Flood Risk Assessment in Pagham

Pagham sits right on the West Sussex coast, where the land meets the tide at Pagham Harbour and the low coastal plain drains slowly out to sea. That makes flood risk here unusually layered: the harbour and the shingle spit on one side, the Pagham and Aldingbourne Rifes and the highway drains on another, and a high water table beneath the brickearth and raised beach deposits below. A flood risk assessment in Pagham reads those sources together and shows your local planning authority that a development will stay safe for its whole lifetime without pushing flood risk onto a neighbour.

We prepare flood risk assessments in Pagham for planning, for property purchase and mortgage, for insurance and for BREEAM, alongside sequential and exception tests and surface-water drainage strategies (SuDS). Whatever brought you here — a planning condition, a lender's question, a search result that flagged the harbour, or a drainage objection from the county — the right report starts with how water actually behaves on this stretch of coast.

On the open coast Pagham Beach is held to roughly a 1 in 200 year standard by a rock revetment, but the real flood threat is the harbour overtopping its defences in the south-west corner of the village — where around 88 properties and the Church Farm caravan park sit closest to the water.

Flood risk assessment in Pagham at a glance

For most people the practical question is simple: is one needed, who judges it, and what does it have to prove. The essentials for Pagham are below.

• Coastal and tidal first. Pagham's defining risk is the sea and Pagham Harbour, not a major river. The harbour mouth, the Church Norton shingle spit and the tidal channel all move, so risk here changes over time.
• Two authorities set the rules. The Environment Agency leads on the sea and the harbour defences; West Sussex County Council is the Lead Local Flood Authority for surface water, groundwater and ordinary watercourses, and Arun District Council determines planning.
• Surface water and groundwater matter inland. Behind the beach the Pagham and Aldingbourne Rifes, the highway drains and a high water table drive most of the everyday flooding — the kind that closed roads here in January 2023.
• An FRA is usually required for development in Flood Zones 2 or 3, for sites of one hectare or more in Flood Zone 1, and for smaller sites where the Flood Map for Planning now shows surface water risk.
• Send us the site address and one of our experienced flood risk consultants will tell you quickly whether an assessment is needed, and reply to a quote within 60 minutes.

Check flood risk anywhere in Pagham

Pagham parish is outlined below. Screen a local postcode 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 assessment — for that, start a quote or use Unda's free flood risk map.

How flood risk behaves in Pagham: the harbour, the rifes and the water table

Pagham faces three sources of flooding at once, and they rarely arrive together in the way national mapping suggests. Tidal flooding from Pagham Harbour is the headline risk; surface water from the rifes and drains is the most frequent; and groundwater rising through the coastal plain is the one the maps miss. A credible assessment separates them, then shows how the proposal copes with each.

Tidal and coastal flood risk

Pagham Harbour is a 629-hectare Site of Special Scientific Interest and a Special Protection Area, Ramsar site and Local Nature Reserve, made up of saltmarsh, mudflats, lagoons and shingle. It is also a restless piece of coast. The Church Norton shingle spit grows and breaches on a cycle of years: it grew naturally from 2003, breached in April 2016, and a managed channel was cut through it in October 2021 to reset the harbour mouth and ease the flood and erosion pressure on Pagham Beach. The land in Pagham village mostly sits higher than the beach, so the EA's defence work has focused on the south-west corner, where the harbour can overtop its bunds.

For a site anywhere near the harbour edge, an assessment has to treat the defences honestly. EA flood maps show the floodplain as if the defences were not there, which is why a defended plot can still sit in Flood Zone 3 — and why residual flood risk from overtopping or breach is usually where a Pagham application is won or lost.

Surface water, the Pagham Rife and the Aldingbourne Rife

Behind the shingle, Pagham is flat, low and slow to drain. The Pagham Rife and the Aldingbourne Rife carry surface water off the coastal plain to the harbour, and when they silt up or the tide holds the outfall shut, water backs up across low-lying ground. In January 2023 persistent rainfall and a high water table overwhelmed both the natural and the highway drainage, forcing road closures including Pagham Road and Lower Bognor Road. Surface water is now the most widespread source of flood risk in England, and on a Pagham site it usually drives the drainage strategy as much as the flood risk assessment.

Groundwater and ground conditions

The Pagham coastal plain lies on London Clay and the Bognor Sand, overlain by brickearth, river-terrace gravels and raised storm beach deposits up to about four metres thick, with the chalk of the South Downs feeding groundwater from the north. That combination gives a shallow, responsive water table that rises in wet winters. Groundwater appears on no national flood map and breaks soakaway assumptions, so infiltration drainage here often fails without infiltration testing to BRE 365. You can get an early read on the ground with Unda's free geology and ground conditions map before committing to a drainage approach.

A history of flooding in and around Pagham

Dated events are the clearest measure of how this coast actually behaves, and they are why Arun and the county scrutinise development here so closely. Each one fed into the defences and the policy a developer now has to design around.

• 1933 — harbour breach. An early recorded breach of the shingle showed the harbour's tendency to flood low ground when the sea finds a way through.
• Winter 2013–2014 — the storm winters. The successive storms of 2013, 2014 and 2015 stripped beach volume at West Front Road. A rock revetment installed in 2013, costing about £500,000, is credited by Arun and the EA with saving several front-line properties.
• April 2016 — natural spit breach. The Church Norton spit breached and the channel migrated south-west, welding the severed spit back to the mainland and easing the scour that had eroded the beach.
• 2020 — breach into the Little Lagoon. Continued spit movement forced the outflow channel into a tighter bend and breached the shoreline into Pagham's Little Lagoon.
• October 2021 — managed channel cut. The Pagham Flood Defence Trust cut a new outflow channel through the spit, under the Imperative Reasons of Overriding Public Interest test, to reduce flood and erosion risk to homes and the Church Farm holiday park.
• January 2023 — surface water and groundwater. Torrential rain on an already high water table overwhelmed the rifes and the highway drains, closing Pagham Road and Lower Bognor Road — a reminder that the everyday risk here is inland, not only at the beach.

Planning and drainage policy for a flood risk assessment in Pagham

Three bodies set the requirements between them. The Environment Agency leads on the sea and the harbour defences; West Sussex County Council is the Lead Local Flood Authority and the statutory consultee for surface water drainage on major development; and Arun District Council is the local planning authority that determines the application against its Local Plan and Strategic Flood Risk Assessment. Getting all three satisfied early is what keeps a Pagham application moving.

Arun has tightened its expectations recently. Its 2026 Strategic Flood Risk Assessment carries the long-term climate-change layer to 2125, the emerging Local Plan (2023–2041) is reshaping where growth can go, and the council's October 2025 drainage checklists now ask for infiltration testing and construction-level drainage detail before determination rather than after. Sites can also fall within a critical drainage area, which can trigger an assessment even in Flood Zone 1.

What an assessment has to show is consistent: the design flood level for the relevant event plus a climate change allowance, finished floor levels set safely above it referenced to Ordnance Datum, safe access and egress, and a drainage scheme that follows the four pillars of SuDS and the discharge hierarchy. On the coast, the climate change allowance is not optional — sea level rise over a 100-year residential lifetime reshapes both the flood level and the freeboard you have to design in.

Development and flood risk assessment in Pagham

The kind of site you bring forward shapes the assessment you need, and Pagham throws up a particular mix. The coast, the holiday parks and the protected harbour all sit alongside ordinary infill, so the right scope is the difference between a clean approval and a drainage objection that holds an application up for months.

• Coastal and beach-edge plots. Replacements, extensions and new homes near the harbour or Pagham Beach turn on tidal flood level, defence condition and residual risk, with finished floor levels and safe refuge often the deciding points.
• Holiday parks and tourism sites. Caravan and holiday accommodation around Church Farm sit close to the harbour, where flood warning, evacuation and seasonal occupancy all feed into the assessment.
• Infill and replacement dwellings. Plots set back from the beach are usually driven by surface water and groundwater rather than the sea, and by a drainage scheme that works on slow-draining ground.
• Sites near the rifes. Land beside the Pagham or Aldingbourne Rife brings ordinary watercourse and surface water questions, and riparian responsibilities for the channel and its flow.
• Environmentally constrained sites. The harbour's SSSI, SPA and Ramsar designations limit where and how surface water can be discharged, which can shape the drainage strategy from the outset.

How Unda helps with flood risk assessment in Pagham

We act as the accurate translation layer between your scheme and the requirements set by the Environment Agency, West Sussex County Council as the Lead Local Flood Authority and Arun District Council as the planning authority. We have prepared flood risk assessments and drainage strategies across the West Sussex coast, and we know how differently Pagham behaves from an inland site. We are experts on this coastline's flooding, not a generic report mill.

Unda has prepared more than 5,000 flood risk assessments since 2014, holds a 5.0 Google rating and replies to every quote request within 60 minutes. Our consultants are CIWEM members, and a senior flood risk consultant oversees and signs off every project — so the report that lands on a planner's desk stands up to scrutiny. See our wider Sussex flood risk guide and the Arun district overview for the bigger picture, or browse case studies and meet the team on our about page.

Flood risk assessments and related reports for every situation in Pagham

People come to us in Pagham for several different reasons, and each needs the right report. It helps to keep three things separate: 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.

• Flood risk assessment for planning. The site-specific report that satisfies the NPPF and shows your development stays safe for its lifetime without increasing risk elsewhere. Groundwater and, where needed, flood modelling are assessed within it rather than as separate reports.
• Flood risk survey for property purchase. An independent, property-specific survey for buyers and their advisers, going beyond the conveyancing search to assess the actual building near the harbour or the rifes.
• Flood risk assessment for insurance. Property-level evidence for brokers and underwriters where cover has been restricted, declined or priced on flood risk.
• Flood risk assessment for BREEAM. Structured around BREEAM Pol 03 so a scheme keeps its flood and surface-water credits.
• Sequential and exception tests. The locational justification that a higher-risk coastal site is the most appropriate available, prepared alongside the assessment.
• Surface-water drainage strategy (SuDS). A scheme that manages runoff to the West Sussex standard, following the four pillars of SuDS and the drainage hierarchy on slow-draining coastal ground.
• Discharge of drainage conditions. The detailed design that discharges a pre-commencement or pre-occupation drainage condition on a permission, with preliminary drainage design available at outline stage.

Not sure which you need? Our flood risk consultants will point you to the right report, and our NPPF guidance explains how the tests fit together. Start with the free flood risk map, live river levels map, drainage calculators and BRE 365 infiltration calculator, then talk to us when you need the report itself. The full flood risk assessment service and our other areas are a click away.

Pagham flood resources and contacts

The most reliable Pagham flood information comes from the lead authorities. For an immediate threat to life during a flood, always call 999; for a power cut during flooding, call 105.

• Check for flooding in Pagham. Environment Agency live warnings, river levels and maps at check-for-flooding.service.gov.uk; the tidal Pagham flood warning area covers the harbour. Sign up for flood warnings or call Floodline on 0345 988 1188.
• West Sussex County Council — Lead Local Flood Authority. Report flooding, and read the Local Flood Risk Management Strategy and SuDS guidance via the West Sussex flooding pages.
• Arun District Council. The Pagham coastal protection page covers the beach and harbour defences; flood risk planning policy and reporting drainage problems cover development and local drains.
• Coastal strategy and monitoring. The Pagham to East Head coastal defence strategy sets the long-term approach; beach surveys are published on the Channel Coast Observatory.

Flood risk assessment in Pagham: frequently asked questions