PERMFILE139063 - Laserfiche WebLink

Home Browse Search

through the project area. Dips range from approximately 9° along the east flank of the Sage Creek Anticline, to 15 - 20° to the north. Faulting associated with the Tow Creek Anticline has been identified within the area by U.S. Geological Survey geologists. Other faulting in the area is likely, but not well understood, and better definition of the occurrence and extent of faulting is one of the primary objectives of the proposed exploration program. Surface Water Resources: The project area is bounded on the north and northwest by Sage Creek, and to the east and southeast by Grassy Creek, perennial tributaries to the Yampa River. The drainage areas that flow northwest toward Sage Creek are characterized by ephemeral flows, typically flowing only in response to spring snowmelt and summer precipitation. Subwatersheds that drain eastward to Grassy Creek include Scotchman's Gulch and Annand Draw and are characterized by ephemeral or intermittent streamflows. The proposed exploration drilling will be conducted so as not to adversely impact any of the potentially affected drainages. Groundwater Resources: Groundwater occurrence within the project area is generally limited to the Trout Creek and Twentymile sandstone units and the shallow alluvial/colluvial aquifers associated with some of the drainages. Localized groundwater occurrences aze also associated with laterally discontinuous, very fine- to fine-grained sandstone, siltstones, and coal beds, which typically have low storativity and are characterized by variable water yields. Groundwater to the shallow alluvial aquifers occurs as infiltration of precipitation and snowmelt, and as seepage losses from streams, while recharge to deeper bedrock aquifers occurs primarily in outcrop areas. Groundwater movement is generally downdip to the north-northwest. The proposed exploration activities will avoid azea drainage channels, and so will not affect alluvial/colluvial aquifers. Since the proposed exploration program will not extend into the Trout Creek Sandstone, it will not be affected, and the only bedrock aquifer that will be penetrated will be the Twentymile Sandstone. Soils: Soils within [Ile project area are formed primarily from weathered fine-grained sandstone, siltstone, and shale. The dominant soils are a Paleborolls-Cryoborolls association, and are moderately-deep to deep, well-drained, and have loam to fine-sandy-loam surface textures. Ve etag_ tion: The project area is dominated by croplands and sagebrush shrub land vegetation community, with limited areas of pastureland, mixed mountain brush and aspen forest woodland, and small inclusions of mesic drainage and herbaceous wetland. Prevailing land uses include cropland, rangeland, pastureland, and wildlife habitat, with cropland/rangeland being the dominate land uses. Dryland wheat is the dominate crop. Generally, rangeland areas are characterized by stands of mixed mountain brush (dominated by sagebrush/snowberry in the lower elevations and serviceberry/ Gamble's oak in the higher areas) interspersed by open meadows with native and pastureland grasses. Pasturelands are (ands converted from native vegetation and seeded to permanent vegetation in order to improve forage quantity, quality or utility. Seeded pastureland is dominated by mixed wheat- grasses. No threatened or endangered (T&E) plant species occur in the project area. In addition, there are no rare plant species identified by the Colorado Natural Heritage Program (CNHP) occurring within the project area. The only CNHP rare plant species with some potential for occurrence in proposed project area are Harrington beardtongue (Penstemon harringtonii) and Autumn willow (Salix serissima). However, previous field reconnaissance did not identify any species occurrences. Access and locations for the proposed exploration activities have been laid-out to utilize existing access roads and two-tracks and previously disturbed areas to the extent feasible, therefore, the proposed exploration activities should not significantly impact existing vegetation communities. Temporary impacts to cropping and grazing activities are anticipated and will be addressed, to the extent feasible, by coordinated scheduling and surface damage agreements with surface owners/lessees. ~-~w r„w v,.~rm Noi c.~m