Flood Alleviation Schemes

Find out more about our programme of work to reduce flood risk in Calderdale.

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.

Latest Updates

We will be carrying out some surveys works from 21st August to 21st September 2023.  As part of informing our continuing design work, looking at potential options to reduce flood risk, we need to carry out a number of in-depth surveys at various locations in the area. This includes Threshold Surveys, Cross Section Surveys and Topographical Surveys. These surveys will give us a good understanding of flooding in the town of Sowerby Bridge.

The surveys will be undertaken by Arup and Survey Operations on behalf of the Environment Agency.  Most of this work will be carried out in the roadside or from public accessible areas and not cause any disruption, but you may see staff from Arup and Survey Operations in and around the area during this time.


Latest Information - June 2024

The Environment Agency is currently investigating options to improve channel resilience and maintain flood defences along Walsden Water.
As part of our continuing design work, our contracting partner BAM Nuttall will be carrying out investigative surveys along Rochdale Road intermittently throughout June and August.  The work will involve digging trial holes (excavations) at a number of locations in the roadway.  This will require small sections of single lane closures to minimise disruption as much as possible.
The work will be carried out on a rolling programme and traffic management will be in place at different locations along Rochdale Road between Hollins Mill and Square Road.  Some days no TM will be required.
We apologise for any inconvenience our work may cause.
June 2004 - Keeping You Informed - Rochdale Road Traffic Management

April 2024

As part of our continuing design work, looking at potential options to reduce flood risk, we are carrying out a number of surveys at various locations in the area. These include culvert surveys, ground investigations, road survey, trial holes and structural wall surveys. These surveys will be used to give us a greater understanding of flood risk in the town of Walsden.

Drone surveys will also be carried out, which will allow inspection of the river channel and provide information on bed levels.  The drone survey work will commence on 30th April and will take approximately three to four days to complete.   The data, images and video recorded are for the purposes of inspection only, and therefore we are extremely unlikely to record any personally identifiable data or personal information as defined under the Data Protection Act 2018.  All drone surveys are to be conducted in line with the CAA legislation governing the use of drones commercially.

The red lines in the maps below show the drone flight areas.


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.

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

Cleaning the streets after flooding with a shovel and a brush.
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.

In November 2023, the Environment Agency’s delivery partner completed a project to construct a flood defence wall on land immediately adjacent to the River Calder and to the west of Nanholme Centre.  The completed work now better protects 17 properties from the River Calder and comprises of a concrete legato block wall which ties into a highway wall at one end and high ground at the other.  The visible section of the wall from the highway has been clad in a rustic stone.  There are also several flapped outfalls within the wall to allow any water trapped behind the wall to drain out once river levels allow.


Underneath an umbrella during a summer shower.
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.

If you would like further information about any of these schemes, please email: CalderdaleFAS@environment-agency.gov.uk

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