WEPP

Last updated

The Water Erosion Prediction Project (WEPP) model is a physically based erosion simulation model built on the fundamentals of hydrology, plant science, hydraulics, and erosion mechanics. [1] [2] The model was developed by an interagency team of scientists to replace the Universal Soil Loss Equation (USLE) and has been widely used in the United States and the world. [3] WEPP requires four inputs, i.e., climate, topography, soil, and management (vegetation); and provides various types of outputs, including water balance (surface runoff, subsurface flow, and evapotranspiration), soil detachment and deposition at points along the slope, sediment delivery, and vegetation growth. The WEPP model has been improved continuously since its public delivery in 1995, and is applicable for a variety of areas (e.g., cropland, rangeland, forestry, fisheries, and surface coal mining).

Contents

Capability and strength

WEPP is applicable for a wide range of geographic and land-use and management conditions, and capable of predicting spatial and temporal distributions of soil detachment and deposition on an event or continuous basis at both small (hillslopes, roads, small parcels) and large (watershed) scales. [4] [5] [6] Hillslope applications of the model can simulate a single profile having various distributions of soil, vegetation, and plant/management conditions. In WEPP watershed applications, multiple hillslopes, channels, and impoundments can be linked together, and runoff and sediment yield from the entire catchment predicted. The model has been parameterized for a large number of soils across the U.S. and model performance has been assessed under a wide variety of land-use and management conditions. In addition, WEPP can generate long-term daily climatic data with CLIGEN, an auxiliary stochastic climate generator. [7] The CLIGEN database contains weather statistics from more than 2,600 weather stations in the United States. The WEPP climate database is supplemented by the PRISM database, [8] which further refines the climatic data based on longitude, latitude, and elevation. WEPP can provide daily runoff, subsurface flow, and sediment output categorized into five particle-size classes: primary clay, primary silt, small aggregates, large aggregates, and primary sand, allowing calculation of selective sediment transport, and enrichment of the fine sediment sizes.

Recent improvement

Over the last decade, researchers have made significant improvements to the WEPP model. These include improved algorithms to simulate the effect of hydraulic structures and impoundments on runoff and sediment delivery, [9] the addition of Penman–Monteith ET algorithms, [10] subsurface converging lateral flow to represent variable source area runoff, [11] improved canopy biomass routines for forested applications, [12] and the incorporation of an alternative, energy-balance-based winter hydrologic routine. [13] A number of modern graphical user interface programs have also been created, to assist in easier application of WEPP. The main interface for the model is a standalone Windows application (downloadable via: http://www.ars.usda.gov/Research/docs.htm?docid=10621), that allows a user to simulate hillslope profiles and small watersheds and have full control over all model inputs (Figure 1). Additionally, web-based interfaces allow rapid use of the model while accessing existing soil, climate, and management databases (Figure 2).

Figure 1. Screen capture of the WEPP Windows interface after completion of a 100-year hillslope simulation, showing text and graphical output results. WEPP Figure1.png
Figure 1. Screen capture of the WEPP Windows interface after completion of a 100-year hillslope simulation, showing text and graphical output results.
Figure 2. Screen capture of one of the WEPP web-based interfaces for simple hillslope profile simulations. Inputs for and results from a 30-year model run are shown. WEPP Figure2.png
Figure 2. Screen capture of one of the WEPP web-based interfaces for simple hillslope profile simulations. Inputs for and results from a 30-year model run are shown.
Figure 3. Screen capture of the WEPP web-based GIS interfaces for simple hillslope profile simulations. A small watershed with spatial soil erosion (red and green pixels) and deposition (yellow pixels) is shown. WEPP Figure3.png
Figure 3. Screen capture of the WEPP web-based GIS interfaces for simple hillslope profile simulations. A small watershed with spatial soil erosion (red and green pixels) and deposition (yellow pixels) is shown.

A number of geospatial interfaces to WEPP (example in Figure 3) are also available:

  1. GeoWEPP [14] [15] [16] – an ArcView or ArcGIS extension that runs in conjunction with the WEPP Windows interface
  2. On-line web-based GIS interface to WEPP using the open source MapServer GIS program [17]
  3. Iowa Daily Erosion Project [18]
  4. NetMap [19]

Forest and rangeland applications

The U.S. Forest Service has developed a suite of internet interfaces, the Forest Service WEPP (FS WEPP) interfaces, for easier applications by stakeholders in forest and rangeland management (forest engineers, rangeland scientists, federal and state regulatory personnel) and the general public. [20] The interfaces can be readily accessed and run through the internet (http://forest.moscowfsl.wsu.edu/fswepp/), and do not require any in-depth understanding of the hydrology, hydraulic and erosion principles embedded in the WEPP model. The FS WEPP interfaces include:

See also

Related Research Articles

<span class="mw-page-title-main">Hydrology</span> Science of the movement, distribution, and quality of water on Earth and other planets

Hydrology is the scientific study of the movement, distribution, and management of water on Earth and other planets, including the water cycle, water resources, and drainage basin sustainability. A practitioner of hydrology is called a hydrologist. Hydrologists are scientists studying earth or environmental science, civil or environmental engineering, and physical geography. Using various analytical methods and scientific techniques, they collect and analyze data to help solve water related problems such as environmental preservation, natural disasters, and water management.

<span class="mw-page-title-main">Soil erosion</span> Displacement of soil by water, wind, and lifeforms

Soil erosion is the denudation or wearing away of the upper layer of soil. It is a form of soil degradation. This natural process is caused by the dynamic activity of erosive agents, that is, water, ice (glaciers), snow, air (wind), plants, and animals. In accordance with these agents, erosion is sometimes divided into water erosion, glacial erosion, snow erosion, wind (aeolian) erosion, zoogenic erosion and anthropogenic erosion such as tillage erosion. Soil erosion may be a slow process that continues relatively unnoticed, or it may occur at an alarming rate causing a serious loss of topsoil. The loss of soil from farmland may be reflected in reduced crop production potential, lower surface water quality and damaged drainage networks. Soil erosion could also cause sinkholes.

<span class="mw-page-title-main">Stormwater</span> Water that originates during precipitation events and snow/ice melt

Stormwater, also written storm water, is water that originates from precipitation (storm), including heavy rain and meltwater from hail and snow. Stormwater can soak into the soil (infiltrate) and become groundwater, be stored on depressed land surface in ponds and puddles, evaporate back into the atmosphere, or contribute to surface runoff. Most runoff is conveyed directly as surface water to nearby streams, rivers or other large water bodies without treatment.

<span class="mw-page-title-main">Gully</span> Landform created by running water and/or mass movement eroding sharply into soil

A gully is a landform created by running water, mass movement, or commonly a combination of both eroding sharply into soil or other relatively erodible material, typically on a hillside or in river floodplains or terraces. Gullies resemble large ditches or small valleys, but are metres to tens of metres in depth and width, are characterized by a distinct 'headscarp' or 'headwall' and progress by headward erosion. Gullies are commonly related to intermittent or ephemeral water flow, usually associated with localised intense or protracted rainfall events or snowmelt. Gullies can be formed and accelerated by cultivation practices on hillslopes in farmland, and they can develop rapidly in rangelands from existing natural erosion forms subject to vegetative cover removal and livestock activity.

There are dozens of erosion prediction models. Some models focus on long-term erosion, as a component of landscape evolution. However, many erosion models were developed to quantify the effects of accelerated soil erosion i.e. soil erosion as influenced by human activity.

Drainage density is a quantity used to describe physical parameters of a drainage basin. First described by Robert E. Horton, drainage density is defined as the total length of channel in a drainage basin divided by the total area, represented by the following equation:

<span class="mw-page-title-main">Surface runoff</span> Flow of excess rainwater not infiltrating in the ground over its surface

Surface runoff is the unconfined flow of water over the ground surface, in contrast to channel runoff. It occurs when excess rainwater, stormwater, meltwater, or other sources, can no longer sufficiently rapidly infiltrate in the soil. This can occur when the soil is saturated by water to its full capacity, and the rain arrives more quickly than the soil can absorb it. Surface runoff often occurs because impervious areas do not allow water to soak into the ground. Furthermore, runoff can occur either through natural or human-made processes.

Runoff is the flow of water across the earth, and is a major component in the hydrological cycle. Runoff that flows over land before reaching a watercourse is referred to as surface runoff or overland flow. Once in a watercourse, runoff is referred to as streamflow, channel runoff, or river runoff. Urban runoff is surface runoff created by urbanization.

The runoff curve number is an empirical parameter used in hydrology for predicting direct runoff or infiltration from rainfall excess. The curve number method was developed by the USDA Natural Resources Conservation Service, which was formerly called the Soil Conservation Service or SCS — the number is still popularly known as a "SCS runoff curve number" in the literature. The runoff curve number was developed from an empirical analysis of runoff from small catchments and hillslope plots monitored by the USDA. It is widely used and is an efficient method for determining the approximate amount of direct runoff from a rainfall event in a particular area.

<span class="mw-page-title-main">Hydrological transport model</span>

An hydrological transport model is a mathematical model used to simulate the flow of rivers, streams, groundwater movement or drainage front displacement, and calculate water quality parameters. These models generally came into use in the 1960s and 1970s when demand for numerical forecasting of water quality and drainage was driven by environmental legislation, and at a similar time widespread access to significant computer power became available. Much of the original model development took place in the United States and United Kingdom, but today these models are refined and used worldwide.

<span class="mw-page-title-main">Burned area emergency response</span>

Burned area emergency response (BAER) is an emergency risk management reaction to post wildfire conditions that pose risks to human life and property or could further destabilize or degrade the burned lands. Even though wildfires are natural events, the presence of people and man-made structures in and adjacent to the burned area frequently requires continued emergency risk management actions. High severity wildfires pose a continuing flood, debris flow and mudflow risk to people living within and downstream from a burned watershed as well as a potential loss of desirable watershed values.

The Universal Soil Loss Equation (USLE) is a widely used mathematical model that describes soil erosion processes.

<span class="mw-page-title-main">Hydrological model</span> Predicting and managing water resources

A hydrologic model is a simplification of a real-world system that aids in understanding, predicting, and managing water resources. Both the flow and quality of water are commonly studied using hydrologic models.

Wildfires consume live and dead fuels, destabilize physical and ecological landscapes, and impact human social and economic systems. Post-fire seeding was initially used to stabilize soils. More recently it is being used to recover post wildfire plant species, manage invasive non-native plant populations and establish valued vegetation compositions.

GSSHA is a two-dimensional, physically based watershed model developed by the Engineer Research and Development Center of the United States Army Corps of Engineers. It simulates surface water and groundwater hydrology, erosion and sediment transport. The GSSHA model is used for hydraulic engineering and research, and is on the Federal Emergency Management Agency (FEMA) list of hydrologic models accepted for use in the national flood insurance program for flood hydrograph estimation. Input is best prepared by the Watershed Modeling System interface, which effectively links the model with geographic information systems (GIS).

SWAT is a river basin scale model developed to quantify the impact of land management practices in large, complex watersheds. SWAT is a public domain software enabled model actively supported by the USDA Agricultural Research Service at the Blackland Research & Extension Center in Temple, Texas, USA. It is a hydrology model with the following components: weather, surface runoff, return flow, percolation, evapotranspiration, transmission losses, pond and reservoir storage, crop growth and irrigation, groundwater flow, reach routing, nutrient and pesticide loading, and water transfer. SWAT can be considered a watershed hydrological transport model. This model is used worldwide and is continuously under development. As of July 2012, more than 1000 peer-reviewed articles have been published that document its various applications.

<span class="mw-page-title-main">Vflo</span>

Vflo is a commercially available, physics-based distributed hydrologic model generated by Vieux & Associates, Inc. Vflo uses radar rainfall data for hydrologic input to simulate distributed runoff. Vflo employs GIS maps for parameterization via a desktop interface. The model is suited for distributed hydrologic forecasting in post-analysis and in continuous operations. Vflo output is in the form of hydrographs at selected drainage network grids, as well as distributed runoff maps covering the watershed. Model applications include civil infrastructure operations and maintenance, stormwater prediction and emergency management, continuous and short-term surface water runoff, recharge estimation, soil moisture monitoring, land use planning, water quality monitoring, and water resources management.

The HUMUS project is a project that was funded by the Natural Resources Conservation Service to model the non-point source loading from 8-digit hydrologic unit cataloging units.

Post-fire hillslope stabilization treatments are treatments aimed at stabilizing fire-affected slopes by counteracting the negative impact of fire on vegetation and soil properties. The final objective of these treatments is reducing the risk of catastrophic runoff and erosion events and protecting valued resources downhill. Post-fire hillslope stabilization treatments are also called post-fire mitigation treatments and emergency stabilization treatments.

<span class="mw-page-title-main">Rainfall simulator</span> Device to study how soil reacts to rain

A rainfall simulator is used in soil science and hydrology to study how soil reacts to rainfall. Natural rainfall is difficult to use in experimentation because its timing and intensity cannot be reliably reproduced. Using simulated rainfall significantly speeds the study of erosion, surface runoff and leaching.

References

  1. ↑ Laflen, J.M., L.J. Lane, and G.R. Foster. 1991. WEPP—a next generation of erosion prediction technology. Journal of Soil Water Conservation 46(1): 34–38.
  2. ↑ Laflen, J.M., W.J. Elliot, D.C. Flanagan, C.R. Meyer, and M.A. Nearing. 1997. WEPP predicting water erosion using a process-based model. Journal of Soil Water Conservation 52(2): 96–102.
  3. ↑ Flanagan, D.C., J.E. Gilley and T.G. Franti. 2007. Water Erosion Prediction Project (WEPP): development history, model capabilities, and future enhancements. Transactions of the ASABE 50(5):1603-1612.
  4. ↑ Flanagan, D.C., and M.A. Nearing (eds.). 1995. USDA-Water Erosion Prediction Project (WEPP) Hillslope Profile and Watershed Model Documentation. NSERL Report No. 10, National Soil Erosion Research Laboratory, USDA-Agricultural Research Service, West Lafayette, Indiana.
  5. ↑ Flanagan, D.C., and S.J. Livingston, (eds.) 1995. WEPP User Summary. NSERL Rep. No. 11. West Lafayette, IN: USDA ARS NSERL.
  6. ↑ Flanagan, D.C., J.C. Ascough II, M.A. Nearing and J.M. Laflen. 2001. Chapter 7: The Water Erosion Prediction Project (WEPP) Model. In (R.S. Harmon and W.W. Doe III, eds.): Landscape Erosion and Evolution Modeling. Kluwer Academic / Plenum Publishers, New York, NY. 145-199
  7. ↑ Nicks, A.D., L.J. Lane, and G.A. Gander. 1995. Weather generator. In: Flanagan, D.C. and M.A. Nearing (eds.), USDA-Water Erosion Prediction Project Hillslope Profile and Watershed Model Documentation. NSERL Rep. 10. West Lafayette, IN: USDA ARS NSERL.
  8. ↑ Daly, C. 2009. PRISM Group. Available at: http://www.prism.oregonstate.edu/.
  9. ↑ Wu, J.Q., and S. Dun. 1998. Upgrading the WEPP watershed version for forest conditions. Final Report to USDA Forest Service, Rocky Mountain Research Station, Moscow, ID.
  10. ↑ Wu, J.Q., S. Dun, W.J. Elliot, and D.C. Flanagan. 2004. Modification and testing of the evapotranspiration (ET) routines in the WEPP model. Presented at the 2004 ASAE Annual International Meeting, August 1−4, 2004, Ottawa, Canada. St. Joseph, MI: ASAE.
  11. ↑ Wu, J.Q., S. Dun, W.J. Elliot, and D.C. Flanagan. 2004. Subsurface water flow routines in the WEPP model: Modification and validation. Presented at the 2004 ASAE Annual International Meeting, August 1−4, 2004, Ottawa, Canada. St. Joseph, MI: ASAE.
  12. ↑ Dun, S., J.Q. Wu, W.J. Elliot, P.R. Robichaud, D.C. Flanagan, J.R. Frankenberger, R.E. Brown and A.D. Xu. 2009. Adapting the Water Erosion Prediction Project (WEPP) Model for forest applications. Journal of Hydrology 366(1−4): 45–54.
  13. ↑ Singh, P., J.Q. Wu, D.K. McCool, S. Dun, C-H. Lin, and J.R. Morse. 2009. Winter hydrologic and erosion processes in the U.S. Palouse region: field experimentation and WEPP simulation. Vadose Zone Journal 8(2): 426–436.
  14. ↑ Cochrane, T.A., and D.C. Flanagan. 1999. Assessing water erosion in small watersheds using WEPP with GIS and digital elevation models. Journal of Soil Water Conservation 54(4): 678–685.
  15. ↑ Renschler, C.S., D.C. Flanagan, B.A. Engel and J.R. Frankenberger. 2002. GeoWEPP – the geospatial interface to the Water Erosion Prediction Project. ASAE Paper No. 02-2171. 10 pp.
  16. ↑ Renschler, C.S. 2003. Designing geo-spatial interfaces to scale process models: the GeoWEPP approach. Hydrological Processes 17(5): 1005–1017.
  17. ↑ Flanagan, D. C., J. R. Frankenberger and B. A. Engel. 2004. Web-based GIS application of the WEPP model. Paper No. 042024. Presented at the 2004 ASAE Annual International Meeting, August 1−4, 2004, Ottawa, Canada. St. Joseph, MI: ASAE. 12 p.
  18. ↑ Cruse, R.M., D.C. Flanagan, J.R. Frankenberger, B.K. Gelder, D. Herzmann, D. James, W. Krajewski, M. Kraszewski, J.M. Laflen, and D. Todey. 2006. Daily estimates of rainfall, water runoff, and soil erosion in Iowa. Journal of Soil Water Conservation. 61(4): 191–199.
  19. ↑ Benda, L., D. Miller, K. Andras, P. Bigelow, G. Reeves, and D. Michael. 2007. NetMap: a new tool in support of watershed science and resource management. Forest Science 53(2): 206–219.
  20. ↑ Elliot, W.J. 2004. WEPP internet interfaces for forest erosion prediction. Journal of the American Water Resources Association 40(2): 299–309.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.