Flood Risk Assessment in Northumberland

A flood risk assessment in Northumberland deals with the Tyne, the Wansbeck and the Coquet in spate, burns and culverts that overflow in summer storms, and a North Sea coast that the December 2013 surge pushed into homes at Blyth, Tweedmouth, Alnmouth and Warkworth. We prepare flood risk assessments in Northumberland for planning applications, house and land purchases, mortgages and insurance, alongside sequential and exception tests and surface water drainage strategies.

Our work covers Blyth, Cramlington, Ashington, Bedlington, Ponteland, Prudhoe, Corbridge, Haltwhistle, Alnwick, Amble, Seahouses and Berwick-upon-Tweed (Berwick, to most people who live there), and the villages and farmland between them, across the NE postcode area and the TD15 district around Berwick. Morpeth, Rothbury and Hexham have pages of their own, linked further down.

On 5 and 6 December 2015 Storm Desmond sent the Tyne to flows not seen since 1771, with record levels at ten gauges from the North Tyne down to Bywell. That winter the county council recorded more than 200 homes and 80 businesses flooded.

Tell us where the site is and what you plan to do there: call 01293 214444 or email enquiries@unda.co.uk.

The rivers, burns and coast behind each Northumberland town

Northumberland drains east to the North Sea. The council's flood strategy lists the Tyne, Wansbeck, Blyth, Till, Breamish and Coquet as the larger rivers, which the Environment Agency manages, and says the risk from surface water, groundwater, small ditches and land drains is far less understood. In 2015 it counted 2,798 homes at high risk of surface water flooding across the county.

Flood monitoring in Northumberland depends on the Environment Agency's river and tide gauges and on about 60 warning areas and nine alert areas across the county, from the North Tyne at Kielder Butteryhaugh to the Tweed at Norham. Current readings at those gauges appear on our live river levels map. The counts in the table come from the strategy's 2015 analysis of undefended flood zones, so they show where risk concentrates rather than today's exact numbers.

Screening a Northumberland address on the county map

Enter a postcode to see the river, sea and surface water flood zones, any reservoir flood extent and the nearest warning area. Our flood risk map offers the same screening for anywhere in England. The coral line traces the Northumberland County Council boundary, which takes in the National Park and Holy Island, the Farne Islands and Coquet Island.

Use the map as a first look only. When the council investigated the summer 2012 floods it noted that many of the places hit had never flooded before, and most of the water came from rain that could not get into drains and watercourses fast enough, not from anything a river map shows.

What Northumberland's flood investigations record, 2008 to 2019

Northumberland County Council investigates a flood under Section 19 of the Flood and Water Management Act wherever five or more homes or businesses flood inside, or critical infrastructure is cut off for more than five hours. The council set the bar that low because in a rural county a few flooded houses can hit a whole village. Since 2012 that has produced five sets of reports.

1. September 2008. Flooding across the county affected about 1,200 properties, the council's strategy records. Morpeth flooded, and the Wansbeck scheme built there afterwards is now complete.
2. 28 June 2012. Thunderstorms locally known as Thunder Thursday, or the Toon Monsoon, dropped rain the council rated a 1 in 195-year event in the south-east of the county. Alnwick and Seaton Delaval town centres were left under water.
3. 25 September 2012. Prolonged rain on saturated ground raised the Wansbeck and the Coquet, and surface water flooded parts of Ponteland. Across that summer at least 187 homes and 37 businesses flooded in 55 separate incidents.
4. 5 and 6 December 2013. A North Sea surge, calculated at about 1 in 450 years, flooded at least eight homes in four settlements and brought flooding or erosion to Amble, Beadnell, Boulmer, Holy Island and Seahouses.
5. 30 April 2014. About 44 mm of rain, most of it within two hours, fell on Haltwhistle. The Hemel Burn spilled at its culvert entrance and 15 to 20 homes flooded, though flood doors fitted shortly before limited the damage on the Mart.
6. December 2015 to January 2016. Storms Desmond, Eva and Frank. At Corbridge the defences overtopped, 43 homes and 12 businesses flooded inside and families were rescued from upper floors; the gauge there set a record of 5.76 m. The county total passed 200 homes and 80 businesses.
7. 9 to 11 August 2019. The Rede rose to its highest recorded level at Otterburn, and 13 properties and businesses flooded across the county, six of them in West Woodburn.

Much of that record comes from burns, culverts, drains and runoff rather than the main rivers, so a flood risk assessment in Northumberland starts with the council's investigation for the nearest community and its own flood records as well as the national maps. Our note on Section 19 investigations explains how those reports come about.

Blyth, Berwick-upon-Tweed and the coastal towns

About 130 km of coast runs from the Scottish Border to Seaton Sluice, mostly natural dunes and sandy bays broken by stretches of cliff. The Environment Agency leads on flooding from the sea. The county council is the coast protection authority but has no legal duty to defend any stretch of it, and the Northumberland and North Tyneside Shoreline Management Plan sets the long-term policy for each stretch.

• Blyth. The council's flood action plan rates the town centre at very high risk of tidal flooding, and the Local Plan lists sea flooding at Blyth among the key challenges for the coast. More than a thousand homes there sit in Flood Zone 3, the largest count in the county in the council's 2015 analysis.
• Berwick-upon-Tweed and Tweedmouth. The Tweed estuary puts the town at high tidal risk. The 2013 surge flooded property in Tweedmouth, and in January 2016 a blocked watercourse surcharged from a culvert on the north side of Berwick.
• Amble, Warkworth and Alnmouth. Amble is rated high and Alnmouth medium for tidal risk, and the 2013 surge brought separate investigations at Alnmouth and Warkworth, where the Coquet meets the sea.
• Seahouses, Beadnell and Holy Island. Each has its own North Sea warning area. The surge reached all three in 2013, along with Boulmer.

Close to the shore, Policy WAT 5 of the Local Plan adds a coastal change management area, drawn from the shoreline to the worst-case erosion line at 100 years plus 30 m. Proposals there can need an erosion vulnerability assessment, which is a separate study from a flood risk assessment. On coastal sites our work covers flood risk assessments and due diligence, and our guide to shoreline management plans explains the hold-the-line and realignment choices behind the policy. Drainage is simpler by the sea: the north east standards accept unrestricted discharge to the sea or an estuary, provided the water is treated first.

When does Policy WAT 3 require a flood risk assessment in Northumberland?

The Northumberland Local Plan, adopted on 31 March 2022, replaced every former district plan, and its Policy WAT 3 sets out when a site-specific assessment is required. The list goes further than the national minimum on land in Flood Zone 1.

• Flood Zones 2 and 3. All development, subject to the exemptions for minor development and changes of use that national policy allows from the sequential test.
• Large sites in Flood Zone 1. Any site of a hectare or more.
• Critical drainage problems. Land the Environment Agency has identified as having them.
• Future risk. Land a strategic flood risk assessment shows at increased flood risk in future.
• A more vulnerable use. Land subject to other sources of flooding, where a scheme would bring in a more vulnerable use, such as a house in place of a barn.

Once an assessment is needed, WAT 3 expects it to allow for climate change, put the most vulnerable uses on the lowest-risk part of the site, build in flood resistance and resilience, deal with residual risk and, where appropriate, show safe access and escape as part of an agreed emergency plan. Behind it sits chapter 18 of the NPPF, whose Policy F4 sets the national triggers and F5 and F6 the sequential and exception tests.

Drainage in Northumberland: the WAT 3 hierarchy, minewater and the north east standards

Northumberland's drainage rules come from the Local Plan and from standards the county agreed with the six other north east lead local flood authorities in July 2020. The council reads the drainage on major schemes, meaning ten or more homes or 1,000 m² of other floor space, and wants a drainage statement or a full surface water section in the flood risk assessment.

The council's SuDS page links the standards and their checklist, and Policy F8 of the NPPF now expects every scheme to follow the 2025 national standards for sustainable drainage. Where infiltration is in question, our ground conditions and soakaway map gives a first read of the geology, and the BRE 365 infiltration rate calculator converts a trial pit result into a rate.

Who decides a Northumberland application, and on what evidence

Northumberland County Council has been a single unitary authority since 2009. It is the planning authority across the county except inside Northumberland National Park, where the National Park Authority decides applications. The county council stays the lead local flood authority on both sides of the park boundary.

The county-wide flood risk evidence dates from 2010, before the Environment Agency's current climate change allowances and its latest flood maps. Until the new study is published, we test a site against the current national data and allowances rather than the 2010 outlines alone.

Typical Northumberland proposals and what each one needs

The table shows how WAT 3 and national policy apply to proposals that come up across the county.

Barn conversions and holiday lets each have a guide of their own: converting a barn and holiday lets.

Reports for Northumberland sites, from Berwick quayside to the Tyne valley

What a Northumberland site needs depends on what could flood it, and who reads the result: the county's or the National Park's planning officer, the council's drainage team, a lender or an insurer. Every report is written by chartered consultants and signed off by a senior consultant, and Unda is a CIWEM Business Partner. Across the county we prepare:

• Every source together. A site at Haltwhistle can face the South Tyne, a culverted burn and runoff from the steep ground above the town at once, and our flood risk assessment weighs each source and how they combine.
• For the application. Whether the county council or the National Park Authority decides it, a flood risk assessment for planning answers WAT 3 and the national tests.
• Before exchange. Searches flag homes along the Tyne valley and the coast, and a flood risk survey for property purchase explains what the flag means for the house you are buying.
• Ruling out other sites. New homes in Flood Zone 2 or 3 at Blyth, Ponteland or Berwick must be shown to have no reasonably available site at lower risk, and our sequential and exception test report sets an area of search that fits the scheme.
• Drainage evidence. WAT 4 makes SuDS a requirement wherever surface water needs managing, and our drainage strategy work covers surface and foul water from outline stage to conditions.
• Runoff on new estates. A surface water drainage strategy works through the WAT 3 hierarchy, sets the discharge rate and shows where the water leaves the site.
• After the decision. Where a permission comes with a drainage condition, we prepare the information needed for the discharge of drainage conditions.
• Homes that have flooded. At least 187 homes flooded in the county in summer 2012 and more than 200 over the winter of 2015, and an insurance flood risk assessment gives an insurer evidence about the building rather than the postcode.
• Shops, pubs and workshops. Eighty businesses flooded over the winter of 2015, a dozen of them at Corbridge alone; a business continuity flood risk assessment sets out how an occupier keeps trading.
• Coastal and port property. On land around Blyth's harbour or along the coast, flood risk due diligence gives a buyer or lender the tidal and surface water picture before the deal completes.
• The old coalfield. The council's strategy flags possible groundwater rebound around Blyth, Ashington, Ponteland and Bedlington, and a groundwater flood risk assessment tests how high the water could rise beneath a basement or soakaway.
• Burns and ordinary watercourses. The Hemel Burn at Haltwhistle and the Whittle Burn at Ovingham have both flooded homes, and the north east standards say a watercourse running through or beside a new development may need one- or two-dimensional modelling. Where it does, flood modelling supplies levels where the national maps stop.
• Safe access and escape. WAT 3 asks for an agreed emergency plan where access matters, as on tidal land at Blyth or the Tyne flood plain at Corbridge, which a flood warning and evacuation plan sets out.
• Off the mains. Parts of rural Northumberland have no public sewer, and the Local Plan blames poorly sited package plants and septic tanks for some failing rivers; a foul drainage strategy shows how a rural scheme deals with its waste water.
• Wind and solar sites. The Local Plan has its own policies for renewable energy and onshore wind, and a wind farm flood risk assessment looks at the flood risk to turbine bases, access tracks and substations spread across open country.

Morpeth, Rothbury, Hexham and the counties around Northumberland

Three Northumberland towns have pages that go further into their own rivers, defences and plans:

• On the Wansbeck. Morpeth, the county town, where the scheme built after 2008 stores floodwater upstream.
• On the Coquet. Rothbury, just outside the National Park, with its own run of Coquet warning areas.
• On the Tyne. Hexham, the market town where the North and South Tyne have just joined.
• Next door. Newcastle upon Tyne downstream on the Tyne, County Durham to the south and Cumbria to the west. All the places we write about are gathered on our areas page.

Flood contacts across Northumberland

Call 999 if anyone is in danger from floodwater and 105 if the power goes off. For everything else, who to call depends on where the water came from.

The council's Local Flood Risk Management Strategy sets out who manages each source of flooding, and it works with Northumbrian Water and the Environment Agency in the Northumbria Integrated Drainage Partnership. It is also leading FloodAI, a Defra-funded trial of flood prediction for six communities including Haltwhistle, Riding Mill, Stocksfield and Ovingham, which our article on AI in flood risk management describes. Our guide to the lead local flood authority explains what the council's role covers.

Questions about flood risk assessment in Northumberland

For a site anywhere from Berwick-upon-Tweed to Prudhoe, call 01293 214444 or email enquiries@unda.co.uk.