ENVIRONMENTAL WATER
C OH UN A F IS H EX CLUS IO N SC REEN PROJEC T • Partnered with the North Central Catchment Management Authority (NCCMA) to design, construct and install Australia’s first conical Fish Exclusion Screen through the Cohuna Irrigation Diversion Screen Project. Funding for the project was provided by the Victorian Environmental Water Holder (VEWH). • All native fish species are crucial in sustaining a balanced aquatic ecosystem. Once fish enter irrigation systems they are lost to their natural environment. AWMA is dedicated to assisting fundamental projects aimed to increase environmental sustainability.
• The aim of this project is to boost native fish populations by preventing fish movement out of the natural waterway into irrigation channels. Uninterrupted irrigation flows were also critical, with minimal headloss through the fish screen structure being a key design criteria. • Conical (cone) fish screens were chosen for this site due to their suitability in shallow water. They have been well proven in diversion pools, rivers and channels, to protect fish from entrainment and impingement. Located in-town, the screens were submerged below the water level to ensure the area remains aesthetically pleasing.
• An internal flow baffle distributes flow evenly across the screen surface. • A marine-duty hydraulic drive motor rotates cleaning brushes with a control panel allowing user defined cleaning cycles. The cone shaped design is very strong and hydraulically efficient. • The screens weigh 28 tonnes in total and will pass 600ML/d through 3mm wedge wire screens with a head loss of less than 20mm.
• The screens are self-cleaning with a positive brushing action preventing debris build-up, sedimentation, and bio-fouling.
33
