2012-06-20_PERMIT FILE - C2010089A (13)

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requirements and definitions as well as the new information which was collected relative to the environmental baseline studies performed in connection with the NHN Mine permit application. According to the current regulations, alluvial valley floors are defined in Section 1.04.10(10) as those areas containing "unconsolidated stream laid deposits holding streams with water availability sufficient for subirrigation or flood irrigation agricultural activities but does not include upland areas which are generally overlain by a thin veneer of colluvial deposits composed chiefly of debris from sheet erosion, deposits formed by unconcentrated runoff or slope wash, together with talus, other mass movement accumulations, and windblown deposits." Unconsolidated stream - laid deposits holding streams, are defined in Section 1.04(142) as including those areas "with respect to alluvial valley floors, all floodplains and terraces located in the lower reaches of valleys which contain perennial or other streams with channels that are greater than 3 feet in bankfull width and greater than 0 5 feet in bankfull depth." Upland areas are defined in Section 1.04(147) as including those areas "with respect to alluvial valley floors, those geomorphic features located outside the floodplain and terrace complex, such as isolated higher terraces, alluvial fans, pediment surfaces, landslide deposits, and surfaces covered with residuum, mud flows or debris flows, as well as highland areas underlain by bedrock and covered by residual weathered material or material deposited by sheetwash, rillwash, or wind." Relative to the proposed NHN Mine area, it can be conclusively determined that the EPA study fmdings regarding the negative occurrence of AVF's in this vicinity still apply to this site. No AVF's exist in this area because according to the definition of unconsolidated stream - laid deposits holding streams there is no stream which has a bankfull width of greater than 3 feet in width of greater than 0.5 feet in bankfull depth. Based upon the section describing the " Bankfull Characteristics of Streams" found on pages A -24 through A -30 of the OSM Guideline, it can be concluded based upon detailed measurements taken of the drainage swales that cross Chiles, Meehan and Nygren Draws in connection with the formal wetland delineation required for the U.S. Army Corps of Engineers 404 Permit application, which is addressed in Section 2.05.6(2) Fish and Wildlife Plan, that none contain streams greater than three feet in width. As are documented on Map 2.05.6(2) -1 - Wetland Map, there is no defined stream channel in either Chiles Draw or Nygren Draws, while the drainage channel in Meehan Draw ranges in width from 0.5 feet to a maximum width of 2 feet with an average width of 1.34 feet. In a few segments, it is deeper than 0.5 feet but over nearly three fourths of the length of this defined drainage channel it is typically less than three or four inches in depth. Thus, since the mapped stream channel does not meet the regulatory definition of a stream as defined by the regulations, it is impossible for unconsolidated stream - laid deposits holding streams to occur next to this stream. For this reason there can be no AVF's in any of the three draws with mapped wetland vegetation and which are designated as corresponding to the Grazingland - Subirrigated Land Use for this site. In connection with the detailed soil survey performed on this property, which is described in Section 2.04.9 - Soils Resource Information, numerous backhole soil test pits were excavated in Section 2.06.8 Page 3 April 2011