Flood Risk Assessment in Nottingham

A flood risk assessment in Nottingham starts with the River Trent, which runs along the south of the city behind the Left Bank flood defences. It then turns to the smaller rivers and the storms that have done most of the recent damage: the Leen through Bulwell and Basford, the Day Brook in Sherwood and Old Basford, and the Tottle Brook in Wollaton.

Our consultants prepare flood risk assessments in Nottingham for planning applications, house purchases, mortgages and insurance, as well as sequential and exception tests and surface water drainage strategies. Nottingham here means the city as the council governs it and ONS maps it. That takes in the centre, the Meadows and Sneinton by the river; Lenton, Radford, Hyson Green and St Ann's; Basford, Bulwell, Bestwood and Sherwood to the north; Wollaton and Bilborough to the west; and Wilford and Clifton across the Trent, in the NG1, NG2, NG7 and NG8 postcode districts among others. Nottingham City Council is a unitary authority, so it decides planning applications and is the lead local flood authority, separately from the county council. West Bridgford, Beeston, Arnold and Carlton lie in neighbouring boroughs and are covered on our Nottinghamshire page.

In 1947 the Trent flooded about 3,000 properties and 86 factories in Nottingham. The £45 million Left Bank scheme now holds the river to a 1% annual chance, yet none of the floods the city council has investigated since 2013 came over the Trent banks: storms, sewers and the city's brooks caused every one.

Call 01293 214444 or email enquiries@unda.co.uk to discuss a Nottingham site with one of our flood risk consultants.

The Trent's left bank: one defended flood cell from Sawley to Colwick

Most of Nottingham's river flood risk comes from the Trent, and most of the land at risk sits behind one line of defences. The Environment Agency opened the Nottingham Left Bank scheme in September 2012: £45 million of walls and embankments along 27 km of the north bank from Sawley to Colwick, cutting the risk to about 16,000 homes and businesses to a 1% chance in any year. In the city itself the works run for about 1.8 km through Victoria Embankment Park in the Meadows.

• What changed. The council's Land and Planning Policies document says the scheme shrank the area at risk most around the University, Lenton, Queens Drive and the Meadows.
• What remains. The Environment Agency's 2017 climate change and breach modelling for the Trent found new and larger areas at residual risk behind the banks, so a protected site may still need raised floors and a dry escape route.
• How the planning map shows it. The Flood Map for Planning draws Flood Zones 2 and 3 as if the defences were absent, which is why the Local Plan still lists Waterside sites such as the Cattle Market as high flood risk.
• South of the river. Wilford and Clifton sit on the right bank, outside the Left Bank scheme. The Environment Agency issues separate warnings for the Trent at Wilford, covering the Fairham Brook, Ruddington Lane and Main Road.

An assessment behind the defences therefore deals with residual flood risk as well as the mapped zone, and our note on why a site stays in a flood zone after new defences are built sets out the reasoning. The river's whole course is covered on our River Trent page.

What the gauges at Colwick, Clifton Bridge and Bulwell have recorded

Environment Agency gauges give a working scale for the rivers in and beside the city. The Trent at Colwick, just downstream of the city boundary, is the reading most riverside assessments in Nottingham refer to, and our live river levels map shows what each of these stations reads now.

A gauge shows how the river is behaving; a site still needs its own levels. The planning flood zones come from modelled floods with a 1% and a 0.1% annual chance, and new Environment Agency models are changing them: the Leen and Day Brook models were delivered in 2023 and the 2010 Trent model is being updated. Each assessment therefore starts from the current outlines.

Screen a Nottingham postcode, from Bulwell to Clifton

Type a postcode into the map below to see what Environment Agency data shows for rivers, surface water and reservoirs at a Nottingham address, or open our full flood risk map for anywhere in England. The coral outline joins three ONS built-up areas that together make up the city: Nottingham north of the Trent, and Wilford and Clifton on the south bank. West Bridgford, Beeston, Arnold and Carlton fall outside it because other councils govern them.

The Leen, the Day Brook, the Tottle Brook and the culverted streams under the city

Away from the Trent, flood risk in Nottingham follows a set of short, fast urban rivers. The council's 2011 preliminary flood risk assessment found that about 54% of the city drains to the River Leen, and that many smaller valley streams were culverted as the city grew, leaving a combined sewer as their main channel. These watercourses rise within hours of a storm:

Culverts are where a city brook most often fails: a blocked trash screen helped flood seven homes on Athorpe Grove in 2010, and our note on how culverts work and why they flood explains the mechanics. The city's one sizeable reservoir is Wollaton Lake, held by an earth dam with about 100,000 m³ of water and silt; the Environment Agency's reservoir mapping shows a breach reaching homes downstream in Wollaton.

Nottingham floods on record, from the 1947 Trent to Storm Henk

Nottingham's flood history has two halves. Trent floods are rare and large; since 2010 the city's own record is of short storms and brook floods returning to the same streets. These dates come from the Environment Agency, the council's Section 19 investigations and the 2012 scheme announcement:

1. March 1947. The 1947 floods put the Trent over its banks across the city, affecting 28 miles of road, about 3,000 properties and 86 factories. The city's first flood defence was built afterwards.
2. 8 November 2000. The Trent reached 5.50 m at Colwick and 5.39 m at Clifton Bridge, still the highest readings on both gauges. The Environment Agency's study after this flood led to the Left Bank scheme.
3. 2010. A storm on 5 and 6 June flooded six homes at Moores Place off Haydn Road, and seven homes on Athorpe Grove flooded that year when a blocked trash screen held back the Day Brook.
4. 23 July 2013. About 17 mm of rain in ten minutes flooded 19 homes and a business in Sherwood and Carrington, 11 homes in Top Valley, 10 at Strelley and 6 on Bestwood Road in Bulwell.
5. 12 June 2019. After three days of rain the Day Brook overtopped the wall at Athorpe Grove and flooded nine homes.
6. 17 June 2020. About 52 mm fell in two and a half hours near Bramcote Lane. The Tottle Brook overtopped and 19 homes flooded on Wollaton Vale and Larchdene Avenue, with 11 more on Kingswood Road and Hollinwell Avenue.
7. 20 October 2023. Storm Babet, the wettest three days on record in the Midlands, took the Leen at Bulwell to 2.23 m and flooded 14 homes in Bulwell, Bulwell Forest and Basford.
8. 4 January 2024. In Storm Henk the Trent crested at 5.36 m at Colwick. Fifteen homes flooded in Basford, on Wollaton Vale and on Roland Avenue in Wilford, where surface water drains could not empty into the swollen Trent.

The council's 2011 preliminary assessment put about 10,000 homes in the city at risk of surface water flooding, one of the highest totals for any unitary authority, so rain falling on a site carries as much weight as the river in a Nottingham assessment. Each investigation is published as a Section 19 report, and the full set is in the council's flood document library.

Sandstone, cellars and combined sewers under Nottingham

What happens to rain on a Nottingham site depends on whether the ground will take it and, if not, which sewer will. Much of the city stands on sandstone that can accept infiltration, while the older districts drain to combined sewers that spill into the brooks in a storm.

Groundwater flooding has little recorded history in Nottingham, but the risk is growing. The council's preliminary assessment notes that levels in the sandstone have recovered since brewing, bleaching, lace-making and mining stopped drawing water from under the city, and it has had reports of water in cellars in Basford. Our geology and ground conditions map gives a first read before a trial pit, and the BRE 365 infiltration rate calculator turns test results into a soakaway size. Our guide to foul, surface and combined sewers explains why the older networks matter.

Which flood and drainage policies apply to a Nottingham planning application?

Nottingham City Council decides the application and, as lead local flood authority, comments on surface water drainage for every major scheme; the Environment Agency advises on sites by the Trent, the Leen, the Day Brook and the other main rivers. Five documents set the local rules:

The council also began a new city Local Plan with a formal notice on 30 June 2026, which is at an early stage. National policy for a Nottingham application sits in chapter 18 of the August 2026 NPPF: policy F4 sets when an assessment is needed, F5 and F6 carry the sequential and exception tests, and F8 expects all development to follow the 2025 National Standards for sustainable drainage. Our guide to the lead local flood authority explains what the council's drainage team looks for, and its developer guidance adds the Leen and Day Brook runoff rule.

Waterside, the Canal Quarter and Boots: allocations with flood conditions attached

The Local Plan's larger regeneration sites lie beside the Trent, the canal and the Leen, and each allocation carries flood principles an application must meet:

• Trent Lane Basin (SR73). A 9.01 ha riverside site at Waterside allocated mainly for family housing, with a 10 m path along the Trent that doubles as an 8 m maintenance easement.
• Cattle Market (SR70). A 3.43 ha mixed-use site in high flood risk, where the assessment must consider the Trent, the culverted Tinkers Leen beneath the site, and overtopping or breach of the defences.
• Island Site (SR59). A 9.76 ha Canal Quarter site lying partly in medium and partly in high flood risk, with each application needing its own assessment.
• Boots (SR45). The city's share of the Boots campus, an Enterprise Zone, where assessments must consider breach and overtopping and show the layout adds no risk on or off the site.
• Wilkinson Street (SR23). A former factory site by the Leen with part of it in the functional floodplain: any raising of ground must be matched by lowering an equal area and volume of land next to it, as our note on level-for-level compensatory storage describes.
• Stanton Tip (SR11). A strategic site at Hempshill Vale lying wholly in Flood Zone 1, where drainage and surface water shape the scheme rather than the river.

At Broad Marsh, where the bus station, the Central Library and the Green Heart park have opened, the strategic plan's flood review recorded that the site has planning permission and that the Environment Agency's flood concerns had been settled.

Meadows extension or Waterside block: which Nottingham schemes need an assessment?

It turns on the flood zone, the size of the scheme and its use. The city council asks for an assessment in Flood Zones 2 and 3, on sites over a hectare and for all major development, and national policy adds sites at risk from surface water or another source:

Schemes that need the sequential test have to show that no reasonably available site at lower risk exists within the search area. That evidence can take longer to gather than the assessment itself, so it is worth starting before the layout is drawn.

From the Meadows to Bulwell: the reports Nottingham sites need

Each report below answers a different question for a Nottingham site. Our consultants are chartered, Unda is a CIWEM Business Partner, and a senior consultant reviews and signs off every report.

• Applications by the Trent and the Leen. New homes, student schemes and commercial buildings in Flood Zones 2 and 3 need a flood risk assessment for planning that answers Policy CC3 and the breach scenarios behind the Left Bank defences.
• Every source on one site. A flood risk assessment for a Nottingham site weighs the Trent, the city brooks, storm runoff, the combined sewers and groundwater in the sandstone against one another.
• Before exchange. Searches flag much of the Meadows, Wilford and the Leen valley, and a flood risk survey for property purchase looks at the actual house, its floor level and its flood history.
• Housing in the flood zones. Residential and other more vulnerable schemes in Flood Zone 2 or 3, including the riverside allocations at Waterside, usually need the sequential and exception test before the council can approve them.
• Drainage for the LLFA. The city council reviews drainage on major schemes itself, so most applications here need drainage strategy evidence that meets the 30% brownfield runoff cut in Policy CC3.
• Soakaways or storage. A surface water drainage strategy tests whether the sandstone will take water and, where it will not, sizes storage and a controlled outfall to a brook or a sewer.
• Clearing the condition. Where a Nottingham permission has a drainage condition attached, discharge of drainage conditions provides the calculations, details and maintenance plan the council needs before work starts.
• Levels where national maps are coarse. The Trent model dates from 2010 and is being updated, and the Leen and Day Brook models were redone in 2023, so flood modelling can set a design level or test a breach where a site needs more than the national outlines.
• A way out when the rivers rise. Twelve Environment Agency warning areas cover parts of the city, from the Meadows to Highbury Vale, and a flood warning and evacuation plan ties a scheme's occupants to them.
• Homes with a flood record. With homes flooded in Sherwood, Top Valley, Wollaton, Basford and Bulwell since 2013, a flood risk assessment for insurance gives an insurer evidence about one address.
• Water in the sandstone. Recovering groundwater and wet cellars in Basford are the reason a groundwater flood risk assessment checks basements and deep soakaways against seasonal water levels.
• Older combined networks. About 60 combined sewer overflows serve the older city, and a foul drainage strategy shows Severn Trent how a scheme's waste water will be carried.
• Firms in the warning areas. The Meadow Lane industrial area, Castle Meadow Retail Park and the businesses off Lenton Lane all sit in Trent warning areas, and a business continuity flood risk assessment plans how a firm keeps trading.
• Commercial floorspace. Offices and research space at Boots and the Island Site can earn flood risk credits, which a BREEAM flood risk assessment covers under Pol 03.
• Land at Waterside. With breach modelling and an 8 m easement written into the Waterside allocations, a flood risk feasibility study shows early how much of a site can be built on.

Nottingham flood contacts: the city council, the Environment Agency and Severn Trent

Anyone in danger from floodwater in the city needs 999, and a power cut goes to 105. For anything else, the organisation to contact depends on where the water came from:

The same river carries on through Nottinghamshire to Newark-on-Trent, and the Derwent from Derby joins it upstream of the city. Other towns and counties are listed on our areas we cover page.

Questions about building, buying and draining land in Nottingham

Whether the site is a plot at Trent Basin, a semi in Basford or a block near the station, Unda Consulting Limited can advise on 01293 214444 or at enquiries@unda.co.uk.