Houghton-Carr, H.A.

English

NERC Open Research Archive

HydrologyARCHIVE:I ci JooInstitute of CcNiaiPLEASE DO NOT DESTROYNatural Environment Research Council••NaturalEnvironmentResearchCouncil I••••••••PROJECTFD0403ARCHIVEOFRUNOFFANDRAINFALLDATA•UK FLOODEVENTARCHIVEANNUALREPORT••H.A.HOUGHTON-CARR••••This report is an official documentpreparedunder contract between the Ministry ofAgriculture, Fisheries and Food and theNatural Environment Research Council. Itshould not be copiedwithoutthe permissionofboththe Instituteof Hydrologyand theMinistryof Agriculture.Fisheriesand Food.9lnsdtute of HydrologyCrowmarsh GiffordWallingfordOxfordshireOX 10 8BBUK•Tel:0491 838800Fax: 0491 832256Telex: 849365 Hydrol G•March 1993•••••••••••••••••••••••••••••••••••Executive summary•The MAFF-supported UK Flood Event Archive at the Institute of Hydrology is a uniquecollection of flood event and catchment data for hydrological studies.•The archive currently contains 4448 flood events from 308 catchments throughout the UK.In the past year analysis has been completed on 442 flood events, and is continuing onanother 132. Descriptive summaries, data and results from the project are published in thefive-volume Representative Basin Catalogue for Great Britain. Since the catchment entries inthe catalogue are collated and printed automatically from data stored in the archive, theinformation presented will change with time as existing data are reviewed and updated, andas new data and new facilities are added to the archive. There are currently 129 catchmentsdesignated 'representative basins', five of which have been designated within the past year.Another four potential representative basins are awaiting confirmation. The number ofrequests for data from the archive has increased following publications of the RepresentativeBasin Catalogue and the higher profile given to the archive by the Institute of Hydrology.The collection, processing and analysis of flood event data and the review of therepresentative basin network will continue through 1993.•••••••••••••••••••••••••••••••••••••••••ContentsPage• I. INTRODUCTION I•2. BACKGROUND I•• 3. FLOODEVENTARCHIVE 4••4. REPRESENTATIVEBASINCATALOGUE 4•5. PUBLICATIONS 5•• 6. SUMMARY 6••7. REFERENCES 60•••1 Introduction•The MAFF-supported UK archive of runoff and rainfall data at the Institute of Hydrology isan outstanding example of the many large datasets available to hydrologists. The archive,known at the UK Flood Event Archive, is a unique collection of flood event and catchmentdata held on an ORACLE relational database management system on an IBM 4381 mainframecomputer. The archive contains details of nearly 4500 flood events from more than 300 UKcatchments and is used extensively, not only to support flood modelling studies at theInstitute, but also by National River Authority (NRA) regions, Scottish River PurificationBoards (RPBs), consultancies and universities for a broad range of scientific and engineeringapplications.The year 1991-2 saw the successful launch of the five-volume Representative Catalogue forGreat Britain (Boorman et al, 1991), the publication of a publicity brochure promoting theproject to the hydrological community (Boorman et al, 1991), and the presentation of a paperabout the archive and catalogue at the British Hydrological Society's Third NationalSymposium in Southampton (Houghton-Carr & Boorman, 1992). This annual reportsummarises the achievements of the project in the past financial year 1992-3.After this introduction the report is divided into five sections. The first section considers thebackground to the archive and to the Representative Basin project. This is followed by asection devoted to the archive, and containing details of the numbers of events analysed inthe past year. Section three is correspondingly focused on the Representative Basin project.The fourth section describes the publications from the project. In the final section theprogress of the project is summarised, and the proposed work in the next financial yearoutlined .2 Background•The requirement for an archive of flood event data at the Institute of Hydrology came fromthe Flood Studies project which began in 1969 and required data from many catchmentsthroughout the UK. The Flood Studies Report (FSR) was published by the NaturalEnvironment Research Council in 1975, and has been augmented by 18 supplementary reportspublished by the Institute of Hydrology between 1977 and 1988. However there are stillmany uncertainties involved in flood estimation, and a need for great knowledge andunderstanding of the physical processes involved. This MAFF project is one of several piecesof research being conducted at the Institute of Hydrology, with the aim of improving on themethodologies of the FSR and subsequent supplementary reports.•The objective of the project is to assemble a national archive for the development of rainfall-runoff modelling for flood hydrology, and the project supports project FD0404 on floodhydrograph estimation procedures. The project achieves this goal through the collection.processing and analysis of runoff and associated rainfall data from past flood events. A floodevent is essentially defined as a rise and subsequent fall in the river level, together with thecausative catchment rainfall. Figure 2.1 is a standard retrieval from the archive illustratinga typical flood event. River discharge is plotted against time to depict the catchmenthydrograph, and hourly rainfalls through the event are plotted as hyetographs of bothcatchment average and point estimates.••OBSERVED HYDROGRAPH AND RAINTALLrum norr Iaus UMW CATCHINT C. 23000 CCM 143. 4232 Mt071C1, PINT Ti..d 11.1•11 InsSCUM TINE AT rEAT10ERsTDWIIKA mar, m' Dor 01-7/44-02I.4 I..0maws.. In•me •InnIII 1 1 2.v.r31o.0 MS120.•2.O..00. 02 07ono atoms enFigure 2.1 A typical rainfall-runoff eventDay-today work entails liaison with gauging authorities to discuss catchment selection, datatransfer and future data requirements, as well as collection, processing and analysis of floodevent data and evaluation of results. The collection of high quality runoffand rainfall dataremains at the heart of this project, and gathering the data together from many different data •suppliers, abstracting the particular periods of interest and collating the various data types isinevitably a time-consuming process.•Catchments appear in the Representative Basin Catalogue for Great Britainif flood event dataare held at the Institute of Hydrology or if the catchment has been identified as one whichcould supply good quality data in the future. The five-volume catalogue of 333 catchmentsincludes not only details of the flood events, but also the descriptions andstatistics necessaryfor a full understanding of their hydrological regimes. Figure 2.2 shows the locations of therepresentative basins and other catchments with flood event data in the UK. The data fromthe network provide a ready-made, long-term resource that will enable flooddefence projectsto make rapid progress during the currently time-consuming phases of catchment assessmentand data preparation. Catchment entries in the catalogue are collated and printedautomatically from data stored in the archive, so the information presented will change withtime as existing data are reviewed and updated, and as new data and newfacilities are addedto the archive.•The motivation behind establishing a network of representative basins is threefold. Firstlya full range of catchment types is necessary to understand the variability of hydrologicalprocesses, and by promoting the idea of a Representative BasinCatalogue and the uses thatcan be made of it, gaps in the geographical coverage and in the range of catchment types•2•mID •.ID KEY41110 • Reprnentot ive begins1,9i lor vs	151/40 Other sites •Itli 15 or more eve411/a a • , x Other sites •ith 1 — 14 snots0 0••K ill., 3 . ..... •. 0°•00us•0 •„wx •Is	 wx • • x 00 pa XII II • KXX..0 • 00 X X41 itXaxKlc ES x xW 0•o10•XRex .X K- x8 x x xX X x aft N X @• K.• •. so K• •xx • CPli . ' 01• 1 It 0• xl• la X tt ••XXX • W X	KKO:•0 • •• I s • _xa	U'I4s • '• x •0•• • •40• 95OCII0 •I x • 0•x•••I .,ir . ttIISco l• — 1:5 000 00000 Figure 2.2 Map showing the distribution of catchments0030••represented will be highlighted and hopefully filled. The second reason is to ensuremaintenance by gauging authorities of a least a minimum set of gauges that can characteriseboth rainfall patterns and flow regimes. Finally the project highlights the requirement forhigh quality, long term flow and rainfall records at a variety of resolutions for both regionaland national strategic studies.•3 FloodEventArchive•The UK Flood Event Archive currently contains 4448 events, the majority of which are fairlysimple short duration rainfall-runoff events of the type used for the FSR, and illustrated inFigure 2.1. In the past year, analyses have been completed on 196 events fromNorthumberland, 139 events from southwest England, 96 events from eastern England, andI I events from northeast Scotland. Analyses are continuing on 95 events fromNorthumberland and 37 events from the Welsh Borders region. Although the majority ofevents have return periods of less than 10 years (Houghton-Carr, 1990), when a substantialflood does occur, efforts are made to collect and analyse the flood event data. Analysis hasrecently been completed on the February 1990 flood on the Tay river system in Scotland(Houghton-Carr & Boorman, in press). This was an extreme flood event with lesscomprehensive raingauge coverage and a snowmelt component, but can nevertheless easilybe accommodated within the archive framework.Figure 3.1 shows the distribution of event dates with a breakdown according to the projectfor which they were collected, though of course once entered on the archive events may beused for many different projects. Results from analyses are also stored on the archive andit is very easy, using Standard Query Language (SQL), to access these data in any numberof ways and to select them according to many different criteria.••4 RepresentativeBasinCatalogue•There are currently 129 catchments designated 'representative basins' and 209 othercatchments with flood event data on the archive. The designation of representative basins wasmade in conjunction with gauging authority staff during the early 1980s, This designationrequires reappraisal, and the past year saw the start of this review process in consultation withthe gauging authorities, with the first edition of the catalogue providing the basis fordiscussion. The Scottish RPBs are particularly enthusiastic, and to date two of the seven RPBregions have been formally reviewed. An additional five basins (included in the 129 totalabove) have been designated in Highland RPB region to join the two already there, and fourothers have been earmarked in North-East RPB reeion where there were formerly none.awaiting confirmation of the installation of new recording raingauges. The review willcontinue through 1993, concentrating mainly on the ten NRA regions of England and Wales.• The response to the Representative Basin Catalogue from the hydrological community hasbeen eood. The five volumes of the catalogue are available individually or as a set, and to0411111FSRFSSR160 Other protects4W7 evade prior to 1955Figure 3.1 Distribution of flood events by date and project•ensure up-to-dateness individual catchment entries may also be obtained. Volumes of thecatalogue have been distributed to MAFF regional engineers, and the catalogue has beenpromoted to the NRAs and RPI3s, several of whom have purchased the volumes for theirparticular region.•5 Publications•Inevitably the past year could not be as productive as the previous one in temis ofpublications. Apart from this annual report, there are two publications from the project. Thefirst of these is another edition of the UK Representative Basin and Flood Event DatabaseManual which is a comprehensive guide to the Flood Event Archive and the analysisprograms (Boorman & Houghton-Carr, 1992). The second publication is the report on thefloods on the Tay river system in Scotland in February 1990 (Houghton-Carr & Boorman,in press) which also lists other references to Tay flood research. In view of the recent andeven larger flood in January 1993 a similar study needs to be undertaken.1955 1980 1985 1970 1975 1980 1985 1990Year of record30056 Summary•The UK Flood Event Archive at the Institute of Hydrology is a unique collection of floodevent and catchment data for hydrological studies. One of the principal objectives of thearchive project is to extend the number of catchments for which large numbers of events areavailable and to increase the range of catchment types represented, in order to understand thevariability of hydrological processes and improve the accuracy of design flood estimationusing rainfall-runoff modelling techniques. Another objective is to incorporate more datadescribing extreme flood events within the archive e.g. all floods of return period greater that25 years. The final objective is to maintain the continuity of data collected by a number ofoperators and promote the value of longer-term data. With the current uncertainty over howthe climate may be changing, it is essential that these strategic data sets are established andmaintained efficiently. The number of requests for data from the archive has increasedfollowing publication of the Representative Basin Catalogue and the associated publicity.Future data requirements from the representative basin catchments are likely to focus on long-sequences of daily or sub-daily rainfall and runoff data for continuous simulation models.Such models will be an exciting prospect for the future, providing another investigative routefor flood hydrograph estimation, and the necessary data will be easily incorporated within thearchive framework, whilst.maintaining the current facility to isolate individual flood events.The archive has capitalised directly from advancements in database management systems,digital mapping and information technology within the computer industry. The latest stepwithin this process is movement from an IBM 4381 mainframe to a workstation-based UNIXenvironment in May 1993. Computing power and graphical capability will be significantlyenhanced, but some of the archive's software will need considerable modification to operatesuccessfully under the new system. Many additions to the Representative Basin Catalogueand improvements to the existing components will be made after the transfer. The prioritiesfor publication after transfer will be a new edition of the database manual and a secondedition of the catalogue. Progress will be described in the next annual report.The project had no progress milestones to meet in 1992-3, but now looks forward to fulfillingthe December 1993 milestone of completing the review of the representative basin network.the progress of which will again be described in the next annual report. An additionalmilestone for March 1994 is a study of the feasibility of adding radar rainfall to the archive.This development would provide the opportunity to evaluate rainfall over poorly instrumentedcatchments, with the possibility of analysing otherwise unusable flood events.••7 ReferencesBoorman, D.B., Clayton, M.C., Gannon, B. & Houghton-Carr, H.A. 1991. RepresentativeBasin Catalogue for Great Britain. Institute of Hydrology. Wallingford.Boorman, D.B., Clayton, M.C., Gannon, B. & Houghton-Carr. H.A. 1991. UKRepresentative Basin and Flood Event Data. Institute of Hydrology, Wallineford.•Boorman, D.B. & Houghton-Carr, H.A. (ed.) 1992. UK Representative Basin and FloodEvent Database Manual. Institute of Hydrology Report to MAFF, Wallingford.•6••Houghton-Carr, N.A. 1990. Investigation of Event Periods. Institute of Hydrology, AppliedHydrology Informal Note No. I I, Wallingford.Houghton-Carr, H.A. & Boorman, D.B. 1991. A national archive of floodevent data forthe UK. BHS Third National Hydrology Symposium, Southampton.Houghton-Carr, N.A. & Boorman, D.B. (in press). The floods of February 1990 on the Tayriver system, Perthshire. Institute of Hydrology Report to MAFF, Wallingford.Natural Environment Research Council 1975. Flood Studies Report. NERC, London.7

UK flood event archive annual report

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UK flood event archive annual report

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