Drainage assessment services with sustainable solutions.
Advice with flood mitigation measures.
Early design advice with viable solutions.
Flood Risk Assessments Service
Basic to enhanced studies tailored for each site.
Flood Risk Assessments
Scott White and Hookins can undertake Flood risk assessments (FRAs) for a range of developments, from individual dwellings to large-scale commercial schemes.
Our engineers are fully conversant with current legislation and the latest research in flood management techniques and offer the following solutions:
Preparation of flood risk assessments
Assessment of current and future risks
Modelling flood risk
Design of flood alleviation schemes
Design of Sustainable Drainage Systems
A significant proportion of the UK is at risk of tidal, river or groundwater flooding. Flood Risk Assessments (FRA) are now required for many Planning Applications in England, ensuring compliance with the National Planning Policy Framework (NPPF).
Therefore it is imperative that developments satisfy the recommendations of the Environment Agency (EA) requiring adequate mitigation measures to ensure that a development is sustainable and safe in terms of flood risk. Similar legislation applies in other parts of the UK.
The NPPF requires the Local Planning Authority (LPA) to consult with the EA on planning applications for sites that are over one hectare in size or that are located in Flood Zones 2 and 3.
A Flood Risk Assessment, as part of the planning process, ensures that developers are aware of any risks and are advised of any mitigation measures that may be required. Managing flood risk is an important part of achieving sustainable development.
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Flood Risk Assessment Service
We have many years of experience in producing FRA’s which are compliant with the NPPF (and the now superseded Planning Policy Statement 25 [PPS25]).
Recognising that developments are at different stages within the planning process we offer three levels of Flood Risk Assessment. The level of service included in each of these is set out below:
Level 1 – Appraisal Study
This is a basic level service to identify any existing flooding issues, whether from fluvial or pluvial sources, confirms the sites flood zone(s) and highlights the flood risks based on this information.
Level 2 – Planning
This level of assessment includes all of that in a Level 1 FRA and appraises the proposed site in accordance with NPPF requirements. It will contain advice on how to reduce any potential flood risk based on a qualitative appraisal. Relevant asset plans from the local water authority (where available) will be included along with any local requirements from the local flood authority. An outline drainage strategy will be provided for the site.
Level 3 – Design
This enhanced assessment contains all items provided in Level 2 FRA. It also contains a surface water catchment analysis, relevant hydraulic calculations and flood modelling as required. From this a detailed drainage strategy is provided together with advice on any flood mitigation measures required.
The table below summarises the service provided by each of the above levels:
Level 1 Appraisal
Level 2 Planning
Level 3 Design
Identify flooding issues
Identify Surface water issues
Risk based on issues
Qualitative appraisal to NFPP
Advice to reduce flood risk
Risk rating based on qualitative
Flood mitigation measures
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In addition to our FRA service we are able to give ‘pre-advice’ before a site layout is developed.
Where a topographic survey is available, we can assess and advise on the natural flow paths of surface water runoff across a site. The benefit of this is that it allows developments to be designed to take account of natural flow paths and therefore be more viable. This can greatly simplify drainage solutions, provide a more sustainable drainage system (SuDS) and lead to possible cost savings.
Where infiltration is not a feasible method of discharge, on-site attenuation is nearly always required. The location of any attenuation should be considered as early as possible. Gravity dictates that such features be positioned at the downstream end of the drainage system i.e. Often at the low point of the site.