We specialise in surface water management and drainage design including SuDS, Flood Risk Assessments, and external works.
Our services include:
By undertaking a desktop study and visiting a site we can begin assessment of the existing drainage and prepare a preliminary design strategy for a proposed development. This helps to guide the client’s decision-making and will involve:
- Reviewing the ground investigation survey
- Assessing the existing drainage infrastructure
- Calculating the existing surface water run-off and storage requirements
- Assessing the flood risk
Flood Risk Assessments
A Flood Risk Assessment (FRA) may be compulsory to gain planning approval for a proposed development. The development categories are described in the National Planning Policy Framework and Environment Agency guidance.
All types of new development must consider the impact the design will have on existing flood flow routes, the potential depth of flooding at the site, and access and egress from the site. A proposed development must not increase flood risk at the site or unintentionally affect neighbouring buildings. The FRA will offer guidance on how to mitigate the flood risk through design and construction.
We can provide FRAs to support planning applications for all types of development, including commercial, residential and highway developments anywhere in the UK.
Early in the design process we will explore the viability of using sustainable techniques for the drainage solution. Sustainable drainage systems (SuDS) can reduce the impact of new and existing building developments on the surface water drainage, which in turn minimises the chances of flash flooding in extreme weather conditions. Instead of channelling surface water through pipes to a watercourse, sustainable systems attenuate this water, allowing natural processes to break down pollutants, and release it in a more controlled way.
Benefits of using SuDs include:
- reducing water pollution
- creation of green spaces
- providing habitats for wildlife in urban areas
At this stage we will:
- Determine the FW and SW flow rates, and points of outfall
- Fully assess the capacity and suitability of any existing drainage systems to accommodate additional flow created by the new development
- Use hydraulic analysis and simulation modelling of the proposed FW and SW drainage systems
- Design attenuation measures and SW storage
- Incorporate the feasible sustainable drainage techniques
- Prepare detailed drainage schedules, plans and sections for the purpose of construction and obtaining technical approval for Building Regulations, or for adoption by the local authority
We have excellent working relationships with water companies and lead local flood authorities (LLFAs), plus a wide network of local authority contacts. We understand the importance of early discussions to manage potentially contentious issues. We help our clients obtain the following:
Section 104 agreement
- We can assist a developer obtain approval to adopt a new sewer built to an agreed standard.
Section 185 agreement
- We can assist a developer with the application requesting a public sewer being altered, diverted, or removed to allow a site to be developed.
- We can help a developer apply to the local water company asking them to adopt a private operational sewer previously installed and to be brought up to adoptable standards.
Consents from other parties
- We collaborate with stakeholder bodies such as the Environment Agency/ Conservation Officers/ Listed Buildings.
We use the latest design tools and software including:
- Microdrainage and InfoDrain, for Hydraulic design software for SW, FW and Combined drainage system
- Infodrain for Hydraulic design software for SUDs and Biophilic measures
- AutoCAD, Civil 3d and Site 3d for infrastructure modelling and producing detailed design drawings