Your Watershed
What is a Watershed?
A watershed is a basin-like landform defined by highpoints and ridgelines from which water runs down into lower elevations, streams and valleys. A watershed carries water “shed” from the land after rain falls and snow melts.
Drop by drop, water percolates into soils and groundwaters and runs into creeks, and streams, eventually making its way to larger rivers and eventually the sea. Water is a universal solvent, affected by all that it comes in contact with: the land it traverses and the soils through which it travels. It’s important to remember that what we do on the land affects water quality for all communities living downstream.
About the Blue River Watershed
The Blue River drains an area of about 680 square miles in the central Rocky Mountains, west of the continental divide in Colorado. The watershed drains northward, from elevations reaching 14,270 feet along the southeastern perimeter, to where it flows into the Colorado River south of Kremmling at an elevation of 7,400 feet.
Three major tributaries in the Blue River watershed come together at Dillon Reservoir forming the Upper Blue River watershed. These are the Snake River, the Blue River, and Ten Mile Creek. The lower Blue River watershed is approximately the same size as the upper Blue River watershed, and contributes approximately the same virgin yields, which average approximately 160,000 acre feet (af) per year. An acre foot is an acre of water one foot deep or 326,000 gallons.
Most of the total annual stream flow results from snow melt during the spring and early summer. Major snowfall typically occurs January through April. Thunderstorm activity produces significant, though short-lived, rainfall events in July and August. Stream flows above major water storage facilities have marked seasonal variability. Discharges from groundwater systems contribute about a quarter of the total surface water flow.
The Blue River watershed includes all of Summit County, which encompasses approximately 619 square miles. An additional 61 square miles lie within Grand County, and the very head of the Ten Mile basin lies within Lake County.
The major population centers within the Blue River watershed are the towns and unincorporated areas of Blue River, Breckenridge, Copper Mountain, Frisco, Keystone, Dillon and Silverthorne. The permanent resident population of Summit County in 2000 was 20,946 and the peak seasonal population was 121,496!
Generally, water in the Blue River watershed is of high quality. A portion of the Blue River below Dillon Reservoir has been designated as a gold medal fishery by the Division of Wildlife. Four segments have significantly impaired water quality due to impacts associated with historical hard rock mining.
The major water quality challenges include runoff from old mining areas, urban areas and construction activities, trans-basin diversions (which reduce dilution and flushing flows), nutrients from septic systems, and, to a smaller degree, municipal treatment systems.
Future project needs in the Blue River basin include the continued work on Straight Creek (sediment impacts); Peru and French Creeks (heavy metals and acid mine drainage impacts); Ten Mile Creek (heavy metals and acid mine drainage impacts, I-70 impacts); lower Blue River (reservoir operation modifications to minimize water quality concerns, reducing nonpoint source nutrient loads); upper Blue River (hydraulic dredging impacts); and removal of “high risk” septic systems. Additional needs include Blue River restoration of hydrologic modification, sediment/erosion control practices for construction/land disturbance areas, wetland functional assessment/protection strategies and enhanced septic system management.