Lagacherie P., Rabotin M., Colin F., Moussa R., Voltz Marc. (2010). Geo-MHYDAS : a landscape discretization tool for distributed hydrological modeling of cultivated areas. Computers and Geosciences, 36 (8), p. 1021-1032. ISSN 0098-3004.
Titre du document
Geo-MHYDAS : a landscape discretization tool for distributed hydrological modeling of cultivated areas
Lagacherie P., Rabotin M., Colin F., Moussa R., Voltz Marc
Source
Computers and Geosciences, 2010,
36 (8), p. 1021-1032 ISSN 0098-3004
The representation of landscape variabilities by means of an adequate landscape discretization is of major importance in distributed hydrological modeling. In this paper, we present Geo-MHYDAS, a landscape discretization tool that allows explicit representation of landscape features, particularly man-made ones, that are known to have a great impact on water and mass flows across the landscape. The landscape discretizations that are produced include user-controlled delineated irregular, linear or areal units connected to each other along a tree-like structure. Geo-MHYDAS includes three steps: (i) processing (i.e., the importation or the creation), followed by the modifications of the geographical objects, the limits of which are considered in the modeling as hydrological discontinuities, (ii) creation of the areal and linear units for hydrological modeling by a "selective cleaning" procedure after overlay that preserves, as much as possible, the object limits defined in the previous step, while having sizes and shapes that remain compatible with the application of the water flow functions of the hydrological model and (iii) building an oriented topology between irregularly shaped areal and linear units that allows the routing of the simulated water flows across the landscape. Geo-MHYDAS was developed using the open source free Geographic Information Systems (GIS) software GRASS. The use of Geo-MHYDAS was illustrated by running the hydrological model MHYDAS for different scenarios of man-made features, their presence and spatial organization within a small vineyard catchment located in the south of France (the Roujan catchment). Comparisons with hydrological modeling performed with usual landscape discretizations showed significant differences in the simulated hydrograms. This comparison illustrates well the strong impact of landscape discretizations on hydrological modeling, specifically on the man-made landscape features represented in Geo-MHYDAS.
