Flood Risk Assessment in Doncaster

Our team at Unda use years of experience to prepare comprehensive flood risk assessments and drainage strategies for commercial and residential sites across Doncaster. A flood risk assessment in Doncaster shows your local planning authority that a development will stay safe from flooding for its whole lifetime, without pushing flood risk onto anyone else.

Doncaster sits on the River Don where it leaves the Pennine foothills and spreads across the flat, drained Humberhead Levels towards the Trent and the Humber. We assess every source that matters here — the Don and its neighbours the Dearne, Torne, Went and Ea Beck, the surface water that overwhelms drains in the built-up centre, and the groundwater and pumped land drainage of the low-lying east — then deal directly with the Environment Agency, the City of Doncaster Council and the relevant Internal Drainage Board on your behalf. We guide architects, planning consultants, developers, landowners, home buyers and businesses through to a decision, whether the report is needed for planning, a property purchase, mortgage or insurance, BREEAM, or a surface-water drainage strategy.

If you need a quote or want to talk a site through, contact one of our experienced flood risk consultants on 01293 214444.

Much of Doncaster stays dry only because embankments, washlands and pumping stations hold the water back, so flood risk here has to be read river by river and field by field — not lifted from a single national map that cannot see a barrier bank or an Internal Drainage Board drain.

Flood risk assessment in Doncaster at a glance

• The River Don runs through the borough. The Don gathers flow from the Rother and Dearne upstream, so heavy rain over the South Yorkshire hills becomes a flood peak at Doncaster a day or two later.
• Around 760 properties flooded in November 2019, including 173 in Fishlake, when the Don overtopped after roughly 150% of the month's rain fell in two days — the event that still shapes how the council and the Environment Agency review schemes here.
• Two Internal Drainage Boards — the Danvm Drainage Commissioners and Doncaster East IDB — manage the low-lying drained land alongside the City of Doncaster Council as Lead Local Flood Authority. We work with all of them.
• Flood Zone 1 is not a free pass. Since the 2025 PPG update, surface water risk can trigger an assessment even on a Flood Zone 1 site.

Check flood risk anywhere in Doncaster

Doncaster is outlined below. Screen any postcode in the borough against Environment Agency data for rivers and sea, surface water and the planning flood zones, with a climate outlook to 2125. It is an indicative first pass, not a substitute for a site-specific assessment.

Flood risk in Doncaster: the River Don, the drained levels and surface water

Doncaster faces river, surface water and groundwater flooding, often on the same site. River flooding from the Don and its tributaries dominates the valley floors and the low-lying east, surface water overwhelms drains in the built-up centre, and the flat, pump-drained land of the Humberhead Levels carries its own risk where the water table sits close to the surface. Most sites here face more than one source, which is why a desktop map rarely satisfies a planning officer on its own.

Nearly all of Doncaster drains through one river system. The Don gathers the Rother and the Dearne above the borough and carries their combined flow through Sprotbrough Gorge and Doncaster town towards the tidal Trent, joined by the Ea Beck, the River Went, the River Torne and the Idle across the flat eastern levels. A prolonged rainfall event over the South Yorkshire hills becomes a flood peak in the lowlands a day or two later. Understanding which watercourse drives the risk on a given site, and how it behaves, is the heart of a credible fluvial flood risk assessment.

• Rivers (fluvial). The Don through Doncaster, Bentley and the Don Valley carries the highest river risk, with the Dearne, Ea Beck, Went and Torne adding to it. Land in Flood Zones 2 and 3 along these corridors almost always needs an FRA.
• Surface water (pluvial). Now the most widespread flood risk in England. Intense rain overwhelms drains in built-up Doncaster, Bentley and the town centre. Since the 2025 PPG update, surface water on the Flood Map for Planning can trigger an assessment even on a Flood Zone 1 site — see our note on surface water and planning.
• Groundwater. The Sherwood Sandstone and magnesian limestone beneath western and central Doncaster can raise water tables that flood low-lying ground and basements without ever showing on a river map — critical for any soakaway or below-ground level. See groundwater flooding.
• Drained levels, sewers and ordinary watercourses. Across the eastern Levels, field drains, pumped catchments and the surface-water sewer network back up in heavy rain. These ordinary watercourses are the responsibility of the Lead Local Flood Authority and the Internal Drainage Boards rather than the Environment Agency — see the role the LLFA plays.

The eastern half of the borough is the textbook case for why a single map is never enough: villages such as Thorne, Moorends, Stainforth and Hatfield sit on flat land at or near the level of the channels meant to drain them, kept dry by embankments and pumps rather than gravity. A scheme there has to reconcile river level, surface water and the capacity of the drainage system at once. Our wider notes on the sources of flood risk set out how these sources interact.

Internal Drainage Boards and your Doncaster site

Large parts of eastern Doncaster sit within an Internal Drainage Board area, where land below or close to river level is kept dry by a managed network of pumped drains and embankments. If your site falls inside an IDB district, the board — not the council — consents works that affect an ordinary watercourse, and its drainage rates and byelaws shape what you can build and how you must drain it.

Two boards cover most of the drained land here: the Danvm Drainage Commissioners and Doncaster East Internal Drainage Board, both formed in 2012 from older boards and administered through the Shire Group of IDBs. They maintain the channels and pumping stations that protect the Humberhead Levels, and they are a statutory consultee on development that affects their system. Getting them on board early is often the difference between a clean approval and a late objection. Our guide to why Internal Drainage Boards matter for planning explains how they fit into the wider picture.

• Consent comes from the board. In an IDB district, works in, over or near an ordinary watercourse need the board's consent, and a connection that increases flow into its system usually attracts a drainage charge.
• Discharge is tightly limited. Boards typically hold new development to a low, greenfield-style runoff rate because the receiving system is pumped and has finite capacity — making the surface-water drainage strategy central to the application.
• Riparian duties still apply. Owning land beside a maintained drain carries riparian responsibilities for flow and maintenance, which an assessment should flag before it becomes a condition.

A history of flooding in Doncaster

These dated events are why authorities here scrutinise development so closely, and why a flood risk assessment in Doncaster has to be evidence-led rather than generic. Each one reshaped local policy and the flood defences a developer now has to design around.

• 1947 — the post-war thaw. A sudden thaw on deep snow, followed by heavy rain, broke banks along the Don and across the Yorkshire lowlands. It was one of the events that pushed central government towards formal flood-control policy.
• June 2007 — Toll Bar and Bentley. After the wettest June on record, the Ea Beck burst its banks and Toll Bar was left under around five feet of water, with Bentley and Thorpe in Balne flooded and the nearby Ulley reservoir near Rotherham brought close to failure, threatening the lower Don Valley.
• November 2019 — Fishlake and the Don. Roughly 150% of the month's rain fell in two days; the Don overtopped and around 760 homes and businesses flooded, including 173 properties in Fishlake. Bentley, Scawthorpe, Conisbrough and Tickhill were hit, residents of Fishlake, Thorpe in Balne, Trumfleet and Bentley were asked to evacuate, and 39 roads were closed.
• October 2023 — Storm Babet. A slow-moving storm flooded around 18 properties in Doncaster and far more across neighbouring South Yorkshire, forced evacuations and closed roads and the rail line, prompting a Section 19 flood investigation by the council.

A pattern runs through all of it: ground that flooded once tends to flood again. A robust assessment treats this recorded history as evidence, not background colour.

Flood defences, washlands and residual risk around Doncaster

Major investment has followed each of these events, and the schemes change what a development next to them has to prove. A new defence reduces the chance of flooding, but it never removes it, and planning policy still expects the residual risk to be assessed.

• Don washlands. Controlled washlands at Sprotbrough, Hexthorpe and along the Don deliberately flood to take the peak off the river, and the Thorpe Marsh washland is emptied by its own flood-evacuation pumping station — storage that has to be respected, not built on.
• Bentley and Don barrier banks. After 2019 the Environment Agency repaired and raised barrier banks found to be below their design standard, improving protection to Bentley, Fishlake and the surrounding villages.
• Pumped drainage of the Levels. The Internal Drainage Boards' pumping stations and embankments keep the eastern Levels habitable and farmable, but they protect to a design standard and can be overwhelmed — a textbook case of residual flood risk.

The catch for developers is the one we set out in why a site stays in a flood zone after defences are built: the Flood Map for Planning is drawn as if the defences are not there, so a defended site can still sit in Flood Zone 3. Fishlake, where a defence below its design standard was overtopped, is the cautionary tale. Climate change makes this sharper still, which is why an assessment applies the Environment Agency's river-modelling allowances over the development's lifetime.

Planning policy and your Lead Local Flood Authority in Doncaster

Two kinds of authority set the rules. The Environment Agency leads on the main rivers — the Don, Ea Beck, Torne, Went and Idle. The City of Doncaster Council is the Lead Local Flood Authority (LLFA), leading on surface water, groundwater and ordinary watercourses, and in the drained east those ordinary-watercourse powers are shared with the Internal Drainage Boards.

Doncaster is a single metropolitan borough and a unitary LLFA in its own right, which keeps the planning picture simpler than it sounds: you deal with the council as both planning authority and LLFA, alongside the Environment Agency and, where the site is in a board district, the relevant IDB. Our overview of who manages flood risk in England explains how the pieces fit together, and the role the LLFA plays as statutory consultee on surface water drainage.

Your assessment and drainage strategy must satisfy national policy — the NPPF and its Planning Practice Guidance — and the local framework: Doncaster's Local Flood Risk Management Strategy, its Strategic Flood Risk Assessment, the Flood Risk Supplementary Planning Document adopted in 2023 and Local Plan Policy 57. Where a higher-risk site is involved, the Sequential and Exception Tests apply, and the right vulnerability classification has to be argued. On drainage, the 2025 national SuDS standards and the four pillars of SuDS shape what the LLFA and the boards will accept.

What your flood risk assessment in Doncaster must show

• Risk assessed from every credible source, using the Flood Map for Planning, the local SFRA and Internal Drainage Board data.
• An appropriate location, tested against the Sequential Test where policy requires it.
• Safe for its lifetime, once the climate change allowances are applied — generally 100 years for housing.
• No increase in flood risk elsewhere, with attenuation and, where needed, compensatory storage.
• Residual risk managed, with safe access, egress and finished floor levels. Get one of these wrong and the application stalls, as our note on LLFA drainage objections shows.

Development and flood risk assessment in Doncaster

Doncaster is growing fast on the back of its position on the East Coast Main Line, the M18 and the M180, and the kind of site you bring forward shapes the assessment you need. The right scope is the difference between a clean approval and a drainage objection that holds an application up for months.

• Town-centre and Waterfront regeneration. Schemes along the Don through Doncaster, including the Waterfront and Civic and Cultural Quarter, frequently sit in Flood Zones 2 and 3, needing finished floor levels, safe access and egress, and often compensatory flood storage.
• Logistics and employment land. The borough's motorway and rail links and the former airport site at Gateway East have driven large distribution schemes, where extensive impermeable area makes the surface-water drainage strategy central to the application.
• Drained-levels and IDB sites. New build around Thorne, Hatfield, Stainforth and the eastern villages turns on pumped drainage, board consent and tightly limited discharge rates rather than a main river alone.
• Rural and agricultural schemes. Conversions and new builds across the levels and the Don and Dearne valleys often turn on surface water and ordinary watercourses, and on the right drainage information for planning.

Climate change is not optional here. A Doncaster assessment must apply the Environment Agency's allowances for higher river flows and rainfall over the development's lifetime, which sets floor levels, freeboard and how much attenuation a drainage scheme needs.

Home buyers and businesses come to us too. A flood risk question can affect mortgage lending and house prices, and a conveyancing search is not the same thing as a planning-grade assessment. Knowing which you actually need saves time and money, and our guide on doing your own assessment explains where the line falls.

Flood risk assessments and related reports for every situation in Doncaster

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 answer different questions: is the site safe, should the development be here, and where does the surface water go. We prepare all three, alongside the right form of assessment for buyers, lenders and BREEAM.

Flood risk assessments

• Flood risk assessment for planning. Site-specific reports prepared to satisfy the NPPF, the Environment Agency and the City of Doncaster Council. Groundwater and, where needed, flood modelling are assessed within it rather than as separate reports.
• Homebuyer and property-purchase survey. For conveyancing, where a search has flagged Don-valley or surface-water risk and you need the actual building assessed, not a broad map.
• Flood risk assessment for insurance. Property-specific evidence for brokers and underwriters where premiums have risen, cover has been restricted, or a property has flooded.
• Flood risk assessment for BREEAM. Structured around BREEAM Pol 03 so a scheme earns its flood and surface-water credits from the outset.
• Groundwater flood risk assessment. A defensible design water table for sandstone, limestone and basement sites, not a guess.

Location, drainage and the wider service

• Sequential and Exception Test reports. The locational case, prepared alongside the assessment where policy requires development to justify its position.
• Surface water drainage strategy and SuDS. Designed to the council's and the boards' standards from the first sketch, following the discharge hierarchy.
• Discharge of drainage conditions. The detailed design that clears a pre-commencement or pre-occupation drainage condition.
• Chartered flood risk consultants. Specialists who stay involved past the report to answer objections from the EA, the council or an IDB.
• How a flood risk assessment is done. What a robust report contains and how the process runs.

How Unda helps with flood risk assessment in Doncaster

We act as the accurate translation layer between your scheme and the requirements set by the Environment Agency, the City of Doncaster Council, the Internal Drainage Boards and national planning policy. We are experts on the borough's flooding, not a generic report mill.

A flood risk assessment in Doncaster from Unda assesses every credible source — the Don, Dearne, Ea Beck, Torne and Went, down to surface water, groundwater, sewers and any ordinary watercourse or board drain on the boundary — compares modelled flood levels against your proposed floor levels, sets safe access and egress, and recommends mitigation the regulators will accept. We are a CIWEM Business Partner with chartered members, and a senior consultant signs off every report. Where the council or a board needs it, a surface-water drainage strategy sits alongside the assessment as a separate report so the two cases stay consistent and an objection has nowhere to land.

Doncaster flood resources and contacts

The most reliable Doncaster flood information comes from the lead authorities. For an immediate threat to life during a flood, always call 999; for flooding advice call Floodline on 0345 988 1188; for a power emergency call 105.

• Check for flooding in Doncaster. Environment Agency live warnings, river levels and maps at check-for-flooding.service.gov.uk.
• City of Doncaster Council flood risk and drainage. Development and flood-risk guidance at doncaster.gov.uk, and reporting and strategy at the council's flood risk management pages.
• Doncaster Flood Risk SPD. The council's adopted Flood Risk Supplementary Planning Document (2023) sets out what local applications must address.
• Internal Drainage Boards. The Danvm Drainage Commissioners and Doncaster East IDB, administered through the Shire Group of IDBs.
• Yorkshire Regional Flood and Coastal Committee. Regional investment and priorities via the Yorkshire RFCC.
• Live river levels. Whether the Don or Ea Beck are running high right now via our live river levels map.

For flooding from blocked or burst sewers, contact Yorkshire Water. For the regional picture and how Doncaster sits within it, see our flood risk assessment in Yorkshire page, and our notes on the Environment Agency's planning role and on flood zones 1, 2 and 3.

Flood risk assessment in Doncaster: frequently asked questions