Butterley Spillway Improvement Works

Following on from a partial spillway failure in 2002 during a flow event significantly below Probable Maximum Flood (PMF), and a lengthy planning process, works have now started on site for the much-needed spillway improvement works at Butterley Impounding Reservoir. This paper will describe the project journey, the challenges faced by the project team and the design details.

The existing spillway is Grade II listed and an iconic structure within the local landscape. The solution that has currently been awarded planning permission has been reached through compromise between the Client, the All Reservoirs Panel Engineer (the Inspecting Engineer), The Project Team and Local Planning Authority.

The upper two-thirds of the spillway will be refurbished including replacement of the existing masonry invert and raising of the right hand side spillway wall. The lower third of the spillway will be completely rebuilt to provide a more consistent gradient. A number of existing features are to be retained and incorporated into the new spillway including masonry piers, copings and curved wing walls to help preserve the character of the original spillway.