Flood Modelling
Flood modelling is becoming a significant tool in the way that we can develop an understanding of the mechanisms that cause flood problems. This is essential in preparation both Strategic Flood Risk Assessments (SFRA) and Site Specific Flood Risk Assessments (SSFRA) under PPS25.
As computers have become more powerful, software has been developed to aid us in predicting the likely extents and severity of flooding, whether from rivers and culverts not being able to cope with rainfall events or from breaches in existing tidal defences, flood modelling has proved to be an essential tool in our work as engineers and hydrologists.
The Flood Estimation Handbook provides guidance on estimating the magnitude of floods and river hydrology. There are a number of methodologies within the FEH (and subsequent guidance from DEFRA/CEH), which we can call upon to develop our understanding of the way sites within the UK behave following the more significant rainfall events. At CES we use our technical knowledge and experience to obtain the best possible estimation of flows from the available data.
Flood modelling has also benefited considerably from the data obtained by the Environment Agency over recent years:
River flows are measured using gauging stations all over the UK, this data set is available for download from the Environment Agency Hiflows website. In excess of 30 years worth of river data is available for many sites which helps us greatly in our work;
LIDAR (LIght Detection And Ranging) information has been gathered by the Environment Agency for many flood risk sites in the UK. This data set allows us to prepare high resolution and accurate models of the ground levels within our flood risk site. This sis used by our software to predict how the water travels overland when it starts to flood out of a river, culvert or over a coastal flood defence system.
At CES we use some of the most sophisticated hydrodynamic and mapping software available to provide the best possible advice/information on likely flood risk to specific areas. The following is an example of some of the software that we currently use:
- TUFLOW – Two-dimensional Unsteady FLOW hydrodynamic modelling software.
- HEC-RAS - From the United States Army Corps of Engineers. One-dimensional hydrodynamic modelling software for rivers and flood areas.
- ISIS – One dimensional river analysis software.
- InfoWorks RS by Wallingford Software, UK.
- MapInfo Professional – GIS mapping and database.
- WINFAP FEH and FEH CD ROM - from the Centre for Ecology and Hydrology, Wallingford.
We are able to provide a number of modelling solutions and are not simply intent on using just one programme. This allows us to provide our clients with the best modelling for their specific needs. This obviously helps to keep costs to a minimum.
