USGS Northern Rocky Mountain Water Quality Assessment

To address water resources protection at a national level, Congress appropriated funds in 1986 for the USGS to begin a pilot program in seven project areas to develop and refine the National Water Quality Assessment (NAWQA) Program. In 1991, the USGS began full implementation of the program. The NAWQA program builds upon an existing base of USGS water quality studies as well as those of other Federal, State and local agencies. The objectives of the NAWQA program are to:

• Describe current water quality conditions for a large part of the Nations’ freshwater rivers and aquifers;
• Describe how water quality is changing over time;
• Improve understanding of the primary natural and human factors that affect water quality conditions.

The Northern Rockies Intermontane Basins (NROK) study area (which includes areas in eastern Washington, northern Idaho and western Montana) is one of 59 study units selected by the USGS for full-scale implementation of the NAWQA program. The NROK study area includes the Spokane Valley Rathdrum Prairie (SVRP) Aquifer. Biological (Maret and Dutton, 1999), hydrological and hydrogeological (on-going) studies of the SVRP Aquifer area are planned within the NROK study area.

In 2000, 18 wells were drilled by the USGS within 0.6 miles of the Spokane River between Post Falls, Idaho and Harvard Bridge near Spokane, Washington. These wells, and an additional 7 wells drilled for Ecology and Spokane County, were sampled 8 times from August 2000 to August 2001. Samples were analyzed for major ions, trace elements and stable isotopes (oxygen / deuterium). Ten of the wells were instrumented with continuous data loggers that recorded temperature and pressure. Continuous measurements of temperature, stage and specific conductance were also recorded at the USGS gage on the Spokane River at Post Falls. Elevations of the wells and elevations along cross sections of the river channel were surveyed. This data will be summarized and interpreted in a USGS Water Resources Investigations Report. The USGS data and results (if available) will be incorporated into the water resources management model for WRIA 57.

Project Contact:

Terry Maret (208) 387-1328 -or- Dorene MacCoy (208) 387-1354

Project links:

http://montana.usgs.gov/nrok/nrokpage.htm

http://wwwidaho.wr.usgs.gov/projects/spokane/

http://water.usgs.gov/nawqa/