Flood Risk Assessment in Lynmouth

A flood risk assessment in Lynmouth starts where the East Lyn and West Lyn meet, a few hundred metres from the sea. Both rivers fall off Exmoor in a few miles, rise within hours of heavy rain and run through the village to a harbour where storm tides have come over the Esplanade wall. We prepare flood risk assessments in Lynmouth for planning applications, house and business purchases, mortgages and insurance, alongside sequential and exception tests and surface water drainage strategies.

Planning applications here go to Exmoor National Park Authority, not North Devon Council, because the whole of the Lynton and Lynmouth parish sits inside the National Park. Devon County Council is the lead local flood authority. The page covers the harbour village of Lynmouth in the EX35 postcode district, Lynton on the cliff above, Barbrook up the West Lyn, and the East Lyn valley towards Watersmeet and Countisbury.

On the night of 15 to 16 August 1952 the Lyn rivers killed 34 people across the area and swept away 55 of Lynmouth's 212 properties. The channel and overflow built afterwards are sized for one and a half times that night's flow, yet the tide has overtopped the village's defences at least four times since 1990.

To talk through an address in Lynmouth or Lynton, call 01293 214444 or email enquiries@unda.co.uk and one of our flood risk consultants will come back to you.

Two rivers off Exmoor and a harbour wall: where flood risk in Lynmouth comes from

Lynmouth has four ways for water to reach a building, and two of them can arrive together on a stormy high tide. The Environment Agency treats both the East Lyn and the West Lyn as main rivers. The 2014 addendum to the Exmoor Strategic Flood Risk Assessment found that most recorded incidents in Lynton and Lynmouth were tidal, even though the village is best known for its river flood.

The 2014 addendum dates tidal overtopping in Lynmouth to February 1990, March 2006, October 2012 and January 2014, and river flooding to January 1983 and October 2000. So the Lynmouth flooding of 2014 came from a January tide over the defences, not from the rivers. A site-specific assessment has to look at every source, because the cellar that floods from the drains is often the same one that would take river water.

Checking a Lynmouth or Lynton postcode

The map below screens a postcode against the Environment Agency's river and sea, surface water and reservoir data; our flood risk map runs the same checks for anywhere in England. The coral line is the Lynton and Lynmouth civil parish, which takes in both villages, Barbrook and the moorland to the south. The national statistics office maps the two villages as one built-up area, so there is no separate outline for Lynmouth alone.

Most of the parish is high ground in Flood Zone 1. The flood zones follow the narrow floors of the East and West Lyn and the harbour, so a property on Lynmouth Street can sit in Flood Zone 3 while a house on the hill in Lynton is nowhere near it. Our explainer on flood zones 1, 2 and 3 sets out what each zone means for planning. The screen tells you which side of that line an address falls on; it cannot tell you a floor level or what the wall in front of the building is worth in a storm.

The Lynmouth flood of August 1952, and what the rebuild left behind

The Lynmouth flood of 15 and 16 August 1952 is still the event every assessment here is measured against. The Royal Meteorological Society records 229 mm of rain within 24 hours over Exmoor, after a wet first half of August had left the ground saturated. The water ran off the steep northern slopes of the moor into the two Lyns, and a dam of fallen trees in the upper West Lyn gave way and sent a surge of water and debris into the village.

• The toll. 34 people died, 420 were made homeless, more than 100 buildings were destroyed or seriously damaged and 28 bridges were lost across the area (Royal Meteorological Society).
• In Lynmouth itself. 55 of the village's 212 properties were lost, and 12 more were demolished afterwards so the river channel could be widened, among them the Lyn Valley, Falls, Granville and West Lyn hotels (Lynmouth Flood Memorial Hall).
• The new river course. Riverside Road was built along the river's old course behind the Lynmouth Street buildings, and the channel was widened and deepened with a floodplain made for it.
• The overflow above the Maybridge. The flood overflow area above the Maybridge is designed to take one and a half times the water that came through the village that night (Visit Lynton and Lynmouth).
• Bridges built for floodwater. Lyndale Bridge was completed in 1954 and angled for the freest possible flow of floodwater; all five bridges in the conservation area post-date the flood (Exmoor National Park conservation area appraisal, 2019).
• Six years to finish. The rebuild took nearly six years. The Flood Memorial Hall, on the site of the old lifeboat station, opened on 10 July 1958 and marked its completion.

For a site today, 1952 matters in two ways. It sets the scale of what the Lyn catchments can produce, and it explains the layout the Authority now protects: the conservation area, designated in 1973, takes in the rebuilt village and its open river frontage, which a new building is not expected to crowd. Steep catchments elsewhere in the South West have flash-flooded since, and our article on the 2004 Boscastle flood looks at the closest recent parallel.

Lynmouth floods since the rebuild: tides, river peaks and warnings

Since the rebuild the sea has caused more of Lynmouth's floods than the rivers. The dated events below come from the Exmoor SFRA addendum, Environment Agency gauge records and contemporary reports.

1. January 1983. River flooding recorded in Lynton and Lynmouth (SFRA addendum, 2014).
2. February 1990. Tidal overtopping of the defences (SFRA addendum).
3. May 1996. Flooding from the rivers and the tide together; the number of properties affected is not recorded (SFRA addendum).
4. 30 October 2000. The East Lyn at Brendon reached 3.41 m, still the highest level on that gauge; the Environment Agency treats property flooding as possible above 3.30 m.
5. March 2006. Tidal overtopping (SFRA addendum).
6. 17 October 2012. Spring tides and strong winds sent water over the defences on Riverside Road and over the sea wall and quay. One home and a pub cellar flooded, and silt blocking the drains behind the wall left about 600 mm of standing water at the lowest point (ITV West Country, 18 October 2012).
7. 22 December 2012. The West Lyn at Barbrook Bridge reached 0.84 m, the highest on that gauge, flooding low-lying land.
8. January 2014. Tidal overtopping again, during the winter storms on the North Devon coast (SFRA addendum).

Three Environment Agency warning areas cover the village: River Lyn (East and West) at Lynmouth, which names Lyndale Bridge, Riverside Road and Lynmouth Street; North Devon coast at Lynmouth for the low-lying and exposed seafront; and River Lyn (East) from Brendon to Lynmouth, covering Rockford and Watersmeet. A wider coastal alert runs from Hartland Point to Lynmouth and was in force on 26 October 2026. Levels on the East Lyn at Brendon and the West Lyn at Barbrook Bridge are published online, and our live river levels map shows them beside other gauges on the moor.

The Esplanade wall and the Shoreline Management Plan

The policy for Lynmouth's seafront is to keep the wall. In the Shoreline Management Plan for Hartland Point to Anchor Head, unit 7D12 is Hold the Line in all three epochs to 2105: the existing sea wall is maintained and later replaced with larger structures to keep protecting the village. The Exmoor Local Plan repeats that the sea defences at Lynmouth will be maintained.

The plan itself warns that delivery depends on funding and approvals, and that storm surge risk remains behind the defences; the Esplanade is shown in the Environment Agency's tidal flood zones. A flood risk assessment for a seafront building therefore deals with overtopping and wave spray, the drains behind the wall that can back up, and the sea level rise allowances over the building's lifetime. Our guides to Shoreline Management Plans and UK sea level rise give the background. Lynmouth is not in a Coastal Change Management Area; on Exmoor the only one is at Porlock Weir.

What Exmoor National Park Authority asks of a flood risk assessment in Lynmouth

Exmoor National Park Authority decides every planning application in the parish, using the Exmoor National Park Local Plan 2011-2031 adopted on 5 July 2017. Its flood evidence is the 2009 Level 1 SFRA, prepared jointly with West Somerset Council, and the 2014 SFRA addendum, which kept the functional floodplain in Lynton and Lynmouth as first drawn. Devon County Council comments on drainage as lead local flood authority, and the Environment Agency on the main rivers and the sea.

Nationally, chapter 18 of the NPPF governs flood risk: policy F4 sets when an assessment is needed, F5 and F6 the sequential and exception tests, and F8 the 2025 National Standards for sustainable drainage. Exmoor's Local Plan predates that chapter, so an assessment here is written to satisfy both. Our explainer on the lead local flood authority covers Devon's part in the process.

Drainage on steep ground above the village

On the hillside sites surface water, not the rivers or the sea, decides the drainage. Rain on Lynton's roofs, roads and gardens heads downhill to the Lyns or straight into the village, and Exmoor's thin soils over hard rock soak up little of it. A drainage strategy here starts from the slope: where water leaves the site, which way it travels and whether the ground below can take it.

Soakaways rarely work well on shallow soil over Devonian rock, so the Authority and Devon will want infiltration tests before relying on one. Our ground conditions and soakaway map gives a first read of the geology, and the BRE 365 infiltration rate calculator turns test pit results into a rate. Where infiltration fails, attenuated storage with a controlled outfall is the usual answer, released at the greenfield rate Devon expects. Discharge over a steep bank above the river needs particular care, because a new outfall can start erosion on its own.

From cellar conversions to new homes: when a flood risk assessment in Lynmouth is needed

Three things decide it: the flood zone, the size of the site and whether the use becomes more vulnerable. In Lynmouth most applications that need one are small, and they cluster on the valley floor; our guide on when an assessment is needed covers the national rules.

A change of use is the common one here, because so much of the village is hotels and guesthouses. Our articles on holiday lets and flood risk and on converting a house into flats explain why a conversion can need an assessment when no wall moves. The sequential and exception tests explainer covers the second hurdle for new homes on the floodplain.

Reports for the harbour, the riverside and the hillside streets

Someone buying a guesthouse on the Esplanade, an owner extending a cottage on Lynmouth Street and a builder with a plot in Lynton each need a different answer. The first report tests whether the building is safe, the sequential test whether the Authority should allow it in that spot at all, and the drainage strategy where its rainwater ends up. Our chartered consultants prepare each one, a senior consultant signs off every report, and Unda is a CIWEM Business Partner.

• Rivers, sea and hillside runoff together. A flood risk assessment for a Lynmouth address looks at the Lyns, the tide over the Esplanade wall and water coming down the valley sides at once, because the record shows each of them reaching the same few streets.
• Applications to the National Park. An application in Flood Zone 2 or 3 in Lynmouth needs a flood risk assessment for planning, and Exmoor's policy CC-D1 asks it to show the scheme fits the Shoreline Management Plan as well as the river mapping.
• Buying on Lynmouth Street or the Esplanade. Before exchange on a cottage, flat or guesthouse by the harbour, a flood risk survey for property purchase reads the warning areas, the overtopping record and the building's own floor and cellar levels.
• New homes or holiday lets on the valley floor. CC-D1 opens with the sequential test, so a new dwelling or a change to a more vulnerable use near the harbour usually needs a sequential and exception test, and the search for a lower-risk site will take in land on the higher ground nearby.
• Where the water goes on a slope. A drainage strategy for a site in Lynton or Lynmouth has to show where roof and yard water ends up when the ground falls steeply towards the rivers and the village below.
• Major schemes and Devon's standard. Devon County Council reviews a surface water drainage strategy on major applications against its 2023 guidance: greenfield rates, the 1 in 100 year storm with the upper climate allowance, and 10% for urban creep.
• Conditions on an Exmoor permission. Where a permission in the parish includes a pre-commencement drainage condition, our discharge of drainage conditions work sets out the calculations and details the Authority and Devon need to sign it off.
• Three warning areas and minutes of lead time. Riverside Road, Lyndale Bridge and Lynmouth Street sit inside the River Lyn and coastal warning areas, so a hotel, holiday let or flat often needs a flood warning and evacuation plan showing guests a dry route uphill.
• Two steep main rivers. The East and West Lyn are main rivers that rise within hours, and national mapping may not capture the confluence or the overflow above the Maybridge, so a site there may need flood modelling to fix its levels.
• Homes with a flooding history. The tide has overtopped Lynmouth's defences in 1990, 2006, 2012 and 2014, and a flood risk assessment for insurance gives a broker property-level evidence where cover has been restricted.
• Hotels and shops changing hands. Much of Lynmouth's trade is in harbourside hotels, pubs and shops inside the tidal flood zone, and a due diligence report gives a buyer or lender the flood position before a sale completes.
• Keeping a seasonal business open. In October 2012 the tide flooded a pub cellar and businesses on the front sandbagged their doors; a business continuity assessment plans for the next tide before it arrives.

Who deals with flooding in Lynmouth and Lynton

If floodwater puts anyone in danger, call 999; report a power cut on 105. Otherwise the job is split by source and by role, and in Lynmouth the planning authority is not the council that collects council tax.

Our flood risk assessment in Devon page covers the rest of the county, and Barnstaple is the nearest town with its own page, on the Taw estuary. The other half of Exmoor, around Porlock and Dulverton, falls under our Somerset page.

Lynmouth flood risk questions

Whether it is a cottage below Lyndale Bridge, a hotel on the Esplanade or a plot in Lynton, our consultants at Unda Consulting Limited will tell you which reports it needs. Call 01293 214444 or email enquiries@unda.co.uk.