Belgian hydropower barrier diverted about half of migrating trout from turbine outflow channel

Hydropower plays a strategic role in Belgium, but it is affecting local aquatic life.

Renewable energy capacity is rapidly scaling globally, but system flexibility is vital.

For Belgium, this source not only diversifies its energy mix but also helps phase out nuclear assets.

This is vital to balancing and diversifying the nation’s energy portfolio with renewable energy sources alongside its nuclear capacity.

To protect vulnerable native biodiversity near turbine discharges, engineers integrated innovative solutions into the infrastructure.

What do these interventions entail, and how do they help fragile species navigate human-made barriers?

How Belgium’s relationship with nuclear power has become complicated

The rise of atomic power for electricity generation has triggered complicated relationships worldwide.

In Belgium, nuclear power has historically been responsible for 40 to 50% of its domestically generated electricity.

Despite this, a federal law passed in 2003 banned new nuclear plant projects and limited existing facility lifespans to 40 years.

The plan further entailed completely phasing out nuclear power generation by 2025.

Safety concerns about aging infrastructure and technical issues drove this legislation.

Additionally, the nation is intent on shifting its grid toward renewable energy sources.

However, energy crises followed.

Power demand surged, and green capacity was deployed more slowly than expected, triggering a policy “U-turn.”

Key reactors received 10-year life extensions to secure energy independence and meet climate targets.

Despite this complete resurgence, policymakers acknowledge that these aging assets alone cannot satisfy future clean power demand.

As a result, hydropower rose to a strategic role in Belgium’s energy mix.

Treating hydropower as a strategic asset

Hydropower is crucial in keeping Europe’s clean energy grid operational.

The infrastructure itself has been around since the twentieth century’s heavy industrial expansion.

In Belgium, engineers tapped the country’s river basins, such as the Meuse and the Our, to secure reliable baseload power.

Presently, these hydroelectric facilities deliver almost 1.4 gigawatts of installed capacity when run-of-river plants and large pumped-storage infrastructure are combined.

The source’s role has become invaluable, despite representing a smaller percentage of total generation.

It provides vital energy storage, rapidly stabilizes grids, and provides essential peak-load support.

Despite its strategic significance, the expansion and operation of hydroelectric dams quietly reshape rivers and aquatic life.

Hydropower infrastructure severely fragments river networks and impacts natural water flow.

Migrating fish are especially affected near turbine discharges.

To address these ecological trade-offs, engineers created an innovative solution to ensure effective conservation.

The intervention method’s data was captured in a study led by the University of Liège.

Targeted protection of migrating fish in rivers

Innovative technologies are being explored to help fish species revive and thrive in rivers.

Profish Technology S.A. partnered with the university’s research team to investigate a hydropower facility along the Our River in Belgium.

A behavioral barrier was installed underwater directly downstream of the plant’s turbine output channel.

The barrier serves as a “traffic cop” that directs fish behavior.

It uses water flow dynamics and physical cues to prevent fish from entering dangerous discharge areas.

Migrating fish such as brown trout are then guided to safer, allocated fishway passages to continue swimming upstream.

Advanced tracking of trout movement

Advanced radio telemetry was used to monitor individual movements.

Data indicated that approximately 50% of the trout were successfully deterred from the misleading and dangerous outflow channel.

Additional data showed that the fishway achieved a 58% usage rate for passing trout.

The study’s results prove that behavioral barriers hold promise, but design improvements are needed to boost ecosystem conservation.

Existing and prospective projects should incorporate similar interventions to mitigate ecological disruption.

This is vital to balancing and diversifying the nation’s energy portfolio with renewable energy sources alongside its nuclear capacity.

Ultimately, hydropower is fundamental for national energy storage and grid stability, but it should not compromise native aquatic wildlife.

The study findings can be reviewed using:  Benitez, J. P., Sonny, D., Colson, D., Dierckx, A., & Ovidio, M. (2025). Hydroelectric power plant and upstream fish migration: evaluation of the efficiency of a behavioural barrier. Journal of Ecohydraulics, 1-14.