Damflask reservoir: scour system reservoir safety improvements

Abstract

Designed by Thomas Hawksley, and completed in 1896, Damflask reservoir was constructed to provide compensation flows to the growing industries downstream in Sheffield. The earth embankment dam incorporates two modified bottom outlets used to release water from the reservoir, each comprising sections of tunnel and pipework together with a series of guard and control valves, to form the reservoir scour system. In 2015, a statutory inspection recommended that improvements were made to comply with modern safety standards and enable the reservoir to be drawn down in a reasonable time, if required in an emergency. This paper provides a brief background to the works at Damflask reservoir and summarises the key technical challenges, which were overcome to improve the existing drawdown facilities; from design development through to construction, commissioning and ongoing operation of the final scheme. It provides an insight into the complex two-year project from the author's perspective as project leader and designer, within the design and build team, commissioned to investigate and undertake the upgrade works.