Author(s): G. R. Calle; E. A. Varas
Linked Author(s):
Keywords: Geomorphological dispersion; Hydrodynamic dispersion; Geographic information systems; Rainfall-runoff models; Kinematic wave diffusion equation; Geomorphological instantaneous unit hydrograph
Abstract: Until now the effects of the spatial variation of the geomorphologic and hydrodynamic mechanisms on the hydrologic resp onse of watershed have not been analyzed. This work presents a methodlology that yields analytical expressions for the variance of travel time of surface water in the watershed, comlbining a model of propagation, based on the kin ematic wave difusion equation, and digital elevation mo dlels (DEM). The variance in the travel time allows us to analyze the difusive effects in the response; while the use of the DEM permits an examination of the spatial variation of the parameters. The obtained form expresses the variance lilke a separable function of the hydrodynamic dispersion coeffiaient ▲ and of the geomorphol ogical dispersion coeffiaient ▲, when spatial variati on of the parameters exists. It is then posible to analyze the relative importance of the geomorphologic and hydrodynamic mechanisms in the response of the wat er shed through the non-dimensional parameter, ▲, that represents the ratio between ▲ and the sum of ▲ and ▲. This methodology was applied in five South American watersheds considering two flow zones. overland and stream flow, determining relati ons between the coefficients ▲, ▲ and ▲. for different sizes and drainage network configurations.
Year: 2003