Abstract:

The ecological services of forests, especially water and soil conservation, vary spatially due to the spatial heterogeneity of physical geographical elements, such as topography, soil, vegetation, climate. Guansi River hydrological (GSH)model, a general physically based distributed hydrological model on watershed level, was established in this paper. In GSH model, the watershed was distinguished into different regular cells. Each cell was supposed to be homogeneous in canopy structure, litter composition and structure, land surface features, and soil characteristics which were defined as different layers in the model. GSH model calculated water movements through the canopy and soil layers in every cell of the watershed and simulated water flow among neighbor cells, including rainfall, canopy interception, absorption of litter layer, infiltration, evapotranspiration, subsurface runoff and surface runoff. It can be obtained from GSH model the change of water distribution in the watershed when using the change of physical elements in both spatial and temporal dimensions as input of the model. By using GSH model, rainfall runoff processes were simulated in Guansi River watershed, Sichuan Province, Southwest China. The simulated result agreed well with the measured data.

Key words: Forest hydrology, Physically based distributed hydrological model, Ecological services of forest, Spatial heterogeneity