An overview of levees and reservoirs in England

Mitchell, C. and Tarrant, O. and Deakin, T. (2018) An overview of levees and reservoirs in England. In: Protections 2018 (3rd International Conference on Protection against Overtopping), 6-8 June 2018, Grange-over-Sands, UK.

PDF 48_C_Mitchell.pdf Download (1MB)

Abstract

The Environment Agency regulates 2039 reservoirs in England under the Reservoirs Act, 1975, which includes all bodies of water over 25,000m3 above ground level. With 759 different owners for these reservoirs, there is considerable diversity in the way they are managed. Water companies own the majority (~one third), closely followed by private landowners and farms. It is an aging portfolio, with the average age being 125 years old and the oldest being 800 years old. Of the ~5million properties at risk of flooding, 1million are identified as at risk from flooding from a reservoir (www.gov.uk/check-flood-risk). This is a conservative estimate due to the calculations being based on the unlikely scenario of a complete failure of a reservoir. In the future the flood maps will categorise reservoir flooding into categories of risk (high, medium and low), providing managers and emergency responders with a more informative understanding of potential impact to support such decisions as evacuation. In regards to linear raised flood defences there is an estimated 9000km in England (EA National Strategy, 2011) which mainly consist of soil embankments (levees), but also include linear defences such as flood walls. These de-fences protect properties from fluvial and coastal flooding, where 2.4million properties are at risk (www.gov.uk/check-flood-risk). These defences, alongside their point structure assets such as flood gates have recently been collated into one national database of information called AIMS – the ‘Asset Information Management System’. There has been considerable research and development considering overflow in the past decade, enabling the use of fragility based tools for national investment planning and specific modelling tools for overtopping. Consideration of surface protection has recently been reviewed and future research in grass/surface protections and soil is under consideration. Closely connected to this research we have also been considering transitions, animal disturbance, design (steep faces) and the connected failure mechanisms leading to breach.

Actions (for site administrators only - login required)

View Item