Related Topics

1a.Objectives (from AD-416)
1) Integrate the WEPP and WEPS model erosion technologies through the use of the Object Modeling System (OMS) into a single wind/water erosion prediction system using common databases and interfaces at the plot and field scale..
2)Incorporate, test and verify new erosion science or related components, such as winter processes, tillage erosion, ephemeral gully erosion, irrigation erosion and rangeland erosion, into the integrated erosion prediction system..
3) Cooperate with all ARS scientists and NRCS staff involved with the CEAP effort to extract relevant modules from existing models such as SWAT (Soil and Water Assessment Tool), RUSLE2 (Revised Universal Soil Loss Equation – version 2), AnnAGNPS (Annualized AGricultural Non-Point Source pollution), CONCEPTS (CONservational Channel Evolution and Pollutant Transport System), WEPP (Water Erosion Prediction Project), WEPS (Wind Erosion Prediction System), and REMM (Riparian Ecosystem Management Model) and integrate them into the OMS for development of regional water and air quality models at the plot, field, and watershed scales.

1b.Approach (from AD-416)
Objective 1: a) Incorporate the core WEPP model erosion component into the Object Modeling System, test and verify against the original WEPP model. b) Develop a single storm hydrology and water erosion model in OMS, then adapt model in OMS to handle temporal (multiple storms) and spatial (multiple flow planes) looping. c) Develop a continuous simulation water erosion model in OMS containing infiltration, ET, percolation, water balance, surface runoff routing, and water erosion calculations (multiple storms and multiple spatial planes). d) Create a single event wind detachment component in OMS based upon the core WEPS erosion code. Test and verify against the original WEPS code. e) Create a single event combined wind and water erosion model in OMS, using the individual water and wind modules. f) Merge wind detachment component into continuous simulation OMS water erosion model. g) Add other required components needed for a complete prediction system, including climate generation, plant growth, tillage disturbance, residue management, baseline hydrologic, and erodibility parameterization, etc. h) Test, verify, and validate modules and models. i) Work with NRCS and other users on interface and database development. Objective 2: a) Develop detailed guidelines and instructions for cooperators on formats needed for new components to be incorporated within OMS for inclusion in combined wind and water model, or as special model applications using existing modules from the combined model. b) Work with ARS and university cooperators on testing, verifying, and validating new component modules within OMS. c) Incorporate, test, and verify new erosion science or related components, such as winter processes, tillage erosion, ephemeral gully erosion, irrigation erosion and rangeland erosion, into the integrated erosion prediction system. Objective 3: This effort is a part of the Conservation Effects Assessment Project (CEAP) Objective 5 which deals with development of regionalized watershed models for assessment of the impacts of field soil conservation practices on off-site resources (water, air, etc.). Hillslope and field components developed in Objectives 1 and 2 may be utilized within larger regionalized models. Alternately, due to much larger scale representations and more coarse process conceptualization, use of simpler types of erosion functions may also be warranted and necessary. CEAP-Objective 5 work is being led by staff in ASRU in Fort Collins, CO.

3.Progress Report
Efforts continue on development of a combined process-based wind and water erosion model. A stand-alone prototype for single storm water erosion and single event wind erosion calculations has been created within the Object Modeling System (OMS) and updated with updates to OMS itself. Also, an alternative approach (to OMS) for a combined model was developed by adding the water erosion modules to the WEPS (Wind Erosion Prediction System) model code. A meeting with NRCS and ARS staff was held March 11-13, 2008 in Fort Collins, Colorado with substantial discussions, and drafting of a user requirements document and action items. Subsequently in mid-July, NRCS officially sent their updated user requirements to ARS, which significantly expanded the requested scale of the combined modeling system from a profile/field scale to a small watershed/multiple wind accounting region scale. To fulfill NRCS needs for a web-based GIS-linked watershed-scale wind/water erosion prediction tool would require a reorganization of the current project plan and resources. Work also continued on simulations of winter hydrology and erosion processes. Cooperators at Washington State University have completed modifications to the WEPP model winter code, with a updated model release expected in July or August 2008. Other code corrections to WEPP will also be included in that release, most notably a fix for a serious error when simulating multiple grass buffer strips in a field. The standalone water erosion code developed as part of the OMS effort has been used by a cooperating Purdue University graduate student, who has linked it with the VIC (Variable Infiltration Capacity) model, which simulates hydrology and winter processes at very large basin scales. The linked simulation model allows erosion assessments at these large scales through a statistical approach and has been used to evaluate effects of land-use changes in the Great Lakes basin from pre-settlement to the present.

Presentations on the common erosion modeling project were given at the SSSA Meeting in New Orleans in November 2007 and at the AgroEnviron2008 Workshop in Antalya, Turkey in April 2008.

4.Accomplishments
1. WWEM User Requirements Development. In 2004, NRCS requested development of a combined wind and water erosion prediction model, which was the basis for this research project. A set of User Requirements for the common wind and water erosion (WWEM) model was developed through communications and a meeting with NRCS in March 2008. Impact: These requirements lay out the basic requested system from NRCS to ARS, and will impact all future work on this project. WWEM when developed and implemented will affect conservation planning on millions of acres of agricultural land, and billions of dollars in federal program fund allocations. NP Area Addressed: This accomplishment addresses NP201 Component 4 - Integrated Soil Erosion and Sedimentation Technologies Problem Statement - Customers have identified two basic areas for new and improved soil erosion and sedimentation technologies: (1) better erosion control technologies and (2) improved decision support systems for planning and assessment. Development is needed of an integrated conservation-planning tool that uses a common interface, common databases, and sound science to allow comprehensive assessment of the impact of alternative management scenarios on resource conservation and environmental quality.

2. WEPP Model Update. Problem: Erosion prediction technology has consistently performed poorly for areas dominated by frozen soil conditions, in which processes including freezing, thawing, snow accumulation and snow melting significantly affect soil loss. Accomplishment/Impact: Release of an updated version of the WEPP model in August 2008 with improved winter hydrology/erosion code will immediately impact the many users of this technology, with better predictions of soil freezing, thawing, and snow melt driven runoff and erosion, which are very important in more northern latitudes. Portions of enhancements to the WEPP code can be used in future modular components to be incorporated into the common wind/water modeling system. NP Area Addressed: This accomplishment addresses NP201 Component 4 - Integrated Soil Erosion and Sedimentation Technologies Problem Statement - Processes associated with soil erosion by wind and rain has received the attention of previous ARS and university research. However, experience and understanding of processes driving specialized forms of erosion have a much smaller scientific knowledge base: winter erosion processes, irrigation-induced erosion, ephemeral gully and head-cut erosion, rangeland erosion, tillage erosion, and channel erosion and evolution.

6.Technology Transfer