There are over 450 large dams for public water supply in the UK, of which 80% are in upland areas. Most of these large dams were constructed during the Industrial Revolution when the needs of industry and the population’s health in the expanding industrial cities were paramount. This often meant that the environmental consequences were given a lower priority. The last major public water supply reservoir to be constructed in the UK for water supply purposes was Carsington in 1991, and although several water supply reservoirs have been proposed since 1960, very few have made it to completion. However, UK water companies have recently offered several new reservoir schemes. The reasons can mainly be attributed to the pressures on water supply availability experienced in recent droughts, the reduction in supply due to the need for increased river flows to meet sustainability criteria, and the prospect of severe shortfalls in the future under many climate change scenarios. Three new reservoirs are being proposed in the UK at Oxfordshire, Lincolnshire, and Cambridgeshire.
This comes at a time following the dam-related disasters in Libya, where a storm caused two dams to burst, resulting in a disaster that killed thousands of people and destroyed livelihoods. Previous research by the United Nations University Institute for Water, Environment and Health has found that dams have a limited life span, degrading over time and requiring maintenance. Following an assessment of over 50,000 large dams around the world, finding that 50 years is the reasonable safe age limit and concluding that many countries’ dams are, on average, older than 50 and subsequently at increasing risk of failure,
At a time of heightened concerns around dam safety resulting from the impacts of climate change and extreme weather on dam infrastructure, increasing demand and pressure on water supplies are driving a greater need for new dams. New Research from Brunel University London, Benha University and Zagazig University in Egypt, published in the Journal of Hydrology: Regional Studies explores the the ongoing complex challenges of water resource management, dam investment efficiency, and public safety. Based on hazard maps, the new research identifies cost-effective locations for dams to prevent flash floods, potential collapses and harvest rainfall. The study considered rainfall data, soil types, rock types, slopes, highways, and storage capacity to identify the best dam sites.. Whilst the research is predominantly for arid and semi-arid regions, the researchers believe these factors uncovered by the research are useful for decision-makers in selecting the best investment locations for storage dams worldwide.