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Ephemeral gully erosion rates are controlled by various factors out of which topography plays an important role. This study investigates the possibility to predict the location of ephemeral gullies using two topographic attributes only: i.e., local slope gradient (S) and upslope contributing area per unit length of contour (A s ). An inverse relationship between S and A s , in which...
Generally, spatially distributed erosion models are `validated' using only data on runoff and sediment load collected at the catchment outlet. This implies that one of the most important aspects of such models, i.e. the prediction of the spatial variation of erosion and deposition within the catchment is not at all tested. After an extreme event in a small agricultural catchment in the Belgium loam...
Catchment resources, generated from multi-source data (remotely-sensed, map- and ground-based systems), were input to a raster-based Geographical Information Systems (GIS) after geometrically co-registered to a standard grid (pixel). The GIS used was the PC-based, indigenously-developed package, called GRAM (Geo-Referenced Area Management). A set of knowledge-based rules, for assessing the soil erosion...
Data from the Catsop catchment in South Limburg, Netherlands was simulated with the model KINEROS2. The results of calibration and validation on a split set of runoff and sediment data are reported and the variations in apparent parameters are analyzed. Calibration was performed with regard to the temporal distribution of runoff and sediment rather than single values such as total or peak rates. Based...
The soil erosion model for Mediterranean regions (SEMMED) is presented and used to produce regional maps of simulated soil loss for two Mediterranean test sites: one in southern France and one in Sicily. The model demonstrates the integrated use of (1) multi-temporal Landsat Thematic Mapper (TM) images to account for vegetation properties, (2) a digital terrain model in a GIS to account for topographical...
One consequence of global change will be shifts in the probability of occurrence of soil erosion by water. This could have serious consequences for those areas of the world which are present-day `hotspots' for erosion. By means of a case study, this paper suggests an approach to quantifying the change in risk of serious erosion for sites in such areas. The case study focuses on future erosion under...
One of the tasks of the International Geosphere-Biosphere Programme-Global Change and Terrestrial Ecosystems (IGBP-GCTE) Soil Erosion Network is to determine the suitability of modelling approaches for the estimation of soil erosion under global change. To achieve this, current erosion models are being evaluated in a series of GCTE meetings. This paper presents a synthesis of results from the first...
During rainstorms, physical properties of the soil surface change significantly. As a result of surface sealing, variations in infiltration rate, water content, water suction, bulk density and surface roughness can be observed and quantified. Dynamic processes taking place on the soil surface were investigated in laboratory and field experiments on a typical loess-derived soil in Germany. This study...
Validation of spatially distributed models using spatially distributed data represents a vital element in the development process; however, it is rarely undertaken. To a large extent, this reflects the problems associated with assembling erosion rate data, at appropriate temporal and spatial scales and with a suitable spatial resolution, for comparison with model results. The caesium-137 ( 1 ...
The Natural Resources Conservation Service (NRCS) of the US Department of Agriculture provides assistance for land management planning and the use of conservation measures on private farmland in the United States. The NRCS must concern itself with a broad range of issues with regard to models and their application to support the assessments and decision making associated with these activities. These...
The modified agricultural non-point source pollution model (AGNPSm) was used in this study to predict runoff volume, peak flow rate, and sediment yield in three different watersheds in Germany. It is a distributed parameter soil erosion model which uses simple approaches to hydrological and sediment calculations. Simulations were carried out in the Glonn G1 (1.2 km 2 ), and Glonn G2 (1.6 km...
Within the framework of the GCTE Soil Erosion Network the Limburg Soil Erosion Model (LISEM) has been tested and validated in two catchments in South-Limburg (the Netherlands) and Zululand (South Africa). The calibration and validation of the Green-Ampt version of the LISEM model using 10 storms from the Catsop catchment in the Netherlands shows that differences in measured and simulated hydrographs...
This paper describes the attempt to apply the MEDRUSH model to the Catsop basin in the Netherlands. The model is intended to run on hourly time steps for periods of up to 100 years and for areas of up to 2500 km 2 . The Catsop basin has an area of 0.42 km 2 and storm durations of up to 2 h in total. Model and catchment are therefore rather ill-matched, and the comparison is not successful...
This paper describes the application of the EROSION 3D soil erosion model to the CATSOP catchment in the Netherlands using data of 10 storms from the period of 1987 to 1993. Based on observed runoff data the model was calibrated by adjusting initial soil moisture. The computations result in a raster map showing the spatial pattern of predicted erosion and deposition within the catchment. The map corresponds...
The performance of the EUROSEM model is evaluated for a catchment in the Netherlands. The model is calibrated using observed hydrographs and sedigraphs by interactively changing the input parameters net capillary drive, initial soil moisture content, saturated hydraulic conductivity, cohesion, Manning's n and the detachability of soil particles. Storms with characteristics similar to the calibration...
Erosion of farmland due to concentrated flow is very severe on many unprotected fields across the United States. Small channels can turn into large gullies if not controlled. These small channels are routinely obliterated by tillage of the field and other routine farm operations only to be reformed again. Opposing slopes adjacent to an ephemeral gully allow runoff to reestablish a channel in approximately...
The main causes of gully formation are anthropogenic factors: the clearing of native forests, tilling of fallow lands and associated change of the hydrological conditions in the rainfall-runoff system. Gully channels formation is very rapid during the period of gully initiation, when morphological characteristics of a gully (length, depth, width, area, and volume) are far from stable. This period...
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