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TRANSBOUNDARY WATER MANAGEMENTImage: CHRImage: CHRRiver regulation works in the Lütschine basin in SwitzerlandThe works in the Polder Ingelheim, north of Mainz in GermanyThe starting point for morphological analyses is bed level surveys.These are combined with sediment transport measurements in orderto get data on the sediment load and on the mechanism of sedimenttransport. Echo soundings and transport measurements willnot answer questions such as where the sediments come from andwhere are they going, or how changes in one part of the catchmentare related to other regions. Therefore, a sediment budget is needed,incorporating the collection of data and analyses to check the qualityof measurements and available datasets, fill in the data gaps andidentify sources and sinks. This action incorporates quite a challengebecause maximum data density is found in the navigation channelbut data density is at a minimum next to the navigation channel, infloodplains and groyne fields and at tributaries. Another challenge liesin the varying quality and methods used in the several river reachesand countries. Due to the number of existing gaps (data, data gapsand a need for regional data), a variety of assumptions were made.A strategy has been developed based on a status quo combined withideas on how to improve the situation around the gaps.Continuation of the RheinBlick2050 study is planned under theumbrella of ‘Climate impact studies in the Rhine basin’. Comparedto the regional climate models used in RheinBlick2050, 5 there isnow a much larger ensemble (~200 runs) of new global climatemodels available in the Coupled Model Intercomparison ProjectPhase 5 (CIMP5) data repository. These models are also used forthe Intergovernmental Panel on Climate Change (IPCC) FifthAssessment Report (AR5), to be published in 2013.The Royal Netherlands Meteorological Institute (KNMI) is analysingthe CIMP5 data in order to use it in updating the KNMI climate scenarios.Cooperation with BfG and Deltares has begun to analyse this dataset and calculate corresponding river discharges for representative setsof runs. The new KNMI scenarios will be published in autumn 2013.The scope of this cooperation is, however, broader. It targets thecomparison methodologies and coordination involved in derivinga common set of climate and discharge scenarios for the internationalbasins of the Elbe, Rhine and Meuse. It is largely based onthe climate model output used for IPCC AR5. Eachinstitution brings its own expertise, observed data andmodels. One question to be answered with this analysisrelates to the RheinBlick2050 results and the extentto which these are still valid with regard to IPCC AR5.CHR eventsIn recent decades CHR has organized several conferences,symposia and workshops, with themes selected from ascientific point of view or as the closing events of large CHRstudies. They include workshops on sediment transport(2003, 2007 and 2008), climate change (2003), extremedischarges (2005) and flood forecasting and ensemblepredictions (2006 and 2010), as well as the closing symposiumof the RheinBlick2050 project in 2010. 6Future projects and tasksIn spring 2014 CHR will organize the new first springseminar in combination with biannual CHR meetingin Austria. The series of spring seminars will start withthe ‘Impact of socioeconomic changes to the dischargeregime in the Rhine catchment’. The seminar outputmay lead to a new project.Concerning the future, the tasks agreed during CHR’sfoundation are still valid and important, while thecommission’s approach has become increasingly multifunctionaland multidisciplinary. The need for enoughwater of good quality, as well as for maintaining a safeenvironment for livelihoods, is still growing.Another special event will come in 2020, when a newmonograph on the Rhine will be published celebratingthe 50th anniversary of CHR – and commemorating thefact that all CHR member states will have been takingcare of the catchment and solving problems togetherfor half a century.[ 60 ]