Project

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Riverbank filtration under climate change scenarios (RIBACLIM)

Applicant von Gunten Urs
Number 125856
Funding scheme NRP 61 Sustainable Water Management
Research institution Eawag
Institution of higher education Swiss Federal Institute of Aquatic Science and Technology - EAWAG
Main discipline Other disciplines of Environmental Sciences
Start/End 01.01.2010 - 28.02.2013
Approved amount 492'772.00
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Keywords (10)

micropollutants; water supply; dissolved organic matter; redox processes; water quality; transformation; climate change; riverbank filtration ; dissolved oxygen; particulate organic matter

Lay Summary (German)

Lead
Von Flüssen gespiesenes Trinkwasser: Noch sauber genug? Fast ein Drittel des Grundwassers wird aus Flusswasser gespiesen. Das manchmal durch Abwasser belastete Flusswasser gelangt über eine Uferfiltration ins Grundwasser. Wie sich der Klimawandel auf diesen Prozess auswirkt ist noch unbekannt. Lässt sich die Qualität des Trinkwassers durch eine verbesserte Abwasserbehandlung erhöhen?
Lay summary

Hintergrund
Das Schweizer Trinkwasser wird vorwiegend aus dem Grundwasser gewonnen. Ungefähr 25-30% des Grundwassers stammen aus Flusswasser, das durch das Gewässerufer infiltriert. Oftmals ist die Uferfiltration die einzige Barriere, die das von Abwasser belastete Flusswasser vom Trinkwasser trennt. Sauberes Trinkwasser hängt deshalb direkt mit den chemischen, physikalischen und biologischen Reinigungsprozessen in dieser Zone zusammen. Werden diese Prozesse in der Infiltrationszone durch veränderte Wassertemperaturen und einem zeitweilig erhöhten Abwasseranteil beeinträchtigt? Flusswasser enthält oftmals beträchtliche Anteile an Abwasser, das aus Kläranlagen stammt. Wie verändert sich die Zusammensetzung des Flusswassers, wenn das Abwasser besser gereinigt in die Flüsse eingeleitet würde?

Ziel
Das Projekt untersucht klimabedingte Veränderungen der Infiltrationsprozesse von Flusswasser ins Grundwasser. In dieser Studie wird mit Labor- und Feldexperimenten an gut instrumentierten Standorten gearbeitet, um so „normale“ Veränderungen von klimabedingten Veränderungen zu unterscheiden. Die gewonnenen Erkenntnisse bilden die Basis für ein numerisches Modell, mit dem die Prozesse in typischen Sommer- und Wintersituationen sowie Extremszenarien berechnet werden.

Bedeutung
Das Projekt liefert Resultate über das Verhalten der Uferfiltration unter verschiedenen Klimaszenarien. Auf dieser Basis wird die bestehende Wasserversorgung aus Uferfiltrat beurteilt. Allfällige Verbesserungen in der Wasserversorgung oder der Abwasserreinigung werden vorgeschlagen.

Direct link to Lay Summary Last update: 08.02.2013

Lay Summary (French)

Lead
L’eau potable provenant des rivières est-elle encore suffisamment propre? Presqu’un tiers de l’eau souterraine provient des rivières. L’eau fluviale, parfois contaminée par des eaux usées, est filtrée par les berges. Mais on ne sait pas encore comment le changement climatique influence cette filtration sur berge. La qualité de l’eau potable peut-elle être augmentée grâce à un traitement amélioré des eaux usées?
Lay summary

Contexte
L’eau potable suisse est avant tout tirée de l’eau souterraine. Environ 25-30% de l’eau souterraine provient de l’eau fluviale, infiltrée par les berges. Les berges constituent souvent la seule barrière séparant l’eau fluviale, contaminée par des eaux usées, de l’eau potable. La propreté de l’eau potable dépend donc directement des processus de purification chimiques, physiques et biologiques dans cette zone. Des changements de la température de l’eau et une augmentation passagère des eaux usées dans la zone d’infiltration nuisent-ils aux processus qui y ont lieu? L’eau fluviale contient souvent une part considérable en eaux usées provenant de stations d’épuration. Dans quelle mesure la composition de l’eau fluviale change-t-elle lorsque les eaux usées sont mieux traitées, avant d’être déversées dans les rivières?

But
Le projet examine les changements des processus d’infiltration de l’eau fluviale dans les eaux souterraines en réponse aux changements climatiques. Dans cette étude, des expériences en laboratoire et sur le terrain dans des sites de recherche existants sont faites dans le but de distinguer entre des changements «normaux» et des changements dus au climat. Les résultats obtenus serviront de base pour un modèle numérique permettant de calculer les processus typiques de situations estivales et hivernales, ainsi que des situations extrêmes.

Portée
Ce projet fournit des résultats sur le comportement de la filtration sur berge dans différentes conditions climatiques. L’approvisionnement en eau existant, dérivant de ces filtrats, est jugé sur cette base. D’éventuelles améliorations dans l’approvisionnement en eau ou dans l’épuration des eaux seront proposées.

Direct link to Lay Summary Last update: 08.02.2013

Lay Summary (English)

Lead
Is drinking water derived from rivers still clean enough? Almost one third of the groundwater is recharged by river water. River water, sometimes contaminated by wastewater, is cleansed through riverbank filtration. The consequences of the changing climate on riverbank filtration are not yet known. Can drinking water quality be enhanced by means of improved wastewater treatment?
Lay summary
Background
Switzerland’s drinking water is mainly derived from groundwater. Approximately 25-30% of the groundwater comes from river water that has filtered through the riverbanks. Frequently, this is the only barrier that divides wastewater-bearing rivers from drinking water systems. Clean drinking water is therefore directly connected with the chemical, physical and biological purification processes occurring in this zone. Do temperature changes and occasional increases in wastewater effluents interfere with the processes within this infiltration zone? River water often contains significant amounts of wastewater effluents from sewage plants. How does river water composition change when wastewater is better treated before it is discharged into rivers?

Objectives and methods
This project examines climate-induced changes of the infiltration processes of river water into the groundwater. This study will include laboratory experiments as well as field investigations in existing research sites, in order to differentiate between “normal” and climate-induced changes. The results will build a basis for a numerical model which can then be applied to calculate the processes in typical summer and winter situations, as well as in extreme scenarios.

Significance
The project will provide results on the behaviour of riverbank filtration under various climatic conditions. On this basis, the existing water supply through riverbank filtrates can then be assessed. Possible upgrades of water supplies or wastewater treatment will be proposed.
Direct link to Lay Summary Last update: 08.02.2013

Responsible applicant and co-applicants

Employees

Publications

Publication
Degradation rates of benzotriazoles and benzothiazoles under UV-C irradiation and the advanced oxidation process UV/H2O2
Bahnmüller Sabrina, Loi Clara, Linge Kathrin L., von Gunten Urs, Canonica Silvio (2015), Degradation rates of benzotriazoles and benzothiazoles under UV-C irradiation and the advanced oxidation process UV/H2O2, in Water Res., 74, 143.
Column studies to assess the effects of climate variables on redox processes during riverbank filtration
Rudolf von Rohr Matthias, Hering Janet, Kohler Hans-Peter, von Gunten Urs (2014), Column studies to assess the effects of climate variables on redox processes during riverbank filtration, in Water Research, 263.
Assessing the effect of different river water level interpolation schemes on modeled groundwater residence times
Diem Samuel, Renard Philippe, Schirmer Mario (2014), Assessing the effect of different river water level interpolation schemes on modeled groundwater residence times, in Journal of Hydrology, 510, 393-402.
Sunlight-induced transformation of sulfadiazine and sulfamethoxazole in surface waters and wastewater effluents
Bahnmüller Sabrina, von Gunten Urs, Canonica Silvio (2014), Sunlight-induced transformation of sulfadiazine and sulfamethoxazole in surface waters and wastewater effluents, in Water Research, 183.
Modeling the dynamics of oxygen consumption upon riverbank filtration by a stochastic-convective approach
Diem Samuel, Cirpka Olaf, Schirmer Mario (2013), Modeling the dynamics of oxygen consumption upon riverbank filtration by a stochastic-convective approach, in Journal of Hydrology, 505, 352.
New methods to estimate 2D water level distributions of dynamic rivers
Diem Samuel, Renard P, Schirmer Mario (2013), New methods to estimate 2D water level distributions of dynamic rivers, in Ground Water, 51, 847.
NOM degradation during river infiltration: Effect of the climate variables tempereature and discharge
Diem Samuel, Rudolf von Rohr Matthias, Hering Janet, Kohler Hanspeter, von Gunten Urs (2013), NOM degradation during river infiltration: Effect of the climate variables tempereature and discharge, in Water Research, 47, 6585.
Qualität des Uferfiltrats: Einfluss der klimabestimmten Variablen Temperatur und Abfluss
Diem Samuel, Schirmer Mario, Rudolf von Rohr Matthias, Kohler Hans-Peter, Hering Janet, von Gunten Urs (2013), Qualität des Uferfiltrats: Einfluss der klimabestimmten Variablen Temperatur und Abfluss, in Aqua&Gas, 2013(11), 14.

Collaboration

Group / person Country
Types of collaboration
University of Neuchatel Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
Université de Poitiers France (Europe)
- Research Infrastructure
- Exchange of personnel

Knowledge transfer events

Active participation

Title Type of contribution Date Place Persons involved
Herausforderungen einer nachhaltigen Wasserwirtschaft Talk 14.09.2012 Dübendorf, Switzerland Bahnmüller Sabrina; Hering Janet; von Gunten Urs; Rudolf von Rohr Matthias; Schirmer Mario; Diem Samuel;
Klimaänderungen und deren Auswirkungen auf die Grundwasserressourcen Talk 11.05.2012 Solothurn, Switzerland von Gunten Urs;


Self-organised

Title Date Place
Workshop mit Begleitgruppe Grundwasserprojekte 05.10.2011 Bern, Switzerland

Communication with the public

Communication Title Media Place Year
Media relations: print media, online media Interview zum Projekt RIBACLIM Aqua & Gas German-speaking Switzerland 2012
Talks/events/exhibitions Information der Bevölkerung an der Thur German-speaking Switzerland 2011

Associated projects

Number Title Start Funding scheme
169003 Water distribution 01.03.2017 Project funding (Div. I-III)
149126 River Floodplains 01.10.2013 Project funding (Div. I-III)
140815 Antioxidant effect of dissolved organic matter (DOM) on indirect photochemical transformation of contaminants in surface waters ("Oxindom 3") 01.09.2012 Project funding (Div. I-III)
134801 The role of dissolved organic matter as an antioxidant in triplet-induced oxidation reactions 01.04.2011 Project funding (Div. I-III)

Abstract

Switzerland derives 25-30% of its drinking water from groundwater that is recharged and cleansed through riverbank filtration. Frequently, this is the only barrier that divides wastewater-bearing rivers from drinking water systems. Processes occurring in rivers and infiltration zones are therefore crucially important for safe drinking water. Riverbank filtration can be influenced by source water composition, infiltration rate, and groundwater temperature, each of which can change with a changing climate. The composition of surface water, which supplies water for groundwater recharge, is particularly important as many Swiss rivers contain significant concentrations of wastewater effluent, which may also vary in composition due to the implementation of polishing treatment processes for wastewater effluents. Despite these important changes to the natural and engineered processes that affect drinking water supplies, no comprehensive assessment of groundwater infiltration has been made under scenarios of climate change. Because it is difficult to simulate the combined effects of the regular variability of riverbank filtration systems with effects caused by climate change, we investigated water quality in surface waters and groundwaters from riverbank filtration in tailored laboratory experiments, conducted selected and limited field investigations at an existing research site, and upscaled the findings by numerical modelling. Baseline conditions for typical summer and winter situations were studied and overlaid with possible extreme scenarios expected for climate change conditions. To guarantee an integral assessment of riverbank filtration under various climate change scenarios, Eawag will provide support (see attached letter) so that this project will be effectively coordinated with other NFP61 Eawag projects dealing with “historical development of groundwater impact due to climate change” (Livingstone), “groundwater in the water cycle under changing climatic conditions” (Hunkeler), “integrated river water quality management” (Stamm), “sustainable water infrastructure planning” (Lienert), and “integrated water governance with adaptive management (Klinke).The proposed research will provide the scientific basis for sustainable management of riverbank filtration systems as the climate changes (e.g., for assessing the reliability and planning for upgrades of water supplies or planning for enhanced wastewater treatment). It will examine groundwater infiltration under several scenarios, with specific goals to:•Investigate alterations in surface water composition due to climate change, with specific attention to phototransformation of dissolved organic matter (DOM) and the consequent effects on the photodegradation of micropollutants;•Assess the effects of T, infiltration rate, and surface water composition on biogeochemical processes during riverbank filtration;•Determine the degradation rates and degradation intermediates of micropollutants during riverbank filtration under varying redox conditions in laboratory column studies; •Assess the upscaling of groundwater infiltration processes by combining modelling of the column experiments with modelling of a representative field site in the River Thur Valley, to provide practical management guidelines for adapting to climate change; and•Engage the participation of stakeholders from urban water management on local (River Thur catchment), cantonal and federal levels and disseminate research results in a series of seminars and workshops.Participation of stakeholders will be based on the experiences from the Eawag cross-cutting project Wave21, in which results from basic research were successfully transferred to the drinking water industry and practice. The stakeholders will be engaged on different levels , namely, by (i) a core group consisting of representatives of cantonal agencies, water supplies and wastewater treatment plants in the River Thur Valley to provide immediate input on the planned approaches, (ii) an advisory board consisting of important stakeholders in urban water management (cantonal and federal agencies, Swiss water works associations, the Swiss water industry) to give input on a strategic level and catalyze the dissemination of the outcomes, (iii) coordination of the proposed research with the multidisciplinary RECORD project (CCES, ETHZ), which assesses and models coupled ecological and hydrological dynamics in a restored corridor of the River Thur, (iv) seminars and workshops to disseminate the outcomes of this project to the water supply and scientific communities and (v) participation on commissions and through individual contacts to provide direct input for management decisions.
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