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Site Description
The ORACLE observatory is located 70 km East of Paris, France. Most of the area, in a sedimentary basin, is made of a relatively flat plateau (Alt. 140 m a.m.s.l.), which is incised by the Grand Morin and the Petit Morin rivers (Alt 100m). Several aquifers are associated with layered tertiary formations (Eocene and Oligocene). The Morin Rivers are affluents of the Marne River, known to have contributed to large historical floods in Paris in the 20th century. The observatory is mainly rural (76%) with small towns, villages and hamlets, the whole covering 7% of the area. Forests cover up to 20% of the area. The dominance of agricultural activity within the catchments means that diffuse pollution is regarded as the main environmental pressure. Several perennial device of environment observation are installed since 1962. This site is used for multivariable observations (water cycle, water quality, biodiversity, agricultural practices, sociology…) and multiscale observations (from the canopy to the aquifer, from one m² to 1200 km²). Temporary observations also exist, like soil property measurements, remote sensing data, depending on the specific collaborative projects between different research and operational units. These two observation approaches, the perennial and the temporary ones, are a real advantage to investigate environmental issues. The Observatory and its embedded sub-catchments allow to conceptualize the change in scale and to study sub-catchments with different behaviors.
Last modified
2020-06-29 10:06:49
General Characteristics, Purpose, History
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Year Established
The creation of the ORACLE / BVRE Orgeval Research Observatory grouping together the watersheds of Orgeval, Grand Morin and Petit Morin, enables the study and understanding of the hydrological and biogeochemical functioning of anthropized rural areas, mainly sedimentary. The joint efforts of Irstea for more than 50 years and all of its partners have made it possible to set up and maintain this system of long-term observation of the environment. This system is now used to (i) identify the processes responsible for water and pollutant transfers at different scales, (ii) the establishment of hydrological and biogeochemical balances at the watershed scale, (iii) Term monitoring of the periodicity and stationarity of these assessments with regard to climate and anthropogenic changes as well as their ecosystem impact. The ORACLE / BVRE Orgeval research observatory is also an essential tool for reflection on environmental observation strategies, both for research questions and for operational objectives. Thus, the scientific project of the Observatory revolves around the following three axes:  Multi-scale and multi-parameter monitoring for the study of processes and the establishment of hydrological and biogeochemical balances (diffuse pollution) at the watershed scale;  Long-term monitoring to assess the periodicity and stationarity of the assessments in the light of global changes and their ecosystemic implications;  Measurement strategies and reflection on the modes of representation of systems: Optimization of data acquisition methods; Assimilation; Optimal representation scale; Conceptualization. The exceptional nature of this system means that it must be sought, on the one hand, for the best possible valuation, and on the other hand for extrapolation and comparison with data and results obtained elsewhere. It also leads to the implementation of multidisciplinary and interdisciplinary approaches to improve knowledge and modeling of the territorial entity that the watershed represents at different spatial and temporal scales. All these operations involve the provision of data, as well as the coordination of research and measurement devices deployed on the ORACLE / BVRE Orgeval Observatory.
In 1962, when the city of Coulommiers, just downstream the Orgeval confluence with the "Grand Morin", was faced to several damaging floods, they asked Irstea to study the hydrological behaviour of the Orgeval River. This was the beginning of a long-term observation with two objectifs, operational and immediate, on the one hand, scientific and deferred on the other, always overlapped, demonstrating over time in a pragmatic way their existing and necessary connection . Today, ORACLE /BVRE Orgeval gathers 9 research institutions and regional directorate through a "Group of Scientific Interest" (GIS ORACLE) created in 2005 for scientific exchanges, data sharing and research coordination. ORACLE /BVRE Orgeval is also one of the experimental area of the LTSER Zone Atelier Seine and its interdisciplinary research program, the Piren-Seine. ORACLE / BVRE Orgeval is dedicated to knowledge, education, information and public decision. Since 1962, a first hydro-meteorological device has been installed (rain gauges, meteorology, piezometrics and limnimetrics stations) to monitor the hydrosystem water balance. Water quality (rain, aquifer, drains and rivers) is monitored since 1975 to response to agricultur pollutions questions. If this network of "basic" measurements is maintained permanently to evaluate global changes, temporary observations also exist, like the high-frequency monitoring (flux tower, river-lab), remote sensing data, stream-aquifer exchanges or the environmental DNA monitoring depending on the specific collaborative projects.
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Affiliation and Network Specific Information
ILTERThis site is a verified "ILTER" member.
LTER EuropeThis site is a verified "LTER Europe" member.
LTER France (CZO_EU_FR_150)This site is a verified "LTER France" member.

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