MHYDAS (Modélisation Hydrologique Des AgroSystèmes) is an hydrological model for water exchanges, pollutants and erosion transport in cultivated landscapes
The MHYDAS model (Moussa et al., 2002, Hydrol. Process. 16) allows the representation of water production and transfer on surface, the surface-subsurface simplified exchanges and the water balance at different scales - from plot to watershed, and from rain event to annual or pluri-annual simulations. It also includes thematic modules as pollutant fate and transport, and erosive transfer.
The MHYDAS model takes into account specific features of agricultural landscapes : the influence of landscape discontinuities (reachs, plots, banks...), runoff-infiltration partition according to land use, exchanges between groundwater tables and ditches, pollutants fate ...
It is available through the OpenFLUID modelling software, as a pluggable set including a graphical extension for the digital landscape representation (Geo-MHYDAS) and several coupled simulators for processes modelling.
The dynamics of the MHYDAS model is based on coupled simulators allows the representation of several processes. Currently, the surface hydrology module is available as free download : it is composed of a production function and a transfer function. The production function splits the rainfall into infiltration and runoff on the surface units with the Morel-Seytoux method (1978). The transfer function transfers the runoff onto the different spatial units (surface and reach segments) and is based on the semi-analytical solution of Hayami (1951).
This module requires the rainfall as inputdata, a parametrisation related to the choosen resolution methods and a parametrisation of the spatial units based on geographical and hydrological data (spatial units geometry, soil hydraulic properties and initial moisture).
The actual research focuses on modelling processes such as surface hydrology, surface-subsurface exchanges, erosion transport, contamination and pollutant transport... Several numerical approaches for modelling of a same process are also considered: finite differences methods or (semi-)analytical solutions,...
If you want to use the MHYDAS model for other processes or using other numerical solutions, please feel free to contact us.
- H. Morel-Seytoux. Derivation of equations for variable rainfall infiltration. Water Resources Research , 14:561–568, 1978.
- Hayami, S. 1951. ‘On the propagation of flood waves’, Disaster Prev. Res. Inst. Bull., 1, 1–16.
Landscape representation for the MHYDAS model is based on taking into account the spatial heterogeneities of the cultivated landscape. They lead to hydrological discontinuities and fast responses at high spatial resolutions.
The digital landscape representation for MHYDAS model requires :
The MHYDAS model was used to model the hydrological processes at various scales, from plot to watershed.