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R&D TECHNICAL SUMMARY W5C-013/5/TS/1 R&D Technical Summary W5C-013/5/TS/1 Fluvial Flood Forecasting for Flood Warning Real Time Modelling Background to R&D project The Agency aims to deliver accurate, reliable and timely forecasts of flooding at locations in England and Wales where the benefits justify the costs and where the provision of this service is technically possible. There are several R&D projects helping to further this aim covering different sources of flooding - estuarial, fluvial and coastal. The estuarial project is complete and was reported on in R&D Technical Summary W5-010/TS/3. The project covering coastal flood forecasting is due to report later in 2003. The fluvial flood forecasting project comprises two components - Rainfall Measurement and Forecasting (RMF) and Real Time Modelling (RTM). This Technical Summary covers the RTM component; the RMF component is reported on separately in R&D Technical Summary W5C-013/4/TS/1. In addition, Guidelines have been produced covering both RMF and RTM. These are published separately but referred to in the Technical Summaries for completeness. Results of R&D project The project carried out a review of current forecasting methods and problems and produced guidelines for the selection of real time models for the use of flood forecasting staff. Technical Report W5C-013/5 This report provides supporting material used in preparation of the Guidelines for RTM together with a summary of priorities for future R&D in RTM. The report also describes modelling studies performed during this project into the impacts of uncertainties in rainfall and other input data on the accuracy of flood forecasts. The main topics considered in this report are: • A description of existing flood forecasting approaches currently used ranging from simple relationships such as level correlations and time of travel relationships, though to rainfall runoff models, hydrological routing and hydrodynamic routing models. The assumptions and ease of use of each approach are also identified. • An overview of forecast uncertainty and a description of the practical approaches that can be adopted to minimise uncertainty in flood forecasts (e.g. model updating), together with a summary of exploratory modelling studies into the magnitudes of some of these effects. • The main forecasting problems identified by Agency staff. • The technical background to the Guidelines for RTM. The report considers a number of issues which are relevant to RTM including the indicative accuracy of models, methods for evaluating model and overall forecasting system performance, approaches to dealing with uncertainty, how errors in data, forecasts etc propagate through to flow forecasts and current active research areas in RTM. The report summarises the main conclusions for the categories of model defined currently in operational use within the Agency and includes findings on a range of other issues such as post event analysis and error propagation. Defra / Environment Agency Flood and Coastal Defence R&D Programme
Transcript of Fluvial Flood Forecasting for Flood Warning Real Time ... · for Flood Warning, Head Office,...
R&D TECHNICAL SUMMARY
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Defra / Environment Agencyd Coastal Defence R&D ProgrammeW5C-013/5/TS/1
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od Forecasting for Flood WarningReal Time Modelling
taccurate, reliable and timely forecasts of flooding at locations in benefits justify the costs and where the provision of this service ise several R&D projects helping to further this aim covering differental, fluvial and coastal. The estuarial project is complete and wascal Summary W5-010/TS/3. The project covering coastal floodater in 2003. The fluvial flood forecasting project comprises tworement and Forecasting (RMF) and Real Time Modelling (RTM). vers the RTM component; the RMF component is reported onl Summary W5C-013/4/TS/1. In addition, Guidelines have been and RTM. These are published separately but referred to in thepleteness.
view of current forecasting methods and problems and produced real time models for the use of flood forecasting staff./5ng material used in preparation of the Guidelines for RTM togetheror future R&D in RTM. The report also describes modelling studies into the impacts of uncertainties in rainfall and other input data ons.
this report are:
flood forecasting approaches currently used ranging from simple correlations and time of travel relationships, though to rainfall runoffting and hydrodynamic routing models. The assumptions and easere also identified. ncertainty and a description of the practical approaches that can beertainty in flood forecasts (e.g. model updating), together with aodelling studies into the magnitudes of some of these effects.
blems identified by Agency staff. to the Guidelines for RTM.
er of issues which are relevant to RTM including the indicative for evaluating model and overall forecasting system performance,certainty, how errors in data, forecasts etc propagate through to flowsearch areas in RTM.
ain conclusions for the categories of model defined currently inency and includes findings on a range of other issues such as post
agation.
R&D TECHNICAL SUMMARY W5C-013/5/TS/1 Science Product Code: SCHO0405BJAR-E-P
Guidelines for Real Time ModellingThe Guidelines provide a structured decision making framework for selecting real time models fora given Flood Warning Area accounting for:
• Agency targets for flood warning systems• Different physical types of catchment and river, including floodplains and control structures• The varying levels of data availability and quality• The levels of risk and the consequences of error• The cost and time of developing or improving a system
Guidance is also provided on real time updating methods, post event evaluation criteria, and on theneed for model recalibration after significant flood events. The Guidelines include a methodology(similar to that developed for the estuarial project covered by R&D Technical Summary W5-010/TS/3) to allow estimates to be made of the potential benefits of improved forecasts throughdamage avoidance. The Guidelines are maintained by and available from the Technical Managerfor Flood Warning, Head Office, Environment Agency.
R&D Outputs and their use The Guidelines are aimed primarily at Agency staff having some hydrological expertise that areresponsible for designing, commissioning, managing, operating and maintaining real timemodelling systems. The Guidelines are supplemented by the Technical Report and it may also benecessary to refer to the Guidelines for RMF for information on topics such as best practice use ofweather radar or raingauges. The Technical Report will be of interest to all involved in operationalreal time flood forecasting modelling. Based on the modelling studies the Technical Report offersa possible way of thinking about the relative magnitude of the various errors and uncertainties andhow they propagate through to errors or uncertainties in forecasts of levels. Although the finalresults are only indicative they may be useful in focusing attention on the aspects of a model whichgenerate the largest uncertainty.
This R&D Technical Summary W5C-013/5/TS/1 relates to the Guidelines for Real Time Modellingand Forecasting and R&D Technical Report W5C-013/5 – Fluvial Flood Forecasting for FloodWarning: Real Time Modelling. Published February 2003.
Publication Status : Unrestricted Report Product Code: :SCHO0405BJAQ-E-P
The Environment Agency’s Project Manager for Project WSC13/4 was Andrew Grime ofWeetwood Services, Tarporley, Cheshire CW6 0NQ Tel/Fax: (+44) 1829 752500 Email:[email protected] Website: www.weetwoodservices.demon.co.uk
This document was produced under R&D Project W5C-013/5 by WS Atkins Consultants Ltd.,Woodcote Grove, Ashley Road, Epsom, Surrey, KT18 5BW Tel: (+44) 1372 726140 Fax: (+44)1372 740055 Website: www.atkinsglobal.com
Copies of these documents can be obtained from the Environment Agency's National Customer Contact Centre Email: [email protected] Tel: 08708 506 506 orthrough the Environment Agency's Science publication catalogue http://publications.environment-agency.gov.uk/epages/eapublications.storefront. Alternatively they may be downloaded from theDefra FCERM Programme website www.defra.gov.uk/environ/fcd/research.
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