The GIS ORACLE is a "Group of Scientific Interest" created to work on the Research Observatory of the "Grand Morin" and "Petit Morin" river catchments, and particularly to develop studies on floods, low water periods, water quality and the impact of human activities on the environment.
The elaboration of a Research Observatory in Environment concerning the Orgeval , Grand Morin and Petit Morin basins which have been continuously studied for many years (since 1962 for the Orgeval), enables us to better understand hydrological processes in anthropized rural environments with a sedimentary dominant.
The GIS ORACLE is articulated around the three following points:
Observation and modeling of water and pollutants transfer processes at various scales; Hierarchisation of these processes ;
Observation and modeling of streamflow to improve risk forecast. Development and validation of methodology;
Strategies of measurement and consideration of the modes of representation of the systems: Optimization of the data acquisition methods ; Assimilation; Optimal scale of representation; Conceptualization.
The objective of this observatory is to identify the processes involved in the transfers of flow and pollutants at various scales, by the creation of a perennial device of observation of the variables and parameters concerned. The aim is to improve water quality, forecast and prevention of flood risks related to extreme hydrological events.
Accordingly, the occurence of novel data acquisition methods (hydrological radars, satellites), will make it possible to study the contribution of new spatialized data within modeling.
The experimental site of the GIS ORACLE is composed of the Grand Morin and Petit Morin catchments. These two basins, with a total surface area of 1675 km2, are representative of the highly anthropized rural Seine basin, with a moderate oceanic climate.
The availability of long hydrological and climatic time series on this geographical area makes it an exceptional site and should allow for a statistical approach of the phenomena and evolutions of the landscape, often difficult to obtain. Currently, on the Orgeval catchment area (affluent of Grand Morin, 104 km²), 47 years of chronicles of streamflow and 35 years worth of water quality data are available as well as many specific time series of measurement (hydrous state, biomass, roughness …)….).
The Orgeval experimental catchment studied by Irstea makes it possible to assess various scales of embedded catchments. A hydrological and climatic network followed by the DRIEE Ile de France and Météo-France on the two basins (Grand Morin and Petit Morin) supplements this device.