Expertise in flood hydrology, hydraulic modelling

and flood risk assessment.

Approximately 5 million properties in the UK are at risk of flooding-

1 in every 6 homes. We offer a range of flood risk management services to support developers, architects, planning consultants and the public sector.

 

Flood Risk Assessment

A flood risk assessment (FRA) is generally required for development proposals which fall into areas at risk of flooding or where surface water runoff presents a potential flood risk downstream.

Flood risk

mitigation

Technical Expertise

Our approach

Our flood risk assessments are undertaken in-house by Jonathan Vann, a Chartered Geographer and Fellow of the Royal Geographical Society. Before founding Waterside Consultants, Jonathan worked for the Environment Agency as a Senior Advisor and Development & Flood Risk Technical Specialist, reviewing flood risk assessments submitted by consultants in support of planning applications, advising planning authorities of their fitness-for-purpose, working with local authorities on Strategic Flood Risk Assessments and attending hearings and public inquiries as an Expert Witness on flood risk and environmental matters. As such you can be confident that we know what constitutes a high quality flood risk assessment!

 

Flood Risk Assessment

brochure (pdf)

Aside from the technical work, a key part of our service lies in the advice we give to developers, architects and planning consultants during the process- sharing knowledge gained from years of experience in flood risk management.

 

We offer three levels of assessment, following DEFRA and CIRIA guidance in our methodology, and where possible we take a 'phased approach' which breaks the process into stages. This enables us to minimise costs by avoiding unnecessary work, and allows decisions to be made about how best to develop a site as the flood risk analysis progresses.

 

We can also limit the flood risk assessment to a consideration of surface water drainage for those sites where fluvial and coastal flood risk is not an issue.

 

Understand the limitations!

We offer a professional, bespoke service, supporting people  through the entire planning process. We do not churn out generic flood risk assessments with little valuable content, or make promises to resolve flooding issues on a development site within 24 hours without even contacting the risk management authorities for data. This is not our market!

 

 

 

Importantly, we always stress the need to be realistic: some proposals will be fine once the flood risk has been fully investigated, other proposals may simply be incompatible with the risk of flooding and may need to be changed. We will always give honest, realistic advice from the very outset, because the last thing we want to see is people investing time and resources in proposals which the National Planning Policy Framework will not allow on flood risk grounds. This is why we advocate a phased approach to flood risk assessment.

 

 

 

Our particular expertise is in those borderline cases (and there are many) where technical analysis can improve the understanding of flood risk, or where creative design can mitigate the problems. This is where our unique experience gained with the Environment Agency really adds value. We are always happy to discuss sites, and to give informal advice on the most appropriate type of flood risk assessment for a development site.

 

Planning

policy

Hydraulic

modelling

Surface water

drainage

Climate

change

Cost: £400-500 inc VAT

Cost: site specific

Cost: site specific

Hydraulic Modelling

We have extensive experience in hydrological analysis and hydraulic modelling, ranging from small urban watercourses to some of the UK's largest and most complex river systems.

 

Flood Modelling

We can undertake flood modelling using a variety of 1d, 2d and hybrid methods to establish flood levels, extents, depths, velocities and hazard ratings for flood risk assessments, flood mapping studies and flood alleviation projects.

 

 Our capabilities include re-running existing complex models (e.g. Environment Agency, Local Authority or IDB) to test new development proposals, and in some cases improving those models to define local flood risk in more detail. We can also use these models to test extreme events such as overtopping and flood defence breach scenarios.

Flood Map Challenges

The flood zone maps used by planning authorities for assessing development proposals are derived from a range of sources. Most flood risk mapping is undertaken at a strategic scale and is based on LiDAR (remotely sensed ground level data). In some cases it may be possible to refine the flood maps locally through topographic survey data, or hydrodynamic river modelling. We understand the processes involved and have the technical capability to supply mapping to the standards required to enable the Flood Map for Planning to be updated. However, landowners and developers should always be aware that more detailed analysis could show the extent of flood risk to increase rather than decrease! This is a field where expert judgement is required.

Hydrological Studies

Our hydrological studies are undertaken in accordance with the UK Flood Estimation Handbook and Environment Agency guidelines. This includes statistical methods, rainfall-runoff modelling, direct rainfall modelling, and complex approaches for dealing with highly urbanised catchments as well as methods used more widely outside the UK. We are active participants within the field of hydrological science.

Flood Risk Sequential Test

When developing a site in an area known to be at risk of flooding, it is first necessary to demonstrate that the site passes the 'sequential test' set out in the NPPF. The purpose of the sequential test is for Planning Authorities to direct development towards areas of low flood risk, and only when such sites are not available should sites at a higher risk of flooding be considered. The test is undertaken against all reasonably available sites, not just those within the same land ownership.

 

 We can contact local planning authorities and gather evidence for submission of a sequential test assessment. Our capability in flood modelling and familiarity with flood map challenges can help with the flood risk sequential test, if it is found that the flood zone maps are inaccurate.

 

Other Flood Risk Management Services

Third party (peer) reviews of flood risk assessments, hydrological studies and hydraulic models

Flood risk mapping and appraisal

Additional support for modelling projects

Specialist hydrological input for complex catchments

Rating reviews

Scoping reports for modelling studies

Expert witness services

Contact us for more information on flood risk assessments- we would be pleased to discuss your project

Riverscape

 

Riverscape Environmental Consultants Ltd

128 Forest Road, Leicester, LE19 3ET

Registered in England 10310178

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