Summit County

The Summit County Region aligns with the Summit County boundaries and includes the Blue River, Tenmile Creek, Snake River, Straight Creek and Swan River, to name a few of the main tributaries. The region is home to some of the largest and most visited ski resorts in Colorado including Keystone, Breckenridge, Copper Mountain, and Arapahoe Basin ski resorts. These resort communities are not only known for their winter activities but sport great boating and fishing opportunities in their rivers, streams and lakes during other times of the year. Summit County is also home to many productive ranches.

The Colorado State Demographer estimated Summit County population in 2012 at 28,160 people and forecasts population growth to 50,350 by 2040. SWSI concluded that Summit County 2008 water supply demands of approximately 8,000 AFY will grow to 16,800 AFY by the year 2050. According to the UPCO Study, “Approximately 25% of the future demands are in the upper Blue River area above Dillon Reservoir. The remaining future demands are primarily in the Silverthorne, Eagles Nest and Mesa Cortina areas. Keystone and East Dillon Water District will experience water supply shortages under future demands due primarily to lack of physical supply during fall and winter months” (Hydrosphere Resource Consultants, 2003). Other water providers in the county have adequate water supplies to support anticipated future growth and demands.

Summit County is a major donor basin, providing approximately 75,000 AFY through Dillon Reservoir, Straight Creek Tunnel, Vidler Tunnel and the Continental Hoosier Tunnel. Dillon Reservoir, owned by Denver Water, has a capacity of 254,000 AF, diverting the largest amount of water from the Blue River through the Roberts Tunnel to the South Platte River Basin. The Blue River between Dillon and Green Mountain is significantly impacted by TMDs and Dillon Reservoir. Portions of the region, including the upper Blue River, have been impacted by historical mining practices and resulting significant water quality challenges. The Snake River and Upper Blue Watershed Plans have been actively identifying and implementing projects to remediate these issues.

The Colorado Springs Utilities’ Hoosier Pass Collection System and Vidler Tunnel impacts flows in the Blue River and Snake River. Streamflows in the Blue River below Dillon Reservoir under additional anticipated diversions through the Roberts Tunnel would be at or just above the decreed minimum stream flows of 50 cfs as identified by the CWCB instream flow program, and well below flows needed for recreation purposes during normal water years. In very dry years, flows below Dillon Reservoir have fallen below 50 cfs and may continue to decrease below the ISF target if inflows to Dillon Reservoir are less than 50 cfs and Denver Water reduces outflows in accordance with the 1966 right-of-way from the Department of Interior (subject to conditions of the CRCA).

Summit County government is proactive in water issues including assisting water providers, ski areas, and smaller water users in unincorporated areas of the County. The County offers water allotment contracts for legal water supplies and augmentation plans with water from Dillon Reservoir, Old Dillon Reservoir, Clinton Reservoir and Green Mountain. Ruedi Reservoir serves as a source of replacement water for Green Mountain Reservoir, when needed. The County is actively pursuing plans that will stress comprehensive land use and development codes, promoting smart land use, water efficiency and conservation, density, open space, and Best Management Practices.

Although the County has taken a lead in countywide legal augmentation water, the infrastructure to support drinking water treatment, conveyance, and storage of this water is not as organized. The Town of Breckenridge, however, has been proactive in long range planning to provide potable water from current town boundaries to Dillon Reservoir. There is an identified need to develop additional storage that can provide more physical water above water users’ points-ofuse to protect against drought, climate change and uncertainty in the future. Further regional collaboration of all water users in the County and including Denver and Colorado Springs could result in additional storage projects and better instream flow management.

The needs of the Summit County Region primarily are focused on protecting, maintaining and restoring healthy rivers and streams. The County, individual town plans, CRCA and the UPCO Study identified projects to meet these needs and are further identified in the following tables. Summit County is very interested in participating in the development of a basinwide stream management plan (SMP) necessary to identify criteria for restoration projects and multi-use projects.

(The above information was extracted from the Colorado Basin Implementation Plan and edited slightly to fit)