Fisheries & Hydropower

Hydropower Project Advice

We have provided advice to a large number of hydropower projects (over 60 to date), specifically in relation to the minimisation and mitigation of impacts from hydropower on fish and fisheries.

The projects we have been involved with and the work they entail has been extremely varied and includes:
– R&D investigations into the impact of Archimedean screw turbines (see below)

– Research into the potential impact of a novel ‘venturi’ hydropower turbine on fish during passage through the turbine

– Design of appropriate flow regimes for proposed new hydropower schemes, with reference to the ecology and fish populations within the river where the scheme is proposed

– Assessments of the impacts of hydropower schemes on fish migration, habitat and mortality (both direct and indirect)

– Advice on fish passage facilities (both upstream and downstream) at a large number of hydropower schemes and design of these facilities, once the optimal solution has been identified. This has included significant input into fish passage facilities on some very large hydropower schemes such as the Xayaburi and Don Sahong hydropower projects on the Mekong

– Input into other stages of the mitigation process such as the use of hatcheries and offsetting proposals

– Design of a novel prawn pass (including field tests to generate empirical data for the design of the pass) at a hydropower project in West Africa

Research and Development

Archimedean screw turbines

We have previously conducted extensive monitoring of low-head hydropower turbines (the Archimedean screw turbine), involving live fish trials, fish behaviour at the intake, outflow and within the turbine chamber, and risk assessments of the probability of fish being damaged during passage through hydroturbines. Our work on Archimedean screw turbines has been used to inform current national guidelines on hydropower and fisheries, including the current Environment Agency “Good Practice Guidelines on Hydropower”. Many of our assessment methodologies have become the industry standard for investigating the potential impact of a proposed hydropower scheme on the fisheries ecology of a river.

Our assessments of the impact of Archimedean screw leading edges on fish resulted in the development of fish friendly compressible bumpers to mitigate the effects of higher impact speeds on the largest screw turbines now in use. These bumpers are now required as standard on larger Archimedean screws.

Low-head hydro-turbine R&D

We have also conducted extensive R&D on a unique low-head hydro-turbine which utilises venturi principles to reduce the size of turbine required to generate a given amount of energy. We investigated the rates of mortality and injury to fish when passing through this turbine as part of the required process to determine its installation as part of hydropower projects in the UK.

Our R&D work has also included unique projects investigating the best passage option for enabling prawns to pass a dam, extensive studies into the swimming ability of wild-caught Mekong fish species (using a custom-built test facility on the bank of the River Mekong) and assessments of unique passage facilities for eels at gauging sites.

General hydropower consultancy

UK and international projects

We have worked extensively on hydropower projects in the UK and internationally and have provided advice to a large number of organisations and developers on how to minimise the potential impact of hydropower on fish. Specific project examples include:

• Providing advice on the type, size and location fish passage facilities as well as the hydraulic and civil design of these structures. We have provided this type of advice to numerous projects, including the 1.3 GW Xayaburi hydropower project in Laos, 650 MW hydropower project in Laos and 88 MW Mount Coffee hydropower project in Liberia as well as over 50 hydropower projects with a capacity < 5 MW
• Reviews of proposed hydropower projects and the impact of a proposed scheme on fish and fisheries. This has included consideration of proposed fish passage facilities (both upstream and downstream) and their optimisation, environmental flows, proposed hatcheries, screening facilities and holistic catchment approaches to hydropower development