Flood Risk Reduction Schemes - Eye on Calderdale

Cottonstones Mill Pond

Cottonstones Mill Pond, located in the hamlet of Cottonstones in Calderdale, is believed to have once served as a historic mill dam. The pond is fed by two ordinary watercourses, Lumb Clough from the west and Sparable Clough from the north and features an overflow system that returns surplus water downstream into Lumb Clough.

+ Structural concerns and planned improvements

In recent years, concerns have grown over the aging structure’s stability, particularly the deteriorating spillway, which has shown signs of potential failure. To address these issues and enhance flood resilience, Calderdale Council’s contractor began major construction works at the site in December 2025.
The project focuses on strengthening the pond’s hydraulic performance, reducing future flood risk to nearby homes, and improving environmental protection. Key elements of the works include:

A new valve on the Lumb Clough inlet, regulating water flow into the pond.
A manhole installation on Sparable Clough, designed to capture debris before it enters the pond.
A replacement spillway, built to modern standards to eliminate the failure risk associated with the existing structure.
Extensive silt removal, clearing years of accumulated material to restore the pond’s capacity and function.

The programme marks a significant step in safeguarding both the local community and the surrounding environment.

Construction work at Hebble Brook. onstruction works along a riverside channel with barriers, walkways and heavy machinery, as workers carry out flood resilience works in a wooded area.

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. This project started on site on 1 September 2025 and is expected to take up to 18 months. The project will better protect over 100 properties in Wheatley, Halifax.

+ Site works and planned enhancements

The compound has been set up, access into the site has been constructed and a temporary piles have been installed. The preferred option for Hebble Brook is re-aligning the watercourse away from the existing right bank which has failing assets; a new bypass channel at the existing trashscreen, improved access arrangements for maintenance and new debris catchers upstream of the trashscreen. There will also be environmental enhancements to the park area along with additional tree planting at Mixenden.

Progress Update 1 - January 2026

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.

+ Flood risk and next steps

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.

Sowerby Bridge

Sowerby Bridge is at risk of flooding from two rivers: the River Calder and the River Ryburn. These rivers meet in the center of town. Major flood events occurred in 2012, 2015, and 2020.

Please Note: Due to funding limits for 2025/26, this project is currently on hold. Before the pause, the team completed hydraulic modeling and started planning the next stages. No further work will take place until new funding is secured.

+ Why does the area flood?

Natural Geography: The River Ryburn flows from high peatlands and five large reservoirs.
Narrow Channels: Steep hillsides and old mill buildings squeeze the river.
Bottlenecks: Narrow channels and bridges cause water to overflow during heavy rain.
Local Impact: Flooding blocks the A58 and local roads, affecting many businesses and homes.

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.

Please note: Unfortunately, the project received a minimal funding allocation for the current financial year 25/26 meaning it has had to pause. However, the project team have completed several tasks to ensure that once the project re-starts it is in the best possible position to commence at pace.

+ Flooding history and proposed measures

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.

During the project development we have completed several tasks including a detailed hydraulic river model of Walsden, undertaken ground investigation, and moved from a long list down to shortlist of options to reduce flood risk to Walsden. This had led to an economically viable and technically feasible preferred option. The preferred option is a suite of measures due to the complex catchment. The measures include:

Strengthening existing and constructing new walls at Square Road, Sun Valley Drain and Vulcan Street
Floodwater storage at Scott Street recreational ground
Additional culvert from Unity Street to downstream of Hollins Mill
Debris deflectors on Ramsden Wood Road and gravel trap on Kershaw Road.

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.

+ Flood history and completed defences

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.