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Vantage to Pomona Heights Chapter 3 230 kV Transmission Line Project FEIS Affected Environment PAGE 3-300 3.15.4.17 Route Segment NNR-8 The short Route Segment NNR-8 crosses the Columbia River just north of the Saddle Mountains and ends at the Vantage Substation. The six-mile study area contains several Class B structure faults associated with the Saddle Mountains Fault System. The portion of the fault lying east of the Columbia River is Class A—considered late Quaternary Period in age (<130,000 years) and ends just within the six- mile study area. As Route Segment NNR-8 crosses the Columbia River, there are significant areas mapped as exhibiting moderate to high liquefaction potential. There are no ephemeral/intermittent stream crossings or landslide deposits near NNR-8. Route Segment NNR-8 corresponds to 0.0 acres of soils with high water erosion potential, 113.0 acres of soils with high wind erosion potential, and 135.1 acres of soils with low soil restoration potential. 3.15.4.18 Route Segment MR-1 The Route Segment MR-1wraps around MR and crosses the ridge at I-82. The route segment crosses a Class B structure fault associated with the Saddle Mountains Fault System. The six-mile study area contains several historic/quaternary landslide deposits and the route segment passes through one large deposit. Recent movement was not evident in aerial photography; however, to maintain the stability of these features field review and determination of BMPs for this area would be prudent. The landslide deposits are classified as low-to-moderate liquefaction susceptibility. The route segment crosses 22 intermittent/ephemeral creek washes. Route Segment MR-1 contains 23.4 acres of soils with high water erosion potential, 0.0 acres of soils with high wind erosion potential, and 60.7 acres of soils with low soil restoration potential. Table 3.15-1 Soil Units By Route Segment MAP UNIT NAME/SLOPE WIND EROSION POTENTIAL WATER EROSION POTENTIAL SOIL RESTORATION POTENTIAL ACRES WITHIN 500-FOOT CORRIDOR (WITHIN 250 OF CENTERLINE) 1a/NNR-1 Esquatzel silt loam, 0 to 2 percent slopes Moderate High Moderate potential 4.4 Harwood-Burke-Wiehl silt loams, 15 to 30 percent slopes Moderate High Low potential 6.8 Harwood-Burke-Wiehl silt loams, 2 to 5 percent slopes Moderate High Low potential 0.4 Kiona stony silt loam, 15 to 45 percent slopes Low High Low potential 53.2 Meloza-Roza complex, 15 to 30 percent slopes Low Low Moderate potential 0.6 Ritzville silt loam, 8 to 15 percent slopes Moderate High Moderate potential 71.7 Roza clay loam, 15 to 30 percent slopes Moderate Low Moderate potential 11.0 Starbuck-Rock outcrop complex, 45 to 60 percent slopes Moderate High Moderate potential 0.6 1b Argabak-Horseflat complex, 3 to 15 percent slopes Low Moderate Low potential 1.2 Disage very cobbly loam, 3 to 15 percent slopes Low Moderate Not Rated 2.0