Hounslow Council's Cabinet has approved plans to progress Sustainable Drainage Schemes (SuDS) across the borough as part of its ongoing Flood Alleviation Programme, aiming to address significant surface and fluvial flood risks. The decision, made at a meeting on Monday, March 16, 2026, saw the Cabinet agree to the Hounslow Flood Alleviation Programme Strategic Business Case and the North West Hounslow Stansfield Road Outline Business Case.
Councillor Katherine Dunne, Cabinet member for Climate, Environment and Transport, presented the report, highlighting the importance of SuDS in managing water runoff, enhancing biodiversity, and building climate resilience. The programme targets key catchment areas including Northwest Hounslow, Feltham, Chiswick & Grove Park, and Isleworth & Brentford End. In these areas, approximately 2,900 residential and 476 non-residential properties are at risk during a 1-in-100-year storm event.
Beyond the Stansfield Road scheme, the Hounslow Flood Alleviation Programme is progressing with five other projects: Kingsley and Alexandra Schools, Windmill Road in Brentford, Isleworth (St John's Gardens), and Isleworth (Redlees Park). The overall programme aims to receive over 60% of its funding from external sources, with current schemes projected to receive approximately £1.79 million in Environment Agency grants towards a total projected cost of £2.93 million by the end of the financial year 2026/27.
The North West Hounslow Stansfield Road scheme, which has secured outline design approval from the Environment Agency, will involve the creation of a storage basin/pond or wetland. This feature will divert surface water drains and slowly release water back into the sewer network, reducing flood effects locally and downstream. The overall scheme cost is projected at £538,000, with £286,000 in Environment Agency grants and £252,000 in match funding from the Capital Strategy Board, Community Infrastructure Levy (CIL), and the Hounslow Green Investment Fund.
Authority has been delegated to the Executive Director of Finance and Resources to approve the implementation of schemes that have secured funding and are added to the general fund capital programme. Furthermore, authority has been delegated to the Executive Director Strategy and Transformation to enter into funding agreements with third-party funders and to procure and award contracts for scheme delivery.
The Hounslow Flood Alleviation Programme aims for the completion of construction for its current schemes by March 2027. The Stansfield Road scheme is estimated for completion by October 2026, Kingsley and Alexandra Schools by August 2026, Windmill Road, Brentford by October 2026, Isleworth (St John's Gardens) by March 2027, and Isleworth (Redlees Park) by March 2027. Beyond March 2027, the programme will continue to explore new funding opportunities and reassess potential sites based on the Surface Water Management Plan.
The success of the SuDS in managing water runoff and reducing flood risk will be measured by the reduction in flood risk to approximately 47 properties identified in the Surface Water Management Plan during a 1-in-100-year rainfall event, and by diverting runoff from Grantley Road into an attenuation basin to reduce peak flows to the downstream sewer network. The scheme also aims to improve water quality in the River Crane by promoting sedimentation and filtering pollutants from surface water sewers. Additionally, the enhancement of local amenities and biodiversity through planting native vegetation will contribute to the evaluation of success.
The long-term maintenance costs for the Stansfield Road SuDS scheme are estimated at £5,500 per annum. For the North-West Hounslow Stansfield Road scheme, maintenance costs are estimated at £5,500 per annum, with £500 per annum for below-ground civil elements handled by Hounslow Highways and the remainder by Greenspace. The responsibility for maintenance is being discussed with Thames Water for potential funding, and with Hounslow Highways and Greenspace for the above-ground elements.
More information on the Flood Alleviation Programme can be found in the Sustainable Drainage Schemes SuDS for the Borough report.
