Labex DRIIHM Transversal Research Program - Hydeco


contacts - lead investigators

François-Michel Le Tourneau, Senior Researcher at the CNRS, OHMI Pima County Director

David Blanchon, Professor, University of Paris Nanterre, Department of Geography


The HYDECO research project, funded by the CNRS (French National Research Center) and the INEE (Institute for the Environment) through the Labex DRIIHM, is an interdisciplinary and multi-site project. The research project relies on the network of Human-Environment Observatories (Observatoires Hommes-Milieux, OHM), in place since 2007. 

The Santa Cruz River in Downtown Tucson, on the left: the bike path of the Loop (Boyer)
The Santa Cruz River in Downtown Tucson, on the left: the bike path of the Loop (Boyer)

The relationship between societies and their hydrosystems can be understood as a series of connections and disconnections that occur in all domains (e.g., hydrological, geomorphological, ecological, etc.) and dimensions (e.g, longitudinal, vertical, lateral). The use of watercourses and water resources creates material and symbolic connections which leads water stakeholders to also consider the sociological and political, aesthetic and spiritual dimensions of the socio-hydrosystem. However, the development of physical (e.g, dams) and social  infrastructures (e.g, waterbodies are so artificialized that local residents forget about their existence) generates important disconnections. As a result, recent water and environmental policies emphasize the importance of connectivity between the various elements and compartments of socio-hydro-systems and focus especially on reconnection at all levels. In this context, the objective of the HYDECO project is to test the effectiveness of the connection/disconnection/reconnection reading grid applied to socio-hydro systems and re-explore the notion of connectivity in a critical and exemplified way. Thus, the project proposes a fertile ground to re-explore to the concept of socio-hydrosystem and its socio-ecological implications, by emphasizing both socio-cultural evolutions and functional interactions between all its components. To do so, the project articulates the following theoretical frameworks: the visible/invisible opposition as developed in landscape theory, and the concept of tipping point coming from the fields of climate science, environmental sciences and ecology. The tipping point corresponds to a critical level of an external condition where a system shifts to an alternative state, which can be interpreted in certain cases as a catastrophic bifurcation. The innovative contribution of this project is to use the concept of "tipping point" to understand how and where connections and disconnections take place in the socio-hydro systems. Are there thresholds beyond which the functioning of socio-hydrosystems will be irreversibly altered? Is it possible to predict them? Conversely, can connections/disconnections lead to a shift of socio-hydrosystems into radically different modes of functioning?

Drinking water wellfield in Lyon (Boyer, 2019)
Drinking water wellfield in Lyon (Boyer, 2019)

To answer these questions, the project mobilizes a team of 40 researchers, distributed in 7 different study sites over 2.5 years: Pima County (OHMI Pima County at IRL iGlobes - CNRS University of Arizona); the Rhône Valley (OHM Rhône Valley, University of Lyon); the Mediterranean lagoons of Etang de l'Or and Biguglia (OHM Mediterranean Coast at the University of Montpellier and the University of Corsica); the Rhine Valley (OHM Fessenheim at the University of Strasbourg) ; the Atlantic lagoon of Estarreja (OHM Estarreja at the University of Aveiro, Portugal); the watershed of Umiujaq (OHM Nunavik, University of Laval, Québec); the peatland of Bernadouze and high mountain lakes in the French Pyrenees (OHM Pyrénées-Haut Vicdessos at the University of Toulouse). 


The objective is to collect data and analyses produced for all socio-hydrosystems which will then be examined from a comparative and interdisciplinary perspective and methods. This comparison and dialogue between the different situations observed will be made possible by the development of a common lexicon based on the vocabulary widely accepted by the scientific community for socio-hydrosystems. The goal is to find out if there are common determinants of connections/connections/reconnections, but also if we can identify recurrent effects that could be used to anticipate future developments within the observed territories or, more broadly, in all the world's socio-hydrosystems subject to the same conditions. 

list of case studies

1. OHM Pima County: Tucson Active Management Area and the Santa Cruz River. Research Topics: 

  • Groundwater and surface water hydrological, geomorphological and ecological interactions in the context of climate change: approaching the tipping point?
  • Groundwater and surface water disconnections in stakeholders' perceptions: law and socio-economic challenges
  • Social perceptions of intermittent streams: towards an improved visibility?

2. OHM Rhône Valley: The Rhône corridor from Lake Geneva to the delta

  • Water contaminant and pollutions in the Rhône corridor: the invisible threat?
  • Groundwater and surface water interactions in the context of climate change: approaching the tipping point?
  • Urban waterfronts: towards a social reconnection between cities and rivers?

3. OHM Mediterranean Coast: The lagoons of Etang de l'Or (Montpellier) and Biguglia (Bastia, Corsica)

  • Groundwater and surface water interactions in the hydrological functioning of lagoons
  • Water contaminant and pollutions: connectivity as a potential issue in the functioning of a lagoon
  • Connection sea/lagoon/flood plain: impacts of human infrastructures on the functioning of the lagoon

4. OHM Fessenheim: The Rhine islands between the Grand canal d'Alsace and the Rhine River

  • Hydrological reconnections and invisibility of groundwater dynamics in the framework of the rehabilitation of the Alsace potash mines on the Rhine River
  • Water contaminant and pollutions: re-mobilization of polluted sediments
  • Connection/disconnection events on pollutant levels in alluvial sediments and ecological processes - chemical, physical and ecological modelling of tipping points

5. OHM Estarreja: The Atlantic lagoon of Estarreja (Portugal)

  • Delineation of freshwater/saltwater interface in the area of Baixo Vouga Lagunar (Aveiro) using geochemical and geophysical techniques
  • The effect of multiple climatic factors on the toxicity of historically contaminated soils.
  • Microplastics in Estarreja rivers and their role in the spread of pathogens and antibiotic resistance

6. OHM Nunavik: The Watershed Umiujaq (Québec, Canada)

  • Evolution of the hydrosystem in response to climate change and following the recent establishment of the village of Umiujaq in 1986
  • Impacts of changes in the hydrosystem on the village of Umiujaq (increase in river turbidity caused by landslides, presence of contaminants in the water, growth of shrubs in the watershed resulting in the decline of the endemic vegetation, appearance of thermokarst ponds as a result of the degradation of the permafrost, appearance of beaver dams, etc.)

7. OHM Pyrénées-Haut Vicdessos: The Peatland of Bernadouze and high moutains lakes

  • Understanding of the landscape configurations that favor water storage in winter by analyzing vertical snow flows and groundwater tables in order to allow active management of territories to favor storage and support of low water levels in the summer. 
  • Assessment of nutrient and micropollutant flows which are impacted by invasive species, themselves associated with very specific and punctual (spatially and temporally) practices such as fish rearing.
  • Geo-historical reconstruction of upstream/downstream connectivity over the long term (18th-21th centuries) in relation to the development and exploitation of the water resource