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. Some visible work will be starting in Spring 2022 however, with Ground Investigation along the existing embankment surrounding Copley and the railway embankment adjacent to the cricket club to inform the detailed design of the project.

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.

We now have an approved Strategic Outline Case (SOC) which as identified potential options for flood risk reduction. The preferred option is likely to be a suite of measures to reduce flood risk in Sowerby Bridge. The next step for this project is to develop a sound baseline hydraulic river model for the River Ryburn and its confluence with the River Calder. The current data we hold is limited and over 10 years old, so requires updating. Once we have a sound baseline, we can then assess the potential options to see which have the greatest benefit to reducing flood risk.

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 (SOC) has been approved and we are progressing to Outline Business Case (OBC) in 2022. The long list of options is being refined by the project team to produce a short list to investigate in more detail. Further, more detailed modelling will be undertaken to see what benefits the short listed options have on reducing flood risk. 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.

The Outline Business Case (OBC) has been approved and we are currently reviewing the tender applications for a preferred contractor to undertake the works. We currently plan for the work to take place on site during Summer 2022.

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 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. The planning application has now been submitted for this project and we are looking to commence early works in Summer 2022.