The Water Erosion Prediction Project (WEPP) model is a physically based

erosion Erosion is the action of surface processes (such as Surface runoff, water flow or wind) that removes soil, Rock (geology), rock, or dissolved material from one location on the Earth's crust#Crust, Earth's crust and then sediment transport, tran ...

simulation model built on the fundamentals of

hydrology 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 hydro ...

plant science Botany, also called plant science, is the branch of natural science and biology studying plants, especially their anatomy, taxonomy, and ecology. A botanist or plant scientist is a scientist who specialises in this field. "Plant" and "botany ...

hydraulics Hydraulics () is a technology and applied science using engineering, chemistry, and other sciences involving the mechanical properties and use of liquids. At a very basic level, hydraulics is the liquid counterpart of pneumatics, which concer ...

, and

mechanics. The model was developed by an interagency team of scientists to replace the

Universal Soil Loss Equation The Universal Soil Loss Equation (USLE) is a widely used mathematical model that describes soil erosion processes. Erosion models play critical roles in soil and water resource conservation and nonpoint source pollution assessments, including: se ...

(USLE) and has been widely used in the United States and the world. WEPP requires four inputs, i.e.,

climate Climate is the long-term weather pattern in a region, typically averaged over 30 years. More rigorously, it is the mean and variability of meteorological variables over a time spanning from months to millions of years. Some of the meteoro ...

topography Topography is the study of the forms and features of land surfaces. The topography of an area may refer to the landforms and features themselves, or a description or depiction in maps. Topography is a field of geoscience and planetary sci ...

soil Soil, also commonly referred to as earth, is a mixture of organic matter, minerals, gases, water, and organisms that together support the life of plants and soil organisms. Some scientific definitions distinguish dirt from ''soil'' by re ...

, and management (

vegetation Vegetation is an assemblage of plants and the ground cover they provide. It is a general term, without specific reference to particular Taxon, taxa, life forms, structure, Spatial ecology, spatial extent, or any other specific Botany, botanic ...

); and provides various types of outputs, including

water balance The law of water balance states that the inflows to any water system or area is equal to its outflows plus change in storage during a time interval. In hydrology, a water balance equation can be used to describe the flow of water in and out of ...

(

surface runoff Surface runoff (also known as overland flow or terrestrial runoff) is the unconfined flow of water over the ground surface, in contrast to ''channel runoff'' (or ''stream flow''). It occurs when excess rainwater, stormwater, meltwater, or other ...

, subsurface flow, and

evapotranspiration Evapotranspiration (ET) refers to the combined processes which move water from the Earth's surface (open water and ice surfaces, bare soil and vegetation) into the Atmosphere of Earth, atmosphere. It covers both water evaporation (movement of w ...

), 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 Rangelands are grasslands, shrublands, woodlands, wetlands, and deserts that are grazed by domestic livestock or wild animals. Types of rangelands include tallgrass and shortgrass prairies, desert grasslands and shrublands, woodlands, savanna ...

forestry Forestry is the science and craft of creating, managing, planting, using, conserving and repairing forests and woodlands for associated resources for human and Natural environment, environmental benefits. Forestry is practiced in plantations and ...

fisheries Fishery can mean either the enterprise of raising or harvesting fish and other aquatic life or, more commonly, the site where such enterprise takes place ( a.k.a., fishing grounds). Commercial fisheries include wild fisheries and fish farm ...

, and surface

coal mining Coal mining is the process of resource extraction, extracting coal from the ground or from a mine. Coal is valued for its Energy value of coal, energy content and since the 1880s has been widely used to Electricity generation, generate electr ...

Capability and strength

WEPP is applicable for a wide range of geographic and

land-use Land use is an umbrella term to describe what happens on a parcel of land. It concerns the benefits derived from using the land, and also the land management actions that humans carry out there. The following categories are used for land use: fore ...

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 Watershed may refer to: Hydrology * Drainage divide, the line that separates neighbouring drainage basins * Drainage basin, an area of land where surface water converges (North American usage) Music * Watershed Music Festival, an annual country ...

) scales. Hillslope applications of the model can simulate a single profile having various distributions of

, and plant/management conditions. In WEPP watershed applications, multiple hillslopes,

channels Channel, channels, channeling, etc., may refer to: Geography * Channel (geography), a landform consisting of the outline (banks) of the path of a narrow body of water. Australia * Channel Country, region of outback Australia in Queensland and pa ...

, and impoundments can be linked together, and runoff and

sediment Sediment is a solid material that is transported to a new location where it is deposited. It occurs naturally and, through the processes of weathering and erosion, is broken down and subsequently sediment transport, transported by the action of ...

yield from the entire

catchment A drainage basin is an area of land in which all flowing surface water converges to a single point, such as a river mouth, or flows into another body of water, such as a lake or ocean. A basin is separated from adjacent basins by a perimeter, th ...

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

and management conditions. In addition, WEPP can generate long-term daily climatic data with CLIGEN, an auxiliary

stochastic Stochastic (; ) is the property of being well-described by a random probability distribution. ''Stochasticity'' and ''randomness'' are technically distinct concepts: the former refers to a modeling approach, while the latter describes phenomena; i ...

climate generator. The CLIGEN database contains weather

statistics Statistics (from German language, German: ', "description of a State (polity), state, a country") is the discipline that concerns the collection, organization, analysis, interpretation, and presentation of data. In applying statistics to a s ...

from more than 2,600

weather station A weather station is a facility, either on land or sea, with instruments and equipment for measuring atmosphere of Earth, atmospheric conditions to provide information for weather forecasting, weather forecasts and to study the weather and clima ...

s in the United States. The WEPP climate database is supplemented by th
PRISM database
which further refines the climatic data based on

longitude Longitude (, ) is a geographic coordinate that specifies the east- west position of a point on the surface of the Earth, or another celestial body. It is an angular measurement, usually expressed in degrees and denoted by the Greek lett ...

latitude In geography, latitude is a geographic coordinate system, geographic coordinate that specifies the north-south position of a point on the surface of the Earth or another celestial body. Latitude is given as an angle that ranges from −90° at t ...

, and

elevation The elevation of a geographic location (geography), ''location'' is its height above or below a fixed reference point, most commonly a reference geoid, a mathematical model of the Earth's sea level as an equipotential gravitational equipotenti ...

. WEPP can provide daily runoff, subsurface flow, and

output categorized into five particle-size classes: primary

clay Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolinite, ). Most pure clay minerals are white or light-coloured, but natural clays show a variety of colours from impuriti ...

, primary

silt Silt is granular material of a size between sand and clay and composed mostly of broken grains of quartz. Silt may occur as a soil (often mixed with sand or clay) or as sediment mixed in suspension (chemistry), suspension with water. Silt usually ...

, small aggregates, large aggregates, and primary

sand Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is usually defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a textural ...

, allowing calculation of selective

sediment transport Sediment transport is the movement of solid particles (sediment), typically due to a combination of gravity acting on the sediment, and the movement of the fluid in which the sediment is entrained. Sediment transport occurs in natural systems wh ...

, 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

algorithm In mathematics and computer science, an algorithm () is a finite sequence of Rigour#Mathematics, mathematically rigorous instructions, typically used to solve a class of specific Computational problem, problems or to perform a computation. Algo ...

s to simulate the effect of

hydraulic structure A hydraulic structure is a structure submerged or partially submerged in any body of water, which disrupts the natural flow of water. They can be used to divert, disrupt or completely stop the flow. An example of a hydraulic structure would be a da ...

s and impoundments on runoff and sediment delivery, the addition of Penman–Monteith ET algorithms, subsurface converging lateral flow to represent variable source area runoff, improved

canopy Canopy may refer to: Plants * Canopy (biology), aboveground portion of plant community or crop (including forests) * Canopy (grape), aboveground portion of grapes Religion and ceremonies * Baldachin or canopy of state, typically placed over an a ...

biomass Biomass is a term used in several contexts: in the context of ecology it means living organisms, and in the context of bioenergy it means matter from recently living (but now dead) organisms. In the latter context, there are variations in how ...

routines for forested applications, and the incorporation of an alternative, energy-balance-based winter hydrologic routine. 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 Windows is a Product lining, product line of Proprietary software, proprietary graphical user interface, graphical operating systems developed and marketed by Microsoft. It is grouped into families and subfamilies that cater to particular sec ...

application (downloadable via: https://www.ars.usda.gov/midwest-area/west-lafayette-in/national-soil-erosion-research/docs/wepp/research/), 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

, and management databases (Figure 2). A number of

geospatial Geographic data and information is defined in the ISO/TC 211 series of standards as data and information having an implicit or explicit association with a location relative to Earth (a geographic location or geographic position). It is also call ...

interfaces Interface or interfacing may refer to: Academic journals * ''Interface'' (journal), by the Electrochemical Society * '' Interface, Journal of Applied Linguistics'', now merged with ''ITL International Journal of Applied Linguistics'' * '' Inter ...

to WEPP (example in Figure 3) are also available:
GeoWEPP
– an

ArcView ArcView, now referred to as ArcGIS for Desktop Basic, is the entry-level licensing level of ArcGIS Desktop, a geographic information system software product produced by Esri. It is intended by Esri to be the logical migration path from ArcView ...

ArcGIS ArcGIS is a family of client, server and online geographic information system (GIS) software developed and maintained by Esri. ArcGIS was first released in 1982 as ARC/INFO, a command line-based GIS. ARC/INFO was later merged into ArcGIS De ...

extension that runs in conjunction with the WEPP Windows interface
On-line web-based GIS interface to WEPP
using the open source

MapServer MapServer is an open-source development environment for building spatially enabled internet applications, built in the C language, and is widely known as one of the fastest Web mapping engines available. It can run as a CGI program or via MapSc ...

GIS A geographic information system (GIS) consists of integrated computer hardware and software that store, manage, analyze, edit, output, and visualize geographic data. Much of this often happens within a spatial database; however, this is not ...

program
Iowa Daily Erosion Project

NetMap

Forest and rangeland applications

The

U.S. Forest Service The United States Forest Service (USFS) is an agency within the U.S. Department of Agriculture. It administers the nation's 154 national forests and 20 national grasslands covering of land. The major divisions of the agency are the Chief's ...

has developed a suite of internet

, th
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.Elliot, W.J. 2004. WEPP internet interfaces for forest erosion prediction. ''Journal of the American Water Resources Association'' 40(2): 299–309. 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

hydraulic Hydraulics () is a technology and applied science using engineering, chemistry, and other sciences involving the mechanical properties and use of liquids. At a very basic level, hydraulics is the liquid counterpart of pneumatics, which concer ...

and

principle A principle may relate to a fundamental truth or proposition that serves as the foundation for a system of beliefs or behavior or a chain of reasoning. They provide a guide for behavior or evaluation. A principle can make values explicit, so t ...

s embedded in the WEPP model. The FS WEPP interfaces include: * Cross Drain – to predict sediment yield from a road segment across a

buffer Buffer may refer to: Science * Buffer gas, an inert or nonflammable gas * Buffer solution, a solution used to prevent changes in pH * Lysis buffer, in cell biology * Metal ion buffer * Mineral redox buffer, in geology Technology and engineeri ...

* Rock:Clime – to create and download a modified WEPP climate file * WEPP:Road – to predict erosion from a forest road segment * WEPP:Road Batch – to predict erosion from multiple forest road segments * Disturbed WEPP – to predict erosion from rangeland and forest disturbances (

wildfire A wildfire, forest fire, or a bushfire is an unplanned and uncontrolled fire in an area of Combustibility and flammability, combustible vegetation. Depending on the type of vegetation present, a wildfire may be more specifically identified as a ...

, harvest operations) * Tahoe Basin Sediment Model (under construction) – to predict runoff and erosion for the

Lake Tahoe Lake Tahoe (; Washo language, Washo: ''dáʔaw'') is a Fresh water, freshwater lake in the Sierra Nevada of the Western United States, straddling the border between California and Nevada. Lying at above sea level, Lake Tahoe is the largest a ...

Basin * WEPP FuME (Fuel Management) – to predict erosion from fuel management practices * ERMiT (Erosion Risk Management Tool) – to predict the

probability Probability is a branch of mathematics and statistics concerning events and numerical descriptions of how likely they are to occur. The probability of an event is a number between 0 and 1; the larger the probability, the more likely an e ...

of sediment delivery with various mitigation treatments in each of five years following

References

{{Reflist

External links

WEPP – Official site
�
National Soil Erosion Research Laboratory (NSERL), USDA Agricultural Research Service

�
NSERL, USDA Agricultural Research Service

Forest Service WEPP Interfaces
–

USDA Forest Service The United States Forest Service (USFS) is an agency within the U.S. Department of Agriculture. It administers the nation's 154 national forests and 20 national grasslands covering of land. The major divisions of the agency are the Chief's ...

Rocky Mountain Research Station The Rocky Mountain Research Station (RMRS) is one of five regional units that make up the United States Forest Service Research and Development organization — the most extensive natural resources research organization in the world. The station ...

GeoWEPP
–

SUNY Buffalo The State University of New York at Buffalo (commonly referred to as UB, University at Buffalo, and sometimes SUNY Buffalo) is a public research university in Buffalo and Amherst, New York, United States. The university was founded in 1846 as ...

NetMap
– Earth Systems Institute Environmental science Environmental soil science Water and the environment Water pollution Water resources management Hydrology models

Capability and strength

Recent improvement

Forest and rangeland applications

See also

References

External links