Water quality of the lower Columbia River basin: Analysis of current and historical water-quality data through 1994. Water resources investigations

The purpose of this report is to describe the water-quality conditions in the lower Columbia River and major tributaries to the extent possible, by (1) Examining seasonal variations in concentrations of water-quality constituents in water (filtered and unfiltered) and suspended sediment; (2) Portraying spatial variations in historical water-quality data; (3) Determining trends in concentrations of water-quality measurements (for example, water temperature) for sites with adequate historical data; (4) Analyzing the suitablity of surface water for maintenance of aquatic life and protection of human health; (5) Determining instream loads for selected water-quality constituents and comparing instream loads in major subbasins to instream loads in major subbasins to instream loads in the Columbia River; and (6) Listing point sources and, to the extent possible, the associated discharges.