Flood Risk Assessment in St Ives

St Ives sits on a wide bend of the River Great Ouse, and the river has made its presence felt more than once in recent years: on Christmas Day 2020 the gauge at St Ives recorded its highest level on record. Anyone bringing forward a site near the river, Parsons Drove or the town's low-lying streets needs to understand that record before they design around it. Unda prepares a flood risk assessment in St Ives, Cambridgeshire for planning, property purchase, mortgage and insurance, and BREEAM, alongside sequential and exception tests and surface-water drainage strategies (SuDS), for developers, planning consultants, landowners and home buyers across the town.

If you would like a quote or want to talk a site through, contact one of our experienced flood risk consultants on 01293 214444 or email enquiries@unda.co.uk.

On 25 December 2020 the Great Ouse at St Ives reached 1.52m — its highest recorded level at the town gauge — triggering a statutory Section 19 flood investigation and underlining why river levels here have to be read carefully, not assumed from a national flood map alone.

Flood risk assessment in St Ives, Cambridgeshire at a glance

• The Great Ouse is the dominant source. Fluvial flooding from the river running through the town is the main flood mechanism affecting St Ives, with land closest to the river and its historic floodplain falling within Environment Agency Flood Zones 2 and 3.
• Parsons Drove Drain is a genuine local risk. An Environment Agency flood warning area named "Parsons Drove at St Ives" covers Harding Way, Nursery Gardens, Farthing Lane, Brookway, Abbey Retail Park and Parsons Drove itself.
• Cambridgeshire County Council is the Lead Local Flood Authority for surface water, groundwater and ordinary watercourse flooding, and a statutory consultee on planning applications in St Ives.
• Growth pressure meets flood risk. Proposals for hundreds of new homes on the edges of St Ives, including land off Marley Road next to the Parsons Drove Drain drainage system, make an early flood risk assessment or drainage strategy essential rather than optional.

Check flood risk anywhere in and around St Ives

St Ives, Cambridgeshire is outlined below. Screen any postcode in or near the town 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 flood risk assessment in St Ives.

Local flood risk and hydrology in St Ives

The River Great Ouse runs directly through St Ives on its route from Bedfordshire towards the Fens and the Wash, and fluvial flooding from the river is the dominant flood mechanism in the town. The Environment Agency's gauge at St Ives (station 6178) has tracked river levels here for years, and its record now includes the December 2020 event described above. Land closest to the river and its historic floodplain generally falls within Flood Zones 2 and 3 on the Flood Map for Planning, though the exact boundary varies street by street and should always be checked for the specific site rather than assumed from the town's general reputation.

The river is not the only watercourse that matters. Parsons Drove Drain runs through the eastern side of the town, and the Environment Agency maintains a dedicated flood warning area, "Parsons Drove at St Ives," covering Harding Way, Nursery Gardens, Farthing Lane, Brookway, Abbey Retail Park and Parsons Drove itself. A documented mechanism, recorded in the Anglian River Basin District Flood Risk Management Plan 2021–2027, sees high levels in Parsons Drove Drain back up under Marley Road Bridge into Houghton Field Drain, blocking gravity drainage on St Ives Industrial Estate. Any scheme near this drainage network, including proposed housing off Marley Road, has to design around that backup mechanism rather than treat the drain as a minor ditch.

St Ives sits on gravel and river-valley terrace deposits typical of the Great Ouse corridor, so groundwater is a source worth checking on individual sites, particularly where basements or deep foundations are proposed; no town-specific groundwater statistic is published, so this should be assessed site by site rather than assumed. The town sits directly on the Great Ouse main river, which the Environment Agency manages, rather than within the Internal Drainage Board network that covers parts of the Fens further downstream — worth knowing because it affects who you deal with on drainage consents.

Historic flood-area data referenced by the Environment Agency and FloodAssist names a number of streets that have been identified as at risk at various times: London Road, Enderby's Wharf, Westwood Road, Ramsey Road, Broad Leas, Warren Road, The Broadway, West Street, East Street, Needingworth Road, Station Road, New Road, Low Road, Dunnock Way and Greenfields, along with The Waits, the riverside area referenced by name in resident reports during the October 2024 event. A site on or near any of these roads should treat flood risk as a live design consideration rather than a box-ticking exercise. You can check any of these streets today on our own flood risk map, or look at current conditions on the live river levels map.

Has St Ives flooded before? A history of flood events

St Ives has a well-documented recent flood history, and the Great Ouse has produced two clearly dated events within the last five years that any flood risk assessment in St Ives should reference directly.

• 25 December 2020 — record river level. The Great Ouse at the St Ives gauge reached 1.52m, its highest level on record at this location. Cambridgeshire County Council opened a dedicated "St Ives December 2020 Flood Investigation" under Section 19 of the Flood and Water Management Act 2010, meaning the event independently met the statutory threshold for a formal investigation.
• 16 August 2020 — town centre flooding. Torrential rain flooded St Ives Market Square and the High Street after the Great Ouse burst its banks following days of heavy rain. This was significant enough to trigger a separate "St Ives August 2020 Flood Investigation" Section 19 report from Cambridgeshire County Council.
• 1 October 2024 — a near-record level, without a formal investigation. The St Ives gauge reached 1.36m, below the December 2020 record of 1.52m and below the Environment Agency's approximate 1.58m marker for possible property flooding. Residents raised concerns about drain and gully maintenance along The Waits. No formal Section 19 investigation exists for St Ives for this specific event, unlike December 2020.
• The St Ives Staunch factor. Environment Agency hydraulic modelling carried out in May 2024 found that the town's Staunch (a historic sluice and lock structure) gives only limited flood risk benefit and is uneconomic to repair. In July 2024 the Environment Agency formally reclassified the Staunch's purpose from drainage to navigation, and it is understood to be only around 40% operational — a change worth understanding for any assessment that has previously assumed the Staunch plays an active flood-management role.

St Ives is also reported, in less well-documented secondary sources, to have flooded in 1947, at Easter 1998 and in January 2003. These earlier events are worth being aware of as background, but without confirmed primary detail we would not rely on them for a site-specific case — the two 2020 Section 19 investigations and the 2024 gauge record are the strongest, best-evidenced local reference points.

The St Ives Staunch no longer functions as a meaningful flood-management asset. With its purpose reclassified from drainage to navigation in July 2024, an assessment that leans on the Staunch as mitigation is starting from the wrong premise.

Planning and drainage policy for flood risk assessment in St Ives

Cambridgeshire County Council is the Lead Local Flood Authority for St Ives, responsible for surface water, groundwater and ordinary watercourse flooding, and a statutory consultee on planning applications that raise drainage or flood risk issues. Huntingdonshire District Council, the non-unitary district authority covering St Ives, is the local planning authority that determines planning applications, working alongside the county council on flood risk matters. Cambridgeshire's Local Flood Risk Management Strategy runs from 2021 to 2027 and sets out how the county manages local flood risk.

The relevant strategic evidence base for St Ives is the Huntingdonshire District Council Level 1 and 2 Strategic Flood Risk Assessment (SFRA) — not the separate Greater Cambridge SFRA, which covers Cambridge City and South Cambridgeshire only and does not apply here. Site-specific SFRA assessments exist for St Ives sites including "St Ives West," "West of London Road, St Ives" and land north of Houghton Road, so a scheme on or near these sites should check what the SFRA already says before commissioning fresh assessment work.

The Huntingdonshire Local Plan to 2036 addresses flood risk and sustainable drainage, primarily through Policy LP5, alongside other policies covering the wider environment. Huntingdonshire is currently consulting on an update to the Local Plan that would extend its horizon to 2046, so developers should check which version of the plan applies to a given application as that process progresses.

• Lead Local Flood Authority. Cambridgeshire County Council, for surface water, groundwater and ordinary watercourses.
• Local planning authority. Huntingdonshire District Council, determining planning applications for sites in St Ives.
• Strategic evidence base. The Huntingdonshire Level 1 & 2 Strategic Flood Risk Assessment, with site-specific assessments already prepared for several St Ives allocations.
• Local Plan policy. The Huntingdonshire Local Plan to 2036, principally Policy LP5, with a Local Plan update to 2046 in consultation.

For the national framework behind these local policies, our guides to the climate change allowances for flood risk assessment and when you need a flood risk assessment are useful starting points, and the NPPF flood risk guidance and advice page covers the planning test in full. St Ives sits within the wider Cambridgeshire flood risk picture explored on our Cambridgeshire area page.

Local development context in St Ives

St Ives is under real growth pressure, with several substantial housing proposals on its edges that bring flood risk and drainage directly into the planning conversation. Land off Marley Road has been put forward for up to 650 homes across more than 89 acres on the northern edge of the town, with up to 40% affordable housing proposed. This site sits close to the Parsons Drove Drain and Marley Road Bridge drainage system described earlier in this page, so the documented backup mechanism into Houghton Field Drain is directly relevant to how surface water and drainage would need to be managed here.

Bellway Strategic Land has brought forward a proposal for up to 295 homes on 37.4 acres north of Houghton Road, on the western edge of St Ives, again with a 40% affordable housing component. A further proposal for 130 or more homes on around 26 acres at Old Ramsey Road was withdrawn and subsequently resubmitted, while a smaller scheme at 71 Ramsey Road has been recommended for support by St Ives Town Council. A much larger proposed allocation of over 4,000 homes near RAF Wyton was removed from the Local Plan owing to concerns about access and road impact, and is worth noting as context even though it is not a live scheme.

This weight of development sits against a backdrop of local concern reflected in the St Ives Neighbourhood Plan, which records community feeling that the town may have reached a natural limit for new development and that further major schemes may not be appropriate. Whatever view is taken on that question, every one of these sites will need a flood risk assessment, a sequential or exception test, or a drainage strategy — often more than one of the three — before it can be approved, precisely because St Ives combines river floodplain, a documented drainage backup mechanism and genuine local sensitivity about growth.

• Land off Marley Road. Up to 650 homes proposed on 89+ acres, directly adjacent to the Parsons Drove Drain/Marley Road Bridge drainage system.
• North of Houghton Road. Bellway Strategic Land proposal for up to 295 homes on 37.4 acres.
• Old Ramsey Road. 130+ homes on around 26 acres, withdrawn then resubmitted; a smaller scheme at 71 Ramsey Road recommended for support locally.
• RAF Wyton allocation. A proposed 4,000+ home allocation was removed from the Local Plan over access and road-impact concerns.

How Unda helps with flood risk assessment in St Ives

We act as the accurate translation layer between your scheme and the requirements set by the Environment Agency, Cambridgeshire County Council as Lead Local Flood Authority, Huntingdonshire District Council as local planning authority, and national planning policy. We are experts in flood risk assessment in St Ives, not a generic report mill working from a national dataset alone.

A flood risk assessment in St Ives from Unda assesses every credible source — the Great Ouse, Parsons Drove Drain and the Marley Road Bridge backup mechanism, surface water, groundwater and any ordinary watercourse on the site 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 a scheme needs it, a drainage strategy or a sequential and exception test sits alongside the flood risk assessment as its own separate report, so the whole planning case stays consistent.

Flood risk assessments for every situation in St Ives

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 for sites in St Ives, alongside the right form of assessment for buyers, lenders and BREEAM.

Flood risk assessments

• Flood risk assessment for planning. The core report, site-specific and prepared to satisfy the NPPF, the Environment Agency and Huntingdonshire District Council. Groundwater and, where needed, flood modelling are assessed within it rather than as separate reports.
• Flood risk survey for property purchase. For conveyancing, where a search has flagged Great Ouse or surface-water risk and you need the actual building assessed, not a broad national map.
• Flood risk assessment for insurance. Property-specific evidence for brokers and underwriters where premiums have risen or cover has been restricted.
• Flood risk assessment for BREEAM. Structured around BREEAM Pol 03, which is credit-driven rather than safety-driven, so a planning FRA alone rarely satisfies it.
• Groundwater flood risk assessment. A defensible design water table for gravel and river-terrace sites and any basement — assessed as a source within the FRA, or as a standalone hydrogeological assessment on complex sites.
• Flood modelling services. 1D and 2D hydraulic modelling brought in where national mapping is not detailed enough, particularly useful given the documented Parsons Drove/Marley Road Bridge backup mechanism.

Sequential and Exception Test reports

The Sequential and Exception Test is a separate, locational report about whether a development should be in a higher-risk location at all. The Sequential Test defines an area of search, identifies reasonably available lower-risk sites and justifies the proposed site; the Exception Test is the second gate where development still needs to proceed. A clean site-specific assessment showing the development is not actually within an area at risk can remove the need at application stage — a live policy area, as our note on the Yatton judgment and the planning balance explains, alongside our wider guide to what the Sequential and Exception Tests are.

Sustainable drainage strategy and design

• Sustainable drainage strategy and design (SuDS). Surface-water engineering that calculates existing versus proposed runoff and proposes SuDS to hold discharge within local standards — essential on sites near the Parsons Drove Drain network.
• Preliminary drainage design for planning. The early, outline read that flags infiltration issues before they affect layout and land value.
• Discharge of drainage planning conditions. The detailed stage to discharge a pre-commencement or pre-occupation drainage condition.

Early in a drainage strategy it helps to know whether the ground will take water: our free geology and ground conditions map and BRE 365 infiltration rate calculator give an indicative read before a trial pit, and the drainage calculators help size the scheme. You can screen a postcode on our flood risk map, and every report is overseen by a chartered flood risk consultant who stays involved past the report to answer objections. If you own land along the Great Ouse, our note on riparian ownership rights and responsibilities is worth reading — in 2024 a homeowner in Cambridgeshire was told she was personally responsible for clearing the watercourse along her boundary, at a cost of thousands of pounds. Our broader flood risk consultancy services and the areas we cover page set out the full picture of what we do.

Local flood risk management and emergency contacts for St Ives

The most reliable information about flooding in St Ives comes from the lead authorities and the Environment Agency. For an immediate threat to life during a flood, always call 999; for a power cut during flooding, call 105.

• Check flooding in St Ives. Live river level for the Great Ouse at the St Ives gauge (station 6178) and the Parsons Drove at St Ives flood warning area, both from the Environment Agency.
• Cambridgeshire County Council. The Lead Local Flood Authority's flood risk management hub, and where to report a flood.
• Huntingdonshire District Council. The Level 1 & 2 Strategic Flood Risk Assessment that underpins planning decisions for St Ives.
• Long-term flood risk. Check your own long-term flood risk for any address via GOV.UK.
• Anglian (Great Ouse) Regional Flood and Coastal Committee. Regional investment and priorities via the Anglian RFCC.
• Cambridgeshire & Peterborough Prepared. The Local Resilience Forum's emergency planning information at cpprepared.org.uk.
• Anglian Water. Sewer flooding guidance and reporting via Anglian Water, or call 03457 145 145.

For wider background on how flood risk works in the Fens and East Anglia, our articles on why flood risk management in the Fens is reaching its limits and on what new UK river research means for flood and drought risk — which names the Anglian region, covering Cambridgeshire and the Fens, as facing longer dry spells alongside a rising flood extreme — give useful regional context. St Ives itself sits upstream of Peterborough and Wisbech, and downstream of Bedfordshire, on the Great Ouse's route to the Wash; our Bedfordshire area page notes that in September 2024 the upper Great Ouse recorded its wettest September since records began in 1871, with the A421 near Marston Moretaine standing under up to eight feet of water for three weeks — a reminder that what happens upstream of St Ives shapes what happens here. Our Cambridge, Peterborough and Wisbech area pages cover the neighbouring parts of the Great Ouse and Fenland catchments.

If you're a riparian owner along the Great Ouse or Parsons Drove Drain, it's worth understanding the difference between a main river and an ordinary watercourse, and whether any works you plan near the bank need a Flood Risk Activity Permit — non-tidal main rivers require a permit within 8 metres of the riverbank. If your site is drained by a board rather than the Environment Agency, our guide to why Internal Drainage Boards matter for planning explains the distinction. And if a flood risk finding affects a mortgage or valuation, our notes on whether flood risk affects house prices and flood risk and mortgage lending explain what lenders look for.

Flood risk assessment in St Ives: frequently asked questions