• Phase II - Soil Erosion

Potential At-Risk Maps and Information

The following are the proposed model potential at-risk maps produced during the Arkansas Resource Assessment - Phase II. The NRCS definition of the natural resource concern and the input layers and land use designation weights that were used for modeling each of the natural resource concerns within the Soil Erosion Resource Concern are listed to the right of each map.
Sheet, Wind and Rill Erosion  (View Individual Data Layer Extents)

    NRCS Definition:
       
Detachment and transportation of soil particles caused by rainfall runoff or
        splash, irrigation runoff, or wind that degrades soil quality.


    Land Use Designation Weights:

        Crop (Weight 5); Pasture (Weight 2);
        Forest, Range, and Urban (Weight 1); Water and Assoc. Agland (Weight 0)

    Binary Input Layers and Associated Weights:

        – SSURGO K Factor Kw >= 0.37 (Weight 1)
    
    – SSURGO RKLS/T (most limiting EI) >= 8 (Weight 2)
        – SSURGO Wind Erodibility Group Classes 1 and 2 (Weight 2)
        – Soil Vulnerability Model - Runoff High or Moderately High (Weight 1)
        – HUC12s containing 303(d) Streams Impaired by Sediment (Weight 1)




Concentrated Flow (View Individual Data Layer Extents)

    NRCS Definition:
        Untreated classic gullies may enlarge progressively by head cutting, lateral         widening, or both. Ephemeral gullies occur in the same flow area and are             obscured by tillage. This includes concentrated flow erosion caused by
        
runoff  from rainfall, snowmelt, or irrigation water.
    
    Land Use Designation Weights:
        All land use designations (Weight 1),
        except Water and Assoc. Agland (Weight 0)
    
    Binary Input Layers and Associated Weights:
        – SSURGO RKLS/T (most limiting EI) >= 8 (Weight 1)
        – Soil Vulnerability Model - Runoff High or Moderately High (Weight 1)
        – HUC12s containing 303(d) Streams Impaired by Sediment (Weight 1)







Excessive Bank Erosion from Streams, Shorelines or
Water Conveyance Channels
(View Individual Data Layer Extents)

    NRCS Definition:
        Sediment from banks or shorelines threatens to degrade water quality and
        limit use for intended purposes.


    Land Use Designation Weights:

        Crop, Pasture, Forest, Range, Urban, Assoc. Ag and Water (Weight 1)

    Binary Input Layers and Associated Weights:
        – SSURGO RKLS/T (most limiting EI) >= 8  (Weight 1 and clipped
                                                            by NHD Variable Riparian Buffer)
        – SSURGO Representative Slope RV  >= 3% (Weight 1 and clipped
                                                            by NHD Variable Riparian Buffer)
        – Soil Vulnerability Model - Runoff High or Moderately High (Weight 1
                                            and clipped by NHD Variable Riparian Buffer)
        – HUC12s containing 303(d) Streams Impaired by Sediment (Weight 1)
        – NHD Variable Riparian Buffer (Weight 1)
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