Drainage Design

The drainage of a development is very rarely seen or thought about by people when looking at a new development which has been constructed. However the drainage designed and installed underground or on the surface as part of surface features is an important and integral part of the design and layout of developments in terms of both dealing with the anticipated flows from a new development, but also ensuring the development does not contribute to increased flood risk to the site itself or other sites in the vicinity.

Design of drainage for a new development or re-development of a current site form a very important part of the site strategy and are closely linked to flood risk. Indeed, some flood risk mitigation measures directly affect the type and design of proposed drainage systems.

From assessment of existing drainage infrastructure on a site to obtain current run-off rates, Greenfield and Agricultural run off rate calculations and preliminary drainage strategies through to final detailed design of attenuation and Sustainable Urban Drainage Systems (SuDS) can have a major impact on the development proposed and the layouts and viability of such developments.

It is important from an early stage in any development that drainage is considered and impact dealt with to ensure the site development encompasses all the requirements necessary to meet with the required standards and constraints to meet planning requirements. This is often required to be materially considered as part of a Planning Application.

Drainage can form simple private systems connecting into existing adopted sewers but can also form large adopted systems with integrated SuDS structures to control and manage run off rates from proposed development sites.

Other important considerations which must be borne in mind at the initial stages of development are identifying viable points of discharge from the site for both foul and surface water and acceptable rates of discharge. These can be absolutely critical to the development viability and layout.

Whilst for some Outline Planning Applications a full detailed design for the drainage is not required, the viability of the development to be drained adequately is required to be proven as part of the Outline Planning process.

For Full Planning Applications and reserved matters (discharging planning conditions on a valid planning permission) a full drainage design is required to ensure that the site can be drained adequately and meet the requirements of the Planning Conditions imposed. This usually involves construction drawings and full hydraulic calculations to support the design and drawings.

Sanderson Associates Drainage Design Services.

• Highway Drainage Design
• Section 104 Agreements (Water Industry Act 1991) Surface Water and Foul Sewer Design
• Sustainable Urban Drainage Systems Design (SuDS)
• SAB Applications
• Drainage Impact Assessments
• Preliminary Design for both Surface Water and Foul Drainage
• Detailed Design for both Surface Water and Foul Drainage

Sanderson Associates provide a comprehensive drainage design service which include assessment of existing drainage infrastructure through to design of new systems including attenuation and other forms of SuDS to adoptable standards for development.

Sanderson Associates have undertaken many and varied types of drainage design from preliminary assessments for small developments through to full detailed design and adoption through S104 agreements for large employment and residential developments.

Our drainage design service offers valuable advice to clients on the most cost effective and viable solutions to drainage problems and options available including sustainable systems.

Our drainage expertise also follows through into our Flood Risk Assessment Services which ensures that any drainage or flood risk mitigation measures recommended as part of a Flood Risk Assessment are best value design and bespoke to any such development. Please visit our dedicated flood risk site www.floodrisk.co.uk for further information on our flood risk services and expertise.