Flood Risk Assessment in Sheffield

Sheffield's rivers rise fast. The Don, the Loxley, the Rivelin, the Sheaf and the Porter Brook run off the Pennine moors through steep valleys. Above the city, the council's flood strategy puts the time from rain to peak at as little as two hours. Our consultants prepare a flood risk assessment in Sheffield for a planning application, a purchase, a mortgage or an insurer, and also sequential and exception tests and surface water drainage strategies.

On this page Sheffield means the city's built-up area as the Office for National Statistics maps it. That takes in the city centre and Kelham Island (S1 and S3), Neepsend, Hillsborough and Malin Bridge (S6), the Lower Don Valley through Attercliffe, Brightside and Meadowhall (S9), and the suburbs from Heeley and Totley round to Mosborough. Chapeltown, Ecclesfield, Stocksbridge and the upper Loxley valley lie outside that outline, although the same council, rivers and flood evidence cover them.

On 25 June 2007 the Don reached 4.68 m at the Hadfields gauge beside Meadowhall, its highest level on record there. That summer 1,200 homes and 1,000 businesses flooded in Sheffield, most of them in the Don Valley.

To talk through a site, call 01293 214444 or email enquiries@unda.co.uk.

Five rivers off the moors: where Sheffield's flood water comes from

Most of the city's flood risk comes from rivers that are short, steep and partly buried. The council's strategy describes narrow valleys with little room to store water, 23 reservoirs upstream that hold flow back until they are full and then spill, and industry built right up to the banks. The Environment Agency manages the main rivers and the council handles the smaller watercourses, surface water and groundwater.

Two rivers have pages of their own: the River Don, which we follow from the moors through Rotherham to Doncaster, and the River Loxley, from Low Bradfield down to Hillsborough. The Sheaf, the Porter and the Rother are covered here.

Look up a postcode between Malin Bridge and Mosborough

The map below works as a flood risk map of Sheffield. Enter a postcode to screen it against Environment Agency data for rivers, surface water, reservoirs, recorded floods and warning areas, or open our full flood risk map for anywhere in England. The coral line is the city's built-up area, with Chapeltown, Ecclesfield and Stocksbridge beyond its northern edge. In the Lower Don Valley the planning flood zone takes no account of the walls built since 2007. A street can therefore show as Flood Zone 3 here while the government's long-term risk service, which counts defences, rates it lower.

From the Dale Dyke dam to Storm Babet: Sheffield's flood record

Each of the city's big floods changed what a developer is asked to show, and the council's own investigations record what happened. The dates below run from the night the Loxley valley was swept away to the floods that tested the new walls.

1. 11 March 1864. The new Dale Dyke dam at Low Bradfield failed as its reservoir was first filled, and the water tore down the Loxley through Malin Bridge and Hillsborough into the town. The Chief Constable recorded 240 deaths, and about 4,000 houses were flooded, with 100 buildings and 15 bridges destroyed, according to the city archives' study guide. It is the reason a Sheffield assessment near the Loxley still considers reservoir flooding.
2. December 1991. The Sheaf reached its highest recorded level and flooded Sheffield station. The council's strategy blames a blocked debris screen at Granville Square for much of the damage; the screen has since been replaced.
3. 25 June 2007. After days of rain the Don broke out from Kelham Island to Meadowhall, and the Sheaf rose with it. The council counted 1,200 homes and 1,000 businesses flooded; a teenager was swept away in the Sheaf and a man drowned beside the Don. Kelham Island Museum did not reopen for two years. The summer's floods led to the national Pitt Review.
4. June 2009. The Jervis Lumb culvert in Norfolk Park collapsed during a storm, flooding homes, schools and roads, and showing that the city's buried brooks can fail as well as fill.
5. January 2018. The Lower Don Valley scheme was finished: about 8 km of walls and flood gates and more than 300 flap valves from the Wicker to the M1, for £21 million.
6. 7 and 8 November 2019. 82 mm of rain fell in 24 hours and the Environment Agency put river levels second only to 2007. The council closed the Don flood gates from Kelham Island to Meadowhall before dawn, and the new walls held the river in its channel for most of the valley. Its investigation still found 41 homes and 36 businesses flooded inside, most of the businesses along the Don at Attercliffe, Brightside and Meadowhall or on the Loxley at Hillsborough and Owlerton. Meadowhall put up stranded shoppers overnight.
7. Autumn 2023. The £11 million first phase of the Upper Don scheme was completed on the Loxley, giving more than 60 homes and 150 businesses between Holme Lane and the Don a higher standard of protection.
8. 20 October 2023. Storm Babet brought 61.4 mm to Sheffield, its wettest October day in 139 years of records. The Porter Brook set a new record at the station gauge and the Sheaf came close to its 1991 peak, yet the council found no homes or businesses flooded by the Don or the Loxley. The Rother, carrying water down from Chesterfield, flooded homes at Beighton.

The council, as Lead Local Flood Authority, has published Section 19 reports on the larger floods since 2012, street by street. The Rother's flooding in 2023 reached well beyond the city: just over the Rotherham boundary at Catcliffe the river rose 160 mm above its 2007 record and overtopped the defences. The Rother rises in Derbyshire; the Don runs on to Doncaster.

Behind the new walls: what the flood protection programme has built

Since 2007 the council and the Environment Agency have been defending the city reach by reach, and more phases are planned. A defence lowers the chance of flooding behind it but leaves a residual risk if it is overtopped or a gate stays open. The Flood Map for Planning, meanwhile, is drawn as if it were not there. An assessment for a site behind one has to answer both points.

The council's flood protection schemes page sets out each phase. Our article on flood zones after new defences explains why a defended street can still sit in Flood Zone 3. On a riverside site, floodplain storage lost to new building is normally replaced through level-for-level compensatory storage.

Kelham Island, the station and the rivers under the streets

Much of central Sheffield is built on top of its rivers. The lower Sheaf and Porter Brook run in culverts around the station, and a network of smaller brooks runs in pipes beneath the hillsides. Sites here can flood from water that has nowhere to go when a culvert is full or blocked, and a river flood map does not show that.

• Kelham Island and Neepsend. The Don flooded this area in 1907 and again in 2007. Walls at Kelham Island, Nursery Street and the Wicker were built to a 1-in-100 standard, and the next phase of the Upper Don scheme, for about 250 homes and 250 commercial properties, is funded with construction expected in 2028. A conversion or new block here needs floor levels and safe access set against the Don with climate change.
• The station and Sheaf Street. The Environment Agency's warning area for the Sheaf and Porter from Granville Square to Commercial Street takes in Sheaf Street, Pond Hill and the Midland station. A masterplan for Sheffield Midland Station and Sheaf Street forms part of the Sheffield Plan evidence.
• Castlegate. Where the Sheaf meets the Don, the council's Castlegate park project is opening the Sheaf to the sky for the first time since 1912. A site beside it has an open channel to deal with as well as the culvert.
• Culverted brooks. The council's strategy describes culverts from 150 mm to 1.5 m across, many old and in poor condition. Works that alter or obstruct one usually need ordinary watercourse consent from the council, and the site layout should show where water goes if the culvert blocks. Our guide to culverts covers ownership and responsibility.

Policy CS67, the Sheffield Plan and the 2023 SFRA

Sheffield City Council is both the local planning authority and the Lead Local Flood Authority, so one council decides an application and comments on its drainage, while the Environment Agency advises on the main rivers. The adopted local flood policy is still CS67, Flood Risk Management, in the Core Strategy of 4 March 2009. Its replacement, the Sheffield Plan, was submitted for examination in October 2023 and had not been adopted by October 2026; consultation on further main modifications opened on 14 September 2026.

• The 2023 SFRA. The council's Strategic Flood Risk Assessment, at Level 1 and Level 2, was completed in 2023 for the Sheffield Plan. The council warns that Environment Agency modelling since then has moved some Flood Zone 2 and 3 boundaries, so a site is checked against both. Our explainer on how an SFRA is used describes what one contains.
• When the council asks for an assessment. For all development in Flood Zones 2 and 3; for sites of 1 ha or more in Flood Zone 1; for smaller Flood Zone 1 sites changing to a more vulnerable use where surface water, drains or reservoirs could reach them; and in areas with critical drainage problems notified by the Environment Agency. The list is on the council's flood risk assessment requirements page.
• The sequential test comes first. The same guidance tells applicants to pass the sequential test before preparing an assessment, because an assessment cannot save a scheme that has lower-risk sites available. Our article on how the sequential test works sets out the steps.
• A SuDS Design Statement on major schemes. Major applications with surface water drainage need a SuDS Design Statement, which can be combined with the flood risk assessment into one document.

Above the local policy sits chapter 18 of the NPPF, revised in August 2026. Policy F4 screens whether a scheme in the city needs an assessment, F5 and F6 hold the sequential and exception tests, and F8 expects development of every size to follow the 2025 National Standards for sustainable drainage. What changed in that revision is set out in our note on the August 2026 NPPF.

Brownfield, conversions and hillside plots: when a flood risk assessment in Sheffield is needed

Many schemes in the city reuse old industrial land beside the Don and its tributaries, while others sit on steep streets well above any river. The table shows how typical proposals fall under the council's checklist and national policy.

What our consultants prepare for Don valley, city-centre and hillside sites

A buyer in Hillsborough, a developer at Kelham Island and a warehouse operator near Meadowhall each need a different report. Our flood risk consultants are chartered, Unda Consulting Limited is a CIWEM Business Partner, and each report is signed off by a senior consultant.

• Every source on one site. A flood risk assessment in Sheffield looks at the river, surface water, culverts, sewers and the reservoirs upstream together, because a valley-floor site can face all of them.
• Applications to the council. A flood risk assessment for planning answers the council's checklist and policy CS67 and, in Flood Zones 2 and 3, the Environment Agency's questions about the Don, Sheaf, Porter and Loxley.
• Before exchange in Hillsborough or Kelham Island. Homes near the Don and the Loxley stand on streets that flooded in 2007, and a flood risk survey for property purchase tells a buyer what that record and the new defences mean for one building.
• Homes in the floodplain. New housing in Flood Zones 2 and 3 along the Don and the Loxley needs the sequential and exception test, the exception test applying where a more vulnerable use goes into Flood Zone 3a.
• Water leaving the site. Our drainage strategy work covers how runoff behaves on steep streets and flat valley floors, and feeds the SuDS Design Statement the council asks for on major schemes.
• Brownfield runoff. A surface water drainage strategy shows how a redeveloped site will discharge, to a brook, a culvert or a Yorkshire Water sewer, in line with the 2025 national standards.
• After permission. When the council attaches a drainage condition, our work on the discharge of drainage conditions supplies the calculations and details it needs before building starts.
• Culverts and moved flood zones. Where the Flood Map for Planning has changed since the 2023 SFRA, or a culverted reach of the Sheaf or Porter has not been modelled in detail, flood modelling sets the levels for one site.
• Rivers that peak within two hours. With the Don able to peak within two hours above the city and the Lower Don Valley gates shut ahead of a flood, a flood warning and evacuation plan sets out who leaves, when and by which route.
• Cover after 2007. With 1,200 Sheffield homes flooded that summer, a flood risk assessment for insurance gives an insurer evidence about one house rather than its postcode.
• New workspace. Offices, laboratories and industrial buildings in the Lower Don Valley and at Attercliffe can use a BREEAM flood risk assessment to secure the Pol 03 credits.
• Buying commercial land. More than 500 businesses sit behind the Lower Don Valley walls, and flood risk due diligence for a purchase or loan sets out the flood risk, the defences and how the gates are run.
• Keeping a business open. 1,000 businesses flooded in 2007 and 36 in 2019; a business continuity flood risk assessment looks at warnings, access and what floods first on one site.
• Land for the Sheffield Plan. The inspectors asked for land for a further 3,529 homes and 53 ha of employment uses, and a flood risk feasibility study tests a site's flood constraints before it is promoted or bought.

Gates, gauges and sewers: who handles flooding in Sheffield

If floodwater puts anyone in danger, call 999; for a power cut, call 105. Report a flooded road or blocked gully to the council and sewer flooding to Yorkshire Water; the Environment Agency looks after the main rivers and issues the warnings.

Warnings are issued for named reaches, among them the Don at Saville Street, the Don at Meadowhall and Carbrook, and the Sheaf and Porter around the station. Levels at Hadfields, Lady's Bridge, Malin Bridge and the station gauge can be followed on our live river levels map. The council's flood risk management strategy explains who does what in more detail.

Before you apply or buy in Sheffield: common questions

Unda Consulting Limited prepares flood risk assessments, sequential and exception tests and drainage strategies for sites across Sheffield, from the Lower Don Valley to the southern suburbs. For the wider county see our page on flood risk assessment in Yorkshire, or browse all the areas we cover. To discuss a site in Sheffield, call 01293 214444 or email enquiries@unda.co.uk.