Adjustable Lakebed Habitats Give Researchers Insight into the Environmental Impact of Hydropower

Forskning med höj- och sänkbara bottnar i Gardiken för att undersöka påverkan av vattenkraftsreglering.

ImageKarin Nilsson

The fluctuations caused by hydropower regulation can create major challenges for bottom-dwelling plants and animals. In some reservoirs, water levels vary by more than 10 meters, meaning that certain lakebeds can periodically dry out, erode, freeze, or end up at such great depths that barely any light reaches them.

Under the leadership of the Swedish University of Agricultural Sciences (SLU), researchers are now conducting a unique, large-scale study in hydropower reservoirs in northern Sweden. This part of the study is being carried out in the Gardiken reservoir in the municipality of Storuman, where the researchers have three specially built adjustable lakebeds, each measuring 10 square meters.

The containers within the lakebeds are prepared with several types of bottom substrate and various nutrient treatments. The idea is that algae, plants, and small bottom-dwelling animals—such as snails, insects, and small crustaceans—will be able to establish themselves.

Jenny Ask, Environmental analyst at Umeå Marine Sciences Centre

ImageJenny Ask

The lakebeds are designed to follow changes in water level and are currently installed so that they always remain at a depth of two meters, but they can be raised to facilitate sampling.

“Hopefully, the lakebeds will survive the winter in Gardiken, and next year more will be installed in other reservoirs as well as in a reference lake,” says Jenny Ask.

In a later phase of the project, the researchers will also examine how measures such as constructing thresholds—built to prevent drying—affect plant and animal life.

“Overall, we hope these experiments will help develop practical measures that benefit biodiversity and ecosystem functioning in regulated lakes. The experiments are also important from a broader and more general perspective, where we hope to learn more about what governs the growth of bottom-dwelling algae, plants, and animals,” says Jenny Ask.

Towing the adjustable lakebeds in Gardiken.

ImageKarin Nilsson