Identifying Changes in Background Water-Quality Conditions, Arkansas River and Fountain Creek, near Pueblo, Colorado

Effective management of existing water-storage capacity in the Arkansas River Basin is anticipated to help satisfy the need for water in southeastern Colorado. Additionally, the development of more water-storage capacity in the basin is anticipated as the population along the Arkansas River and Fountain Creek corridors increases over the next 40 years. An overall strategy to meet these needs was developed and is defined in the Preferred Storage Options Plan. In 2002, a basic water-quality monitoring program was established in the basin to collect additional data needed to support the plan. Because no known methods were available to determine what effects future changes in operations will have on water quality, the U.S. Geological Survey, in cooperation with the Southeastern Colorado Water Activity Enterprise, began a study in 2002 to develop methods that could identify if future water-quality conditions have changed significantly from background (preexisting) water-quality conditions.

Methods were developed to identify changes in background water-quality conditions using dissolved-solids concentrations and dissolved-solids loads as indicators at selected sites in the Arkansas River and Fountain Creek in the vicinity of Pueblo, Colorado. Daily dissolved-solids concentrations were estimated from daily specific-conductance values. The techniques are described in the USGS Scientific Investigation Report 2004-5024. Specifically, the report designates background conditions at selected sites in the study area with respect to estimated daily dissolved-solids concentration, flow-adjusted concentration, and dissolved-solids load, establishes the use of tolerance limits to identify statistically significant future daily departures from a background condition, and presents other analysis techniques to help identify long-term changes in dissolved-solids load along selected reaches of the study area. The report also provides information for this internet-based decision-support tool that can be used on a real-time basis to monitor estimated dissolved-solids concentration and load as a surrogate for water-quality conditions in the study reaches and determine whether future water-quality conditions are significantly different from background conditions.

Generate comparison plots of water-quality conditions:

Comparison of Current Dissolved-Solids Data to Tolerance Limits for Background Period:

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View 14 days of concentration, flow-adjusted concentration and load (at selected Site):

Map of Arkansas River in the vicinty of Pueblo, CO

Arkansas River at Portland, CO Arkansas River above Pueblo, CO Fountain Creek at Pueblo Arkansas River at Moffat Street at Pueblo, CO Arkansas River near Avondale, CO

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Compare plots between two sites for the last 14 days: