Surface Water & Flood Risk

Planning authorities and the Environment Agency will require you to demonstrate how surface water will be managed as part of your proposed development if you are building a new structure or increasing the developed footprint of your site.
SuDs Design

The required document you will need is typically referred to as a Surface Water Drainage Strategy or a Sustainable urban Drainage Systems (SuDS) Report. You may also be required to provide a second stage detailed surface water drainage design report and a Sustainable Drainage Operation and Maintenance Plan when submitting a planning application for major development.

From April 2015 any development of 10+ units (residential, commercial, industrial, and mixed use sites) is required by law to consider the potential use of Sustainable urban Drainage Systems as part of a drainage strategy. You are also likely to need a drainage strategy if your development is located within an area designated as Flood Zones 2 and 3, or within an area identified as having a surface water flooding problem.

BCL's Site Investigation & Surveys work with specialist consultants to offer you an integrated approach to deal with the surface water, to protect your development from flooding, prevent pollution, and deliver a controlled flow of clean water that can be used for amenity and wildlife benefits.

Reports will:

  • Give recommendations for SuDs and provide initial design parameters for drainage components (ie soakaways, ponds, swails etc).
  • Identify appropriate surface water runoff management options.
  • Comply with National Planning Policies for England, Wales, Scotland and Northern Ireland and with the relevant environmental agency guidance and local planning policy.
  • The reports can be presented as standalone documents or combined as part of a Flood Risk Assessment.

BRE Soakaway (Soil Infiltration Rate) Tests

You may be considering soakaways as part of a surface water drainage strategy for your development proposal. However, an effective soakaway will require sufficient storage capacity to handle the immediate run-off volume from a storm and also to be constructed within soil of sufficient drainage capacity to allow the stored water to disperse sufficiently before the next rainfall event. In order to achieve this you will need to establish the drainage capacity of the soil.
Surface Water & Flood Risk