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###### Department of Agriculture

###### Natural Resources Conservation Service

# AGENCY:

Natural Resources Conservation Service.

# ACTION:

Notice of availability of the Wind Erosion Prediction System (WEPS) for soil erodibility system calculations scheduled for implementation for public review and comment.

# SUMMARY:

                        Notice is hereby given of the intention of the Natural Resources                               ( print page 75962)                            Conservation Service (NRCS) to implement the WEPS which will replace the use of the Wind Erosion Equation (WEQ) where applicable.                    

# DATES:

*Effective Date:*                         This is effective December 7, 2010.                    

*Comment Date:*                         Submit comments on or before January 6, 2011. Final versions of these new or revised conservation practice standards will be adopted after the close of the 30-day period, and after consideration of all comments.                    

# ADDRESSES:

Comments should be submitted using any of the following methods:
      -  Mail:                          Eric West, National Highly Erodible Lands and Wetlands Conservation Specialist, Ecological Sciences Division, Department of Agriculture, Natural Resources Conservation Service, 1400 Independence Avenue, SW., Room 6150 South Building, Washington, DC 20250.                    
      - E-mail: eric.west@wdc.usda.gov.

# FOR FURTHER INFORMATION CONTACT:

Eric West, National Highly Erodible Lands and Wetlands Conservation Specialist, Ecological Sciences Division, Department of Agriculture, Natural Resources Conservation Service, 1400 Independence Avenue, SW., Room 6150 South Building, Washington, DC 20250.

# SUPPLEMENTARY INFORMATION:

The WEQ, a simple two-factor linear model for calculating the effects of wind erosion, will be replaced by WEPS for selected regulatory permissible applications. The WEPS model will be used where wind erosion is the primary causal factor for comparing the annual level of erosion before conservation system application to the expected annual level of erosion after conservation system application (i.e., substantial reduction for highly erodible land conservation). The WEQ is the current method in the regulations for calculating substantial reduction and potential erodibility due to the effects of wind. The use of WEQ to calculate potential erodibility remains unchanged. The regulation for WEQ is located at 7 CFR 610.14.

The implementation of the WEPS system does not affect the Highly Erodible Map Unit List contained in the NRCS Field Office Technical Guide as of January 1, 1990. This 1990 list will continue to be used for all erodibility index calculations, including sodbuster determinations and review of previous determinations.

The WEPS computer model is a process-based, daily time-step computer model that predicts soil erosion via simulation of the fundamental processes controlling wind erosion. WEPS can calculate soil movement, estimate plant damage, and predict PM-10 emissions when wind speeds exceed the erosion threshold. The WEPS model can also provide the user with spatial information regarding soil flux, deposition, and loss from specific regions of a field over time. The model is intended for conservation planning, assessing wind erosion for the Department of Agriculture (USDA) NRCS' National Resources Inventory, and aiding the development of regional and national policy.

The WEPS modular design is amenable to incorporation of new features. Thus, WEPS utility will also be for estimating long-term soil productivity, determining physical damage to crops, depositional loading of lakes and streams, as well as estimating visibility reductions near airports and highways. Further, WEPS will aid in calculating both onsite and offsite economic costs of erosion and assess impacts of management strategies on public lands when used in conjunction with other models.

                    A complete summary of the processes utilized by the WEPS computer model can be found in An Overview of the Wind Erosion Prediction System (                    *http://www.ars.usda.gov/​SP2UserFiles/​Place/​54300520/​wepsoverview.pdf*). A thorough discussion and review of the WEPS model processes is available in the draft WEPS technical document (                    *http://www.ars.usda.gov/​SP2UserFiles/​Place/​54300520/​weps_​tech.pdf*). Further, both of the previously referenced documents, as well as other WEPS related topics, can be found at the USDA Agricultural Research Service Engineering and Wind Erosion Research Unit (                    *http://www.ars.usda.gov/​Main/​docs.htm?​docid=​18371*) home page.                

The implementation timeframe for WEPS in each field office with a wind erosion concern is January 1, 2011. Title 16-Conservation, Chapter 58-Erodible Land and Wetland Conservation and Reserve Program, Subchapter I-Definitions, 9(C) Equations (i.e., 16 USC section 3801(a)(9)(C)) requires NRCS to make available for public review and comment all proposed changes to equations to carry out HEL provisions of the law in a manner consistent with section 553 of title 5.

Signed this 30th day of November, 2010, in Washington, DC.

Dave White,

Chief, Natural Resources Conservation Service.

[FR Doc. 2010-30673 Filed 12-6-10; 8:45 am]

BILLING CODE 3410-16-P