Arkwood is working with Lambeth Council to develop a borough-wide flood attenuation plan, as part of the Council’s ‘Soak up Lambeth’ programme. The programme looks to reduce flood risk for residents and businesses while simultaneously providing new and enhanced green spaces, supporting biodiversity and enhancing mental and physical health and wellbeing outcomes. The Lambeth flood attenuation project incorporates methods of mitigating fluvial flooding via stormwater retention systems, while also providing additional amenity value for park users and positively contributing to biodiversity enhancement. This project also links to our Lambeth Estates SuDS project, where further SuDS are being implemented in several estates around the borough to aid in the reduction of flooding.
Client and Contract Period
Lambeth Council
2023-2025
Project Objectives
As part of its 2019 Climate Action Plan, Lambeth adopted 20 Goals for Climate Action to be achieved by 2030. Amongst these, the Borough has committed to sustainably managing 10% of all water on impermeable surfaces by 2030. Compared to other London boroughs, Lambeth is more prone to flooding due to the outdated Victorian sewer systems and several ‘lost’ rivers which have been culverted underground either in conduits or straight into the sewer system, making them likely to overflow during heavy rainfall.
Arkwood have developed several masterplans setting out the designs for the implementation of Sustainable Urban Drainage Systems (SuDS) in public parks including Norwood Park, Brockwell Park, Valley Road Playing Field, and Hilly Four Acres. We have set out plans to install rain gardens, swales, leaky dams, and attenuation basins which will aid in alleviating the overworked sewer system. The masterplan for Norwood Park has since been carried out with construction completed in the summer of 2025.
Issues, Challenges, and Outcomes
Due to the nature of the project, flooding has been an issue in all of the parks that compose the scheme. This includes the overflowing attenuation ponds in Norwood Park. Prior to the Flood Attenuation Scheme, the attenuation pond was overflowing onto the adjacent railway line. Part of our proposal was to add an additional attenuation pond to the west of the existing pond with a swale to direct water into this tiered attenuation system, which has now completed construction.
In Brockwell Park we worked to balance the flood alleviation strategy with existing uses and needs of the space. With an existing tree planting initiative in place and large music festivals held in the park, it was important to create a masterplan that balanced all needs while capturing the most amount of surface runoff possible. With the help of stakeholder consultation, we were able to develop a masterplan that met everyone’s needs. Some of the attenuation strategies included a series of planted and playable swales to direct water to our planted attenuation basins. We also incorporated an open tiered attenuation basin that would double as a sports pitch in dry months. Our attenuation basins were supported by ‘Hydrorock’ (a plastics-free sub-surface attenuation medium) to increase the potential quantity of water possible for capture.
Services
- Masterplanning and detailed design
- Engagement and consultation
