Surface and foul water drainage

Weetwood is a leading independent consultancy specialising in flood risk, drainage, water management and utilities.

Our delivery and infrastructure team provides a full drainage advice and design service. From initial appraisals through the planning and )if required) the adoption process to construction - we will be with you every step of the way - advising on the most viable and cost effective solutions that comply with the requirements of the lead local flood authority and sewerage undertaker and preparing the information required to enable your development to proceed. We develop and design surface and foul water drainage systems for small private developments through to large scale residential, employment, retail and industrial developments. Our designs include the most appropriate components for the site and proposed development and may include sustainable drainage (SuDS) components. You can be confident that your development is in safe hands.

Services we provide include:

  • Drainage Assessments for Site Appraisal and Promotion: We develop surface water and foul water drainage strategies to demonstrate that surface water runoff and foul water from a potential development can be managed in accordance with planning policy and technical guidance. Our appraisals can help to demonstrate the technical viability of a development from a drainage perspective, highlight relevant constraints including sewer easements, diversions and reinforcement requirements and set out how they may be overcome with budget cost estimates.

  • Surface Water Drainage Schemes for Planning: We develop surface water drainage schemes to accompany planning applications (outline, full, discharge of conditions, reserved matters). Our drainage schemes comply with planning policy and technical guidance and incorporate SuDS where appropriate. As well as minimising the amount of attenuation storage required to reduce scheme cost and land-take we also assess runoff volumes, prepare exceedence pathways, undertake SuDS audits, develop SuDS maintenance schedules and provide scheme budget cost estimates.

  • Foul Water Drainage Schemes for Planning: We develop foul water drainage schemes to accompany planning applications (outline, full, discharge of conditions, reserved matters). Our foul water drainage schemes demonstrate how foul water from a development can be managed in accordance with planning policy and technical guidance. We develop foul water drainage schemes for mains and non-mains sewered areas, for gravity and pumped systems and for privately owned and adoptable systems. We can provide budget cost estimates.

  • Detailed Drainage Design for Adoption: We develop detailed designs of surface water and foul water drainage schemes to accompany applications to have drainage systems adopted by sewerage undertakers under Section 104 agreements. Our designs are developed using detailed hydraulic network modelling (MicroDrainage) and we can prepare CAD drawings of the drainage networks, Section 104 agreement plans, manhole schedules, longitudinal sections, drainage network construction details, levels and flood routing plans.

  • Detailed Drainage Design for Tender and Construction: We develop detailed designs of surface water and foul water drainage schemes for the RIBA’s design and construction stages. Our expertise knowledge in drainage, SuDS design and hydraulic network modelling allow us to propose and design with detail the cost effective solution for each site and associated conditions. Our designs are developed using detailed hydraulic network modelling (MicroDrainage) and we can prepare all the necessary CAD drawings for construction and provide the drainage networks in 3D CAD for implementation in the Revit model of the development to meet BIM Level 2 compliance.

  • Civil Engineering Works for Site Delivery: We provide external works and roads design services for small developments and private sites. We can prepare CAD drawings of the drainage networks, finished floor levels, external levels, road contours, manhole schedules, drainage network construction details, roads construction details and external surfacing. This service includes liaising with highway authorities on Section 278/38 Agreements and obtaining the necessary technical approvals.

Using industry standard software (MicroDrainage, AutoCAD, AutoCAD Civil 3D, Revit) and best in class techniques, our drainage design service provides clients with a full design service from initial site appraisal, through the planning process to construction. No matter how big or small your development is and where it is in the project lifecycle, we will be able to provide the advice you need to help deliver a successful development.