Swinden No.1 and No. 2 and Lee Green impound reservoirs are large raised reservoirs as defined by the Reservoirs Act 1975 and are subject to periodic inspection. At an inspection, it was identified that the existing overflows and spillways were unable to pass the Probable Maximum Flood without overtopping.
The purpose of the project was to improve the overflow and spillway facilities.
The work scope at Swinden No 1 comprises construction of:
a new labyrinth weir and tumble bay; a new access track; a new spillway channel through the crest; a bridge over the spillway channel at the crest; a new spillway channel between the crest and the lower stilling basin, approximately 170m in length; a new lower stilling basin; and a new stepped spillway. It also involves the demolition and removal of the existing circular overflow structure and associated pipework; remedial works to the wave wall; Part demolition of the existing circular stilling basin, the upper scour channel and the tunnel from the draw off building to the stepped spillway. Other works include abandonment of a section of the existing by-wash channel; supply, installation and hosting of a web-based camera to overlook the site and create a time lapse movie at project end and installation of 10 No bat boxes in the scour tunnel.
The work scope at Lee Green comprises construction of:
a new 20m long overflow weir; a new debris barrier; a new 20m wide baffled spillway down the embankment; a bridge over the spillway at the crest; a new concrete apron; and a new 10m long overflow weir. The work involves reduction of the level of the existing crest by approximately 2.8m over a 20m length; demolition of the existing D-structure; abandonment of the existing spillway channel and stilling basin; remedial works to the wall adjacent to the compensation building; extension to the scour tunnel and supply, installation and hosting of a web-based camera to overlook the site and create a time lapse movie at project end.
The project was considered exemplary and was subject to a visit from the British Dam Society as a case study project.
VolkerStevin’s work on the Swinden and Lee Green reservoir improvement scheme has been recognised by the Institution of...