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Analysis of Water Quality and Sediments

San Juan River monitoring sites map
Monitoring locations, San Juan River, Utah. Click to view larger.


After the Gold King Mine spill in 2015, the Utah Division of Water Quality (DWQ) collected data in the San Juan River Watershed and Lake Powell System to determine if metal concentrations and sediment loads pose a risk to the beneficial uses in the river. Designated beneficial uses for the San Juan River include:

  • Drinking water
  • Recreation
  • Aquatic life
  • Agriculture

DWQ and the U.S. Geological Survey (USGS) collected and analyzed a variety of parameters, including water quality, sediment, and sediment cores, and compared their findings with water-quality and sediment standards. In 2018, DWQ completed a report that details the data collection and analysis, interprets current and historical data for the San Juan River Watershed, and evaluates the impact to Utah’s waters from long-term and ongoing mine drainage. Topics include:

  1. Data compilation
  2. Sampling methodology and lab analysis
  3. Water-quality assessment and screening
  4. Sediment-data assessment and screening
  5. Spatial and temporal water-quality trends
  6. Sediment trends
  7. Potential soil and bedrock source contributions

The report also includes extensive references, appendices, and data tables.

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