OMERE observatory

Scientific context

The Franco-Tunisian OMERE observatory (Observatoire Méditerranéen de l’Environnement Rural et de l’Eau) includes two Mediteranean cutivated watersheds: Kamech (Tunisia), and Roujan (Languedoc, France). These are two elementary watersheds (2,63 km² for Kamech, 0,91 Km² for Roujan) characteristic of Mediterranean climate marked by a strong rainfall inter-annual variability and a high reference evapotranspiration. This basins are at low altitude (about 100 m) on tertiary molassic sedimentary formations: sandstone and marl in Kamech, calcareous silt in Roujan. The land-use is viticulture for Roujan and grain farming (wheat, barley, oats). OMERE is representative of a social and human context, where anthropogenic actions on the environment are milennia old and widespread, and which is currently undergoing considerable changes (intensification of agricultural production in favorable regions, abandonment in unfavorable regions, increased pressure on resources, hydro-agricultural developments or conservation of the environment) linked in particular to a rapid increase in population density.

Summary

Année de départ : 1992

Localisations: Kamech, East of Tunis. Roujan East of Montpellier

Keywords: Mediterranean climate, sedimentary formations, agrosystems, agricultural practices, erosion, evapotranspiration, hydrology, soil properties

Database: https://www.obs-omere.org/fr/donnees

Web site: https://www.obs-omere.org/

PIs:

Jérôme MOLÉNAT (Roujan) and
Damien RACLOT (Kamech)

Vue aérienne des bassins versants de Kamech (Tunisie) et de Roujan (France) de l’observatoire OMERE, avec des zooms sur les principaux dispositifs et équipements de mesure et d’observation. — Aerial view of the catchment of Kamech (Tunisia) and Roujan (France) of the OMERE observatory, with zooms on the main devices and equipment of measurement and observation.

Scientific questions

OMERE was initially built around the following scientific questions:

What is the impact of land use and environmental development on the hydrological regimes and balances of elementary Mediterranean catchments?
What are the dynamics and the respective intensities of the associated erosion?
What is the impact of human activities on the fate and ecodynamics of phytosanitary products used in agriculture?

OMERE aims to develop a distributed hydrological model in a cultivated environment that allows the simulation of the impacts of development and land use scenarios in cultivated environments.

Sites and measured variables

OMERE is based on the joint acquisition of mid and long-term observation of hydrology (river flow, soil moisture, ground water table), meteorological variables, chemical and physical soil erosion processes, change in surface and groundwater quality, and the spatio-temporal evolution of anthropogenic actions (land use, hydro-agricultural developments, agricultural and water use practices, water withdrawals…)

OMERE develops on its two watersheds, Kamech and Roujan, an observation strategy with nested scales from the plot to the elementary watershed through intermediate sub-watersheds. The scheme includes flow and meteorological stations, flux towers, in situ probes for water quality, automatic surface water samplers, piezometers, turbidimeter. The nesting of scales aims to better understand the processes, their dynamics and their variability within the watershed and thus to link these observations to the agricultural operations, themselves carried out at the plot level.

Une parcelle de vigne du bassin versant de Roujan de l’observatoire OMERE — A vineyard plot in the Roujan catchment of the OMERE observatory © Guillaume Coulouma

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