Land on Gareth Drive
The Brief
RIDA Reports Ltd was appointed by the site owner to undertake a detailed flood risk assessment for a proposed residential development on land adjacent to 34-36 Church Street, Gareth Drive, London (N9 9GB). The project involves the construction of two new residential dwellings (Unit A and Unit B), complete with garden offices, cycle storage, and integrated green roofs.
Why the Client Chose RIDA
Developing new residential units within an urban setting requires a thorough understanding of local flood risk compliance and sustainable water management. The client required a specialist consultancy capable of delivering a robust assessment to evaluate potential site-specific hazards and provide the technical evidence necessary to support their planning application. RIDA was selected for its proven expertise in navigating the National Planning Policy Framework (NPPF) and integrating sustainable drainage solutions into new developments.
The Challenge
The primary constraint for this site was an identified risk of surface water flooding. EA mapping indicated that parts of the site interact with the 1 in 30-year and 1 in 100-year surface water flood extents, with potential pooling depths requiring careful consideration. Furthermore, the introduction of a new residential footprint necessitated a strategy to safely manage generated surface water runoff without increasing flood risk elsewhere. A secondary site-specific challenge involved identifying and demonstrating a viable, safe egress route for future occupants in the event of an extreme weather emergency.
The RIDA Difference
RIDA conducted a detailed flood risk assessment, analysing local hydrological data, topographic surveys, and surface water flood maps to evaluate the exact level of risk. To directly mitigate the surface water runoff challenges and comply with NPPF guidelines, the team formulated a site-specific Sustainable Drainage System (SuDS) strategy. A central component of this mitigation was the specification of green roofs to cover 66% of the development area, significantly enhancing the site’s ability to naturally attenuate rainwater. To address the risk of surface water pooling on-site, RIDA assessed the topographical layout and confirmed that safe egress is achievable by utilising the adjacent footpaths on Gareth Drive, which sit elevated 150mm above the road level.
The Outcome
The assessment successfully demonstrated that the proposed dwellings could be safely accommodated. By incorporating extensive green roofs and a compliant SuDS strategy, RIDA ensured the development would effectively attenuate surface water runoff and manage identified surface water risks without causing adverse off-site impacts. The comprehensive report provided the robust, policy-compliant technical justification required to support the client’s planning application.