Flood Risk Assessment in Salford

A flood risk assessment in Salford, Greater Manchester, starts with the River Irwell, which loops through Lower Kersal and Lower Broughton before it turns into the Manchester Ship Canal opposite Manchester city centre. Two Environment Agency flood basins, at Littleton Road and Castle Irwell, now hold back its peaks. Even so, on Boxing Day 2015 the river came over the defences by Heath Avenue and flooded around 500 homes and 198 businesses. We prepare flood risk assessments in Salford for planning, for house buyers, for mortgage lenders and for insurers, along with sequential and exception tests and surface water drainage strategies.

Salford, for this page, is the built-up area drawn by the Office for National Statistics, taking in the riverside districts of Lower Kersal, Kersal, Broughton Park, Higher Broughton and Lower Broughton; Charlestown, Pendleton, Irlams o' th' Height and Claremont; Seedley, Langworthy, Weaste and Ordsall; Greengate and Chapel Street facing Manchester Cathedral; and Salford Quays with MediaCityUK, across the M3, M5, M6, M7 and M50 postcode districts. Eccles, Swinton, Pendlebury, Walkden, Worsley, Irlam and Cadishead are in the same City of Salford but are separate built-up areas, covered further down. Salford City Council decides the planning applications and is the lead local flood authority; Manchester, over the river, has a page of its own.

Salford's Local Plan says the Littleton Road and Castle Irwell basins protect Lower Kersal, Charlestown and Lower Broughton against a 1% annual chance river flood, while the council's own flood strategy puts water up to 4.5 m deep in parts of Lower Broughton in an extreme event.

For a Salford address, ring 01293 214444 or write to enquiries@unda.co.uk. A consultant will check it against the Irwell warning areas and the council's drainage rules before quoting.

Where the Irwell reaches Salford homes: three warning areas and their gauges

The Environment Agency issues flood warnings for three stretches of the Salford bank, from the playing fields at Kersal down to the bridges opposite the cathedral. Each warning area lists the streets it covers, and each has a river gauge whose readings drive it:

The council's flood strategy counts several thousand properties in Broughton, Charlestown and Kersal within reach of the Irwell, and more than 15,000 homes across the whole city inside the 1 in 1,000 year river flood outline, the Ship Canal included (Salford LFRMS, 2015). The racecourse gauge takes its name from the old Castle Irwell racecourse, now the second flood basin. When a warning is in force, our live river levels map shows all three gauges.

Put a Salford postcode into the map

Enter a postcode below to see the Environment Agency's planning flood zones, surface water extents and any live warnings for that spot, or open our flood risk map for an address anywhere in England. The coral line is the ONS built-up area of Salford, with the Quays inside it and Eccles and Swinton outside. Behind the Lower Broughton and Lower Kersal defences the map will often still show Flood Zone 2 or 3, because the planning zones are drawn as if the walls and basins did not exist.

Salford's flood record, from 1866 to Boxing Day 2015

The Environment Agency holds river flood records for Castle Irwell from 1866, and the council's own table of major floods runs from 1888. The list is short, but the numbers in it are large:

1. 1866 and 1888. Flooding at Castle Irwell in 1866 is on the Environment Agency's record. In 1888 the Irwell spread over 800 hectares of crowded tenements, up to 2 m deep, according to the council's 2016 report.
2. 1946. The worst on record: 5,300 properties and 243 hectares flooded in Salford (Salford Boxing Day report).
3. 1954 and 1980. About 600 properties flooded in 1954. In 1980 the river overtopped the defences at Douglas Green weir and reached flats in Lower Kersal.
4. 26 December 2015, Storm Eva. The Littleton Road basin filled for the first time in earnest, but the river still rose over the defences south-east of Frederick Road Bridge, beside Heath Avenue, helped by debris caught on Hough Lane footbridge. Water ran down Lower Broughton Road towards Mocha Parade, through the Heath Avenue streets to Riverside, and across Green Grosvenor Park into the Cambridge industrial area. Around 500 homes and 198 businesses flooded, mostly 300 mm to 600 mm deep, and 168 more properties lost access or power.
5. The same day at the Quays and in Irlam. Water at Salford Quays rose higher than rowing club members had seen and pontoons were torn loose. In Irlam, Cadishead Way flooded, probably because its drains could not empty into the high Ship Canal.

Two findings from 2015 still shape every riverside application. The council noted that newer buildings inside the flooded area stayed dry because it had required floor levels above the 1 in 100 year flood plus climate change. It also found the Irwell peaked 750 mm higher than in 1946, yet far fewer properties flooded, which it put down to the basin and the walls. The Greater Manchester investigation adds that the racecourse gauge read 1.3 m above anything in its 75 years (GM Section 19 report). Our note on return periods and annual probability explains what a 1 in 100 standard does and does not promise.

Littleton Road, Castle Irwell and the protection they give

Salford's river defences work as a chain: walls and embankments along the river, and two flood basins at Kersal that fill only when the Irwell is high. Together they set the standard an assessment starts from:

• Littleton Road basin. The older of the two, holding 650,000 m3 when full. The council's 2016 report judged that on its own it defended Lower Broughton to about a 1 in 75 year flood.
• Castle Irwell basin. Built by the Environment Agency on the old racecourse for about £10 million, working from December 2016 and opened in February 2018 with 5 hectares of wetland. It holds more than 250 Olympic pools of water (Defra) and, with the existing defences, better protects about 1,900 homes and businesses (The Flood Hub).
• Walls and the rock wedge. In 2013 the Environment Agency strengthened the embankments between Trinity Way and Hugh Oldham Drive with a rock wedge of large stone blocks (Environment Agency plan).
• What Policy WA3 adds. The Local Plan protects both basins and other flood features; their loss or alteration is allowed only with no increase in flood risk. It supports new open space in the Cambridge area and higher river banks as further measures.

A 1% standard still leaves a 1 in 100 chance in any year, and climate change raises the river the defences have to hold. Beyond that, Lower Broughton is deep land: the 2015 strategy models up to 4.5 m there in a 1 in 1,000 year event, even with the second basin. An assessment for land behind these defences therefore tests what happens if they are overtopped. Our guides to residual flood risk and how flood defences work cover the reasoning.

The Ship Canal, Salford Quays and groundwater near the docks

Below the cathedral steps the Irwell becomes the Grey Irwell and, at Woden Street footbridge, the Manchester Ship Canal, opened in 1894. In high flows the canal carries all the river water arriving at Salford. Mode Wheel Locks at the Quays, with four sluices, control its level. The canal is not a main river: the Manchester Ship Canal Company runs it with the Environment Agency, and modelling quoted in the council's strategy puts the chance of flooding from it at typically under 1% a year while the sluices work.

Groundwater is the other Quays question. The council's strategy records groundwater rising near the canal since industry at Trafford Park stopped pumping so much, and it maps shallow groundwater across parts of the city (MST groundwater map 2.1). Policy WA4 bars basement flats from land in the undefended 1% flood outline, so a lower ground floor or car park at Ordsall or MediaCityUK needs groundwater and river levels looked at together. Our article on basements in a flood zone sets out the 2026 planning rules.

Combined sewers, critical drainage areas and surface water

Away from the river, the risk comes from rain the drains cannot take. Much of Salford's network is combined sewer owned by United Utilities, carrying foul water and runoff in one pipe, so storms fill it fast. The council's strategy found 7,713 homes across the city in surface water at least 0.1 m deep in a 1 in 200 year storm, rising to 10,817 with climate change.

• Critical drainage areas. Defined in the 2010 Manchester, Salford and Trafford SFRA (map 4.5). Any site of 0.5 hectares or more inside one needs a flood risk assessment under Policy WA4. Our explainer on critical drainage areas goes further.
• Duchy Road, Pendleton. The May 2026 Level 2 SFRA found the road beside this proposed site modelled up to 0.9 m deep in a medium-risk storm, with groundwater within half a metre of the surface in a 1% event (Level 2 SFRA).
• Storms of 2021 and 2023. The council's two Section 19 reports record short, intense storms on 9 and 30 September 2021, peaking above 32 mm an hour, and on 12 June 2023, worst in Eccles, Winton, Worsley, Boothstown, Irlam and Cadishead.
• Hidden watercourses. The strategy notes that Victorian culverts carried brooks underground and that, unlike Manchester, Salford has few records of where they run.

So the drainage question follows a site well away from the river. Policy WA5 keeps new runoff out of the combined sewers whatever the flood zone, and a scheme of five homes or more needs a drainage strategy at validation.

WA3, WA4, WA5 and the other policies behind a flood risk assessment in Salford

Salford City Council applies its own Local Plan alongside the joint Greater Manchester plan and chapter 18 of the National Planning Policy Framework. These come up on almost every Salford site:

The council's validation list repeats the WA4 triggers and asks for a drainage strategy on five or more homes as well, with the North West SuDS pro-forma on major schemes and a detailed drainage strategy at the reserved matters or full stage. Our guide to the SuDS pro-forma walks through it, and the council's flood risk assessment checklist lists the questions an officer expects answered.

Chapel Street, Langley Road and the other places Salford is building

Salford's plan accepts building in areas that could flood, on the basis that the benefits of investment there outweigh the risks, and that well-designed buildings cut the number of people a flood would seriously affect. The test falls on each site. These are the places where the questions come up most:

A change of use counts too: turning a Chapel Street office into flats raises its vulnerability class, and our note on converting a building to flats explains what that triggers.

What we prepare for Salford addresses

Each report is scoped to the address, its warning area, the sewer it drains to and what Salford City Council or a lender has asked for:

• Applications to Salford City Council. A scheme in Flood Zone 2 or 3 from Kersal to the Quays needs a flood risk assessment for planning that answers Policy WA4 and the Greater Manchester SFRA.
• River, sewer and ground in one report. A flood risk assessment weighs the Irwell, the basins, the Ship Canal, surface water, the combined sewers and groundwater for one site.
• Buying in a warning area. Before exchange on a house in Lower Kersal or a flat in Greengate, a flood risk survey for property purchase checks floor levels against the 2015 flood and the defences.
• Homes in Flood Zone 3. A new home on Flood Zone 3 land outside the plan's allocations needs a sequential and exception test report; even the allocated Langley Road sites have to meet the exception test.
• Foul and surface water together. Because WA5 wants the two kept apart, a drainage strategy sets out where each goes and what United Utilities will accept.
• Staying out of the combined sewer. A surface water drainage strategy works down the WA5 hierarchy and shows the 50% brownfield cut or the greenfield rate.
• After permission. We prepare the detailed drainage strategy and evidence for the discharge of drainage conditions on Salford consents.
• Depths if the defences are beaten. Where national maps stop short, flood modelling built on the Environment Agency's Irwell models gives overtopping depths and flow routes for one plot in Lower Broughton or Charlestown.
• Getting people out. WA4 asks riverside schemes for a safe route out and evacuation procedures, so flats in the three warning areas often need a flood warning and evacuation plan.
• Firms in the Cambridge area and on Chapel Street. 198 businesses flooded in 2015, so a business continuity flood risk assessment helps an occupier plan for the next warning.
• Owners after 2015. Homeowners in streets that flooded on Boxing Day can use a flood risk assessment for insurance to show an insurer the risk to their building.

Eccles, Swinton, Irlam and the rest of the City of Salford

Outside the built-up area on the map, the same council, Local Plan and drainage rules apply to Eccles, Swinton, Pendlebury, Clifton, Walkden, Little Hulton, Worsley, Boothstown, Irlam and Cadishead. Their flood picture is different: Worsley Brook and Glaze Brook are main rivers in the west, Irlam and Cadishead sit beside the Ship Canal where the Mersey joins it, and the 2021 and 2023 storms hit Eccles, Winton, Worsley and Boothstown hardest. At Land East of Boothstown, allocated for 300 homes, the flood zones grew markedly in the March 2025 map update. We prepare reports for all of these places.

Upstream, the Roch joins the Irwell above Salford, and our Rochdale page covers that river's town. Downstream, the Ship Canal and the Mersey run on to Warrington, and the Mersey's upper reaches are on our Stockport page. Other places are listed under the areas we cover.

Salford's flood authorities, emergency numbers and warning service

Responsibility in Salford is split by the source of the water:

For works in or beside a brook that is not a main river, the council's ordinary watercourse consent applies; for the Irwell, the Environment Agency's permission is needed. Our note on main rivers and ordinary watercourses explains the split.

Questions from Salford buyers, owners and applicants

For a terrace in Seedley, offices on Chapel Street or a riverside plot in Lower Kersal, call 01293 214444 or email enquiries@unda.co.uk. Our chartered consultants at Unda Consulting Limited, a CIWEM Business Partner, will set out which reports the site needs, and a senior consultant signs off every report.