River Loxley Flooding & Flood Risk

Not many English rivers carry a flood story as grim as the River Loxley’s. On 11 March 1864 the Dale Dyke Dam at the head of its valley failed while being filled for the first time, sending roughly 3 million cubic metres of water down the Loxley through Bradfield, Loxley village, Malin Bridge and Hillsborough. At least 240 people died, and it is still the deadliest reservoir dam-burst in English history. The everyday risk is quieter but real: the Loxley is a short, steep river that rises fast after heavy rain on the Pennine moors and backs up where it meets the Rivelin at Malin Bridge. If you own, are buying, or want to build near it, Unda’s flood risk consultants can tell you what that means for your site. Call 01293 214444 or email enquiries@unda.co.uk.

The 1864 failure of the Dale Dyke Dam is the worst reservoir disaster England has ever seen, and the whole of that floodwater travelled down the River Loxley, killing at least 240 people in a single night.

• Short, steep and quick to flood. The Loxley drops about 85 metres in the six miles from Low Bradfield to the River Don, so it responds fast to rain and peaks early.
• A designated Main River. The Environment Agency regulates the Loxley, so the 8 metre byelaw margin and Flood Risk Activity Permits apply to work near it.
• Two live Environment Agency gauges. Loxley Rowell Bridge and Malin Bridge both appear on the map below, with their latest levels updating in real time.
• The risk bites in the lower valley. Malin Bridge, Hillsborough and Owlerton have flooded repeatedly, and sites there almost always need a flood risk assessment for planning.

Check flood risk along the River Loxley

The map below draws the River Loxley in coral, with the Environment Agency’s live river gauges positioned along it. Click a gauge to see its latest level, its typical range and its record peak. Enter a postcode near the river to zoom in and screen that location against the Environment Agency’s flood data for rivers and sea, surface water, reservoirs and the flood zones used for planning. It is an indicative screening tool, not a flood risk assessment.

Why does the River Loxley flood?

The Loxley floods because it is short, steep and quick to respond. It falls about 85 metres in the six miles between Low Bradfield and the Don, and the same gradient that once powered the valley’s mills and grinding wheels now drives water downstream fast after rain. Its headwaters sit high on Bradfield Moors, where rainfall is heavy and the ground stays wet for much of the year, so a big storm produces a sharp, early peak rather than a slow rise.

Four reservoirs in the upper catchment (Damflask, Agden, Dale Dike and Strines, all owned by Yorkshire Water) regulate the flow of the Loxley and take some of the edge off ordinary events. Damflask, the largest and completed in 1896, holds around 4,250 million litres in the valley above Low Bradfield. These reservoirs help, but they were built to store and supply water rather than to hold back extreme floods, and the moorland below and between them still sheds water quickly into the main channel. The pinch-point is Malin Bridge, where the Rivelin joins the Loxley within a few metres of the historic bridge: when both rivers are in spate at once the combined flow has nowhere to spread, and the valley narrows through Hillsborough towards the Don.

• Rises on Bradfield Moors. Headwater streams gather in Bradfield Dale and converge at Low Bradfield, about 10 miles north-west of Sheffield city centre.
• Joins the Don at Owlerton. The Loxley takes in Storrs Brook near Stannington and the River Rivelin at Malin Bridge before meeting the River Don at Owlerton, Hillsborough.
• Reservoir-regulated, but not flood-proofed. Damflask, Agden, Dale Dike and Strines steady ordinary flows; extreme events still run off the moors into the channel fast.
• Gauged at Rowell Bridge and Malin Bridge. The usual range at Loxley Rowell Bridge is about 0.06 m to 0.56 m; its record is 1.10 m, set on 7 November 2019.

A history of flooding on the River Loxley

No account of the Loxley can skip 1864. The Dale Dyke Dam, newly built at the head of the valley, was being filled for the first time when a crack opened in the embankment on the evening of 11 March. The dam gave way and about 3 million cubic metres of water, some 700 million gallons, swept down the Loxley Valley through Loxley village, Malin Bridge and Hillsborough before joining the Don and running on into the centre of Sheffield. At least 240 people died, more than 600 houses were destroyed or damaged, around 4,000 homes were flooded and 15 bridges were lost. The disaster forced a national rethink of reservoir engineering; the dam was rebuilt in 1875, and the reservoirs above the Loxley are inspected and regulated far more tightly today.

The modern floods have been ordinary river floods rather than dam failures, but they have still hurt. On 25 June 2007, during the floods that overwhelmed much of Sheffield, the Loxley overtopped at Malin Bridge and inundated the businesses along Holme Lane and Penistone Road; the Towsure store recorded water 3.15 metres deep and was shut for months. Afterwards the Environment Agency cleared trees and silt from the river bed at the Loxley and Rivelin confluence to improve the channel’s capacity. On 7 November 2019, the storms that flooded Fishlake and much of the wider River Don catchment pushed the Loxley to its highest recorded level at Rowell Bridge, 1.10 metres. Those repeated events are why the Loxley from Malin Bridge down to the Don is now protected by a major flood alleviation scheme.

Which areas does the River Loxley put at risk?

Flood risk on the Loxley is concentrated in its lower, urban miles. The upper valley around Low Bradfield and Damflask is rural, and its floodplain is mostly fields; the exposure rises sharply once the river reaches Malin Bridge, Hillsborough and Owlerton, where homes and long-established businesses sit close to the channel behind the new defences. The Environment Agency runs two flood warning areas on the river, “River Loxley along Holme Lane” and “River Loxley at Owlerton”, and that is the authoritative list of who gets warned when the river is rising. The table below summarises the settlements at risk from source to mouth.

The “River Loxley along Holme Lane” warning area covers Malin Bridge, Holme Lane, River Terrace, Langsett Road and Riverside Mews, the frontage worst hit in 2007. Sheffield is built where five rivers meet, the Don and its tributaries the Loxley, Rivelin, Sheaf and Porter, so the Loxley’s flood risk cannot be read in isolation from the Don it feeds: a high Don can slow the Loxley’s discharge just when its own flow is peaking. The towns along the river are covered in more depth on our Sheffield flood risk assessment page.

Is the River Loxley a Main River, and what it means for your site

Yes. The River Loxley is a designated Main River, so the Environment Agency, not Sheffield City Council, leads on managing its flood risk, along with the Don and Sheffield’s other main tributaries the Rivelin, Sheaf and Porter. Sheffield City Council remains the Lead Local Flood Authority for surface water, groundwater and ordinary watercourses. Whether a channel is a main river or an ordinary watercourse changes who you deal with and which consents you need, so it is worth getting right early.

• The 8 metre byelaw margin. Works in, over, under or within 8 metres of the Loxley (a wall, a culvert, a new outfall, a raised platform) usually need a Flood Risk Activity Permit from the Environment Agency, sought alongside planning permission rather than instead of it.
• Flood zones drive the assessment. A site in the Loxley’s Flood Zone 2 or 3, or a larger site in Flood Zone 1, will normally need a flood risk assessment for planning, and often a drainage strategy too.
• Riparian duties come with the bank. If you own land along the Loxley you are likely a riparian owner, with responsibilities for the channel and its flow.

Flood defences and catchment policy on the Loxley

The lower Loxley is now one of the better-defended reaches in Sheffield. An £11 million flood alleviation scheme, completed in autumn 2023 as the first phase of the Upper Don Flood Alleviation Scheme, runs from Malin Bridge through Hillsborough to Owlerton. The Environment Agency, Sheffield City Council and the South Yorkshire Mayoral Combined Authority built flood walls and sheet-piling and removed a weir on the Loxley to lower flood levels, cutting the risk to more than 60 homes and over 150 businesses between Holme Lane and the confluence with the Don near Penistone Road.

Defences reduce risk; they do not remove it. Every scheme is designed to a standard, and rarer or more extreme events can still overtop or outflank a wall, which is why a site behind the new defences still has to show it is safe. The Loxley sits within the Don catchment and the Humber River Basin District, and Sheffield City Council’s Strategic Flood Risk Assessment, updated in 2023 and built on the Environment Agency’s flood zone maps, is the starting point for how the council and the Agency judge development along the river.

Flood risk and drainage services for sites near the River Loxley

A development near the Loxley can call for several different reports, and it helps to be clear that they answer different questions. A flood risk assessment, a sequential or exception test and a drainage strategy are three distinct reports. They often travel together in a planning submission, but they address separate things: whether the site is safe from flooding, whether the development should be located here, and where the surface water goes. Unda prepares each of them for sites across the Loxley floodplain.

• Flood risk assessments for planning. The core report the local planning authority and Environment Agency expect for a site in the Loxley’s flood zones. See our flood risk assessment for planning service.
• Assessments for property purchase and insurance. Independent reports for buyers, owners and lenders through our flood risk survey for property purchase and flood risk assessment for insurance.
• Drainage strategies and SuDS. Surface-water designs that keep runoff off the Loxley and meet the discharge limits set by the Lead Local Flood Authority. See our sustainable drainage strategy service, with drainage calculators and the BRE 365 infiltration calculator as free starting tools.
• Sequential and exception tests. Locational justification where policy requires it, through our sequential and exception test reports.
• BREEAM and groundwater. A BREEAM flood risk assessment for the Pol 03 credit, and a groundwater flood risk assessment where a high water table is in play.

Where national mapping is not enough, which is common for sites right beside a Main River, we can bring in hydraulic flood modelling to derive accurate flood levels and extents, and prepare the detailed scheme needed to discharge a drainage condition. Everything we do is framed by the NPPF and its planning practice guidance. You can screen an address quickly with our free flood risk map and check ground conditions on the geology and soakaway map.

Live river levels and who to contact in a flood

You can watch the Loxley yourself. The Environment Agency’s Rowell Bridge and Malin Bridge gauges publish live levels, and our own live river levels map pulls the same data into one view. If the river is rising and property is threatened, sign up for Environment Agency flood warnings and act on them early.

• Live levels. Check Loxley Rowell Bridge and Malin Bridge on the Environment Agency service, or use our own live river levels map.
• Flood warnings. Sign up for Environment Agency flood warnings for the Holme Lane and Owlerton areas, and call Floodline on 0345 988 1188.
• Surface water and ordinary watercourses. Sheffield City Council is the Lead Local Flood Authority; report flooding to the council. Sewer flooding goes to Yorkshire Water.
• In a flood emergency. Call 999 if life is in danger, and 105 for power cuts.

How Unda helps with flood risk near the River Loxley

Unda’s flood risk consultants understand how the Loxley behaves: how fast it rises off the moors, how the Rivelin confluence at Malin Bridge governs levels through Hillsborough, and how the new defences and the Don downstream shape the residual risk your site actually faces. We prepare flood risk assessments and drainage strategies for residential and commercial sites across the Loxley floodplain that show a local planning authority, the Environment Agency and the Lead Local Flood Authority that a development will be safe for its lifetime without pushing flood risk onto anyone else.

Every assessment rests on the same evidence the regulators use: the Environment Agency’s flood mapping, the river’s gauged levels and modelled flows, and the local planning policy that applies to the site. If you are working on a site near the River Loxley, talk to one of our experienced flood risk consultants about what your application will need, or start with an overview of our flood risk assessment service.

River Loxley flood risk: your questions answered