2007-11-01_PERMIT FILE - C1982056A (4)

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llu Fish Crcek "fipple Permit Application (C-036-81) submitted in the fall of 1984 and approved by CMLRD on May 20, 1985 addressed the alluvial valley Floor considerations of the Fish Crcek Tipple and • I I;wlroad areas located on the Fish Creek and Middle Creek drainages. CMLRD issued a Decision and Findings Document for the Fish Creek Tipple Permit Area on May I5, 1985. This document concluded that three areas met the geomorphic criteria of alluvial valley Floors. These areas are: I) the flood plain of Fish Qeek; 2) the flood plain of Middle Creek; and , 3) the flood plain of Trout creek. The alluvial valley Ioor determination concluded by saying: "Based on available information, the unconsolidated streamlaid deposits of Fish and Trout creeks are found to be alluvial valley Floors because of the current or historical existence of flood irrigation and the presumed capability of these areas to support subirrigation during a portion of the growing season. I[ is significant to note that this statement relative to current historic Hood irrigation is applicable only to portions of these to the drainages as a whole. I-his historical perspective is provided to answer concerns relative to how and why the areas marked on M;tp I5, Alluvial Valley Floors and Water Rights was prepared. The basic assumptions used to prepare this map have been accepted in several previous permit submittals prepared by Twen[ymile Coal and its predecessors, Colorado Yampa Coal and Energy Fuels since the promulgation of the interim OSM Regulations in 1977. As can be observed in each of these individual submittals and as painted out previously in this discussion, Map I5, Alluvial Valley Floor and Water Rights, contains all geologically mapped unconsolidated deposits as required under Rule 2.06.8 (3)(b). Tltis approach was taker[ as required under 2.06.8(3}(b), following numerous meetings held with CMLRD. These required consultation meetings were initiated in 1978 and have continued with each permitting action up to and including the present submittal. TCC recognizes that this approach presents a "worse case" scenario since it grossly overestimates the actual extent of alluvial deposits by including all unconsolidated geologic deposits into a designation that should more accurately contain only unconsolidated streamlaid deposits. As :t result, the actual areal extent of alluvium is considerable smaller that depicted on Map I5, Alluvial Valley Floors and Water Rights. TCC recognizes this inconsistency but believes that the present submittal • is consistent with [he regulatory approach of identifying maximum potential impacts and then determining actual anticipated impacts through detailed evaluation. 'The extent of alluvial deposits associated with potential alluvial valley toors can easily be determined front the detailed soil mapping information presented on Map 17, Premining soils, and iit Exhibit 1 G, Soil Mapping Unit Descriptions. By combining the land forms associated with alluvial valley Floors (i.e., alluvial fans, terraces, Floodplains, valley bottoms, and alluvial valleys) with mapped alluvium, the delineation of those alluvial deposits potentially associated with alluvial valley floors can be made. Tltis contparisoit results in the following soil mapping units meeting these two criteria: 2 -Outlet -Slocum Taxajunct complex, 0-2%slopes; 3 -Unnamed -Abel Variant Complex, 0-5%slopes; AW - Aquents-Aquolls Complex; SA - Abslter frne sandy loam, 3%slopes; 23A - Capo clay loam, 0-3%slopes; 27A - mtrtamed sandy loam, I -10%slopes; ~?A -Venable loam, 0-6%slopes; 56A - Tonks loath, 0-5%slopes; and G9c - Milrett loan[. 0-6%slopes. Upon locating these areas on Map 17, Pre-mining Soils, within the potential alluvial valley floor htxmdarics presented on Map 11. Alluvial Valley Floors and Water Rights, the actual extent of alluvial deposits can be determined. • N1R97-I;a ?.OG-9 Revised 1~mnioi