Flood Risk Assessment in Hackney Wick

A flood risk assessment in Hackney Wick usually starts at the water's edge. The Lee Navigation passes the station in the Hackney Cut, a channel dug through the marshes in 1769 and now lined with converted warehouses, and on the night of 4 January 2024 it spilled into the streets of Fish Island. Away from the canal, rain collects in the low roads around Wallis Road and White Post Lane. We prepare flood risk assessments here for planning applications, purchases, mortgages and insurance, together with sequential and exception tests and surface water drainage strategies.

Two wards make up Hackney Wick here, and they meet just south of the station. Hackney's Hackney Wick ward covers the station, Wallis Road and Hepscott Road and crosses the Navigation to East Wick, Here East and the Copper Box. Tower Hamlets' Bow East ward takes in Fish Island and continues south through Old Ford. Most people who live and work here treat Hackney Wick and Fish Island as one place, which is why both are covered, mainly in the E9 and E3 postcode districts. The rest of the Olympic Park and Stratford lie east of the outline, in Newham.

Tower Hamlets counted 61 properties flooded inside when the Lee Navigation overtopped in January 2024, with three of the four Lea Bridge sluices not fully working. Water stood about a metre deep on Dace Road.

Weighing up a site near the canal? Call 01293 214444 or email enquiries@unda.co.uk and one of our flood risk consultants will talk it through. Reports for sites in Hackney Wick come from Unda Consulting Limited, a CIWEM Business Partner.

Which council deals with a site in Hackney Wick or Fish Island?

It depends which side of the borough line the site sits. Since 1 December 2024, applications for the station area and the streets north of it have gone to Hackney Council, and those in Fish Island to Tower Hamlets Council. Before then the London Legacy Development Corporation, set up after the 2012 Games, decided most of them, and its Local Plan still applies.

The Legacy Corporation's planning powers ended on 1 December 2024, and the four boroughs had handled new applications under delegation since 1 September. Hackney's Local Plan 2033 was adopted in July 2020 without the Legacy Corporation area, so its flood policy covers few Hackney Wick sites; Hackney expects to use a new plan from 2029. Tower Hamlets' replacement plan is at examination, with hearings postponed in July 2026. Each council is also the lead local flood authority on its side of the line and comments on drainage proposals for every major scheme.

What happened when the Lee Navigation overtopped in January 2024?

During Storm Henk on 4 January 2024 the canal rose over its bank and ran west into the low streets of Fish Island. Tower Hamlets' Section 19 investigation traced the flood to the Navigation, not the drains. Sluices upstream at Lea Bridge hold the water level in that stretch, and the report sets out how they failed.

1. 2021. Sluice D at Lea Bridge was put out of use by a twisted frame. Later that year sluice C began failing and was locked off, usable only by hand.
2. Morning of 4 January 2024. Sluice B dropped out of automatic control at 10:35 and was left 5% open. The Environment Agency had issued a flood alert for the Lower River Lee two days before.
3. Evening. The second-stage high level alarm sounded at 19:43. Overtopping was reported at Old Ford Lock at 21:25, and the fire brigade reached Fish Island at 22:24.
4. Night of 4–5 January. A Canal & River Trust supervisor opened sluice C by hand at 23:10, then opened the Old Ford Lock sluices at 01:00 under a fire brigade escort. By 9 am the water had gone.
5. Afterwards. Tower Hamlets recorded 61 properties flooded inside, most of them in a live-work building on Dace Road, and paid £67,000 in recovery grants. Its report, revised in April 2025, asks the Trust to return all four sluices to automatic control.

The river itself was not in extreme flood: flows stayed below 50 cubic metres a second, against the 70 the sluices were built to pass, which is why the report puts the cause down to the sluices and not to the weather. Even so, the Environment Agency's River Lee gauge at Lea Bridge reached 6.52 m, the highest on its record, where its normal range is 5.78 to 6.10 m. Our explainer on weirs and sluices shows how structures like these hold a navigation level, and the live river levels map puts the Lea Bridge gauge beside others on the Lee. Why some floods get a formal investigation and others do not is explained in our article on Section 19 reports.

Checking an address between Hackney Wick station and Old Ford Lock

Type a postcode into the map below to screen it against Environment Agency data for rivers, surface water and reservoirs, or open our full flood risk map for anywhere in England. The coral line follows the two wards, with the Hackney Wick ward to the north and Bow East to the south; the Olympic Park and Stratford sit beyond its eastern edge. Screening shows mapped risk only. It cannot show a sluice jamming, and the two government maps behind it can give one street two different ratings (how they differ).

How deep could flooding get in Hackney Wick?

Up to about 2 m in the worst modelled case. Hackney's Level 2 Strategic Flood Risk Assessment of September 2010 used the Lower Lee Valley flood model. Once the Lea Bridge sluices reach capacity, it found, flood flows travel down the Hackney Cut, leave the channel at Wallis Road and pond in the surrounding streets.

Flood reviews by Arup for the Legacy Corporation in 2017 and 2019 put most of the station allocation in Flood Zone 3, largely land that benefits from the canal walls, with undefended pockets on Berkshire Road, Wallis Road and Hepscott Road. Peak modelled levels near the station were 6.29 m AOD for a 1 in 100 year flood with climate change and 6.35 m for a 1 in 1,000 year flood. Only 6 cm separates the two, so a floor set above the 1 in 100 year climate change level also sits within a few centimetres of the 1 in 1,000 year level. On the Hamlet Industrial Estate, mostly Flood Zone 2 on the 2019 national map, a 70% climate change allowance put most of the site under water, so the review treated it as Flood Zone 3a. Levels used for a site today have to follow the current climate change allowances.

Tide matters less this far upstream. The SFRA notes that the Thames' tidal reach runs up the Lea as far as the Lea Bridge sluices, and Old Ford Lock, at the southern end of Fish Island, is semi-tidal. The area is the northern tip of the Isle of Dogs and Lea Valley policy unit of the Thames Estuary 2100 plan, which names Hackney Wick and applies policy P5, further action to reduce risk as sea levels rise. Our River Lea page follows the river from its source to Bow Creek.

Rain, sewers and gravel: flood risk away from the canal

On the Hackney side, the fire brigade's records point to heavy rain as the more frequent problem. Hackney's Surface Water Management Plan names nine critical drainage areas in the borough, and the first covers Berkshire Road, Wallis Road and White Post Lane, where water ponds at low points in the road. Our article on critical drainage areas explains what that label adds to an application.

Under the 2025–30 London Surface Water Strategy, the Lee Valley was one of the first two areas given a surface water catchment partnership, and our summary of the strategy sets out what it means for new schemes.

Policies S.10, S.11 and LP53: the planning rules for flood risk in Hackney Wick

On most Hackney Wick and Fish Island sites, the local flood policies are S.10 Flood risk and S.11 Sustainable drainage measures and flood protections in the LLDC Local Plan 2020–2036, adopted on 21 July 2020. They are read with London Plan policies SI 12 and SI 13 and chapter 18 of the NPPF.

• National policy. NPPF policy F4 sets when a site-specific assessment is needed, F5 and F6 the sequential and exception tests, and F8 expects drainage to meet the 2025 National Standards for sustainable drainage.
• The London Plan. Policy SI 12 asks schemes to address residual risk and stay back from flood defences. SI 13 sets a drainage hierarchy that starts with reusing and infiltrating rainwater and ends with a combined sewer.
• The Legacy Corporation's evidence. Arup's reviews found the station allocation passes the sequential test but must also pass the exception test. They asked for homes above flood level, safe access or refuge, replacement flood storage, an 8 to 16 m strip beside watercourses and no basement dwellings in Flood Zones 2 and 3.
• Hackney's own policy. Where it applies, LP53 asks for an assessment for any development in Flood Zone 2 or 3, minor works and changes of use included, and for all development in Flood Zone 1 inside a critical drainage area. Major schemes need a sustainable drainage strategy that allows for climate change.
• Drainage submissions. Major applications carry the London Sustainable Drainage Proforma, and Hackney asks minor schemes to complete it as well, particularly in critical drainage areas. Hackney's SuDS guidance sets out the council's checklist, and our note on the SuDS proforma covers what goes in it.

Much of the local evidence is old. Hackney's Level 2 SFRA dates from 2010, with a climate change supplement added in 2018, and Tower Hamlets' Section 19 report recommends refreshing its own SFRA, flood strategy and surface water plan. In April 2011 Hackney's cabinet considered the flood risk in Hackney Wick and noted that ways of protecting it carried significant costs and would affect Hackney Marshes. An assessment here often has to bring the modelled levels up to date before a council will accept them.

What the Environment Agency asked of a Wallis Road scheme in 2024

An application for 337 shared-living studios at 115–119 Wallis Road shows what a canal-side site is measured against. The Legacy Corporation's committee report of September 2024 records an Environment Agency objection on four grounds, and officers recommended approval only if it was resolved. None of the four is peculiar to that site.

• Floor levels. The flood risk assessment had not shown floors 600 mm above the 1 in 100 year flood level with climate change.
• A basement in Flood Zone 3. The Agency listed the proposed basement as a failing of the assessment, along with the need to consider an extra flood barrier.
• The river wall. Works within 8 m of the Navigation and its flood wall would restrict access for maintenance and emergencies, and nothing showed what condition the wall was in.
• Ecology. The effect on river habitats needed assessing too.

Hackney's environment team asked for a drainage specification, flood resilience measures and an evacuation plan by condition, and the Hackney Wick Central masterplan caps the non-floodable footprint of each plot. Our guide to answering an Environment Agency objection sets out how points like these are usually resolved, and our explainer on compensatory flood storage shows why floodplain lost to new buildings has to be replaced.

Does my scheme need a flood risk assessment in Hackney Wick?

Almost certainly, if it is close to the canal. Most land near the Navigation is in Flood Zone 2 or 3, and Hackney adds critical drainage areas to the triggers. The table covers the schemes we see most often here.

Reports for sites from White Post Lane to Old Ford Lock

People commission our reports in Hackney Wick to win planning permission, to buy or insure a building, to satisfy a lender and to clear drainage conditions. Each answers its own question: whether the site is safe, whether the development belongs there, and where the rainwater goes.

• Canal, rain and ground together. A flood risk assessment for a Hackney Wick site weighs the Navigation, the critical drainage area, the combined sewers and the gravel beneath it in one report.
• Applications to Hackney or Tower Hamlets. Schemes in Flood Zones 2 and 3 need a flood risk assessment for planning that answers policy S.10 and the Environment Agency's floor-level and river-wall requirements.
• Before exchange on a canal-side flat. Buyers of warehouse flats and live-work units near Dace Road or Wallis Road use a flood risk survey for property purchase to learn what the 2024 flood means for that building.
• New homes in Flood Zone 3. Housing on the station and Hamlet Industrial Estate allocations needs the sequential and exception test, as the Legacy Corporation's own reviews found.
• Runoff and combined sewers. Major schemes need a drainage strategy that follows the London Plan hierarchy before any rainwater reaches a combined sewer.
• Rain in the critical drainage area. Around Berkshire Road and White Post Lane, a surface water drainage strategy shows how a site will hold back water in streets that already pond.
• After permission. Permissions here can carry conditions on drainage, flood resilience and evacuation, as recommended for the 2024 Wallis Road scheme, and we prepare the evidence for the discharge of drainage conditions.
• Levels from a 2010 model. With Hackney's SFRA built on modelling from before 2010, flood modelling can set current climate change levels for a plot on Wallis Road or White Post Lane.
• Water arriving fast. Hackney asked for a flood warning and evacuation plan on the 2024 Wallis Road scheme, and the SFRA maps how quickly water spreads once it leaves the Cut.
• Gravel over clay. Basements and soakaways in the Lea valley gravels call for a groundwater flood risk assessment, since the SFRA describes the Lea valley as north London's lowest ground and susceptible to groundwater flooding.
• Cover after 2024. With 61 Fish Island properties flooded inside in one night, a flood risk assessment for insurance gives an underwriter evidence about one building's floors and defences.
• Buying development land. The Hamlet Industrial Estate allocation is mostly underwater in the climate change model, so flood risk due diligence belongs before terms are agreed.
• Studios and workshops. Fish Island is a Creative Enterprise Zone where artists lost equipment and days of work in 2024, and a business continuity flood assessment plans for the next overtopping.
• Workspace in the masterplan. The Hackney Wick Central masterplan covers about 119,000 m² of mixed floorspace, and a BREEAM flood risk assessment supports the Pol 03 credits on its commercial buildings.
• Testing a layout first. Arup found little room on the Hamlet Industrial Estate to put homes on lower-risk ground, and a flood risk feasibility study tests a layout like that before an application.

Reporting flooding, and the bodies responsible for the Wick

If anyone is in danger, call 999. Water coming over the canal bank is a matter for the Canal & River Trust's emergency line, river levels and warnings for Floodline, and blocked drains or flooded roads for the council on your side of the borough line.

Anyone living or working near the Navigation can sign up for free flood warnings for the area that covers their street; the Section 19 report asks the Environment Agency to keep promoting them in Fish Island.

What people ask us about Hackney Wick, the canal and planning

Unda Consulting Limited prepares flood risk assessments, sequential and exception tests and drainage strategies for homes, studios and development land across Hackney Wick, Fish Island and the lower Lea valley. For a site near the station, the Navigation or Old Ford Lock, call 01293 214444 or email enquiries@unda.co.uk. Our pages on Stratford, Tottenham, the Isle of Dogs and Middlesex cover neighbouring stretches of the Lea and the old county, and every area we write about is listed on our areas page.