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Occurrence of dissolved sodium in ground waters in basalts underlying the Columbia Plateau, Washington

January 1, 1994

Basalt aquifers of the Columbia River Basalt Group are a principal source of water for agricultural, domestic, and municipal use. Concern has been expressed in this agriculture-dependent region about problems associated with the use of groundwaters with a high sodium concentration relative to the calcium and magnesium content (high sodium-adsorption ratio). Continued irrigation with such waters can reduce soil permeability to the degree that water cannot effectively reach plant roots. Groundwaters within a flow path evolved from a calcium magnesium bicarbonate type in shallow and upgradient locations to a sodium potassium bicarbonate type in deeper and downgradient locations. Most of the intermediate and high sodium adsorption ratio values were observed in discharge areas near major streams and in pumping centers within the central part of the plateau. Ninety-six percent of the groundwaters sampled had a low sodium absorption ratio, indicating that, for irrigation purposes, there is probably little danger of harmful levels of exchangeable sodium occurring on soil. However, water from 18 of 418 wells sampled had a sodium absorption ratio grater than 8.0 and were classified as having a medium, high, or very high sodium hazard. 

Citation Information

Publication Year 1986
Title Occurrence of dissolved sodium in ground waters in basalts underlying the Columbia Plateau, Washington
DOI 10.3133/wri854005
Authors Gilbert C. Bortleson, S. E. Cox
Publication Type Report
Publication Subtype USGS Numbered Series
Series Title Water-Resources Investigations Report
Series Number 85-4005
Index ID wri854005
Record Source USGS Publications Warehouse
USGS Organization