Summary of surface-water-quality data collected for the Northern Rockies Intermontane Basins National Water-Quality Assessment Program in the Clark Fork-Pend Oreille and Spokane River Basins, Montana, Idaho, and Washington, water years 1999-2001
Beckwith MA. 2003. Summary of surface-water-quality data collected for the Northern Rockies Intermontane Basins National Water-Quality Assessment Program in the Clark Fork-Pend Oreille and Spokane River Basins, Montana, Idaho, and Washington, water years 1999-2001. U.S. Geological Survey. Boise, Idaho
Water-quality samples were collected at 10 sites in the Clark Fork-Pend Oreille and Spokane River Basins in water years 1999 – 2001 as part of the Northern Rockies Intermontane Basins (NROK) National Water-Quality Assessment (NAWQA) Program. Sampling sites were located in varied environments ranging from small streams and rivers in forested, mountainous headwater areas to large rivers draining diverse landscapes. Samples were collected during a wide range of streamflow conditions, more frequently during increasing and high streamflow and less frequently during receding and base-flow conditions. Sample analyses emphasized major ions, nutrients, and selected trace elements. When all data from all NROK sites were combined, median concentrations of dissolved arsenic, dissolved and total recoverable copper, total recoverable lead, and total recoverable zinc in the NROK study area appeared to be similar to or slightly smaller than median concentrations at sites in other NAWQA Program study areas in the Western United States affected by historical mining activities.