Flood Risk Assessment in Huntingdon

A flood risk assessment in Huntingdon has to deal with a town that mostly stands clear of its river but has floodplain at its edges. The River Great Ouse runs along the south and east side, between Huntingdon and Godmanchester, with the open meadows of Portholme and Mill Common on the west and the riverside streets of Hartford on the east. We prepare flood risk assessments in Huntingdon for planning, property purchase and insurance, along with sequential and exception tests and surface water drainage strategies, for sites from the Old Bridge to Stukeley Meadows.

Huntingdon is a market town in Huntingdonshire district, Cambridgeshire, and most of it falls within the PE29 postcode district. Hinchingbrooke, Oxmoor, Stukeley Meadows and Hartford all sit inside the built-up area the Office for National Statistics draws for the town. Godmanchester, across the Old Bridge, and Brampton, west of Portholme, are separate settlements. They share the river, the gauges and the councils with Huntingdon, and their flood investigations are the nearest written record of what the Ouse does along this reach.

The district's flood evidence lists Environment Agency defences at Godmanchester, a £6.8 million scheme finished in 2014 that protects 556 properties, and none at Huntingdon. On the north bank, a site's safety depends on its own ground level and how close it is to the river or a brook.

To talk through a Huntingdon site with one of our flood risk consultants, call 01293 214444 or email enquiries@unda.co.uk. Reports for sites in Huntingdon come from Unda Consulting Limited, a CIWEM Business Partner.

Where the Great Ouse reaches Huntingdon: Portholme, Mill Common and the Hartford bank

Most of Huntingdon is on a terrace above the Great Ouse, so the town centre around Market Hill and the High Street is not where river flooding begins. It starts at the edges, where the land falls to the meadows and the bank. Huntingdonshire's 2024 Strategic Flood Risk Assessment puts a broad band of Flood Zone 3 along the Ouse as it passes Huntingdon, Godmanchester, Wyton and St Ives. Its edges, from west to east, look like this:

• Portholme. A 91.56 ha meadow between the town, Godmanchester and Brampton, and in JNCC's description the largest surviving traditionally managed meadow in the UK. It floods in winter and is protected as a Special Area of Conservation, so it stays open floodplain.
• Mill Common and the former gas depot. Low ground on the west side of the centre. The Local Plan allocates the gas depot site (HU 6) for about 11 homes, records much of it in Flood Zones 2 and 3a and the southern part in functional floodplain, and sends the homes to the northern end.
• Alconbury Brook. A main river draining 202 km² of clay to the north and west, which the county's Alconbury investigation calls one of the faster responding tributaries of the Great Ouse. It meets the river at Godmanchester after passing the racecourse and Brampton.
• The Old Bridge and the riverside. The low strip by the bridge, the riverside park and the start of the Godmanchester causeway, where the town meets the river most directly.
• Hartford. The old village on the east side of Huntingdon, where Main Street, Church Lane and the houses off Hartford Road come down to the Ouse. The Environment Agency's warning area for the town covers them by name.

Flood Zone 3b, the functional floodplain, covers the meadows themselves. Planning policy keeps new homes out of it, which is why the plan's Huntingdon allocations at Mill Common and the racecourse come with conditions about where on the site building can go.

Check a Huntingdon address, from Stukeley Meadows to the Old Bridge

Enter a postcode in the map below to screen an address in Huntingdon or Hartford for river, surface water and reservoir flooding from Environment Agency data, or open our full flood risk map for the flood zones across the district. A screening tells you whether to look closer. It does not replace a site-specific assessment.

The Godmanchester gauge and the Huntingdon and Hartford warning area

The Environment Agency measures the Great Ouse for Huntingdon at its Godmanchester station, on the reach shared by the two towns. Its scale gives a buyer or applicant a sense of how little the river needs to rise: the normal range is a band only 18 cm wide.

The River Great Ouse at Huntingdon and Hartford flood warning area names Waters Meet, Temple Close, Hartford Road, Tennis Court Avenue, Nursery Road and Brookside in Huntingdon, and Main Street, Church Lane, The Grove and Old Houghton Road in Hartford. Upstream, there are gauges at Brampton Sluice, on Alconbury Brook at Brampton Racecourse and on Brampton Brook; downstream at Houghton and Hemingford. Our live river levels map shows them alongside the Environment Agency's list for the area.

Huntingdon's floods on record, 1947 to Storm Bella and 2024

The county council has no flood investigation report for Huntingdon town itself, but it has published several for Godmanchester and Brampton, its immediate neighbours on the same river. The dated events around the town are these:

1. March 1947. An aerial photograph taken on 18 March 1947 records extensive flooding around Huntingdon and Godmanchester after the snowmelt flood of that spring.
2. 1998. The flood that the Environment Agency still uses as the benchmark for the Great Ouse. Godmanchester came very close to flooding, which led to its defences.
3. January 2003. The Godmanchester gauge reached 1.29 m on 3 January, its highest reading.
4. 23 December 2020, Storm Bella. Rain on a saturated catchment put several Great Ouse gauges above their 1998 levels. In Godmanchester 12 properties flooded internally after 33 mm to 52.8 mm fell in 18 hours, much of it surface water that could not drain because the river had covered the outfalls. In Brampton 9 homes flooded inside, from 24 reports.
5. September and October 2024. About 183 mm of rain fell upstream in Bedfordshire over ten days, and Brampton had 5 properties flooded internally and 58 reports of external flooding, with Brampton Brook backed up against a high Ouse.

Walls at Godmanchester, none at Huntingdon: what the defence list means for a site

Godmanchester's scheme, completed on 28 February 2014, put a 1.5 km line of walls and embankments through gardens backing onto the river and added two pumping stations, at Cooks Stream and Rectory Gardens, to deal with water seeping up through the ground behind them. The SFRA's table of major defences in the district lists that scheme alongside St Neots, Houghton and Wyton, Hemingford Abbots, Fenstanton, Earith and Colne. It lists nothing for Huntingdon.

That works in two directions. A Huntingdon site in Flood Zone 2 or 3 cannot point to a defence and its standard of protection, so the assessment shows the floor levels and access against the undefended flood, allowing for climate change. Across the bridge, a defended Godmanchester site is still in the flood zone on the Environment Agency's map, as our article on why defended land stays in a flood zone explains, and has residual risk from overtopping or a breach to deal with instead.

Surface water, sewers and groundwater under the town

Away from the river, the SFRA picks out Huntingdon for three other sources. On higher ground in the town, these are what an assessment turns on:

The plan's evidence for the former Forensic Science Laboratory site (HU 2) says the existing surface water network could not take its runoff without increasing flood risk, so the plan asks for SuDS instead. Where infiltration is proposed, the county asks for a rate of at least 1.0 × 10⁻⁶ m/s from soakaway testing, and our BRE 365 infiltration rate calculator turns field results into that figure.

What will Huntingdonshire ask of a flood risk assessment in Huntingdon?

Huntingdonshire District Council decides planning applications in Huntingdon, and Cambridgeshire County Council, as lead local flood authority, comments on drainage for major schemes, aiming to reply within 21 days. The adopted Local Plan dates from May 2019, and its replacement has just finished its pre-submission consultation. These are the documents a Huntingdon application is read against:

For new homes in Flood Zone 2 or 3, the sequential test asks whether a lower-risk site is available first. Any building on the floodplain edge also has to replace the storage it takes up, usually by level-for-level compensation.

North Huntingdon, Mill Common and the racecourse: where the Local Plan puts flood conditions

Huntingdon's growth is to the north, on clay land crossed by Alconbury Brook and its ditches, and the new plan calls the whole area North Huntingdon. Inside the town, the allocations with flood conditions are on the meadow edge. The plans attach these conditions:

• Alconbury Weald. The former airfield north of the town, with permission for 6,500 homes and a 150 ha Enterprise Zone. The allocation requires a flood risk assessment and a site-wide water management strategy.
• Ermine Street. About 1,650 homes on 85 ha off Ermine Street, between the northern edge of the town and Great Stukeley. The western corner beside the A1307 is in Flood Zones 2 and 3.
• Lodge Farm, north of the A141. A proposed new community of about 4,900 homes on 317.7 ha, not yet examined. The draft policy asks for an integrated water management strategy, and a flood risk assessment covering river, surface water, reservoir and residual risk with the ordinary watercourses modelled.
• Huntingdon Racecourse. A 72 ha allocation west of the town, mostly functional floodplain beside Alconbury Brook. The plan asks for the brook and its culverts to be modelled and for buildings to move to the lower-risk parts.
• Mill Common gas depot (HU 6). Homes to the north of the site, a route out to higher ground and a flood response plan.
• Hinchingbrooke Hospital. A 22 ha allocation for a replacement hospital, with a flood risk assessment and drainage strategy for surface water now and in future.
• Amber Centre, Mayfield Road. About 12 homes, with surface water and residual flood risk to be covered by the assessment and drainage strategy.

Small streams and ditches on this land are ordinary watercourses, and some of the downstream catchment sits in the Alconbury and Ellington Internal Drainage Board district. Any new outfall or culvert needs ordinary watercourse consent from the county council or the board before work starts.

Which Huntingdon sites need a flood risk assessment, and which report?

Any site in Flood Zone 2 or 3 does, along with sites of 1 ha or more anywhere in the town, and the county adds a drainage review on every major scheme. As a guide:

Our planning-stage assessment page sets out what goes to the council. For a house extension, our guide to extending a home in a flood zone explains when standing advice is enough.

Reports for Huntingdon's riverside, brook-side and growth sites

A house in Hartford, a flat conversion off the High Street and a phase at Ermine Street each need something different. Our chartered consultants prepare each report, and a senior consultant checks and signs it off.

• Riverside and meadow-edge applications. Homes, conversions and commercial schemes in the Great Ouse flood zones need a flood risk assessment for planning that answers LP 5 and the Environment Agency.
• River, brook, sewers and ground together. A flood risk assessment for a Huntingdon site weighs the Ouse, Alconbury Brook, surface water, groundwater and the sewers in one report.
• A house near the Hartford bank. Before exchange on Waters Meet, Temple Close or Hartford Road, a flood risk survey for property purchase shows the buyer and lender the risk to that address.
• Homes proposed on the floodplain edge. A scheme at Mill Common or by the river needs the sequential and exception test against Huntingdonshire's sites before the council weighs the flood evidence.
• Drainage for major schemes. The county reviews the drainage of every major Huntingdon application, and our drainage strategy work answers its February 2026 guidance.
• Runoff from new roofs and roads. A surface water drainage strategy sets the discharge rate and storage for plots at Ermine Street, Stukeley Meadows or the town's brownfield sites.
• Conditions on a Huntingdonshire permission. Where the council has attached a drainage condition, the discharge of drainage conditions supplies the layout, calculations and maintenance plan it asks for.
• Levels where the national map is too coarse. At the racecourse and on Mill Common, flood modelling of Alconbury Brook or the Ouse fixes the flood level a layout has to clear.
• A way out when the warning comes. For homes in the Huntingdon and Hartford warning area, or at Mill Common where the plan asks for one, a flood warning and evacuation plan sets out who leaves, when and by which route.
• Land north of the A141. Before an offer on land at Lodge Farm or near Alconbury Brook, a flood risk feasibility study shows how much can be built and how it drains.
• Homes on the warning-area streets. For a house on Brookside, Nursery Road or Main Street in Hartford, a flood risk assessment for insurance gives the insurer evidence about that one property.
• Water in the ground. Huntingdon sits in the SFRA's highest groundwater band, so a groundwater flood risk assessment checks basements, soakaways and foundations before they are fixed.

Who to call when the Ouse rises at Huntingdon

If anyone is in danger, call 999, and report a power cut on 105. For everything else, responsibility for flooding in Huntingdon is shared like this:

The county's flood risk management strategy runs to 2027. Upstream, the river passes St Neots; downstream it reaches St Ives. For the wider county see Cambridgeshire, and for the river from source to sea, the Great Ouse. Cambridge and Peterborough have pages of their own, and the rest are listed under areas we cover.

What Huntingdon buyers and applicants ask about flooding

To discuss a house in Hartford, a conversion near Market Hill or a plot at Ermine Street, call 01293 214444 or email enquiries@unda.co.uk.