Volume 1 – Overview
Volume 1 contains an overview of the procedures, a summary of how the methods differ from earlier guidance and an introduction to the data and software accompanying the Handbook. It includes important guidance on the choice of method to address a specific flood estimation problem. Later chapters are either topic-oriented or essentially informative. The last section presents a UK-oriented bibliography of technical guidance in the many environmental planning and engineering issues that impinge on flood defence.
Volume 2 – Rainfall frequency estimation
Volume 2 presents the methods for estimating rainfall frequency in the UK. The user obtains results from a model of rainfall depth-duration-frequency. There is a description of the underlying research, illustrations of the results and information on rainfall data. The Volume 2 procedure is built on rainfall growth factors, which relate the rainfall depth of a given return period to an index variable. Growth factors derive from the Focused Rainfall Growth Extension (FORGEX) method, which gives precedence to rainfall extremes observed locally and takes account of inter-site dependence in rainfall extremes to obtain estimates for long return periods.
Volume 2 also gives guidance on applying an areal reduction factor and in choosing a design storm profile: these are required when deriving flood estimates by the rainfall-runoff method.
The parameters of the depth-duration-frequency model and estimates of design rainfall are provided on the FEH CD-ROM, available separately.
Volume 3 – Statistical procedures for flood frequency estimation
Volume 3 presents statistical procedures for using observed flood data to address such questions as “How rare was that flood?”, or “How big is the expected 100-year flood?”. The methods develop a flood frequency curve which shows the relationship between flood size and flood rarity. Where long flow records are available, the flood frequency curve can be estimated using flood peak data from this site alone. More commonly, where the site is either ungauged or has insufficient flow records for design, the flood frequency curve is estimated using data pooled from a group of similar sites.
Methods are presented for selecting appropriate gauged sites for pooling and for combining the data. Procedures for urbanised catchments are also described. Volume 3 statistical methods are implemented within the WINFAP-FEH* software package together with improvements made to the original methods by the CEH research team since the original publication of the handbook.
Volume 4 – Rainfall-runoff method
Volume 4 has been largely superseded by the development of ReFH and its associated publication, the FEH Supplementary Report No. 1. Volume 4 presents a comprehensive re-statement of the Flood Studies Report rainfall-runoff method including a set of updated equations to allow the method to be used with digital catchment descriptors.
Volume 5 – Catchment Descriptors
Volume 5 presents a detailed description of the development and derivation of the catchment descriptors included within the FEH CD-ROM and an introduction to the software. Also included is an appendix listing values for 20 descriptors at the 943 gauged catchments used in the development of the parameter estimation models.
*Sales and support of the Flood Estimation Handbook and related software are provided by Wallingford HydroSolutions. Links to buy these products will take you to an external website.
