Free Flow

[

] 60

ransboundary

ater

anagement

the climate model output used for IPCC AR5. Each

institution brings its own expertise, observed data and

models. One question to be answered with this analy-

sis relates to the RheinBlick2050 results and the extent

to which these are still valid with regard to IPCC AR5.

CHR events

In recent decades CHR has organized several conferences,

symposia and workshops, with themes selected from a

scientific point of view or as the closing events of large CHR

studies. They include workshops on sediment transport

(2003, 2007 and 2008), climate change (2003), extreme

discharges (2005) and flood forecasting and ensemble

predictions (2006 and 2010), as well as the closing sympo-

sium of the RheinBlick2050 project in 2010.

Future projects and tasks

In spring 2014 CHR will organize the new first spring

seminar in combination with biannual CHR meeting

in Austria. The series of spring seminars will start with

the ‘Impact of socioeconomic changes to the discharge

regime in the Rhine catchment’. The seminar output

may lead to a new project.

Concerning the future, the tasks agreed during CHR’s

foundation are still valid and important, while the

commission’s approach has become increasingly multi-

functional and multidisciplinary. The need for enough

water of good quality, as well as for maintaining a safe

environment for livelihoods, is still growing.

Another special event will come in 2020, when a new

monograph on the Rhine will be published celebrating

the 50th anniversary of CHR – and commemorating the

fact that all CHR member states will have been taking

care of the catchment and solving problems together

for half a century.

The starting point for morphological analyses is bed level surveys.

These are combined with sediment transport measurements in order

to get data on the sediment load and on the mechanism of sedi-

ment transport. Echo soundings and transport measurements will

not answer questions such as where the sediments come from and

where are they going, or how changes in one part of the catchment

are related to other regions. Therefore, a sediment budget is needed,

incorporating the collection of data and analyses to check the quality

of measurements and available datasets, fill in the data gaps and

identify sources and sinks. This action incorporates quite a challenge

because maximum data density is found in the navigation channel

but data density is at a minimum next to the navigation channel, in

floodplains and groyne fields and at tributaries. Another challenge lies

in the varying quality and methods used in the several river reaches

and countries. Due to the number of existing gaps (data, data gaps

and a need for regional data), a variety of assumptions were made.

A strategy has been developed based on a status quo combined with

ideas on how to improve the situation around the gaps.

Continuation of the RheinBlick2050 study is planned under the

umbrella of ‘Climate impact studies in the Rhine basin’. Compared

to the regional climate models used in RheinBlick2050,

there is

now a much larger ensemble (~200 runs) of new global climate

models available in the Coupled Model Intercomparison Project

Phase 5 (CIMP5) data repository. These models are also used for

the Intergovernmental Panel on Climate Change (IPCC) Fifth

Assessment Report (AR5), to be published in 2013.

The Royal Netherlands Meteorological Institute (KNMI) is analysing

the CIMP5 data in order to use it in updating the KNMI climate scenar-

ios. Cooperation with BfG and Deltares has begun to analyse this data

set and calculate corresponding river discharges for representative sets

of runs. The new KNMI scenarios will be published in autumn 2013.

The scope of this cooperation is, however, broader. It targets the

comparison methodologies and coordination involved in deriving

a common set of climate and discharge scenarios for the interna-

tional basins of the Elbe, Rhine and Meuse. It is largely based on

River regulation works in the Lütschine basin in Switzerland

Image: CHR

The works in the Polder Ingelheim, north of Mainz in Germany

Image: CHR