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Coal Metbaee Drarnape Projcd - PaneG 16-24 Wert E!k Mnre • Pape 3-5 with total dissolved solids concentrations between 43 and 2,300 mg/I. Sulfate, total dissolved solids (I'DS), and manganese occasionally exceed the drinking water standard. Bedrock contains ground water to a limited degree. The primary bedrock aquifers iti the area are the lower Cretaceous Burro Canyon and Dakota Sandstone Formations. Stratigraphically, these formations lie beneath several thousand feet of Mancos shale (below the Mesa Verde) and are hydrologically isolated from the Mesa Verde Formation. Ground water can also occur as isolated perched ground water occurrences. Perched ground water occurrences are associated with Gthologic units that are hydrologically connected to a recharge source, have sufficient pettneability to store and transmit water, and ate underlain by a low permeability unit. The low permeability unit(s) limits downward water migration, and a small saturated zone builds up in the porous and permeable rock. Perched ground water occurrences are typically relatively small, discontinuous, and have very limited storage volume. Underground water may also occur in the coal seams and associated strata. In the project azea, the coal seams and associated strata dip to the northeast. The upper units outcrop in the North Fork Valley and are drained over a large area such that ground water occurrences in these units aze rare. The D Seam is known to contain water on the north side of the North Fork Valley. The D Seam and the overlying coal interburden and overburden units are generally wets-drained on the south side of the river in the vicinity of the project azea. Ground water quality in the project area is highly variable dependent on rechazge source, flow path, strata with which the water comes in contact, and discharge mechanism. Water quality for alluvial/colluvial ground water and perched ground water is commonly similar to surface water due to close surface and ground water interactions and limited residence times. Deeper perched ground water and any ground water associated with the coal seams that have been in contact with shales and mudstones may exhibit elevated levels of total dissolved solids. 3.1.1:5 Riparian Riparian ecosystems typically occur along drainages where additional moisture (surface or ground water) is available. They aze transitional azeas between terrestrial upland habitat and aquatic habitat. Riparian areas are not necessarily associated with wetlands, which generally have prolonged saturation of the soil. For purposes of this EA, however, the term "riparian" will be used to include aquatic ecosystems (wetlands) as well as riparian ecosystems. In the project azea, riparian zones aze usually narrow in width due to the steep topography and narrow drainage bottoms. There is no "typical" vegetation (for a riparian area}, vegetation varies with elevation and exposure. A spmce-fir community is common to riparian azeas at higher elevations and aspen may be co- dominant. Boxelder and narrow-leaf cottonwood may dominate riparian areas at lower elevations. Wildhfe rely on riparian and wetland areas for many aspects of their survival both day to day and over the long-term. These areas aze typically cooler than the surrounding hillslopes, aze important as sources of food and protection, and attract a diverse composition of speues, more so than other habitats. Additional discussion of riparian areas relative to wildlife habitat and use is provided in Section 3.2.1. Riparian surveys conducted recently in the upper reaches of Sylvester Gulch provide information on representative site-specific riparian conditions for the project azea (Greystone, Nov. 2001a and b). The identification and chazacterization of these "riparian" azeas used protocol in a USFS guidance document (USFS, 1995). Additional information on possible ripazian areas was provided in the Threatened and Endangered Species ('I`ES} survey for Panels 18 through 24 (Greystone, Oct. 2001b). Possible riparian areas were identified by the presence of aspen, bracken ferns, and other EnvironmenlalA.rzerrment Y?'P-/N.nrs~Gf G/EA/0.q1/l+/OIEr V2Ff 3/f/OS dv