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August 2000 CM CD * Krp Racer- Basin Small Rmnw Study - Phase 2 Reprt * Page ? 30 ' Fortification Creek and Fortification Creek. At the public meeting held in Craig on June 6, 2000, a participant expressed interest in the development of this site. ' As with the other creeks in the Fortification drainage, most of the South Fork Fortification Creek streamflow occurs as spring snowmelt runoff. By mid- to late summer, the stream is often dry. Local agricultural users indicated that capture and storage of early season runoff would provide water during the typically dry late summer season. While flow data are not currently available on South Fork Fortification Creek, flow records from Fortification Creek near Craig indicate that the overall basin yield is in the neighborhood of 8,500 acre-feet per year and 250 acre-feet per square mile. Based on ' overall basin yields, yield at the reservoir site is estimated at 1,925 acre-feet per year. During the site visit on June 20, South Fork Fortification Creek was flowing. The streambed was primarily armored with sand, gravels, and some cobbles. While flow appeared clear, there was . indication of some bank erosion and of rock- and landslide areas in the vicinity of the proposed site. Physical Characteristics /Dam Siting ' The South Fork 1 reservoir site is located on the South Fork of Fortification Creek approximately 3 miles southeast of Colorado 1- ighway 13. This reservoir site would impact the headgate for an existing irrigation ditch and would be too low in the drainage to provide water to the upper irrigation ' ditch flowing to the southwest from the South Fork of Fortification Creek. The South Fork 1 site is located on the Wasatch Formation, with small landslide deposits in the area. ' S il i o s n the area of the South Fork 1 reservoir site have been identified as Cochetopa-Gothic and the Routt-Cochetopa-Binco complexes on slopes ranging from 10 to 45 percent. These soils are ' extremely bouldery and soils comprised of colluvium and residuum derived from shale. The typical profile for these soils consists of a bouldery or stoney loam at the surface and grades into a low plasticity clay at a depth of 20 to 30 inches. These soils are typically well drained with a high shrink- swell potential. A significant geotechnical consideration at this site is the presence of active landslides in the areas that would form each abutment for the dam. The removal of the existing landslide deposits would be ' required for construction of a dam and would render this site infeasible. Ecological Evaluation ' Ri i par an habitats at the South Fork 1 site are dominated by dense willow / narrow-leaf cottonwood communities. Because of the relatively flat and broad configuration of the drainage at this site, narrow-leaf cottonwoods create a relatively broad and continuous forest canopy along most of the ' main drainage channel. Other habitats present within the proposed reservoir basin area include big sagebrush / grass inter-nixed with willow / narrow-leaf cottonwood along the drainage bottom and mixed shrub communities along the steeper side slopes. Mixed shrub habitats at this site are ' dominated by big sagebrush, snowberry, chokecherry, and serviceberry. Photo SFFR# 1-2 (Appendix B) provides a representative view of stream, big sagebrush / grass, and willow / narrow-leaf cottonwood habitats at this site. Wetland development at this site was not extensive and appeared to be confined primarily to the stream embankments. Willow / sedge / grass communities were the dominant wetland habitats noted along the creek channel. Aquatic habitat within the creek channel consists primarily of pools and riffles but occasional ' boulders, rock outcrop, and large woody debris piles have created some pools and drop structures ' Montgw a Watson * P.O Box 774018 * StPmy&& Sprig; Colorado 80477 *(970)879-6260 wnr1Pro5s1Pb-2xj- 081301WH