climate change is one of the most important problems in the present century. so assessing and prediction of future changes is important on water resources and so important for economics and socio-economic consequences. the purpose of this research is assessing the effects of climate change on surface runoff volumes under the scenarios: a1b, a2 and b1 using hadcm3 general circulation model and i...

Rainfall simulation experiments were conducted on annual grassland and coastal sage scrub hillslopes to determine the quantities of C and N removed by surface runoff in sediment and solution. Undisturbed coastal sage scrub soils have very high infiltration capacities (> 140 mm h(-1)), preventing the generation of surface runoff. Trampling disturbance to the sage scrub plots dramatically reduced...

introduction flood is an inevitable natural phenomenon occurring from time to time in all rivers and natural drainage systems, which not only damages the lives, natural resources and environment, but also causes the loss of economy and health. so estimation and prediction flood hazard is very important spatially in the watersheds without measurement station. there are many models in the water a...

Estimation of surface runoff in a watershed based on the rate of received precipitation and quantifying discharge at outlet is important in hydrologic studies. In this study, HEC-HMS hydrological model version 3.4 was used to simulate rainfall-runoff process in Abnama watershed located in south of Iran. To compute infiltration, rainfall excess conversion to runoff and flow routing, methods like...

Significant advances in upland erosion modeling have been achieved in the past decade. The TREX (Two-dimensional Runoff, Erosion, and Export) watershed model has been developed at Colorado State University for the simulation of surface runoff from spatially and temporally distributed rainstorms on watersheds. The model has been applied in several countries with different climatic conditions. TR...

Soil and water conservation measures can impact hydrological cycle, but quantitative analysis of this impact is still difficult in a watershed scale. To assess the effect quantitatively, a three-dimensional finite-difference groundwater flow model (MODFLOW) with a surface runoff model-the Soil Conservation Service (SCS) were calibrated and applied based on the artificial rainfall experiments. T...

The effect of soil surface roughness on runoff and sediment production is an area not yet fully quantified. Current erosion prediction models, such as the Revised Universal Soil Loss Equation, predicts a reduced erosion from an increased soil roughness, without considering the functionality associated with different roughness forms. In this research, we used a mechanistic approach in which soil...

Phosphorus losses from agricultural land can cause accelerated eutrophication of surface water bodies. This study evaluated the use of soil test phosphorus (STP) levels to predict dissolved inorganic phosphorus (DIP) concentrations in runoff water from agricultural soils using laboratory rainfall simulation. The objectives of this study were to determine (i) to what extent STP concentrations ca...