2019-12-13_REVISION - M1980244 (64)

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Baseline Technical Report ARCADIS Report for Soils and Biological Resources, MLE2 Project Area 2. SOIL AND GROWTH MEDIUM RESOURCES In order to be consistent with published data, this report presents a revised soils map based primarily on the 2008 NRCS data available through the Web Soil Survey. NRCS data has been supplemented by data collected during the reconnaissance soil survey conducted by Greystone from August 16 to 20 and September 22 to 24, 1999, a follow-up survey by ARCADIS on June 21 and 22, 2007; and a third survey by ARCADIS from July 19 to 21, 2011. Field investigations by ARCADIS in 2011 focused on the MLE2 project areas/survey area. Data collected within the Cresson Project area are considered to represent a more detailed level of analysis than NRCS data, and map unit boundaries have been adjusted accordingly. In addition, aerial photography of the District taken in 2010 was utilized to more accurately define soil map unit boundaries. An explanation of revisions made to soil units presented in the 2007 Baseline Technical Report for Amendment No. 9 (ARCADIS 2007) is incorporated into the descriptions of soil map units in Section 2.1. A revised soil map of Cresson Project area soils is presented in Figure 2-1. Characteristics of the soil types in the area are summarized below and in Table 2-1. Soil map unit OR (Disturbed land, mine areas, overburden storage areas, mine complex) is not included in Table 2-1 due to its variability. Unit OR varies for all characteristics depending on the age, amount, and type of disturbance and original character of the soil. Table 2-2 identifies the soil map units within the survey area. Soil surveys of disturbance areas proposed under MLE2 were conducted concurrently with vegetation mapping, which allowed for close correlation of mapped soil units with vegetative cover. In addition, soil units were differentiated based on geology, aspect, and slope steepness. Exposed soil profiles in road cuts, walls of surface mines and exploration sites, and other excavations were examined. Soil pits were excavated where exposed soils did not exist. In order to confirm accurate mapping by NRCS, soil exposures and pits were selected for examination based on slope, aspect, parent material, and vegetation present that matched published descriptions of the soil unit mapped by NRCS at that specific location. The range in thickness of the salvageable upper horizons of each soil unit profile occurring within the MLE2 project areas are shown on Figure 2-1. 2.1 Soil Resources 2.1.1 BW. Bushpark-Seitz association, 15 to 20 percent slopes Within the Cresson Project area, these soils are found on south-facing mountainsides within the open conifer-dominated woodland vegetation community CCV Baseline Soils Biology Resource Report(11-17-11).doc 6