mathematical models have the potential to provide a cost-effective, objective, and flexible approach to assessing management decisions, particularly when these decisions are strategic alternatives. in some instances, mathematical model is the only means available for evaluating and testing alternatives.  however, in order for this potential to be realized, models must be valid for the applicati...

Abstract The present study was conducted to examine the accuracy and applicability of hydrological models Soil Water Assessment Tool (SWAT) Hydrologic Engineering Center (HEC)- Modeling System (HMS) simulate streamflows. Models combined with ArcGIS interface have been used for in humid tropical Hemavathi catchment (5,427 square kilometer). critical focus streamflow analysis determine efficiency...

Abstrac t . A two-stage approach is discussed for reconstructing a dense digital elevation model (DEM) of the terrain from multiple pre-calibrated images taken by distinct cameras at different time under various illumination. First, the terrain DEM and orthoimage are obtained by independent voxel-based reconstruction of the terrain points using simple relations between the corresponding image g...

preparation of the topographic factor (ls) map in rusle model is a very tedious step because of the complicated effects of topography on soil loss. the objective of this study was to determine the suitable cell size of digital elevation model (dem) for computing ls factor by the method of moore and wilson (1992) in a 5326 ha area, northwest of tehran province. towards this end, cell sizes of 30...

We report on the synthesis of the Discrete Element Method (DEM) modelling the behaviour of granular materials and a finite volume model for the continuous interstitial fluid using Computational Fluid Dynamics (CFD). DEM captures the physics of granular materials best but is computationally time-consuming. For this reason, the DEM is complemented by a Discrete Phase Model (DPM) for disperse gran...

A Digital Elevation Model (DEM) refers to a quantitative model of a part of the earth’s surface in digital form (Burrough and McDonnell, 1998). A DEM consists of either (1) a twodimensional array of numbers that represents the spatial distribution of elevations on a regular grid; (2) a set of x, y, and z coordinates for an irregular network of points; or (3) contour strings stored in the form o...

Topography is a crucial surface characteristic in soil erosion modeling. Soil erosion studies use a digital elevation model (DEM) to derive the topographical characteristics of a study area. Majority of the times, a DEM is incorporated into erosion models as a given parameter and it is not tested as extensively as are the parameters related to soil, land-use and climate. This study compares ero...