The U.S. Geological Survey has mapped the aquifers in the Chamokane Creek Basin in southern Stevens County, giving a more accurate picture of how streams and groundwater interact.
The 179-square-mile basin covers part of the Spokane Indian Reservation. The tribe, the state of Washington and federal agencies wanted a clearer picture about how additional groundwater withdrawals would affect Chamokane Creek. Most of the basin is closed at this time to new water rights.
Two major sand and gravel aquifers were identified in the study, which appear to be hydraulically connected in places. A second phase of study will look at how changes in groundwater use might affect stream flow. That work should be completed in August.