ESPH GP Buckshole Reservoir Safety Works (ESPH361) - AWARD

Hastings Borough Council sought a suitably qualified and experienced Contractor to carry out safety works for Buckshole reservoir.

Buckshole Reservoir is located on the northern side of Alexandra Park in the heart of Hastings, East Sussex. The reservoir was built in 1852 to serve as a water supply for Hastings. However, it is now only used for fishing and provides a public amenity as part of the important Grade 2 listed Alexandra Park. The reservoir is currently owned and operated by the Council.

A report on the reservoir was issued in 2017 following a statutory inspection under Section 10 of the Reservoirs Act 1975. The report included a number of recommendations made in the interests of safety. These recommendations are mandatory and are made with the objective of bringing about improvements to the dam and the associated overflow arrangements that will reduce the risk of dam failure, and thus reduce the risk to life and property downstream. In general terms the recommendations require works to be carried out such that the dam and overflow arrangements satisfy current industry guidance.

The scope of this project is to carry out the following reservoir safety works:

• oRetain the upper 4m wide 1.8m high section of existing spillway channel, raise the sidewalls and construct a new roof slab across the first 10m length of retained channel to support new landscaping.
• oImmediately downstream, retain a 7m long section of the existing channel and raise the sidewalls with the left side wall raising (looking downstream) also incorporating a flow deflector.
• oDemolish the remainder of the existing channel all the way to the downstream toe of the embankment and construct an in-situ reinforced concrete U shaped channel nominally 2m high with a clear opening of 4m.
• oAt the central embankment toe, construct a stilling basin structure, which will comprise a flat U trough channel section with baffle blocks and an end wall.
• oConstruct a roof slab to cover 5m of the stilling basin at the downstream end to support new landscaping.
• oConstruct a further 5m length of new channel downstream of the stilling basin, with sloping wingwalls to tie into existing channel sidewalls.
• oInstall a new siphon draw-off pipeline, including all associated pipe sections and specials, valves, pipe supports and valve chambers.
• oThe upstream end of the pipeline will be installed on the bed of the reservoir.
• oThe pipeline will then pass through the existing spillway structure, by coring through the spillway weir wall and fixing to the left sidewall, internally within the existing overflow structure and the to the left side wall of the spillway channel.
• oThe downstream end of the pipeline terminates in a valve and discharge chamber adjacent to the main spillway channel, including an overflow notch into the spillway channel to discharge flows from the pipeline.
• oLandscaping works including new planting and...