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' � SUG�ET ��UIRO�(f IE�TAL, I�C. II , ENVIRONMENTAL PLANNWG • LANDSCAPE ARCHITECTURE ' October 30, 2006 Ms. Erin Ansell ' CDM Engineering 1331 17th Street, Suite 1200 Denver, Colorado 80202 RE: Wetland Assessment for the Proposed Expansion of the Rio Grande Reservoir Hinsdale County, CO. (Sugnet # 060051) Dea� Ms. Ansell: On September 14r'' and 20`'' Sugnet Environmental, Inc. (Sugnet) conducted a preliminary wetland assessment in and �uound the Rio Grande Reseivoir located in Hinsdale County, Colorado. Specifically, this assessment was conducted to determine the potential impacts to Waters of the US as a result of the two options currently being considered for the expansion of the reservoir capacity. This letter provides a brief summary of the study area limits, the wetland resources found within the study area, the mapping methods applied, and the limitations of this inapping effort. A series of maps and photo documentation are included as Attachments A and B, respectively. GENERAL SITE LOCATION AND DESCRIPTION The study area included the Rio Grande Reservoir and surrounding areas, including a 360-acre area located downstream of the existing dam (see Figure 1). The Rio Grande Reservoir is located in Hinsdale County, Colorado, appro�mately 21 miles to the southwest of the Town of Creede, Colorado. The site can be accessed from Creede by traveling approximately 19 miles north on State Highway 149 to the ' intersection of Rio Grande Reservoir Road (a.k.a. CR 520, which turns into CR 18). Turn west onto CR 520 and continue 10.25 miles to the Rio Grande Reservoir (see Figure 2). This site can be accessed by I� average two wheel drive passenger vehicles. , The study area elevations range from 9,280 ft(2,829 m) at the east end to 9,600 ft(2,926 m) at the west end, and is located in a middle phase volcanic formation in an enh•enched glacial valley that cradles the south edge of the Lost Lake Caldei•a (Chronic 2002). Due to the steep valley walls the north and south ' sides of the reservoir maintain a distinct high water mark. The upstream end of the reservoir is less defined as the fluctuation in reservoir levels ue more subtle in the relatively flat floodplain. Just ' I ' I '