Flood Risk Assessment in Great Yarmouth

Every flood risk assessment in Great Yarmouth begins with the North Sea and its tides. The town sits on a strip of land between the beach and the tidal Yare, with the Bure and Breydon Water behind it. Nearly all of it relies on sea walls and steel quay walls, and the Environment Agency is still renewing them. We prepare flood risk assessments in Great Yarmouth for planning applications, house purchases, mortgages and insurance, and write sequential and exception tests and surface water drainage strategies to go with them.

Great Yarmouth, Norfolk, is taken here as the ONS built-up area: the town centre and the market place, the seafront, Northgate, Newtown and North Denes, South Denes down to the harbour, and Southtown and Cobholm on the west bank of the Yare, across the NR30 and NR31 postcode districts. Gorleston-on-Sea, south of the river mouth, is mapped by ONS as a separate built-up area, but it shares the borough council, the Yare quay defences and the flood evidence, so a site in Gorleston follows the same route through planning.

The 2017 flood study for the borough found that much of Great Yarmouth lies inside the area the Environment Agency's breach model floods if a defence fails. A site behind a newly refurbished quay wall still has to be assessed for the day a wall gives way.

To talk through a site in the town with one of our flood risk consultants, call 01293 214444 or email enquiries@unda.co.uk.

Is Great Yarmouth at risk of flooding from the sea and the rivers?

Yes, and from more than one direction. The borough's Strategic Flood Risk Assessment, prepared by JBA Consulting in November 2017, identifies tidal surges as the main source of flooding, with surface water and groundwater adding to it on the low ground. Each part of the town faces a different mix:

• The North Sea. Surge and waves can overtop the defences along the seafront from North Denes to the Pleasure Beach. The tidal and sea flooding that follows a North Sea surge is the event every assessment in the town has to plan for.
• The tidal Yare. The river runs south through the haven to the harbour mouth, with steel and concrete quay walls on both banks from Breydon Bridge past Hall Quay and South Quay to South Denes. Its tidal reach runs inland past Breydon Water to Thorpe St Andrew on the edge of Norwich.
• Breydon Water and the Bure. The estuary behind the town and the tidal Bure on its northern edge bring the sea in from the other side. Water held in them by a surge reaches Cobholm, Runham Vauxhall, Newtown and Bure Park from the west and north rather than from the beach.
• Heavy rain on low ground. The town's drainage depends on pumps, and when one failed in a storm in September 2006 streets, schools and the railway station flooded. Norfolk County Council's surface water plan for the borough marks four critical drainage areas in the town.
• Groundwater under the marshes. The SFRA notes that the water table near the town is likely held artificially low by pumping, so a pump failure could raise it.

Our check of the Environment Agency's Flood Map for Planning on 20 October 2026 puts about three-fifths of the built-up area in Flood Zone 3 and about seven-tenths in Zone 2 or 3. The town centre, Southtown, Cobholm, Newtown and the riverside all sit in Zone 3, while a few strips of slightly higher ground between the river and the sea fall outside it. Our explainer on the three flood zones sets out what each one means for a planning application.

Seven warning areas, from North Denes to the harbour mouth

The Environment Agency issues its tidal flood warnings for Great Yarmouth street by street rather than for the town as a whole. The agency's East Anglia area divides the town and its edges into seven warning areas, under one flood alert that covers the coast from Caister to Gorleston:

Three gauges give a working scale. The sea level gauge at Great Yarmouth has recorded a highest level of 3.32 m. Upstream on the Yare, the Burgh Castle gauge set its record of 2.36 m on 6 December 2013, and the agency treats anything above 1.80 m there as a level at which property flooding becomes possible. On the Bure, Three Mile House reached 1.93 m on 9 November 2007 against the same 1.80 m threshold. Our live river levels map shows these stations and any warning in force.

Screen an address in NR30 or NR31

Type a postcode into the interactive flood map below to screen a Great Yarmouth address against Environment Agency data for rivers and the sea, surface water and reservoirs, or open our full flood risk map for anywhere in England. The coral line is the ONS built-up area, which runs from North Denes to South Denes and across the Yare to Southtown and Cobholm; Gorleston-on-Sea and Bradwell lie outside it to the south-west.

Surges and storms on record since 1953

Great Yarmouth's flood history is mostly a record of North Sea surges, with one heavy rainstorm that showed what the drains can and cannot take. These are the dated events the Environment Agency, the county council and the local press have set down:

1. 31 January 1953. The east coast surge broke the tidal river defences in several places, and the Environment Agency records loss of life. Local accounts describe the town struck first from the sea and then from behind, when the banks of Breydon Water gave way. Ten people died in Great Yarmouth and Gorleston, according to the Great Yarmouth Mercury's account of the 70th anniversary service. Our article on the 1953 North Sea flood follows the surge down the coast.
2. 25 September 2006. A torrential storm flooded more than 50 properties, six schools in Great Yarmouth among them, and closed the railway station after a pump at the town's pumping station failed. It became the reference event for the borough's Surface Water Management Plan.
3. 9 November 2007. A North Sea surge pushed the Bure at Three Mile House to 1.93 m, still that gauge's highest level.
4. 5 and 6 December 2013. About 9,000 people were urged to leave their homes ahead of what the Environment Agency called the highest tide ever recorded in the town. The defences held; the borough council reported water on the seafront car parks, North Quay, Southtown and South Yarmouth, and a limited number of homes in the borough flooded.
5. 13 January 2017. Police began evacuating more than 5,000 properties in South Yarmouth, North Yarmouth, Caister, Southtown and Cobholm from 10am, ahead of a surge expected to peak in the town at about 9.15pm.

In 2013 and 2017 the defences held, and the evacuations were a precaution against the chance that they would not. Testing that chance is the job of a site-specific assessment in the town, which looks past the defences to the residual flood risk behind them, and to the higher tides that sea level rise will bring over the life of a building.

The quay walls and the three epochs of renewal

Most of Great Yarmouth's defences are steel sheet-piled and concrete quay walls along the Yare and the Bure, many of them more than 50 years old. The Environment Agency is refurbishing them in five-yearly phases it calls epochs, as part of a programme planned to run for 40 years:

• Epoch 1, finished 2017. A £28 million first phase replaced more than 500 m of tidal defences in Southtown and Cobholm, ending with 630 m of new sheet piling and 85 m refurbished.
• Epoch 2, September 2019 to May 2023. The £42.9 million second phase refurbished 40 flood walls over about 4 km. It left 2,115 properties better protected and added 30 to 50 years to the life of the walls. It included a set-back wall at Saul's Wharf with new intertidal saltmarsh, and quiet pile-pressing in Cobholm beside the Grist Mill.
• Epoch 3, late 2026 to early 2028. The next phase covers 20 sections of wall in five compartments, including Hall Quay, South Quay and the walls around Vauxhall Bridge, with patch repairs, corrosion protection and, in places, higher walls.
• The open coast. The Kelling to Lowestoft Ness Shoreline Management Plan, adopted in August 2012, treats Great Yarmouth as its own policy unit, 6.17, and describes the town as a place that justifies full protection against erosion or flooding.

None of this changes the flood zones. They are drawn as if the defences were not there, which is why a site stays in a flood zone after new defences are built. A planning assessment in the town records which compartment protects the site, when its wall was last refurbished or is due to be, and what happens on the site if that wall is overtopped or breached.

What the 2017 SFRA asks of a site behind the defences

The Strategic Flood Risk Assessment is still the borough's Level 1 evidence, and it sets the standards a site-specific assessment in Great Yarmouth is checked against. The points that shape most schemes in the town are these:

• Breach and overtopping. The Environment Agency's 2017 Norfolk coastal breach modelling shows much of the town inside its breach flood extents, and the SFRA expects every site-specific assessment to deal with both breach and overtopping.
• Floor levels. Floors sit 300 mm above the higher of the 0.5% annual chance tidal level and the 1% river level, each with climate change, or 300 mm above the surrounding ground, rising to 600 mm where no reliable modelling exists. The heights are given in metres above Ordnance Datum.
• Getting out. Safe access and egress has to be shown, ideally 300 mm above the design flood level. Where that cannot be done, the hazard on the route is assessed using the FD2320 method.
• Dry islands. The borough has 42 patches of Flood Zone 1 surrounded by higher-risk land. A site on one, even under a hectare, may need an assessment and a warning and evacuation plan, a problem our note on dry island sites explains.
• Climate change. River models were not rerun for climate change in 2017, so an assessment for a site near the Bure or the Yare has to apply the current allowance itself.

The SFRA also logged 144 sewer flooding records across the borough and investigated flooding between May and July 2014 that entered 59 properties. Our guide to the Environment Agency's role in planning covers how the agency reviews the tidal case on an application.

Four critical drainage areas in the town

Rainfall flooding is a separate problem from the tide in Great Yarmouth, and it was behind the September 2006 flood. The borough's plan estimates that about 3,000 properties across Great Yarmouth, Gorleston and Bradwell could flood in a 1 in 100 to 1 in 200 year rainstorm. Norfolk County Council formally adopted the borough's Surface Water Management Plan on 6 January 2014, and it marks eight critical drainage areas in the borough. Four are in the town: North Yarmouth, Northgate, South Yarmouth, and Claydon, Southtown and Cobholm across the river.

On a site inside one of them, the drainage has to show that runoff will not add to flooding downstream. On flat, low ground near the coast, where the SFRA finds groundwater can rise towards the surface, that usually means storing water on site and releasing it slowly. Norfolk County Council, as Lead Local Flood Authority, has been a statutory consultee on the drainage of major applications since April 2015 and sets out its standards in its guidance for developers. National policy now expects every development to follow the 2025 national standards for sustainable drainage.

Watercourses on the marsh edge of the town can sit in an Internal Drainage Board district run by the Water Management Alliance. At the Cobholm waterfront the alliance has told the borough council that altering a watercourse, or discharging to one, needs its board's consent; our article on Internal Drainage Boards explains how that consent sits alongside planning.

Which plan decides a Great Yarmouth planning application?

Great Yarmouth Borough Council decides applications in the town under the Great Yarmouth Local Plan 2024 to 2042, adopted on 24 September 2026 after the Inspectors found it sound with main modifications. It replaced the 2015 Core Strategy and the 2021 Local Plan Part 2. Inside the Broads, which reach the town along the Bure, the Broads Authority is the planning authority, and its emerging local plan includes the Port of Yarmouth Marina at Marina Quays, a Flood Zone 3 site.

The new plan's flood evidence goes further than the 2017 study. A Level 2 SFRA looked closer at the riverside and seafront sites: North Quay, the Cobholm waterfront, Pasteur Road, North River Road, the Beach Coach Station, the former gasworks on Admiralty Road, North Denes Airfield, Harfreys Industrial Estate, the Eurocentre and the South Denes port and harbour. A Flood Risk Sequential Test of December 2024 sits beside it, and a further Local Plan, to run to 2045, began with a call for sites in August 2026.

Above the Local Plan sits chapter 18 of the August 2026 NPPF: policy F4 sets when an assessment is needed, F5 and F6 the sequential and exception tests, and F8 the expectation that all development follows the national standards for sustainable drainage. For a town where most land is in Flood Zone 3, the sequential and exception tests decide whether new homes can go ahead as much as the assessment does. The Herring Bridge, the £121 million crossing of the Yare opened in February 2024, went through the same flood risk process on a larger scale as a nationally significant project.

From South Denes to the racecourse: when an assessment is needed

National policy and the 2017 SFRA decide when a Great Yarmouth proposal needs a flood risk assessment, and the Environment Agency's standing advice covers small extensions. The table applies those rules to the kinds of site that come forward in the town:

Our guide to when a flood risk assessment is needed goes through the national triggers in more detail.

Reports for quayside, seafront and Southtown sites

A buyer in Cobholm, a hotel owner on Marine Parade and the promoter of a riverside site each need something different, and in Great Yarmouth almost every one of them has to answer the tidal question first. Every report is checked and signed off by one of our senior consultants, and our consultants are chartered.

• Applications behind the walls. Homes, conversions and commercial schemes in the tidal flood zones need a flood risk assessment for planning that answers the 2017 SFRA's breach, floor level and access tests.
• Sea, river and rain together. A flood risk assessment in Great Yarmouth weighs the surge, the tidal Yare and Bure, rain on the low streets and pumped groundwater on one site.
• Before exchange in a warning area. Lenders and searches pick up Southtown, Cobholm and the quays, and a flood risk survey for property purchase answers for one house.
• New homes where most land is Zone 3. With about three-fifths of the town in Flood Zone 3, housing schemes often need the sequential and exception test before the design is settled.
• Drainage on low, flat ground. Four critical drainage areas and Norfolk County Council's review of major schemes mean most applications need drainage strategy work of some kind.
• Storage where soakaways struggle. Where groundwater can rise near the surface, as the SFRA warns close to the coast, a surface water drainage strategy usually sizes storage and a controlled discharge rather than relying on infiltration alone.
• Clearing the condition. Where a Great Yarmouth permission comes with a drainage condition, discharge of drainage conditions supplies the details and the maintenance plan the council asks for.
• A plan for warning day. Seven Environment Agency warning areas cover the town, and a flood warning and evacuation plan ties a scheme to its own one and to a safe route or refuge.
• Levels on the Bure and the Yare. The 2017 study did not rerun its river models for climate change, so a riverside site may need flood modelling to fix its design levels.
• Cover after 2013 and 2017. About 9,000 people in the town were urged to leave in December 2013 and more than 5,000 properties were evacuated in January 2017, and a flood risk assessment for insurance gives an insurer evidence for one address.
• Port and industrial land. South Denes, the harbour and the Euro Centre all sit inside tidal warning areas, and a due diligence flood risk assessment sets out the risk before a purchase or a lease.
• Keeping a business running. The railway station and the Euro Centre industrial estate share a warning area, and a business continuity flood risk assessment plans for the day it is issued.
• New commercial buildings. A BREEAM flood risk assessment covers the Pol 03 credits for offices and works on South Denes and the riverside employment land.
• Testing a riverside site early. North Quay and the Cobholm waterfront were among the sites the Level 2 SFRA examined, and a flood risk feasibility study shows early whether a layout can work.

Who handles a flood in Great Yarmouth, from the quays to the sewers

Anyone in Great Yarmouth put in danger by floodwater should ring 999, and a power cut is reported on 105. For everything else, the organisations below each look after a part of the town's flood risk:

The wider county is covered on our Norfolk page. Up the coast, Sea Palling sits behind the sea wall the 1953 surge broke, and to the south Lowestoft faces the same North Sea across the Suffolk border. The full list of areas covers the rest of the country.

Great Yarmouth flood risk: what buyers, owners and applicants ask

Unda Consulting Limited prepares flood risk assessments, sequential and exception tests and drainage strategies for sites across Great Yarmouth, from the quays in Southtown to the seafront and South Denes. To discuss one, call 01293 214444 or email enquiries@unda.co.uk.