Water Quality

OTEQ is a mathematical simulation model used to characterize the fate and transport of waterborne solutes in streams and rivers. The model is formed by coupling a solute transport model with a chemical equilibrium submodel. The solute transport model is based on OTIS, a model that considers the physical processes of advection, dispersion, lateral inflow, and transient storage. The equilibrium...

The Eagle River drains approximately 970 square miles (sq mi) west of the Continental Divide in central Colorado before flowing into the Colorado River. The Eagle River watershed (ERW) is located primarily within Eagle County and includes the towns of Vail, Minturn, Avon, Edwards, Eagle, and Gypsum. The eastern boundary of the Eagle River watershed is drained by Gore Creek, located at Vail Pass...

As part of the National Water Quality Assessment Program (NAWQA), the USGS has evaluated ground-water quality in the High Plains aquifer system. Beginning in 1999 and continuing for a period of 6 years, the High Plains Regional Groundwater Study intensively investigated the quality of groundwater resources within the study area. Water quality impairment coupled with water-level declines focus...

Emerging water-quality issues within Delta, Montrose, and Mesa counties reflect changing land use practices, housing development and related pressures due to growth. Significant amounts of data have been collected by members of the Gunnison Basin Selenium Task Force as it relates to selenium related water-quality problems. Soils within a large portion of the lower Gunnison Basin are derived from...

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...

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...

A thorough evaluation of sediment transport through this stream network is essential to comprehensively evaluate the present dynamic geomorphic conditions in the Fountain Creek watershed and its future consequences. Such an evaluation requires examining both of the fundamental modes of sediment transport: bedload transport and suspended sediment load.

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...