An independent scientific study has shown that the impact of run-of-river hydroelectric projects on salmon has been minimal based on the monitoring data provided to date.

The study analysed 44 sites of Run-of-River hydro facilities in the Canadian province of British Columbia developed since the mid-1980s, but the sites assessed were largely limited to more recent developments (involving 23 of 44 sites).

Following a change in energy policy to encourage renewable energy development in the province, there has been a marked increase in the number of run-of-river projects over the last decade.

The pace of development has given rise to concern among regulators and the public over the impact on fish populations, leading Clean Energy BC – a non-profit organisation – to sponsor and facilitate this evaluation, coordinated by the Pacific Salmon Foundation and completed by independent consulting firm ESSA Technologies.

The study, which you can read in full here, aims to provide an objective evaluation of the potential impacts on salmonids, citing that “much of what people know of run-of-river facilities is likely based on media coverage noting incidences of fish kills”.Its findings indicated that while individual fish are killed at a number of sites, there is minimal effect on the general fish population.

Adam Lewis, who is president of the environmental assessment consulting firm Ecofish Research Ltd., was a member of the independent panel of scientists that reviewed the approach methodology and results of the study. He explains the key findings.

It’s important to emphasise that any one project could have a major effect. But when guidelines for monitoring and offsetting are followed, it appears that major effects from run of river projects are avoided.

“There is enough evidence to say that there aren't major effects on salmon population from run of river projects in general, though evidence is limited to more recent projects” he says. “It’s important to emphasise that any one project, if it didn't employ the correct mitigation and offsetting, could have a major effect. But when the guidelines for monitoring and offsetting are followed, it appears that major effects from run of river projects are avoided.”

While the findings are generally positive, there are some caveats. Mr Lewis emphasises that development can be harmful if not done in the right way, and that effective monitoring is crucial.

“There was little evidence that run-of-river projects were having a negative impact on salmon,” he says. “It’s also emphasised strongly that the monitoring information available is limited.”

Some of the older projects studied had no data available as they were not required to monitor as part of their licence, while more recent projects have only been able to gather a limited amount of data.

For the new projects, Mr Lewis says that “there is a very strong conclusion that current monitoring regime is appropriate and adequate, and if followed through will give good information on the effects of these projects”

Good practice in monitoring

In 2012, the Canadian Government’s department for fisheries and oceans published guidelines on monitoring for new and upgraded hydroelectric projects. This methodology, which you can find in full here, specifies in detail the minimum monitoring standards as well as the methods, timing and procedure for reporting results to government.

The methodology, if applied, could be one way of meeting the Hydropower Sustainability Assessment Protocol’s requirements for the monitoring of biodiversity issues and the effectiveness of management measures.

“I think the next step forward would be to start assessing the risk on a project-by-project basis, and to focus monitoring on the projects with the greatest risks,” says Mr Lewis. “Those would be projects with the most high-risk quality fish or salmon habitat, or where water flows and quality are already limited.

“The message to industry should be that considerable progress has been made in the last decade in terms of mitigation and offsetting impacts from small hydro projects. But there are still questions about effects.”