17th February 2021, 9:00am

On Thursday, we were joined by David Brown from the Canal & River Trust. As part of our series of interviews with speakers, we had a chance to ask David some questions in which we cover the advances made in dam engineering, the Whalley Bridge dam incident in 2019, and biodiversity. We would like to thank David for taking his time to answer our questions. 

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Q: The engineering that underpins dams across the UK has developed over the past century, but could you highlight some of the major advances?

A: The Canal & River Trust, a charity established in 2012, and its predecessors the British Waterways Board, the British Transport Commission and the pre-nationalisation companies have been involved in the development of dams across the UK for over two centuries. Advances have included different materials and techniques for dam building; greater understanding of flood quantification for which we are still learning for example how to deal with the effects of climate change; spillway safety improvements; industry standards and guidance built on lessons learnt from our industry being open and sharing when safety incidents occur; extensive development of risk assessment and methods of mitigation; improved investigation techniques; the UK’s well developed emergency planning procedures and local resilience forums; our legislation has been developed from the lessons learnt and is brought up to date regularly and may be further updated following Toddbrook.

Q: The incident at Whalley Bridge triggered a re-analysis of dam in the UK. What lessons did the Canal & River Trust learn from the 2019 incident?

A: The Trust and the wider reservoir industry have learnt many lessons from the Toddbrook incident. The Trust appointed an independent engineer to review the incident and to give the Trust and the wider industry advice on what improvements could be made. We worked closely with the government’s inquiry and are implementing the initial findings in Part A. We await publication of part B later this year. Some of the improvements include increased investment in remote monitoring of reservoirs, moving our reservoir surveillance from paper records to a digital capture and alert system and improving safe inspection access to difficult areas on dam structures. We are improving our ability to identify change at reservoirs, improving our ability to effectively report and escalate actions and improving our response time if a change at a reservoir requires action. In addition we are using industry best practice methods to risk assess and identify safety measures at our reservoirs and we are heavily investing in the identified safety improvements.

Q: In an article by the BBC, they revisited Whaley Bridge a year later. One resident said that whenever they get heavy rainfall, they feel anxious. What changes are being made to this specific dam to make people feel safer for the future?

A: The Trust has gone of its way to reassure people that the dam is safe. We have provided regular updates on repair progress through a series of newsletters to more than 3,000 local residents. Immediately after the incident, we appointed a dedicated community engagement manager to work with local people, answering their queries and being a named point of contact within the Trust. For several months until covid lockdown, we hosted a weekly drop-in surgery where anyone could come and raise issues. We have held public meetings, open days and a public consultation event last September. We also provide regular updates on a dedicated section on the Trust’s website, plus social media posts and briefings for the national and regional media. We know people are concerned and our key message is always that the reservoir will remained drained until a permanent repair option is completed and the public are safe.

Q: What are some of the ecological impacts of dams on wildlife freshwater biodiversity — and how do you manage the relationship?

A: Many of our reservoirs are sites of special scientific interest (SSSI) or otherwise protected. We work closely with stakeholders, statutory and otherwise, to create water management plans. These take into account nesting birds, exposed mud flats for the waders, protecting fish stocks and the many important vegetation habitats around the reservoirs. Fluctuating water levels are important to the ecology at our reservoirs, some having been rising and falling to fill the canals each year across the UK for over 200 years. These reservoirs also supply water to the canals, which form a ribbon of wildlife habitat across broad swathes of the country. While there are many environmental concerns with the construction of dams and reservoirs, those operated by the Canal & River Trust have become part of the UK heritage and now provide a diverse habitat for wildlife.