Overview of Flood Risk Assessments (FRA)
The Team at Gondolin have extensive experience undertaking Flood Risk Assessments across all Sectors in the UK, Ireland and internationally. In many circumstances, the need for a FRA should be reviewed in accordance with national and local guidance and policy. The level of assessment differs from project to project and our approach is site-specific and commensurate with the scale of each project. Examples of the level of detail provided within our Flood Risk Assessment offering, dependent on the identified flood risk, are summarised below.
Level 1 Flood Risk Assessments
The team are well versed in preparing Flood Risk Assessments required for planning applications which identify no significant flood risk. These assessments are undertaken as a high-level desk based review of available information to determine the level of risk associated with all sources of flooding. These assessments may include the review of available flood mapping, historic flood data, topographic data, sewer plans etc. This would be considered a Level 1 FRA.
Level 2 Flood Risk Assessments
For sites where potential flood risks are identified, Gondolin can prepare a qualitative and semi-quantitative assessment to understand the potential flood risk more accurately. The outcome of this type of assessment will either be, demonstrating that the perceived flood risk is in fact less than the initial high level review would indicate, or a flood risk is present and information regarding flooding extents / depths and relevant mitigation measures would be provided. These assessments may include hydrological analysis, high-level calculations and review of regulator flood modelling data. This would be considered a Level 2 FRA.
Level 3 Flood Risk Assessments
For sites where site-specific modelling of the flooding source is required, Gondolin have in-house capability to undertake detailed flood risk assessments. These detailed studies may include but are not limited to:
- 1D/2D hydrodynamic flood model (fluvial and/or coastal)
- Drainage network model
- Groundwater model
- Surface water flood model
- Integrated Catchment Modelling (ICM), which is a combination of any of the above
Given that the team regularly undertake assessments of varying level of detail we have developed a robust knowledge and understanding of local and national guidance requirements across the UK, Ireland and internationally. The team have access to the latest industry standard flood modelling software endorsed by stakeholders and regulators. Our knowledge of relevant guidance material and experience with flood modelling software enables us to confidently undertake even the most complex Flood Risk Assessments. A notable Flood Risk Assessment recently completed by the Team and accepted by relevant stakeholders included the bespoke hydraulic modelling of a large stretch of the River Clyde including some of its major tributaries. This type of assessment would be considered a Level 3 FRA study.
Expertise in Flood Modeling Software
Our hydrologists are experienced in the use of industry standard flood modelling software such as TUFLOW, Flood Modeller Pro and HEC-RAS to develop 1D, 2D and linked 1D-2D hydraulic flood models and derive design flood flows using UK standard methods such as WIN-FAP, ReFH and FEH methods.