Remedial works at Brent Reservoir to address leaking sluice gates

摘要

Brent reservoir is impounded by a 170 years old embankment dam with a puddle clay core and was constructed as a feeder reservoir for the Grand Union Canal. The reservoir has a chequered history; problems with leakage through the embankment are well documented. The reservoir is now mainly used for recreational purposes and the area upstream is a designated Site of Special Scientific Interest. Two culverts pass through the dam at low level which discharge flood water into the horseshoe shaped stilling basin approximately midway along the dam. The culverts are controlled separately by cast iron sluice gates at their upstream end. During operation of the right hand sluice gate in 2001 severe vibration was experienced in the lifting mechanism; the degree of vibration persuaded the reservoir keeper to close the gate. The two sluices are used as part of the overflow works and are operated in conjunction with the four original fixed weirs, syphon spillways and emergency overflow over the dam crest. Inspection of the gate by divers showed there to be substantial leakage through the top and bottom seals. Binnie Black & Veatch have been appointed to undertake a review of feasible options for stopping leakage through the culvert without affecting the SSSI site. This paper will describe the options considered and detail the recommended solution for stopping leakage through the two sluice gates.