heights from 75mm to 150mm. They can be constructed as individual baffles, baffle plates, which can then be bolted into a specifically constructed concrete channel, or as a self-supporting structure, complete with side walls, braces, collar joints and support beams that can be dropped onto suitable footings.
Alaskan A passes, by dint of their design, are a fixed width. They can be constructed so that they can be bolted into a specifically constructed concrete channel, or like a Larinier, as a self-supporting structure, complete with side walls, braces and support beams that can be dropped onto suitable footings.
Denil passes typically range in width from 600mm to 1200mm and have a similar construction approach as an Alaskan A pass, due to the baffles which extend up the sides of the pass.
In all cases, full fabrication drawings and construction drawings will be produced as necessary and we are able to fabricate passes based on both existing designs and those done in-house.
We are able to provide an installation service for the complete range of fish passes. This includes all ground-works, construction of any concrete structures as required (both in and out of the river channel), piling work, fixing of baffles, the placement and pinning of rocks, boulders and other natural material for rock ramp and bypass channels and the installation of flow-control structures.
Low-cost fish passage solutions
Low Cost Baffles (LCBs) are a solution that is suitable for installation on weirs with a sloping downstream face. A R&D project completed by Fishtek Consulting found that LCBs installed on gauging weirs were an effective means of providing hydraulic conditions suitable for the effective upstream migration of both coarse fish and salmonids.
We are able to design, fabricate LCBs for installation on suitable weirs and have developed a fabrication method that allows us to produce large quantities of these baffles relatively economically from recycled plastic.