Flood Risk Reduction Schemes - Eye on Calderdale

Copley

Flooding at Copley occurs due to overtopping of the embankment on the left bank of the River Calder. Water also seeps through the railway embankment from the cricket field (this is an informal flood storage area) and some flooding can occur from the canal overtopping. Copley Village has a history of flooding, with the most severe incidents occurring on Boxing Day 2015, June 2012 and January 2008. During the flooding in 2015, Copley Bridge, which connects the main village with St. Stephen's Church, was severely damaged and had to be demolished and rebuilt.

As part of the Environment Agency’s winter readiness programme, our contractors, ESH, have now completed works on the temporary flood defences at the North West end of St. Stephens Street. The section of wall is now at the same level of flood protection provided by the embankment. This will better protect the residents of St. Stephens Street and Railway Terrace.

Over the coming months, further work will be undertaken to produce and have assured a business case to progress the wider scheme to construction. The project team are currently exploring options to reduce seepage through the railway embankment, improve the river embankment, and provide flood risk improvements associated with the canal. This work will be mainly a desktop exercise, as most of the modelling and ground investigation is complete. However, works that will be visible on site this year will include monitoring vegetation clearance.

Sowerby Bridge

Flooding in Sowerby Bridge occurs from the River Calder and the River Ryburn – the meeting of which is in the centre of the town. 2012, 2015 and 2020 all saw very similar flood incidents.

The Ryburn (and its tributaries) starts high in the Pennine peatlands, which are drained to fill five large reservoirs. As the river flows further downstream, the Ryburn is heavily restricted by steep hillsides on both banks before entering the town of Sowerby Bridge, where built up mill complexes and restrictive channels and bridges cause bottlenecking and overtopping.

The impact of flooding affects many businesses and some residential properties, as well as creating very restrictive access conditions, blocking the A58 and many minor roads in, around and through the town.

Throughout 2020 modelling and investigation work has been conducted by our consultant, Arup. This modelling has looked at catchment wide natural flood management measures to support any containment options.

The team are in the process of writing and preparing the strategic outline case. This defines the issues and justifies investment in a detailed appraisal. It also identifies viable options for flood risk reduction. The strategic outline case will outline the preferred option and provide an indicative economic case of the costs and benefits of implementing a scheme.

Flooding on Park Road, Elland. All the properties on the street are flooded including the local pub and highway.

Walsden

The Walsden Catchment is approximately 18km2 and is made up of six sub-catchments which all meet in Walsden village. The topography of the catchment is steep, creating rapid run-off following periods of intense rainfall. The valleys are predominantly rural agriculture and Pennine moorland. Within the catchment there are several large water bodies; mainly drinking water reservoirs, as well as several potentially significant millponds.

Walsden has a long history of reported flooding, with the most recent event occurring in February 2020. Other severe flood events occurred in December 2015, July 2013 and June 2012. The flooding can also cause severe damage to infrastructure, including Walsden Railway Station, Calder Valley railway line and Winterbutlee Tunnel. Walsden Cricket Club and the recreational park area can also become inundated during flooding incidents.

Throughout 2020 modelling and investigation work has been conducted by our consultant, Arup. Arup have taken an innovative catchment-wide approach to find potential options to reduce flow in to Walsden from this complex set of sub-catchments. The strategic outline case has now been submitted to the Environment Agency National Project Assurance Service for review and assurance. It defines the issues and identifies viable options for flood risk reduction. The team will then begin investigating a long list of options. Network Rail continue to partner on the project.

Park Road, Elland

Elland has been at flood risk throughout its history, with the earliest recorded instance of flooding being the destruction of Elland Bridge by the floodwaters in 1615. More recently, an event in June 2012 and the Boxing Day floods of 2015 had the same result. The town also flooded in February 2020. This has a detrimental impact on residents and businesses within the town, flooding properties and damaging transport links. Flooding is caused when the River Calder overtops and spills into the Calder and Hebble Navigation, which in turn spills onto Park Road.

A previous scheme involving containment of the river by constructing embankment upstream was investigated, however it was found to be unaffordable and also impacted on businesses downstream.

Following the flooding in 2020, a model review was undertaken to calibrate and check the 2020 flood event against our existing knowledge. The review has been completed and demonstrates no substantial change to the flooding mechanisms previously understood from the prior studies. It did, however, highlight and reinforce that Park Road, Elland suffers from river flooding, compounded by canal overtopping and surface water flooding from the high ground. As such, the Environment Agency are working with Calderdale Council, Canal and River Trust and Yorkshire Water. This partnership working is essential in the success of any flood risk measures proposed.

Shaw Wood Road, Todmorden

The Shaw Wood Road scheme is located on the right bank of the River Calder downstream of Todmorden and is adjacent to the main transport route through the Calder Valley, the A646.

This area, and upstream locations, are characterised by steep narrow valleys which create flashy reactions in the River Calder and its tributaries. At this location, the river overtops the bank and breaches a highway wall.

Shaw Wood Road has a history of reported flooding, with the most severe events occurring in February 2020, Boxing Day 2015 and June 2012. In the Shaw Wood Road location, the impact of both the 2020 and 2015 events were similar, with a number of residential and commercial properties being flooded or surrounded by flood water. During the 2015 event, a large tree partially blocked and subsequently damaged the Shaw Wood Road Bridge.

An outline business case has been produced and the preferred way forward is to construct a flood wall to reduce flood risk. An outline business case sets out the case for the preferred option, which is justified technically, economically and environmentally, along with a funding plan, procurement plan and risk management plan (including suitable contingencies).

Hebble Brook, Halifax

The purpose of this project is to mitigate the blockage and backing up of the water which will create a large dam of water with no access to the screen. The option will provide long term environmental benefits to the area whilst also protecting the erosion and slippage of the steep embankment adjacent to the channel.

The preferred option is likely to be a realignment of the Hebble Brook watercourse to improve the fluvial approach to the culvert. This will help reduce undercutting of the steep sided embankment and provide much improved access for Calderdale Council maintenance teams to safely clean the screen if it becomes blocked with debris in high flows.