The Flood Risk Assessment (FRA) reviews a proposal of development to evaluate the risk of flooding. The risk does not just come from groundwater sources or river sources (fluvial), but also includes sources such as the estuary/coastal, sewer sources and surface water (pluvial).
Flood Risk Assessments are typically required prior to the planning process – if a development is located in an Flood Zone or other at-risk area, it is likely that planning permission won’t be validated without one.
When Is an Flood Risk Assessment Required?
The Environment Agency in England and Wales requires that an expert Flood Risk Assessment be submitted with planning applications for zones at risk of flooding. If the proposed development falls within 20m of the Environment Agency main stream, you’ll need an Assessment of Flood Risk.
You can search on the gov.uk website to determine whether your home is within a flood zone, or what the flood zone is.
The Environment Agency states that:
It is essential to complete an assessment of flood risk for all developments located within one of the zones of flooding.
This covers developments
In flood zone 2 or 3, with minor development and changes of use.
More than 1 hectare (ha) in the flood zone 1
A little less than 1 hectare in flood zone 1 including the possibility of changing the development type to a more vulnerable category (for instance, from commercial to residential), where they could be affected by flood sources other than sea and rivers (for example , surface water drains, reservoirs); and
In a zone within flood zone 1 which has drainage issues that are critical according to the Environment Agency.
It is also recommended that you consult your local planning authorities to verify if the location is located within an area that has been identified as having critical drainage issues.
How Is a Flood Risk Assessment Formed?
Flood Risk Assessments are constructed using data from third-party sources. The sources of these data could include data from the Environment Agency modelling or data that the consultant has collected on their own. An analysis of the data sets will be undertaken to get a full overview of the site and any flood-related dangers identified.
What Factors can Influence Flooding?
Flooding is influenced by a variety of factors, including:
Surface run-off of water
Local topography
the proximity of rivers and coastlines
geology
Groundwater
Current land use
existing drainage
mines
quarries
hardstanding
vegetation cover
rainfall levels
What is Drainage Design/Strategy and what can it do?
Of course one of the primary requirements of the Flood Risk Assessment is to make sure (and be able to demonstrate) that the proposed development will not result in an increase in flood risk elsewhere.
The Local Planning Authority will likely require an Drainage Strategy in this case.
This could be sites that aren’t located within an area of floodplain (river or coastal).
It is necessary to make sure that run-off from the development in question will be minimized.
What can we do to help?
We provide levels 1 as well as 2 Flood Risk Assessments.
Find out if any flooding that is caused by the development site warrant more investigation;
Identify whether the area is at risk of flooding.
Identify whether the site may increase the risk of flooding due to increased run-off;
Check for flooding sources.
Evaluate the accuracy and accessibility of existing information;
Assess the flood risk in an area and the effects of flooding elsewhere.
Evaluate the scope of appropriate design for development, and plan any additional work that is required.
How We Are Qualified To assist you
‘Non-Professional’ Flood Risk Assessments can be prepared by those who aren’t educated or professionally certified in this field. However the nature of the Flood Risk Assessments can make them difficult to evaluate. Authorities may reject evaluations which do not cover all flooding scenarios. This can lead to lengthy delays between the approval of the plan and the beginning of work.
A faulty Flood Risk Assessment can lead to a lawsuit for negligence against the builder should there be a devastating flood event.