Each feature class or feature dataset is in Geographic (GCS) NAD83 unless otherwise noted
Sensitive soils are those soils that are vulnerable to site degradation with a disturbance. The vulnerability to site degradation represents the relative risk of water and wind erosion, salinization, sodification, organic matter and nutrient depletion and/or redistribution, and loss of adequate rooting depth to maintain desired plant communities. Soils play an integral part in plant community development. Plant communities are most noticeably influenced with extremes in soil texture and thickness of soil horizons, depth to restrictive layers including abrupt soil horizon boundaries, and by soil drainage or depth to water table. Top soil erosion influences horizon thickness and depth to restrictive layers. Changes in soil productivity and site type are the end result. Dynamic soil properties or soil properties that vary with time, e.g. microbial biomass/ aggregate stability/ diversity and carbon to nitrogen ratio, are not used since they are not contained within STATSGO or SSURGO databases. The table below was used as a guide for determining vulnerability to site degradation for the John Day RMP area. Weighted average soil surface detachment ability for the upper 12 inches (Kw 0 to 12) was determined for each STATSGO soil mapunit for the RMP area. A 10 meter digital elevation model was used to determine slope. A weighted average depth was determined for each STATSGO map unit, using the depth for each soil type and weighting it by the soil percentage with in the mapunit. Wind erodibility, salinity, and sodicity were not determined as there were minimal acreage of these areas in a high to moderate category for the RMP area. A map showing areas of moderate and high sensitivity to water erosion and depths to restrictive layer are available for the RMP area. Value Count 10m sq Class_name Criteria 0 61,008,921.00 Not Vulnerable Did not meet any criteria below 1 224,262.00 Vulnerable Erosion High 3 Kw>0.36 & Slp >25 2 35,341,228.00 Vulnerable Erosion High 2 Kw >= 0.20 & 35 3 30,282,184.00 Vulnerable Erosion High 1 Kw 40 4 1,359,979.00 Vulnerable Depth High Dp=20 & = 0.20 & = 15 & 0.36 & Slp >=10 &=10&
Data set is intended for the analysis of soil erosion vulnerability within the JDRMP (John Day Resource Management Plan) boundary.
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