Surface Water

High concentrations of dissolved selenium have been detected in the lower Gunnison River basin including the Uncompahgre River basin. Butler and others (1991 and 1996) identified the highest concentrations of selenium in surface waters in areas that are irrigated on soils derived from Mancos Shale. In July 1997, the Colorado Water Quality Control Commission amended the classifications and numeric...

The Upper Gunnison River Watershed, located in the Rocky Mountains 150 miles southwest of Denver, Colorado, drains approximately 3,965 square miles. Forest and rangeland comprise 89 percent of land within the watershed, but the traditional western ranching economy is increasingly supplemented through a tourism economy centered around Crested Butte Mountain Resort and the Curecanti National...

Since 1986, the USGS Hard-Rock Mining Toxic-Substances Hydrology Project has focused on metal transport in streams affected by mining. Tracer-injection studies in St. Kevin Gulch, near Leadville, Colorado, helped the USGS design methods to characterize loading from mining activities on a watershed scale. Tracer-injection studies were done in 1995, in support of the planning needs of ederal Land...

Salinity and dissolved selenium are known water-quality impairments in the lower Gunnison River watershed of western Colorado. Salinity is a concern because of its adverse effects on agricultural land and equipment, and on municipal and industrial users. The Montrose Arroyo watershed in Montrose, Colorado, contains agricultural and residential areas as well as undeveloped land and has undergone...

In southwest Colorado, drought, wildfires, mining activities, agriculture, and population growth have altered the landscape from its natural condition. These changes have potentially degraded the water-quality of streams, rivers, reservoirs, and groundwater by introducing or increasing levels of metals, nutrients, synthetic organic chemicals, and sediment. Recognizing the need to understand how...

Pueblo Reservoir is one of southeastern Colorado's most valuable water resources. The reservoir provides irrigation, municipal, and industrial water to various entities throughout the region. The reservoir also provides flood control, recreational activities, sport fishing, and wildlife enhancement to the region. The Bureau of Reclamation is working to meet its goal to issue a Final Environmental...

Changes in land and water use associated with population growth and agricultural practices within the Arkansas River Basin are likely to affect water-quality on a local and, possibly, a basin-wide scale. To manage the limited water resources in the basin most effectively it is important to understand the processes that affect water quality within the basin and how future changes in land and water...

The St. Vrain River watershed in northeastern Colorado has experienced rapid urban growth over the last two decades. Population growth has led to increased volumes being treated at wastewater-treatment plants (WWTPs) in the basin. In the last two decades, in-stream restoration efforts and new treatment technologies have been implemented by the City of Longmont, with the goal of improving water...

Baseflow will be determined for selected reaches in the South Platte River by using a mass-balance approach and possibly by modifying conventional baseflow analysis techniques.

Since the late 1800's, Colorado has experienced several periods of drought that have varied from about 2 to 12 years in duration. The Statewide drought from 1999 extended into 2002, a year characterized by lower than normal precipitation, snowpack accumulation, and streamflow. Statewide, mountain snowpack was about 53 percent of normal on April 1, 2002, the lowest since 1977 Accumulated...

The Roaring Fork Watershed, located in the Rocky Mountains 150 miles west of Denver, Colorado, has seen rapid development and population growth in recent years. The USGS, in cooperation with Pitkin County, Colorado Water Conservation District, Ruedi Water and Power Authority, and other local entities, conducted a comprehensive surface- and ground-water resource assessment in the Roaring Fork River...

Sulphur Gulch, a new reservoir proposed to be located about 25 miles east of Grand Junction, Colorado, on a tributary to the Colorado River that drains the Sulphur Gulch watershed between De Beque and Cameo, Colorado. The primary use of the Sulphur Gulch Reservoir would be to provide the Colorado River with up to 5,412.5 acre-feet of late-season water in support of the Endangered Fish Recovery...