Flood Protection and Rehabilitation - New Directions for Our Rivers
Eawag News 61, November 2006
complete issue [pdf]
Editorial: Rhone-Thur Project: Moving Towards Integrated River Management
Bruno Schädler, BAFU
Rehabilitation – to What Extent, and Why?
Armin Peter, Eawag
All over the world, watercourses are heavily engineered. But since
intact rivers and streams provide substantial benefits for society, there is a
wish to restore them to a more natural condition. Scientific foundations and
tools for sustainable watercourse management have been developed by the
Rhone-Thur research project. [...]
Meeting the Challenge of Flood Protection
Hans Peter Willi, BAFU
Since the 1987 flooding disaster, Switzerland has been committed to
sustainable flood protection – an approach that has already borne fruit.
However, flood protection is becoming increasingly complex in view of possible
changes in the climate as well as in land use. Forward thinking is essential. [...]
From Decisions by Experts to a Risk Dialogue
Marc Zaugg Stern, Universität Zürich
The implementation of sustainable flood protection projects is an
exceedingly complex process, requiring a detailed analysis of the broader
context and the involvement of all stakeholders. An aid to decision-making is
provided by a handbook on joint planning of river engineering projects
(Wasserbauprojekte gemeinsam planen) that was produced as part of the
Rhone-Thur research project. [...]
Using Ecological Indicators to Evaluate Rehabilitation Projects
Klement Tockner, Eawag
Stream and river rehabilitation projects are currently enjoying a
worldwide boom. But do these efforts in fact significantly enhance the
ecological condition of watercourses? Evaluations are facilitated by the use of
ecological indicators. [...]
River Dynamics and Flood Protection: a Contradiction in Terms?
Anton Schleiss, EPF Lausanne
Near-natural watercourses should provide dynamic – constantly changing –
habitats. This requirement can be met by adopting innovative approaches and
taking advantage of possible synergies, even in cases where only limited space
is available and local construction of river training works are unavoidable. [...]
Predicting the Consequences of Rehabilitation Measures
Peter Reichert, Eawag
What effect will the proposed measures have? Decision makers are
confronted with this question when evaluating alternatives. Mathematical models
can summarise the current level of knowledge on important cause-effect
relationships in a transparent way. They can therefore make a substantial
contribution to support of decision-making. [...]
Landscape Development of Rehabilitated Riparian Areas
Christian Glenz, EPF Lausanne (now Forum Umwelt AG, Visp)
Riparian areas are complex, dynamic habitats, and it is difficult to
predict how they will develop in the long term following rehabilitation
measures. This may impede the acceptance and practical implementation of
restoration projects. Process-based riparian forest succession modelling is a
first possible method of resolution. [...]
Widening as a Rehabilitation Measure
Sigrun Rhode, WSL (now Kanton Aargau)
The “ecological” success of river-widening measures – a preferred method
of rehabilitation – depends crucially on the choice of design and location. The
results of an outcome evaluation provide valuable lessons for the planning and
implementation of future widening projects. [...]
Hydropeaking on Watercourses
Tobias Meile, EPF Lausanne
The operation of storage hydropower plants leads to rapid and frequent
changes in flow regimes. This may have adverse impacts on the ecological
integrity of watercourses. To mitigate hydropeaking effects, both structural
and operational measures can be envisaged. [...]
Effects of Hydropeaking on Groundwater
Markus Fette, Eawag (now Meier & Partner AG, St. Gallen)
As part of the “Third Correction” project, the river bed is to be
widened at various points. Engineering works of this kind may stimulate the
frequently limited exchanges between surface and groundwater – but possibly
with adverse consequences for groundwater use. [...]
All’s Well that Ends Well? A Tool for Outcome Evaluation
Christine Weber, Eawag
The excavators have gone, the plovers have returned and the local
community is enthusiastic. Does this mean that the rehabilitation work has been
successful? The outcome evaluation handbook for watercourse rehabilitation
projects is designed to help answer this question. [...]
Conclusion
Marco Baumann, Amt für Umwelt, Kanton Thurgau
Ion Karagounis, Praktischer Umweltschutz Schweiz PUSCH
Ueli Bundi, Eawag
Publications Rhone-Thur Project
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