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Utah RI.\4 Stone C'ahin 3D Seismic Sut~•cy finvironmcntal rlsscssntcnl Pagc ~ df 17 <br />3.2.1.2.2 Alternative B -BLM Preferred Alternative <br />The impacts on geologic conditions from ,mplementation of the BLM Preferred Alternative would be similar to <br />Ihose described for the Proposed Action with the exception of 228 shot holes wdhm the WSAs being changed <br />Irom buggy drilled 60-foot holes charged with 20 pounds of explosive shot to 50-foot holes charged wuh 10 <br />pounds of explosive shot. At equal distances from the shot detonations, the vibration venerated would be less for <br />the hell-portable tlnlled source points Ihan the buyyy drilled source points In the WSAs The distance between the <br />source of vibration and potentially affected feature would be reduced Irom 300 feel to about 200 feet for the 0.75 <br />inches per second threshold factor <br />Implementation of the No Arlion Alternative within the Project Area would result ~n impacts to geologic conditlons <br />and resources that are consistent with present levels of activity within the Project Area Anticipated artiwbes <br />associated with continued livestock, wildlife, and wild horse yrazing, recreational use by hunters and glhars. and <br />oil and gas exploration activities would include some additional dishrrbance of geologic matenals and posslble <br />slope utslahddy. <br />The effects of these continued development actrvities are ant~cipatetl to be short-term and rnmimized with <br />application of requued mifigation measures. Additional oil and gas wells woultl not preclude access In Iho tar <br />sands resource or prevent production, should a tar sands development be nnplemented <br />dissect the West Tavaputs Plateau and mostly small, isolated, and perched aqufers ,n the upper member of the <br />Grnnn River Formation Ihat caps the upland surface of the plateau. Although the Upper and Middle members of <br />the Green River Formation are aqultards, some groundwater accumulations tit the upper and middle members are <br />evident in the presence of several spnngs and stock wells in the Project Area (Figure 3-1) Based on available <br />data from Stale of Utah Department of Natural Resources, Division of Walor Rights, as many as 22 spnngs and <br />stock water wells are located in the Project Area. Four years of drought condAions have reduced flows of spnngs <br />and many seeps in the Project Area based on observations of both the archaeological and biological lield survey <br />crews Groundwater Flow is down slreamichonnel gradient within the alluvial canyon bottoms and down dip, <br />mostly north, where (low is possible wdhm the mostly consolidated upper Green River member The occurrence of <br />spnngs m the Project Area coincides with exposure of a more porous sandstone tense that overlies a tighter, loss <br />permeable stlt steno or claystonelmudslone litholoyy or a coalescence of a netvork of subsurface cracks in the <br />tighter rocks where water has entered the crack system that has inlets nn the surface to recewe runoff from <br />preapitahon (Figure 3-1 ), Reported sprang and well yield data for 8 of the 22 saes located on the reap present a <br />Tango betweon 0 cubic feet per second and 0.0220 cubic feet per second Five of the eight wells were Identified <br />as being used for stock water No information on quality was available; however, the designation of use for stock <br />water provides an rndicahon that the qualdy is at least sutable for that purpose. <br />Water quality m the alluvial aquifers is likely consistent with the corresponding surface water flows In the overlying <br />stream channels (Price, tg84) USGS water quality information for a sampling paint nn Nine Mile Creek lust <br />above Gate Canyon indicates Nine Mile Creek's total dissolved solid content ranges from 250 to 1000 rmlhgrams <br />per tiler. This range falls within the range deemed suitable for stock watering A regional aquifer does not underlie <br />the Project Area {Darby 2003). <br />3.2.2.1.2 Surface Water, Floodplains, and Riparian Areas <br />Surface water features rn the Project Area consist of mostly ephemeral creeks and Iheir tributaries/watersheds <br />that, rn their lower reaches, have formed deeply incised canyons within the Project Area (Figure 3-1). Principal <br />drainages and associated canyons in the Protect Area from west to east are Harmon Canyon. Prickly Pear <br />Canyon, Dry Canyon, and Cottonwood Canyon, that are Inbulary to Nine Mile Croek/Canyon to the north of the <br />htgr,' www.uLbint.guv~ slunccabimL:l,cheptrr3a.hhn i:5;?IIUh <br />