| Europe Natural dam builders take over


In more unusual developments, beavers in Czechoslovakia have saved tax payers over a million euros by building their own dams and creating wetlands where needed. Negotiations over permits started back in 2018 with proposed plans to dam the Klabava


River and protect endangered crayfish, frogs and other species, from sediments and acidic water spilling over from nearby ponds. Part of the plan was to turn the protected area south of Prague into a thriving wetland. However local beavers overtook stalled discussions by erecting dams on a bypass gully originally built by soldiers at this former military base. Creating wetlands with pools and canals, the beaver designed area is about twice the size of the one originally planned.


low – down to 71TWh, according to data from global energy think tank Ember. For the first five months of 2025, hydro power’s share of the European energy mix shrunk by 2.3% in comparison with the same period last year. According to a Reuters report, snow cover across


the European Alps has been over 30% below normal, impacting snow-fed hydropower. While poor spring rains have also impacted one of Europe’s main river- fed hydro networks, with the Danube catchment area being 60% below normal. With hydro taking such a hit, other dispatchable power sources such as natural gas and coal plants were expected to step up and meet the shortfall during the summer if conditions prevailed.


Update on Toddbrook Over in England, refurbishment takes the spotlight as


a major three-year construction project by the Canal & River Trust charity, to create a new overflow spillway structure at Toddbrook Reservoir in Whaley Bridge, is expected to be finished by Christmas. Construction of this new spillway is key to bringing


the reservoir back into use after the former auxiliary spillway on the dam wall was damaged after excessive rainfall in the summer of 2019. The Trust’s contractor Kier is now in the final stages


of creating a new waterside weir, tumble bay, stepped spillway channel and stilling basin, providing a new route for excess water to reach the River Goyt. This summer, the redundant 1970s concrete panels and some 460 bags of aggregate, dropped by Chinook helicopters on the dam wall during the emergency, were removed. The slope will be repaired and grassed over.


A couple of months ago the spillway channel was


inspected and approved by a government qualified civil engineer, allowing a new opening to be made in the dam crest to enable Kier to complete the final works on the spillway structure. All water from Todd Brook, that feeds the reservoir and gives it its name, is now flowing into the main reservoir, and this will eventually provide a regular flow down the spillway channel to create an attractive stepped waterfall feature through the town’s Memorial Park. Over the coming spring, the reservoir will be allowed to refill naturally in carefully monitored stages. Toddbrook Reservoir will soon be once again capable of performing its vital role of supplying water to the Macclesfield and Peak Forest canals. The reservoir will be re-stocked with fish and soon be fully restored as a community resource for sailing, angling and swimming.


As Dilwyn Parry, Toddbrook Project Manager for the Canal & River Trust, says: “The end is now in sight and by the seventh anniversary of the incident, we should again have a beautiful working reservoir for everyone to enjoy.”


Scottish sediments New research published by Scotland’s Centre


of Expertise for Waters has looked at sediment accumulation behind impoundments and the risks this poses to effective hydropower or water supply operations, as well as likely impacts on river health. The project sought to address: Raising awareness in the hydropower sector about basic river geomorphological processes related to the impact of sediment (dis) continuity on river habitats and species. Improving understanding and raise awareness of the net benefits or costs of different sediment management options available to address the environmental and commercial risks to hydropower and water supply impoundments. Recommendations from the report include raising awareness of the importance of sediment continuity through impoundments. Outputs from this project are encouraged to be shared widely and periodically to relevant teams in Scottish Environment Protection Agency (SEPA), NatureScot and Scottish Canals to raise awareness of sediment management within the regulatory hydropower and impoundment community. Hydro operators are encouraged to consider


site specific sediment-related environmental and commercial risks both in the short and long-term, particularly in the context of expected climate change that is likely to increase sediment production. A forum should be established to enable key stakeholders within the hydropower community to communicate and collaborate for mutual benefit. Overall, a key finding from stakeholder engagement activities conducted during the project was that more communication and collaboration is required between different stakeholders (e.g, regulators, operators, consultants, hydro-morphologists, ecologists, researchers etc) to improve understanding and knowledge sharing. Efforts should be made to develop a community of Scottish hydropower and water supply impoundment practitioners that openly exchange knowledge, enabling the mitigation of impoundment impacts on river health and to improve commercial resilience in the context of climate change. Appropriate leadership will be necessary to achieve this


Below: Silt deposits exposed when the Earlstoun Dam and Loch/reservoir was drained for the first time in 80 years at the Galloway Hydro Scheme in Scotland. New research has looked at sediment accumulation and the risks this poses to effective hydropower or water supply operations, as well as likely impacts on river health


References


www.hydropower.org/ publications/2025-world- hydropower-outlook


Marina Čerpinska et al 2025 IOP Conf. Ser.: Earth Environ. Sci. 1442 012001


https://www.reuters.com/ authors/gavin-maguire/


Williams, R.D., Barre-Tabor, E.M., Daniels, L.J., Hanley, N., Downs, P.W. (2024) Environmentally effective and cost-efficient sediment management at impoundments. CRW2023_01. Centre of Expertise for Waters (CREW). Available online at: crew.ac.uk/publication/hydro- impoundments-sediment- management


www.waterpowermagazine.com | October 2025 | 15


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