NB_290_23_1 - NB 290-23-1 INV – State-Level Peer Review of the Conservation Effects Assessment Project Rangeland Soil Vulnerability Index for Water Erosion
NB 290-23-1 INV – State-Level Peer Review of the Conservation Effects Assessment Project Rangeland Soil Vulnerability Index for Water Erosion
National Bulletin: 290-23-1 Date: November 4, 2022
Subject: INV – State-Level Peer Review of the Conservation Effects Assessment Project Rangeland Soil Vulnerability Index for Water Erosion 


Action Required By:  December 9, 2022
 
Purpose.  This national bulletin requests a selected state-level peer review of the Conservation Effects Assessment Project (CEAP) rangeland soil vulnerability index for water erosion (rSVI-water).
 
Expiration Date.  December 9, 2022
 
Background.  In response to the need for spatial interpretations of potential rangeland soil erosion, the Resource Inventory and Assessment Division, CEAP-Grazing Lands, developed a map-based rSVI-water index for conservation planning and state resource assessments. The index provides a visual risk rating of rangeland soil erodibility from water based on the FY 2022 NRCS SSURGO soil data, Rangeland Hydrology and Erosion Model (RHEM) outputs, and a ruleset using soil surface texture, slope percent and surface coarse fragment cover percent. The index represents the relative risk of erosion by water for each soil component within a map unit, and the weighted average risk for the entire map unit.

The rSVI-water map will be updated based on annual updates of NRCS SSURGO soil data. The index itself will remain as developed following the requested review comments and will be applied to any new or updated soil components each year. This new rSVI-water interpretation will help NRCS planners and ranchers locate areas that are susceptible to water erosion and implement proactive conservation actions before potential issues with rangeland health, soil stability, water infiltration, plant productivity, and invasive species become problematic. The rSVI-water can also help assess if current erosion control practices are targeting areas of concern. The rSVI-water index and map were developed only for rangelands and represents water erosion risks under unvegetated and dry soil conditions.
 
Explanation.  CEAP-Grazing Lands updated the rSVI-water index and map based on NRCS staff reviews from FY 2021, and now requests further review from state soil scientists and state rangeland management specialists (or state resource conservationist, if applicable) in the following States: California, Oregon, Washington, Idaho, Montana, Arizona, New Mexico, Colorado, Utah, Wyoming, Alaska, Hawaii/Pacific Islands, North Dakota, South Dakota, Nebraska, Kansas, Oklahoma, Texas, Louisiana, Florida. Results from the review will affect future adjustments to the rSVI-water rulesets to create products useful to conservation planning efforts.

The review comments should focus on assessing how effectively the rSVI-water index has predicted rangeland water erosion risk. The review period is from November 9, 2022, to December 9, 2022.

The mapped display of the rSVI-water index and associated user guide can be found at: CEAP FY2022 rSVI-Water Web Tool. The CEAP-Grazing Lands team will host a Teams meeting to review the index with reviewers, reintroduce the goals and ruleset of the risk matrix, and kick-off the review process on November 9, 2022, from 12:00pm to 1:00pm PST. The meeting will include a Q&A.
 
Contact.  Please email your comments, or a confirmation that your staff reviewed the tool and had no comments, to Carrie-Ann.Houdeshell@usda.gov by December 9, 2022.

For further information, please contact Daniel Mullarkey, Resource Assessment Branch (RAB) Leader, at (202) 631-1943.
 
 

 /s/

ASTOR BOOZER
Regional Conservationist, West

JAMES TILLMAN
Regional Conservationist, Southeast

XAVIER MONTOYA
Acting Regional Conservationist, Central

LUIS TUPAS
Deputy Chief, Soil Science and Resource Assessment


 
 

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