Kingston House, Macaulay Road
The Brief
RIDA Reports Ltd was appointed to undertake a detailed flood risk assessment for a proposed residential development at Kingston House, Macaulay Road, Clapham. The project involves the construction of a new purpose-built brickwork building comprising four flats set across lower ground (basement), ground, first, and second-floor levels.
Why the Client Chose RIDA
Delivering a new multi-storey residential building with a subterranean level requires a thorough understanding of local drainage constraints and groundwater flood risks. The client required a specialist consultancy capable of delivering a robust technical assessment to navigate national planning policies and evaluate site-specific hazards. RIDA was selected for its proven expertise in providing compliant drainage strategies and the technical evidence necessary to seamlessly support complex residential planning applications.
The Challenge
While the site benefits from a very low risk of surface water flooding and sits outside any sewer flooding zones, the primary constraints involved its location within a designated Critical Drainage Area and an identified medium risk of groundwater flooding. Because the development includes the construction of a new lower ground/basement level, careful evaluation was required to ensure the subterranean structure would not negatively affect local groundwater flows. Furthermore, strict local authority requirements for Critical Drainage Areas dictated that the new building must actively manage surface water runoff using sustainable methods rather than having just a neutral impact.
The RIDA Difference
RIDA conducted a detailed flood risk assessment in accordance with the National Planning Policy Framework (NPPF) to thoroughly evaluate the site’s vulnerabilities. To address the strict requirements of the Critical Drainage Area, the team formulated a strategy to integrate Sustainable Drainage Systems (SuDS). This approach was carefully designed to safely accommodate the required attenuation volume and replicate the site’s existing drainage regime. Additionally, to address the medium groundwater flood risk, RIDA outlined specific mitigation measures for the basement construction to ensure an adequate level of flood protection for future occupants without impeding subsurface water flows.
The Outcome
The detailed assessment successfully demonstrated that the new four-flat residential building could be safely accommodated on the site. By outlining a compliant SuDS strategy and targeted subterranean mitigations, RIDA confirmed the development is unlikely to have a negative effect on groundwater flows and will safely manage surface water without causing off-site impacts. The comprehensive report provided the robust, NPPF-compliant technical justification required to support the client’s planning application and satisfy local authority drainage requirements.
