Flood Risk Assessment
Due to climate change, changing weather patterns over the next few decades will mean wetter periods and so increasing the likelihood of flooding.
As a result, large areas of the UK are considered to be at risk of tidal, river or groundwater flooding.Flood Risk Assessments have become a requirement for planning applications for major development with areas in excess of 1 Hectare; and all development situated in areas with a high risk of flooding.
Planning Policy Statement 25
(PPS25) sets out Government policy on development and flood risk. The aim of the policy is to ensure that flood risk is taken into account at all stages of the planning process to avoid inappropriate development in areas at high risk of flooding. The policy also endeavours to direct development away from areas with the highest risk of flooding.The Environment Agency is the body responsible for enforcing PPS25 and has powers to challenge Local Planning Authorities over development applications in the flood plain.
The Environment Agency may object to planning applications on the following grounds:
· Development is not consistent with Government Planning Policy
· There is a lack of evidence that the Sequential Test and (where needed) the Exception Test have been applied correctly
· Planning Application is not supported by a flood risk assessment
· The site specific Flood Risk Assessment does not demonstrate that the development and its occupants/users will be safe for the lifetime of the development, does not increase flood risk elsewhere and does not seek to reduce risk overall flood risk at the site
The Flood Risk Assessment Team at Paul Waite Associates is experienced in applying a risk based approach to flood assessment in accordance with PP25 with an aim to help you to secure planning permission for your development.
Our team operates a cost effective and efficient service with the expertise to carry out detailed Sequential Tests and devise site specific Flood Warning and Evacuation Plans to further support your planning application.
In the process of preparing a Flood Risk Assessment Paul Waite Associates is able to provide our clients with a drainage strategy for the development, outlining solutions to storm water drainage discharge. This enables our clients to consider the development as a whole. Paul Waite Associates recognizes our clients’ duties of protecting adjoining development and downstream systems so that existing drainage is not over whelmed and flooding is caused.
Paul Waite Associates will consider as part of the assessment the following:
· Assessment of flood depths across the development
· Evaluate the impact of a loss of floodplain storage volume (if applicable)
· Estimate the increase in storm water runoff from the development and analyse the consequences on downstream system
· Evaluation of suitable ground floor levels and other measures to mitigate the effect of flooding.
The preliminary information will identify the sources of flood risk at the development. The next stage is to understand the mechanics that cause the risk of flooding and how these can be managed to provide on acceptable development in accordance with PPS25.
For development sites where flooding data is unavailable from the Environment Agency, Paul Waite Associates has the capability to undertake hydraulic modelling of watercourses utilizing HEC-RAS, to understand these mechanics in order to design flood mitigation measures so that the proposed development is protected without exacerbating flood risk downstream or upstream of the development.
In summary the benefits of Paul Waite Associates carrying out a Flood Risk Assessment or Sequential Test to support your planning application are:
· Greater efficiency during the planning process due to improved communication with the Environment Agency and Planning Authority
· Improved chances of gaining planning permission for your development.
England, Scotland, Wales and Northern Ireland employs different technical guidance on providing flood risk assessment.
England (PPS25)
Planning Policy Statement 25 Development and Flood Risk (December 2006)
Click here to download
Scotland (SPP7)
Scottish Policy 7 Planning and Flooding (February 2004)
Click here to download 
Wales (Tan 15)
Technical Advice Net13 Planning and Flooding (February 2004)
Click here to download
Northern Ireland (PPS15)
http://www.planningni.gov.uk/index/policy/policy_publications/planning_statements/pps15-flood-risk.pdf
The Pitt Review
http://archive.cabinetoffice.gov.uk/pittreview/_/media/assets/www.cabinetoffice.gov.uk/flooding_review/pitt_review_full%20pdf.pdf
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