Lower Todmorden Flood Alleviation Scheme Phase 3

ceequal-excellent-16-9CEEQUAL Excellent (92.4%)
Whole Project Award

Version 4, July 2014.
Tormorden, West Yorkshire, England, UK.

Client: Environment Agency;
Designer: CH2M Hill;
Contractor: VolkerStevin Ltd;

Assessor: Lucinda Farrington (VolkerStevin)
Verifier: Gemma Fenn (Fenn Environmental)

Project summary

The scheme is phase 3 of the Lower Todmorden & Walsden Water Flood Alleviation Scheme, located within the town of Todmorden in West Yorkshire. This phase focuses on an approximately 1.1km section of the watercourse of Walsden Water, which flows from south to north through the town centre. The site includes the existing flood defences, retaining walls and culverts located along this length. Along this section the river flows through a masonry lined channel and passes beneath above ground structures via masonry culverts. The north eastern end of the site , downstream end of Market Hall culvert is located at the approximate national grid reference (NGR) 393781, 424250. The south western end of the site, the upstream end of Shade School culvert is located at approximate NGR 393073, 423204.

The work carried out includes:

Flap Valves: Fitment of Non-return valves to all protruding pipe work in the Lower Walsden and Todmorden Culverts along the Walsden watercourse to prevent the back flow of water into the various runoff pipes.

Obstruction in Walsden Water: Morrisons delivery yard bridge – removal of the Morrisons Delivery Area access bridge, which in a storm event is a major obstacle and impedes the flow of water to Walsden Water. In order to remove this structure, a new access has been constructed around of the supermarket.

Morrisons wall raising work: the wall has been raised where required; a stone clad river training wall comprising a bored pile wall with a reinforced concrete parapet at varying offsets from the existing wall on both left and right banks and where the delivery bridge has been removed.

Rochdale Road: Upstream of 193 Rochdale road culvert strengthening was required through the construction and installation of a 10.0m section of box culverts. A new head wall has been constructed for the existing culvert at 193 Rochdale Road. The river training wall has been raised, the existing wall demolished, and replaced with a bored pile wall with a reinforced concrete parapet at varying offsets on the left bank of the river. Construction of a stone clad river training wall comprising cantilever sheet piles around the garden of 195 Rochdale Road. The existing configuration of the river at the stone weir (Back Waterloo) turned the water course on a 90 degree bend, which in storm conditions impedes flows creating flood problems. The weir has been removed whilst retaining the iron works to create a feature nearby, and the river re-shaped using the demolished stone weir as a new man made river bank on the right hand side and sheet piles installed on the opposite side which are stone clad. The profile is shaped to create a smoother flow with rock armour installed to protect the walls and offer a natural habitat.

Market Hall culvert: the market hall culvert required strengthening. To avoid unnecessary disruption to the market businesses 23.5m of box culverts have been pre-cast and jacked into place inside the existing culvert.

Salford Way: the existing stone wall has been raised; the existing gabion wall removed and replaced; the existing arch soffit is protected with ironworks with a mural effect; the existing land landscaped incorporating the local area community group joint design.

Lower Walsden and Todmorden culverts: some general remedial works have been carried out at various points in the culvert.