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Drainage Design for New Developments

Residential, commercial and industrial developments

Morton-Roberts has a strong capability in the feasibility / outline and detail design of drainage systems for developments on both 'green' and 'brown' field sites. Our services are therefore of interest to everyone involved in developing a site including architects, developers and planning consultants among others.

New housing
Fleet Lane flooding
Flooding Tewkesbury
Flooding River Wye
Housing under construction
Sewer plan
Outlet control from detention basin
Outlet control from detention basin

Drainage Strategy Reports

A Drainage Strategy Report involves an initial investigation of the options for the foul and surface water drainage arrangements for a site and presents the most cost effective solution in each case.

For a site larger than one hectare in England, the part of a drainage strategy report covering surface water drainage duplicates some of the contents of a Flood Risk Assessment, so there may be advantages in combining the two reports.

A drainage strategy report would be tailored to meet the needs of the Client with regards to a particular development site.

Flood Risk Assessments

A Flood Risk Assessment (for use in England) is mandatory for all development sites in flood zones 2 and 3 and for all sites greater than one hectare in area. It is often advantageous to combine an FRA with a Drainage Strategy Report.

Flood Consequence Assessments

A Flood Consequence Assessment (for use in Wales) is required for all development sites in zones C1 and C2 as defined on the Development Advice Map and in all other zones where flood risk is a potential problem.

Flood Warning and Evacuation Plans

A Flood Warning and Evacuation Plan sets out how a development could be safely evacuated in the event of a severe flood. The production of a satisfactory FW&EP will not be possible at all sites.

Code for Sustainable Homes

This was withdrawn at the start of April 2015 but may be applicable to residential developments which gained planning permission before that date. We can undertake work to satisfy the requirements of sections SUR1 and SUR2 (Surface Water Run-off).

Design of Sewers for Adoption

Morton-Roberts can undertake the design of both foul and surface water sewers for adoption by the water company under a section 104 agreement.

The design would be carried out to the requirements of 'Sewers for Adoption', sixth or seventh edition as appropriate. This would be supplemented by the Welsh national standards for foul sewers, where relevant, together with any additional requirements of the adopting water company.

Design of SUDS

We can undertake the design of Sustainable Drainage Systems (SUDS) to dispose of the surface water run-off from a development site. SUDS includes such features as soakaways, rainwater harvesting systems, pervious pavements and attenuation ponds.

Design of Highway Drainage

We can undertake the design of the drainage for new highways subject to adoption under Section 38 agreements together with the drainage associated with section 278 agreements.

The work would be carried out in accordance with the DMRB or the requirements of the relevant highway authority.

Design of Drainage for
Building Regulations

Drainage not for adoption would generally need to comply with the requirements of 'Approved Document H' or other applicable documents.