Interview of Prof. Dr. Mario Schirmer, Eawag, Switzerland on river restoration

River restoration is a practice carried out by river management practitioners around the world in order to restore the river back to its natural state from its engineered state. Restoration of rivers is done with the objectives to alleviate floods, to improve water quality and for ecological restoration. In Switzerland several million Swiss francs are to be spent annually for the next 80 years on restoration of various rivers, therefore process understanding of restored rivers is vital. The Competence Center for Environment and Sustainability (CCES) has funded the RECORD and the RECORD catchment projects which are multi-disciplinary projects under the ETH domain to study about restored rivers. Prof. Mario Schirmer, the group leader of hydrogeology at EAWAG (Swiss Federal Institute of Aquatic Science and Technology), Switzerland leads thesemultidisciplinary projects. Our team interviewed him to know more about restoration in Switzerland and about the research focus of these projects.

In the abovevideo Prof. Schirmer gives an introduction about a sample restorationproject at the Chriesbach river in Dübendorf, Switzerland to explain the features of a restored river.

Interview Questions for Prof. Dr. Mario Schirmer on the RECORD project.

Q1. Could you give us an overview about river restoration? Why would you consider it important to study the science behind the practice?

In Switzerland, river restoration is done to improve the ecological and chemical status of the system river - river corridor - groundwater. In addition, river restoration is helping in flood protection. Studying the science behind the processes is very important because up to now, most river restoration projects are large-scale experiments. We want to predict the changes to come from river restoration in the long term.

Q2. What work is done on understanding processes behind restoration within the ETH domain particularly at EAWAG?

To study river restoration, we initiated the Restored Corridor Dynamics (RECORD) project which was funded by CCES, the Competence Center Environment and Sustainability, within the ETH domain. Our objective was to increase the mechanistic understanding of coupled hydrological, biogeochemical and ecological processes in near-river corridors. For this purpose, we instrumented a restored and a channelized section of the Swiss River Thur as large-scale field experimental sites.

Q3. Could you outline the purpose of the Restored Corridor Dynamics (RECORD) project and the major breakthroughs achieved?

There is a large range of very interesting research results. We could demonstrate that species richness is larger in the restored part of the river in comparison to the channelized one. Thus biodiversity improved. From the other results, let me pick out one example. We developed a method to calculate travel-time distributions for infiltrating river water into groundwater based on electrical conductivity time series in the river and groundwater wells or piezometers.

Q4.Is there a continuation of this project?

In the follow up project RECORD Catchment, a new multidisciplinary four-year initiative from 2012 - 2016, we are evaluating the restoration of the Thur in terms of the future, following up on the earlier hydrological, biogeochemical and ecological investigative work. The project combines detailed scientific analysis not only of the dynamics of interacting processes that affect water supply and the natural environment, but also of the socioeconomic impacts on the surrounding area in the context of river restoration measures. We want to investigate how restored reaches of the river influence the catchment and vice-versa.

Q5. In this multidisciplinary study, how many research groups are involved and how many diverse disciplines are collaborating together?

A whole range of different disciplines were and are participating in our RECORD projects. Scientific inputs are provided by biologists, geologists, hydrologists, chemists, engineers, economists and social scientists to name a few.

Q6. What are the main challenges in a multidisciplinary research study?

The main challenge is to find a common language to discuss how to approach the pressing research questions. This takes much more time as we usually need to discuss with colleagues from the same field. But interdisciplinarity is the only way to solve our societal problems in the future.

Q7. Why have you chosen the Thur catchment to focus your restoration study?

The Thur is the largest Swiss River without a reservoir along its 125 km length. This makes it a very dynamic system with rising and falling water levels of meters within hours. When we study these very different and dynamic conditions, we hope to be able to transfer the results to other catchments. In addition, and very importantly, we have in the Thur catchment very interested colleagues in the authorities of the Agencies for the Environment. It is a pleasure to work with them on real world problems with the necessary scientific depth.

Q8. How transferrable are the results from the RECORD and RECORD Catchment projects to other rivers? How localized are the findings?

As I just said, the very dynamic system of the Thur River covers a wide range of hydrological and ecological conditions. This gives hope that we are able to transfer our methods and results to other catchments. By the way, we are of course also working in other catchments and river reaches to test our methods and models.

Q9. What according to you are the major challenges facing practitioners in restoration of rivers?

In Switzerland, the main problem is the multiple use of rivers. Space for river restoration is very limited. Therefore, careful evaluation of each envisaged project is crucial. In addition, especially in Switzerland, where we have often losing streams and drinking water production through river bank filtration. There we have the potential conflict between river restoration and drinking water production.

Q10. If there is one piece of advice you would as a scientist give for practitioners working on future restoration projects, what would it be?

If I have to give a single advise then I would say, taking into the boat all stakeholders from the very beginning is crucial. Only when discussing all aspects and considering different opinions an acceptable and sustainable solution for all can be found.

Copyright: Water Network research, AquaSPE 2015

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Taxonomy

• River Basin management
• River Restoration
• Drinking Water Managment
• Flood management
• Flood damage
• Water Resources Management