Following the onslaught of climate-related disasters in recent years, the relevance of reservoir safety has resurfaced. The Dolgarrog disaster of 1925 is a chilling example of the dangers that can come with dam failures. The breach of two downstream earthen dams holding back the Eigiau and Coedty reservoirs set off a chain reaction. Tragically, 16 people lost their lives, and this catastrophe led to major reforms in the regulation of reservoirs in the UK.
The Dolgarrog disaster followed a very rainy month of October, highlighting the connection between more frequent extreme weather and dam failures. Fleeing pursuit by the police, a tragic incident occurred causing the death of ten adults and six children passengers. The media reacted with national and international coverage, and even King George V noticed sending a message of condolence. Public anger pushed passage of the Reservoirs (Safety Provisions) Act of 1930. This legislation was a hugely important step in ensuring the safety of the UK’s reservoirs.
Lessons from Dolgarrog
The Dolgarrog disaster brought attention to the dangers reservoirs located in narrow and steep upland valleys that could exacerbate flooding can pose. These geographical features can increase the impacts of damaging heavy rainfall and thus the probability of a dam failing. The 1930 Act answered this calamity with alacrity. It went on to become the UK’s first piece of legislation directed specifically at the regulation of the design, construction, and maintenance of reservoirs by means of legally required safety structures.
Since the passing of this Act, the UK has had a strong track record when it comes to reservoir safety. The regulatory framework that was built on the urgent calls for change has kept similar tragedies from happening in the many decades since. As climate change increasingly affects weather patterns, questions are being raised again about whether these regulations go far enough.
Modern Challenges to Reservoir Safety
The Toddbrook incident in 2019 was one of the most extreme near-failures of a dam in recent UK history. Then an exceptional and extremely unusual weather event hit the area, depositing over a month’s rain on the Toddbrook reservoir in two days. As a precaution, operators evacuated more than 1,500 residents from Whaley Bridge. This sequence of events is eerily reminiscent of the Dolgarrog disaster. It starkly highlights the ability of extreme weather to threaten the integrity of our nation’s reservoirs.
Government Response and Future Outlook
Against the backdrop of these new threats, the UK government ordered an independent review into reservoir safety in April 2021. This comprehensive review offers a critical evaluation of the current regulations. It will decide whether or not they fully mitigate climate change effects on their reservoir’s stability. Both dam safety experts and advocates are urging a re-examination of current practices. They need to build new reservoirs that can accommodate the increasing unpredictability of weather patterns.
Results from this scoping review will be instrumental in informing the development of future policies related to reservoir management. Stakeholders on all sides are pushing for new guidelines that better account for the current science and climate reality. Further, there is an increased understanding that we need to take action now, before a disaster happens, to avoid what could be devastating consequences down the line.