PhD (M/F) position in physical geography and geosciences

Job Description

Thesis Subject

Objective and subject of the PhD project
Intermittent rivers alternate between flowing phases, channel fragmentation and dry phases. In a context of climate change and anthropogenic pressures, the possible increase in the frequency and duration of dry periods is intensifying concerns related to ecological continuity, the maintenance of aquatic habitats and the management of river systems.
The PhD project aims to improve understanding and quantification of the role of channel geomorphology in the formation, evolution and persistence of residual surface-water bodies, particularly pools, which may provide refugia for aquatic organisms during dry phases. The central scientific challenge concerns the relationships between hydrological regimes, bed morpho-sedimentary dynamics and the persistence of these potential refugia.

Scientific fields and themes: fluvial geomorphology, hydrology, geomatics/remote sensing and aquatic ecology.

Scientific questions
• Which hydrological events shape the mesoscale channel forms of an intermittent river?
• How do pools form, evolve or disappear over time?
• Which morphological and hydrological parameters control their persistence?
• Under what conditions do these residual water bodies actually function as biological refugia?

Research objectives and approach
• Identify and quantify the geomorphically effective discharges relevant to intermittent conditions by combining hydrological time series, detection of sediment remobilisation and high-resolution morphological monitoring, in order to identify the events likely to create, transform or eliminate riffles, pools and other mesoscale channel forms.
• Characterise the spatio-temporal dynamics of pools and mesoscale channel forms through repeated topographic surveys using UAV LiDAR and Structure-from-Motion (SfM) photogrammetry, followed by comparison of very-high-resolution digital models.
• Understand the hydrological mechanisms controlling pool persistence by examining pool geometry, the topographic thresholds governing their connection or isolation, and exchanges between the river, groundwater and the hyporheic zone. Targeted monitoring of representative pools will be used to document their local water balance.
• Assess their potential function as biological refugia by combining shading modelling, thermal imaging, in situ physico-chemical measurements and environmental DNA (eDNA) analyses.
The work will be conducted on three contrasting reaches in the lower Albarine valley, distributed along approximately 15 km of intermittent river, in order to cover different degrees of intermittence and a range of morphological configurations (pools, riffles and sediment bars).

Collaborative dimension
The project is interdisciplinary and brings together EVS – UMR 5600 CNRS / Université Lumière Lyon 2 and RiverLy – INRAE. It combines complementary expertise in fluvial geomorphology, hydrology, hydraulic modelling, aquatic ecology, biology and very-high-resolution spatial analysis, with collaborations involving in particular LEHNA – UMR 5023 CNRS, Université Lyon 1, Université du Québec à Chicoutimi and the University of Barcelona.

Scientific, material and financial conditions
The PhD contract is co-funded by the H2O'Lyon Graduate School (École Universitaire de Recherche) and the Agence de l'eau Rhône-Méditerranée-Corse. Project funding will cover fieldwork, the acquisition and deployment of equipment, UAV surveys, analyses, and travel related to national and international collaborations and conference participation.

Research outputs and dissemination
The project aims to produce morpho-hydrological thresholds and indicators that can be transferred to other intermittent rivers and used to support restoration policies and adaptive management. Conference participation is explicitly included in the project resources.

Your Work Environment

Scientific and institutional environment
The PhD project will be carried out within the Environnement, Ville, Société laboratory (EVS – UMR 5600 CNRS), at the Porte des Alpes campus of Université Lumière Lyon 2. It will therefore be hosted within a joint research unit affiliated with the CNRS.

Doctoral school and specialism: the PhD candidate will be enrolled in Doctoral School ED 483 Social Sciences.

Supervisory team: Jérôme Lejot, PhD supervisor (EVS – UMR 5600, Université Lumière Lyon 2; fluvial geomorphology, geomatics and remote sensing), and Thibault Datry, co-supervisor (RiverLy, INRAE; ecology and functioning of intermittent rivers).

Partners and collaborations: RiverLy – INRAE, LEHNA – UMR 5023 CNRS, Université Lyon 1, Université du Québec à Chicoutimi and the University of Barcelona.

Working environment and interactions: the PhD candidate will be fully integrated into the project team and will take part in the scientific activities of UMR 5600 EVS, as well as in meetings and exchanges organised within the project and the H2O'Lyon Graduate School.

Available resources: funding for fieldwork, acquisition and deployment of equipment, UAV surveys, analyses, travel for national and international collaborations, and conference participation.

Constraints and risks

Constraints and specific features of the position: fieldwork on the Albarine River; data-acquisition and measurement campaigns; UAV surveys; participation in collaborations and scientific activities involving travel.

Travel requirements: regular field missions to the three study reaches in the lower Albarine valley; additional travel may be required for national and international collaborations and conference participation.

Compensation and benefits

Compensation

2300 € gross monthly

Annual leave and RTT

44 jours

Remote Working practice and compensation

Pratique et indemnisation du TT

Transport

Prise en charge à 75% du coût et forfait mobilité durable jusqu’à 300€

About the offer

About the CNRS

The CNRS is a major player in fundamental research on a global scale. The CNRS is the only French organization active in all scientific fields. Its unique position as a multi-specialist allows it to bring together different disciplines to address the most important challenges of the contemporary world, in connection with the actors of change.

CNRS

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