Abteilung Oberflächengewässer

Oberflächengewässer - Forschung & Management (Surf)

Wir untersuchen sowohl einzelne Prozesse in aquatischen Systemen als auch ganze Systeme natürlicher Gewässer.
Neben der Grundlagenforschung und der interdisziplinären Systemanalyse stehen anwendungsnahe Projekte besonders im Fokus.

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News

Corona-Lockdowns: Seen wurden weltweit klarer

Satellitenbild vom Govind Ballabh Pant Sagar, dem grössten künstliche See Indiens. (Bild: europäischen Erdbeobachtungsprogramms Copernicus Global Land Service)
9. April 2026 –

Während der COVID-19-Pandemie stand die Welt still – und viele Seen wurden messbar klarer. Eine globale Studie zeigt: Die Lockdowns mit weniger Industrie, Verkehr und Freizeitaktivitäten liessen die Wassertrübung in Seen weltweit...

Während der COVID-19-Pandemie stand die Welt still – und viele Seen wurden messbar klarer. Eine globale Studie zeigt: Die Lockdowns mit weniger Industrie, Verkehr und Freizeitaktivitäten liessen die Wassertrübung in Seen weltweit abrupt sinken, vor allem in Uferregionen und Flussmündungen.
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Weitere News

Neuste Publikationen

Amadori, M., Rahaghi, A. I., Bouffard, D., & Toffolon, M. (2025). Using automatic calibration to improve the physics behind complex numerical models: an example from a 3D lake model using Delft3D (v6.02.10) and DYNO-PODS (v1.0). Geoscientific Model Development, 18(11), 3473-3486. doi:10.5194/gmd-18-3473-2025, Institutional Repository

Models are simplified descriptions of reality and are intrinsically limited by the assumptions that have been introduced in their formulation. With the development of automatic calibration toolboxes, finding optimal parameters that suit the environmental system has become more convenient. Here, we explore how optimization toolboxes can be applied innovatively to uncover flaws in the physical formulations of models. We illustrate this approach by evaluating the effect of simplifications embedded in the formulation of a widely used hydro-thermodynamic model. We calibrate a Delft3D model based on temperature profiles for a case study, Lake Morat (Switzerland), through the DYNO-PODS optimization tool. The results show that higher values of the light extinction coefficient can compensate for neglecting the fraction β of short-wave radiation absorbed at the surface of the water. This leads to unrealistic values of the light extinction coefficient, as the optimization pushes its value toward the limit of no transparency, consistent with the need to reproduce a significant absorption at the surface. Although it is well known that β is significantly larger than zero, its absence from the model was never noticed as critical. Automatic calibration tools provide valuable diagnostic insights into the physical robustness of models, enabling more precise evaluation of their structural integrity and performance.
Dolcetti, G., Piccolroaz, S., Bruno, M. C., Calamita, E., Larsen, S., Zolezzi, G., & Siviglia, A. (2025). Quantification of carbopeaking and CO2 fluxes in a regulated Alpine river. Water Resources Research, 61(2), e2024WR037834 (25 pp.). doi:10.1029/2024WR037834, Institutional Repository

Carbon dioxide (CO2) fluxes in regulated Alpine rivers are driven by multiple biogeochemical and anthropogenic processes, acting on different spatiotemporal scales. We quantified the relative importance of these drivers and their effects on the dynamics of CO2 concentration and atmospheric exchange fluxes in a representative Alpine river segment regulated by a cascading hydropower system with diversion, which includes two residual flow reaches and a reach subject to hydropeaking. We combined instantaneous and time-resolved water chemistry and hydraulic measurements at different times of the year, and quantified the main fluxes by calibrating a one-dimensional transport-reaction model with measured data. As a novelty compared to previous inverse modeling applications, the model also included carbonate buffering, which contributed significantly to the CO2 budget of the case study. The spatiotemporal distribution and drivers of CO2 fluxes depended on hydropower operations. Along the residual flow reaches, fluxes were directly affected by the upstream dams only in the first 2.5 km, where the supply of supersaturated water from the reservoirs was predominant. Downstream ofthe hydropower diversion outlets, the fluxes were dominated by systematic sub-daily fluctuations in CO2 transport and evasion fluxes (“carbopeaking”) driven by hydropeaking. Hydropower operational patterns and regulation approaches in Alpine rivers affect fluxes and their response to biogeochemical drivers significantly across different temporal scales. Our findings highlight the importance of considering all scales of CO2 variations for accurate quantification and understanding of these impacts, to clarify the role of natural and anthropogenic drivers in global carbon cycling.
Twining, C. W., Blanco, A., Dutton, C., Kainz, M. J., Harvey, E., Kowarik, C., … Subalusky, A. L. (2025). Integrating the bright and dark sides of aquatic resource subsidies - a synthesis. Ecology Letters, 28(4), e70109 (20 pp.). doi:10.1111/ele.70109, Institutional Repository

Aquatic and terrestrial ecosystems are linked through the reciprocal exchange of materials and organisms. Aquatic-to-terrestrial subsidies are relatively small in most terrestrial ecosystems, but they can provide high contents of limiting resources that increase consumer fitness and ecosystem production. However, they also may carry significant contaminant loads, particularly in anthropogenically impacted watersheds. Global change processes, including land use change, climate change and biodiversity declines, are altering the quantity and quality of aquatic subsidies, potentially shifting the balance of costs and benefits of aquatic subsidies for terrestrial consumers. Many global change processes interact and impact both the bright and dark sides of aquatic subsidies simultaneously, highlighting the need for future integrative research that bridges ecosystem as well as disciplinary boundaries. We identify key research priorities, including increased quantification of the spatiotemporal variability in aquatic subsidies across a range of ecosystems, greater understanding of the landscape-scale extent of aquatic subsidy impacts and deeper exploration of the relative costs and benefits of aquatic subsidies for consumers.

Surf Seminare

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16. - 21.08.​2026,
9:00 Uhr
Lausanne
Symposium on Ecohydraulics 2026

ISE 2026 + Swiss Ecohydraulics day

08.09.​2026,
9:00 Uhr
Verkehrshaus Luzern
Eawag-Infotag 2026: Energie - Wasser - Zukunft

Infotag 2026

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Graduate Studies in unserer Abteilung

Video über Graduate Studies in der Abteilung Oberflächengewässer

Video über Graduate Studies in unserer Abteilung

Forschungsprojekte

In den kommenden 80 Jahren werden in der Schweiz 4‘000km Fliessgewässer revitalisiert – eine einmalige Chance für einen Lernprozess!

Wirkungskontrolle bei Flussrevitalisierungen
Die Veränderung des Klimas wirkt sich auch auf die Seen aus. Wir untersuchen die Zusammenhänge in diesem komplexen System mit der Analyse von globale Daten und mit lokalen Fallstudien.

Klimawandel und Seen
Une nouvelle plateforme de recherche multidisciplinaire pour le lac Léman.

Lac Léman Exploration
Mikroben können Metalle "atmen", und Metalle können auch als Aufzeichnungen über die Vergangenheit der Erde dienen. In diesem Projekt werden diese Funktionen von Metallen in anoxischen Seen untersucht.

Biogeochemischer Kreislauf an oxisch-anoxischen Grenzen
We try to understand the bulk and compound specific carbon and nitrogen isotopic compositions in food chains.

Ecology of food chain in freshwater systems
Abwasser ist mit antibiotikaresistenten Bakterien belastet. Wir untersuchen ihre Ausbreitung in die Umwelt und Gegenmassnahmen.

Antibiotikaresistenzen als Umweltkontamination
IsoTalk - Dynamik der Isochrysidales Blüte in Schweizer Seen: Auf dem Weg zu einem Alkenone-Paläothermometer für Seen in den mittleren Breiten.

Dynamik der Isochrysidales Blüte in Schweizer Seen
Wie kann die Erdbeobachtung genutzt werden, um die Handlungsspielräume der Wasserwirtschaft im Klimawandel abzuschätzen.

Sichere Optionen im Management von Wasserressourcen

Weitere aktuelle Forschungsprojekte