Detailed Drainage Design
Fully calculated, drawn and specified drainage design to discharge planning conditions and build from — the technical stage beyond a SuDS drainage strategy.
From Strategy to Detailed Design
A SuDS drainage strategy establishes how a site will manage surface water and supports the planning application. Detailed drainage design is the next stage — the fully calculated and specified scheme needed to discharge a pre-commencement condition or to construct from. If your permission carries a drainage or SuDS condition, this is the work that satisfies it.
Flood Risk Environmental provides detailed drainage design for residential, commercial and mixed-use sites across England and Wales, prepared to current standards and structured to gain LLFA or SuDS Approval Body (SAB) technical approval.
What a Detailed Design Delivers
Designs are produced using recognised industry tools and presented with the calculations, drawings and supporting information reviewing bodies expect — ready to build from on sign-off.
- ✓ Greenfield runoff rates and agreed discharge limits
- ✓ Attenuation volumes sized for the critical storm + climate change
- ✓ Pipe and SuDS network design with hydraulic calculations
- ✓ Flow-control devices to restrict discharge to the agreed rate
- ✓ Soakaway and infiltration design supported by BRE 365 testing
- ✓ A submission package ready for technical approval
What Detailed Drainage Design Includes
Runoff & attenuation
Greenfield runoff rates, discharge limits and attenuation volumes sized for the critical storm, with allowance for climate change and urban creep.
Network & flow control
Pipe and SuDS network design, hydraulic calculations, exceedance routing and flow-control devices to restrict discharge to the agreed rate.
SuDS components
Design of geocellular attenuation, permeable paving, soakaways, basins and swales, set within the SuDS management train.
Infiltration & ground
Soakaway and infiltration design supported by BRE 365 testing, with foul drainage design where a scheme needs it.
How It Works
Every detailed design follows a structured route from condition to approval.
Review the condition
We read your decision notice and the exact condition wording, and confirm what the LLFA or local authority needs to see.
Calculate & size
Greenfield runoff, attenuation volumes and flow controls are calculated for the critical storm using recognised industry tools.
Design the scheme
The full SuDS and drainage network is laid out, sized and specified, with drawings and supporting calculations.
Submit for approval
The design package is prepared for technical approval and condition discharge — ready to build from on sign-off.
Why Choose Us for Drainage Design
Drainage specialists. Surface water and SuDS design is core to what we do — not an add-on. Schemes are designed to be approvable and buildable, not just compliant on paper.
Built for LLFA approval. Designs anticipate what the Lead Local Flood Authority and SAB will check, which keeps condition discharge moving rather than stalling on queries.
Fixed fee, clear scope. Send your decision notice and condition wording and you'll have a fixed-fee quote within 24 hours.
Schemes We Design
- ✓ Residential and mixed-use developments
- ✓ Commercial and industrial sites
- ✓ Geocellular attenuation systems
- ✓ Permeable paving and porous surfacing
- ✓ Soakaways and infiltration systems
- ✓ Basins, swales and the wider SuDS train
Frequently Asked Questions
Trusted by Developers, Architects & Planning Consultants
★★★★★ 5.0 from 6 Google reviews
“Antony was great to work with when we needed a Flood Risk Assessment and Emergency Flood Plan. As an architect I would definitely use FRE Consultants again… his report went a good way in helping us get planning permission on a tricky site. Highly recommended.”
“Antony carried out my Flood Risk Assessment and has done a great job. My architect commented that the report was professionally drafted and very easy to follow. I highly recommend Antony's services.”
“Antony carried out a SuDS report for one of our projects and provided an excellent service throughout — quick to respond, clear communication, and a thorough, detailed report within the agreed timescale. We will certainly be using his services on all future projects!”
“Extremely helpful, prompt and friendly service carrying out a Flood Risk Assessment for a home project that required planning permission in a flood risk area… the price was reasonable and given up-front, and the final report was highly professional and exactly as required.”
“I had an extension completed on my house and needed a Flood Risk Assessment for planning. The service received was great and at a competitive cost. We were granted planning after first submission.”
“Nice and quick service. Recommend A++”
Need a Drainage Design to Discharge a Condition?
Send your site details and condition wording — we'll scope the work and quote within 24 hours.
Get a Free QuoteOr contact us directly: 07826 705389 •