Building a hydrological analysis and simulation system for drainage basin application. / Construção de um sistema de análise e simulação hidrológica: aplicação a bacias hidrográfica.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2003

RESUMO

Hydrological models are useful tools to understand the hydrological behavior of watersheds. These models should represent most of hydrological processes to be able to produce realistic results. However, models are only an aproximation of the truth and they require good initialization of state variables and a large amount of data to properly represent the processes. This works aims at presenting a hydrological analysis and simulation system, denominated SASHI (the acronym derives from the Portuguese ?Sistema de Análise de Simulação Hidrológica?). This computer system uses a contourbased method to subdivide a basin into irregular elements (polygons). These elements will be the basic spatial unit for the hydrological model. The implemented hydrological model was designed to enable the simulation of the soil-vegetation-atmosphere system behavior considering the spatial variation of each component and predicting the dynamic interactions as well as energy and water fluxes. The soil hydrology is described by the Richards equation and adopts the roadbridge-White model to simplify the solution of this equation using a finite difference as numerical solution technique. SASHI allows to automatically extract basin boundaries from the contour lines and the drainage, and to calculate some morphometric indices from these basins. It also calculates the topographic index which can be used by the hydrological model to estimate the initial condition of the soil humidity. SASHI was tested in a sub-basin of Corumbataí river in São Paulo State, Brazil. A discussion about the discretization method and the initialization of the hydrological model was presented. Two hydrological simulations were tested for the period August 1994 - July 1995: one considering a 1 m2/m2 LAI forest and the other a 4 m2/m2 LAI forest, using the same soil and climate data. The results of the discretization showed that the irregular elements could satisfactorily represent the variability of slope and aspect of the basin. The simulation pointed out the necessity of defining an upward water flux, below soil profile, in order to maintain the evapotranspiration process during dry seasons.

ASSUNTO(S)

water flow soil moisture modelos hidrológicos fluxos de água hydrology models discretização watershed discretization bacia hidrografica umidade de solo

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