Hydrology and Drainage
The severe flooding experienced in Easter 1998 and the Autumn/Winter 2000, coupled with the calls for greater sustainability in planning, have resulted in changing Government policy on issues of hydrology and drainage. Mayer Brown retain a team of engineers who are working in these areas and who are experienced in the production of hydrology and drainage assessments, which address these emerging and potentially costly issues.
Examples of the documents which are now, or will shortly be, required to be adhered to within planning applications are:
PPG25 – Planning and Flood Risk
This document advises that any application for a development which is proposed within an indicative floodplain, must be accompanied by a Flood Risk Assessment (FRA) that demonstrates whether the development is at risk from flood, or if the development is anticipated to increase the flood risk elsewhere.
Water Framework Directive
This is new legislation that requires a more sustainable approach to ensure that the full range of options for controlling the risks of flooding and water pollution are considered when planning and designing new developments. In anticipation of this directive, the ‘Framework for Sustainable Drainage Systems’ has been published by the SuDS (Sustainable Drainage Systems) working group. This is a consultation document which sets out the advised approach to improve the management of water in the urban setting.
Mayer Brown Ltd, have the skills required to assess site constraints such as, topography, geology and aquifer sensitivity. We can advise on the most appropriate system, including SuDS, as well as more traditional piped foul and surface water systems, for a particular development and produce a design for construction to both private and adoptable standards.
Often, where a development is proposed within an indicative floodplain, an assessment may be able to demonstrate, for example via flood modelling, that the floodplain is no longer functional. Or it may be able to advise on methods by which the development can avoid impacting on the floodplain.
Whatever the outcome, a properly researched and produced hydrology and drainage assessment, which allays the concerns of all the pertinent authorities, can prove to be instrumental in securing the planning permission of Local Authorities.
The skills and resources available to clients include:
- Provision of strategic advice at all stages of the project.
- Project direction and co-ordination.
- Development of environmental management plans for the control of construction and operational impacts.
- Analysis of complex rainfall and flow data.
- Design of SuDs as well as traditional drainage systems.
- Calibration, use and validation of flood modelling software.
- Production of assessments and the provision of individual chapters and non technical summaries for inclusion within environmental statements.