Securing planning permission for residential extensions often requires a clear strategy for managing surface water. Nimbus Engineering recently worked with a homeowner in Oxford to deliver a fully compliant SuDS Report and infiltration testing, ensuring their proposed single-storey extension met all local authority drainage requirements.
Project Overview
Nimbus Engineering Consultants were commissioned to provide a SuDS Report and SuDS Assessment to support a planning application for a single-storey side extension to an existing dwelling at Kennedy Close, Oxford.
The Lead Local Flood Authority (LLFA) requested a SuDS strategy demonstrating how the development would avoid any reduction in the quantity or quality of groundwater recharge, or any increase in surface water run-off.
Further services provided: BRE365 infiltration test (also known as a BRE365 percolation test).
Scope of Work & Expert Details
Our civil engineering team provided a comprehensive surface water management strategy tailored to the site’s specific geology. The technical work undertaken included:
- Conducting on-site BRE365 percolation testing to accurately measure soil infiltration rates.
- Designing a compliant source control strategy using infiltration-based SuDS features.
- Integrating rainwater harvesting and green roof attenuation to satisfy the top tiers of the SuDS hierarchy.
- Producing a complete, submission-ready SuDS Assessment for the LLFA.
BRE365 Infiltration Testing
As the underlying geology looked suitable for infiltration, we carried out in-house BRE365 infiltration testing to establish the feasibility of source control methods of SuDS.
Infiltration proved to be a viable option at this site. We were therefore able to design an effective means of managing and disposing of surface water at the source, in line with the top of the SuDS hierarchy.
Following the SuDS Management Train
To ensure the SuDS management train was fully followed, we proposed rainwater harvesting alongside an area of green roof for the extension. This combination manages surface water as close to its source as possible while delivering additional sustainability and biodiversity benefits.
Our site staff work directly for Nimbus, so they are well versed in the requirements of BRE365 infiltration testing and liaise closely with our engineering team throughout the entire process. This in-house, joined-up approach means a single point of contact and a smoother route from testing to the final report.
Need a SuDS Report or BRE365 Test?
Nimbus Engineering specialises in producing planning-ready SuDS Reports, drainage strategies, and Flood Risk Assessments across the UK, as well as BRE365 infiltration and percolation testing.
If you require a SuDS Report or a BRE365 test for your proposed development, contact Nimbus Engineering Consultants for professional, compliant, and cost-effective drainage design solutions. Call 0800 061 4916 or email us today.
