[currently under construction]
Steward’s House Drain 2015
This scheme was designed to improve the Steward’s House Drain in Thorney Village. The drain approximately 1.600m in length, and provides drainage for both agricultural land and urban surface water run-off.
Approximately 300 houses discharge into Steward’s House Drain at various locations along its length, these discharge via a combination of Anglian Water and privately owned surface water drainage systems. Due to the design of the scheme, 30 of these properties were directly removed from serious risk of flooding.
The scheme was split into three phases.
Phase 1 of the project began on the 8th April and involved the construction of a 100m pipeline in front of the Duke of Bedford Primary School. The work required the closure of the western carriageway. A Polypipe Rigidrain System was sued on the project including 100m of 0.75m dia. 6KN/m² pipe and 3 No prefabricated Polypipe inspection chambers.
In addition to this, 12 No surface water outfalls were connected to the pipeline, 3No serving the highway and 3 No serving the school with 6 serving the adjoining housing estate.
The drain was filled to match existing ground levels and the area grass seeded with a little help from a number of school pupils.
This was completed on the 30th April 2015 and the road re-opened.
Phase 2 of the project began on the 8th June and involved the construction of a new culvert under Wisbech Road, east of Sandpit Road in Thorney.
The road was closed for the duration of the works to ensure the safety of both the general public and the staff working on site.
A significant amount of time was invested in locating all the underground services before the work began on site. In total, 25 No. utility services were safely exposed and remained undamaged for the duration of the work.
The construction of the new culvert which is 36m long x 0.75m dia, was completed on the 29th June 2015.
Phase 3 of the project began on the 15th June 2015, and involved the excavation of a new channel linking the new road culvert to the Board’s Cobblers Fen Drain to the north. Approximately 2,000 cubic metres of spoil was excavated to create the new drain some 245m long.
A new outfall culvert 18m long x 0.9m dia. was also constructed. During the works a number of tile drain outfalls were exposed and these were cleared and headwalls installed.
Grass seed was sown on the drain batters with the works completed on the 30th June 2015.
Foul Anchor Sluice Refurbishment 2015
The Foul Anchor Sluice is a Grade II listed tidal gravity outfall structure constructed by George Robert Stevenson for North Level Commissioners in 1859. It is located 7.5km north of Wisbech and sits some 650m downstream of Tydd Pumping Station, which pumps out surplus water from a catchment area of 17,000 hectares.
Following the tidal surge of 5th December 2013, it was noticed that a greater volume of water was entering the storage pound with every tide. An initial inspection revealed tidal water was entering the pound beneath the large timber mitre doors. As a result of this, the pound was increasingly losing storage capacity owing to the suspended silt being deposited as the tide turned.
An initial survey carried out in September 2014 indicated a problem with the cill to the main mitre doors. A Planning Application was therefore submitted to South Holland District Council seeking Listed Building Consent to carry out the planned emergency works.
Peter Brett Associates were duly appointed to oversee the whole process from preparation of Contract documents, seeking of suitable contractors to tender, project appraisal through to supervision throughout the construction phase.
The Contract required the replacement of the two main timber mitre doors, with the proposal to utilise the steels previously used on the bridge and stored on site ever since, to form the cofferdam (this cofferdam is now on display in the Tydd Pumping Station grounds). For the duration of the works, the 2 No. outer doors were brought into service to evacuate water from the storage pound.
Martin Childs Limited was awarded a fixed price design and build contract including all road closures and traffic management in late January 2015 and work commenced on site in mid-April.
Early works involved extensive use of a dive team to remove silt from the outer doors and to remove the old disused winding gear and penstock doors from the upstream side. The stop logs were installed across the centre section of the structure before installing the cofferdam in early June.
The new Ekki timber doors, some 7.6 metres high by 4.0 metres wide were delivered to site and the old doors were lifted out using a 300 tonne crane in mid June.
Work began on repairing the cill, which had in fact broken free of the bridge foundations and rotated through 90 degrees and lifted with the water pressure on each and every tide.
A new concrete cill was constructed with a timber face prior to installing the replacement doors, using the original hinges and hinge pins.
Finally, the decking was replaced both upstream and downstream before reinstating the original winding gear, as required as part of the Planning Consent.
Works were completed by mid July on schedule and more importantly, on budget.