Volume 34, Number 4, 2010

Use of spatial representation to calculate the topographic factor in the revised universal soil loss equation in watersheds

Jean Paolo Gomes Minella, Gustavo Henrique Merten, Anderson Luis Ruhoff

01/Aug/2010

Methods of spatial representation to calculate the topographic factor (LS) of the Revised Universal Soil Loss Equation (USLE) have been used to estimate soil erosion and sediment yield of watersheds. These procedures are based on equations traditionally used to determine the LS factor and information that characterize the hillslope forms and processes, derived from the Digital Elevation Model (DEM). Two computational methods commonly used to calculate LS factor in soil erosion and sediment yield models were analyzed in this study. […]

Modeling water movement in horizontal columns using fractal theory

Tairone Paiva Leão, Edmund Perfect

01/Aug/2010

Fractal mathematics has been used to characterize water and solute transport in porous media and also to characterize and simulate porous media properties. The objective of this study was to evaluate the correlation between the soil infiltration parameters sorptivity (S) and time exponent (n) and the parameters dimension (D) and the Hurst exponent (H). For this purpose, ten horizontal columns with pure (either clay or loam) and heterogeneous porous media (clay and loam distributed in layers in the column) were […]

Relations of sediment delivery underlying payments for environmental services in catchment areas

Henrique Marinho Leite Chaves

01/Aug/2010

Because of its simplicity, the sediment delivery ratio (SDR), based on the ratio of the sediment yield (Y) and the gross erosion (E) in the basin, is widely used to estimate sediment production in watersheds. Since Y and E are complexly linked, several SDR equations were developed. Financial compensation programs resulting from sedimentation abatement, such as the Water Provider Program, often require the estimation of reduction of the downstream sediment yield as a function of erosion reduction upstream. This study […]

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