Securing planning permission for major commercial developments in London requires a robust approach to flood risk and surface water management. Nimbus Engineering partnered with SM Planning and Herts Heritage Building and Roofing Ltd to deliver a comprehensive Flood Risk Assessment and SuDS Report for a new four-storey office building in the London Borough of Haringey.
Project Overview
Nimbus Engineering Consultants were commissioned to provide a Flood Risk Assessment and SuDS Report to support a planning application for the redevelopment of an existing site. The proposed development comprises the construction of a four-storey commercial office building, with associated parking and landscaping, as required by Haringey Borough Council.
Our assessment confirmed that there are no significant flood risk issues or concerns at the site. In addition, our proposed SuDS solution drastically improves the site’s environmental impact, reducing surface water runoff by 99% compared to the existing site’s Qbar (urban) rate.
Scope of Work & Expert Details
Our civil engineering experts managed the complete surface water design and flood risk analysis to ensure full planning compliance for this commercial site. The specific technical work undertaken included:
- Preparing a detailed Flood Risk Assessment (FRA) confirming the site is safe from all sources of flooding.
- Designing a highly efficient surface water drainage strategy that reduces runoff by 99% compared to the existing site’s Qbar (urban) rate.
- Modelling the drainage system using industry-standard hydraulic software and FEH data in accordance with the London Borough of Haringey’s requirements.
- Conducting capacity checks and direct liaison with Thames Water to ensure full compliance with the London Plan.
Following the SuDS Hierarchy
Areas of sedum roofing have been proposed where feasible, along with rainwater harvesting, ensuring compliance with the top tiers of the SuDS hierarchy. Infiltration was assessed but not considered viable due to the underlying ground conditions.
Commercial Surface Water Drainage Solution
The proposed car parking areas are designated for heavy vehicle use. As a result, our SuDS design incorporates a bypass separator alongside porous surfacing, underlain by a hydrocarbon-removing geotextile membrane to protect local water quality.
The remaining surface water runoff is managed via an underground attenuation tank, with a controlled flow restriction discharging safely to the existing surface water drainage network in the adjacent street.
Outcome
Planning application approved. Our comprehensive reporting, modelling, and design work resulted in a successful outcome and a highly satisfied client.
Need a Flood Risk Assessment or SuDS Report?
If your commercial or residential development requires a SuDS report, drainage strategy, or Flood Risk Assessment, Nimbus Engineering Consultants can help.
Call us at 0800 061 4916 or email info@nimbusengineering.co.uk.
