Observation area

The OPE observation area is located in the departments of Meuse and Haute-Marne, and covers an area of 900 km² and several different ecosystems. This observatory has a very large action field, as it includes several simultaneous studies on numerous environmental physical and biological compartments.

Scope of the study

The OPE territory covers an area of 900 km². Two thirds is located in the department of Meuse, and the remaining third in Haute-Marne, thus grouping together 82 towns. The area has a very low population density, with an average of 22 habitants/km². The boundaries of the study area are defined by natural features (watercourses, forests, etc.) or manmade features (such as roads).

In the middle of this area, a reference sector of 240 km² was marked out so that more detailed observations can be made of the area studied by ANDRA as the future site of the Cigeo geological industrial centre.

Geographical map of the observation areas of the OPE in 2010

This map shows the 2 areas covered by the OPE: the reference sector (240 km²) and the OPE area (900 km²)

Area description

The OPE area is found along the western edge of the Paris basin, in a region characterised by a large area of limestone plateaux whose altitude varies from 300 to 400 metres. The landscapes are very open. The study area is composed of vast farmland interspersed with wooded areas.

There are three main morphological groups:

  • the Barrois plateau, used mainly for field crops;
  • the hills and flats of the Kimmeridgian with a more marked relief;
  • the valleys, of varying size, are often occupied by meadows.

Several watercourses run through the OPE area:

  • the main rivers are the Marne in the west and the Ornain in the east;
  • secondary rivers are the Saulx, Orge, Ormançon, Barboure le Rongeant and the Ognon, which flow into the Ornain at its confluence with the Maldite;
  • the OPE area is also traversed by the canal from the Marne to the Rhine.

Therefore, economic activity in the area is mostly based on agriculture, with a few industrial units (a carpenter's, cheese factory and foundry). The region is characterised by a temperate, maritime climate with slight continental influences.

The different ecosystems

The observed area contains several semi-natural continental ecosystems:

  • meadow: 12%
  • forest: 35%
  • field crops: 40%
  • wetlands (ponds, rivers, watercourses, etc.).

It is home to diverse flora and fauna, including some protected species.

There are a few official boundaries to national parks within the study area. Some areas of environmental interest are grouped in two sectors: the Ormançon valley, and the Marne to Rhine canal. The DREAL Lorraine site lists the areas within the Permanent Environment Observatory that contain heritage sites.

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