Flood Risk Assessment with Sanderson Associates

A Flood Risk Assessment is a requirement of all planning applications for major developments and developments proposed in areas at risk of flooding.

Sanderson Associates undertake site specific Flood Risk Assessments, for all types of developments, in all Flood Zones countrywide, in accordance with the requirements of current Planning Policy PPS 25, "Development & Flood Risk" and the detailed guidelines set out in CIRIA Report 624.

Sanderson Associates have extensive experience of PPS25 throughout the UK and can produce site specific assessments for all types of developments from single units through to major residential, office, retail and industrial developments.

The assessments undertaken are specific to each site and may be a screening report (Level 1 PPS25) through to a detailed flood risk report including mitigation works (Level 3 PPS25) and river modelling using HEC-RAS software and 2D Breach Analysis using InfoWorks RS software.

Sanderson Associates also have experience of Flood Consequence Assessments TAN 15 (Wales), and are also able to produce reports to the Scottish Planning Policy requirements, providing the same level of services as that of a PPS25 assessment.

We aim to provide a high level of service in producing assessments in optimum time scales depending on the complexity of the assessment and consultation required.

In preparing Flood Risk Assessment Reports, Sanderson Associates consider initially: -

The flooding hazards which may cause a risk to the proposed development, or which might affect so as to increase flood risk elsewhere
Whether the proposed development would obstruct maintenance access to watercourses or flood defences or affect the integrity of a flood defence
Whether the development might lead to an increase in run-off

If these preliminary investigations identify no risk of flooding or impact on existing drainage mechanisms, the resulting report will normally satisfy planning requirements. In cases where the risk of flooding is identified, further assessment would be undertaken to identify:-

Flooding mechanisms for each flood source by the preliminary assessment
Review the flood level and flow record data for each flood source identified by the preliminary assessment
The potential impacts of flooding including upstream and downstream of the development and on existing flood defences
Mitigation measures for consideration in the design of the development
If appropriate, the scope of any further work including flow modelling that might be necessary to conclude the Assessment

We are specialists in the use of HEC-RAS, InfoWorks RS and the Flood Estimation Handbook software amongst other packages.

PPS 25 (England)

Planning Policy Statement 25 - Development and Flood Risk - [December 2006] may be downloaded here in PDF format {Opens New Window}. PPS 25 replaced the previous guidelines set out in PPG 25.

Tan 15 (Wales)

Technical Advice Note 15 - Development and Flood Risk - [July 2004] may be downloaded here (English Version) and here (Welsh version) in PDF format {Opens New Window}.

Scottish Planning Policy (Scotland)

Scottish Planning Policy - [February 2010] which superseded the SPP7 document may be downloaded here in PDF format {Opens New Window}

Flood Risk Assessments - Data Sheet

A data sheet detailing the Flood Risk Assessment Services that we can offer is available to view, in PDF format, by clicking on the image on the left.