The Boulder Creek Watershed is approximately 1,160 square kilometers (447 square miles) in area and is located in the Front Range of the Colorado Rocky Mountains, east of the Continental Divide. The watershed includes all the land area that drains water into Boulder Creek. The watershed has great variation in geology, climate, and land cover. Tributaries of Boulder Creek include North, Middle, and South Boulder Creeks, Fourmile Creek, Coal Creek, and Rock Creek, along with several smaller streams. These streams generally flow from west to east. Boulder Creek empties into Saint Vrain Creek, which empties into the South Platte River. The water in Boulder Creek eventually reaches the Mississippi River and the Gulf of Mexico. The communities of Boulder, Louisville, Lafayette, Erie, Superior, and Nederland are in the watershed, along with parts of Arvada, Broomfield, and Frederick. In 2000, about 185,000 people lived in the Boulder Creek Watershed (U.S. Census Bureau, 2001). A reliable source of high-quality water is important for drinking-water supply, recreation, aquatic life, and agriculture. In the semiarid environment of the Colorado Front Range, water resources are limited, and waterways are subject to stress by competing uses. The population of the five largest communities in the watershed (Boulder, Lafayette, Louisville, Superior, and Erie) grew by 36 percent from 1990 to 2000, increasing demands on water resources. This report, prepared by the U.S. Geological Survey in cooperation with the City of Boulder, presents the state of water quality in the Boulder Creek Watershed in 2005 and how it has changed over the past 160 years, and identifies potential future water-quality concerns
Murphy, S. F. (2006): State of the Watershed: Water Quality of Boulder Creek, Colorado. U.S. Geological Survey Circular 1284.