Water Erosion Prediction Project (water + erosion_prediction_project)

Distribution by Scientific Domains

Selected Abstracts

DWEPP: a dynamic soil erosion model based on WEPP source terms

N. S. Bulygina
Abstract A new rangeland overland-flow erosion model was developed based on Water Erosion Prediction Project (WEPP) sediment source and sink terms. Total sediment yield was estimated for rainfall simulation plots from the WEPP field experiments as well as for a small watershed without a well developed channel network. Both WEPP and DWEPP gave a similar level of prediction accuracy for total event soil losses measured from both rainfall simulation and small watershed experiments. Predictions for plot and hillslope scale erosion simulations were in the range of expected natural variability. Sediment yield dynamics were plotted and compared with experimental results for plots and hillslope, and the results were satisfactory. Effects of cover and canopy on the predicted sediment yields were well represented by the model. DWEPP provides a new tool for assessing erosion rates and dynamics, has physically based erosion mechanics descriptions, is sensitive to treatment differences on the experimental plots and has a well developed parameter database inherited from WEPP. Copyright 2006 John Wiley & Sons, Ltd. [source]

First-year post-fire erosion rates in Bitterroot National Forest, Montana,

Kevin M. Spigel
Abstract Accelerated runoff and erosion commonly occur following forest fires due to combustion of protective forest floor material, which results in bare soil being exposed to overland flow and raindrop impact, as well as water repellent soil conditions. After the 2000 Valley Complex Fires in the Bitterroot National Forest of west-central Montana, four sets of six hillslope plots were established to measure first-year post-wildfire erosion rates on steep slopes (greater than 50%) that had burned with high severity. Silt fences were installed at the base of each plot to trap eroded sediment from a contributing area of 100 m2. Rain gauges were installed to correlate rain event characteristics to the event sediment yield. After each sediment-producing rain event, the collected sediment was removed from the silt fence and weighed on site, and a sub-sample taken to determine dry weight, particle size distribution, organic matter content, and nutrient content of the eroded material. Rainfall intensity was the only significant factor in determining post-fire erosion rates from individual storm events. Short duration, high intensity thunderstorms with a maximum 10-min rainfall intensity of 75 mm h,1 caused the highest erosion rates (greater than 20 t ha,1). Long duration, low intensity rains produced little erosion (less than 001 t ha,1). Total C and N in the collected sediment varied directly with the organic matter; because the collected sediment was mostly mineral soil, the C and N content was small. Minimal amounts of Mg, Ca, and K were detected in the eroded sediments. The mean annual erosion rate predicted by Disturbed WEPP (Water Erosion Prediction Project) was 15% less than the mean annual erosion rate measured, which is within the accuracy range of the model. Published in 2007 by John Wiley & Sons, Ltd. [source]


John M. Laflen
ABSTRACT: The objectives of this paper are to discuss expectations for the Water Erosion Prediction Project (WEPP) accuracy, to review published studies related to WEPP goodness of fit, and to evaluate these in the context of expectations for WEPP's goodness of fit. WEPP model erosion predictions have been compared in numerous studies to observed values for soil loss and sediment delivery from cropland plots, forest roads, irrigated lands and small watersheds. A number of different techniques for evaluating WEPP have been used, including one recently developed where the ability of WEPP to accurately predict soil erosion can be compared to the accuracy of replicated plots to predict soil erosion. In one study involving 1,594 years of data from runoff plots, WEPP performed similarly to the Universal Soil Loss Erosion (USLE) technology, indicating that WEPP has met the criteria of results being "at least as good with respect to observed data and known relationships as those from the USLE," particularly when the USLE technology was developed using relationships derived from that data set, and using soil erodibility values measured on those plots using data sets from the same period of record. In many cases, WEPP performed as well as could be expected, based on comparisons with the variability in replicate data sets. One major finding has been that soil erodibility values calculated using the technology in WEPP for rainfall conditions may not be suitable for furrow irrigated conditions. WEPP was found to represent the major storms that account for high percentages of soil loss quite well,a single storm application that the USLE technology is unsuitable for,and WEPP has performed well for disturbed forests and forest roads. WEPP has been able to reflect the extremes of soil loss, being quite responsive to the wide differences in cropping, tillage, and other forms of management, one of the requirements for WEPP validation. WEPP was also found to perform well on a wide range of small watersheds, an area where USLE technology cannot be used. [source]

Erosion modelling approach to simulate the effect of land management options on soil loss by considering catenary soil development and farmers perception

A. C. Brunner
Abstract The prevention of soil erosion is one of the most essential requirements for sustainable agriculture in developing countries. In recent years it is widely recognized that more site-specific approaches are needed to assess variations in erosion susceptibility in order to select the most suitable land management methods for individual hillslope sections. This study quantifies the influence of different land management methods on soil erosion by modelling soil loss for individual soil-landscape units on a hillslope in Southern Uganda. The research combines a soil erosion modelling approach using the physically based Water Erosion Prediction Project (WEPP)-model with catenary soil development along hillslopes. Additionally, farmers' perceptions of soil erosion and sedimentation are considered in a hillslope mapping approach. The detailed soil survey confirmed a well-developed catenary soil sequence along the hillslope and the participatory hillslope mapping exercise proved that farmers can distinguish natural soil property changes using their local knowledge. WEPP-model simulations show that differences in soil properties, related to the topography along the hillslope, have a significant impact on total soil loss. Shoulder and backslope positions with steeper slope gradients were most sensitive to changes in land management. Furthermore, soil conservation techniques such as residue management and contouring could reduce soil erosion by up to 70 percent on erosion-sensitive slope sections compared to that under tillage practices presently used at the study site. The calibrated model may be used as a tool to provide quantitative information to farmers regarding more site-specific land management options. Copyright 2008 John Wiley & Sons, Ltd. [source]

Application of the WEPP model for prioritization and evaluation of best management practices in an Indian watershed

A. Pandey
Abstract The pre-calibrated and validated physically based watershed model, water erosion prediction project (WEPP) was used as a modelling tool for the identification of critical watersheds and evaluation of best management practices for a small hilly watershed (Karso) of India. The land use/cover of the study area was generated using IRS-1C LISS-III (linear imaging self scanner) satellite data. The watershed and sub-watershed boundaries, drainage, slope and soil map of the study area were generated using ARC/INFO geographic information system (GIS). The WEPP model was finally applied to the Karso watershed which lies within Damodar Barakar catchment of India to identify the critical sub-watersheds on the basis of their simulated average annual sediment yields. Priorities were fixed on the basis of ranks assigned to each critical sub-watershed based on the susceptibility to erosion. The sub-watershed having the highest sediment yield was assigned a priority number 1, the next highest value was assigned a priority number 2, and so on. Subsequently, the model was used for evaluating the effectiveness of best management practices (crop and tillage) for conservation of soil for all the sub-watersheds. On the basis of this study, it is realized that cash crops like soyabean should be encouraged in the upland portion of the sub-watersheds, and the existing tillage practice (country plough/mould board plough) may be replaced by a field cultivation system for conservation of soil and water in the sub-watersheds. Copyright 2009 John Wiley & Sons, Ltd. [source]