Hydrologists and modellers from CEH, Wallingford Hydrosolutions, and NRFA will exhibit at the forthcoming Flood and Coast 2017 Conference in Telford (28-30 March 2017).
The material presented will focus on recent developments and improvements to the CEH Flood Estimation Handbook (FEH) and its related software. The FEH offers guidance on rainfall and river flood frequency estimation in the UK. Flood frequency estimates are required for the planning and assessment of flood defences, and the design of other structures such as bridges, culverts and reservoir spillways.
Recent developments in flood frequency estimates:
- Reducing uncertainty in flood frequency estimation and enhancing standard statistical methods by including historical and local data (FEH Local). New data obtained from careful exploration of archives, old newspapers, flood marks or other signs of past flooding can be used to augment traditional gauged data. The inclusion of historical data in flood frequency estimation has been shown to substantially reduce the uncertainty around estimated design events. The work was carried out in collaboration with JBA Consulting, who also managed the project, the University of Bath and the University of Aberystwyth. The project was funded by the Environment Agency.
Estimation of the T-year flood in the UK using wide-area continuous hydrological modelling. A new methodology is being used to estimate floods of return periods from 2 to 100 years at national scale based on continuous simulation from a physically-based hydrological model (Grid-to-Grid). The figure shows the index flood (2-year return period flood) estimated for Great Britain at 1 km2 resolution. The results show promise and support the aspiration that continuous simulation from large-scale hydrological models, coupled with the increasing availability of global weather and climate products, could be used to estimate design floods in regions with limited gauge data or affected by environmental change.
FEH Software Updates:
Since May 2016, the FEH Web Service has included a point data download facility for the rainfall, soil and climate information needed to apply FEH methods to drainage design. The new product allows drainage engineers, SuDS practitioners and developers to better assess suitable drainage design and development viability. It gives access to the latest methodology for rainfall estimates (FEH13), and soil and climate properties for any point on the land surface. It works alongside the standard fluvial catchment data retrievals from the FEH Web Service.
ReFH 2.2 developed by Wallingford HydroSolutions is the latest version of the Revitalised Flood Hydrograph (ReFH) model. New features have been added to the software to support drainage design, importing the new point rainfall and catchment descriptor data feeds from CEH’s FEH Web Service.
WINFAP 4 developed by Wallingford HydroSolutions uses the latest Flood Estimation Handbook methods to provide estimates of peak flows and flood frequency curves for gauged and ungauged catchments. The software includes revised FEH statistical procedures that make use of local data to reduce uncertainty in flood frequency estimates