Lower Columbia River Cooperative
Water Quality Survey and Analysis
HAROLD A. DEERY, Technical Supervisor
Weyerhaeuser Company
Longview, Washington
The Columbia River follows a winding course of about 1, 200 miles from
the continental divide to the Pacific Ocean. With its tributaries it collects
and discharges water at a rate of 0.5 million cfs at high water and maintains
a flow of more than 0.1 million cfs during most of the year. The main stream
is navigable to ocean-going ships for more than 100 miles while the tributaries except for the Willamette and Snake are not navigable even to small
boats for more than a few miles.
The drainage pattern includes many short, small rivers which collect
rain and melted snow from mountain slopes. Snow fields and dam reservoirs
together provide significant storage for the dry season, and the inland agricultural areas depend mostly on this stored water for irrigation. West of the
gorge through the Cascade Mountains the Columbia River collects a mean ad -
dition of more than 40, 000 cfs for streams which may increase in volume by
a factor of five or more during the rainy season or during the early summer
when snow is melting rapidly.
The flow pattern of the entire river responds primarily to melting snow,
and the peak flow occurs during May, June, and early July (Figure 1). The
river annually provides the spectacle of crowding its banks under a cloudless
sky.
The section of the river from Bonneville Dam to the Pacific Ocean defines the lower Columbia River. Tides influence the entire 145-mile section,
and the current actually reverses during low water flood tides as far upstream
as the Cowlitz River 70 miles from the ocean. During ebb tide the current
range is from 1.5 fps at low water to 4.4 fps at high water. The large net
flow of water prevents salt water instrusion into the area included in the reported survey.
During the past two generations the pattern and pace of cultural changes
have been great enough to modify both the flow and quality constituents of
the Columbia River to a measurable extent. Rapidly increasing population
and industries use the Columbia River and tributaries for water supply, power,
transportation, waste disposal, and other uses. Dams change the flow and
temperature, agriculture increases the solids content, and atomic energy increases the temperature and radioactivity.
The river still satisfies the needs of agriculture, industry, fishing, recreation, energy conversion, and transportation.
If available, knowledge of the natural equilibrium of a stream and its
tributaries could help to assess the impact of cultural changes. Continued
study is needed to correlate water quality with the real or imagined influence
of its diverse uses. Fortunately, many studies have been made in the past on
sections of the Columbia River basin (1). Several independent studies in the
pulp and paper industry have measured the impact of individual mills on such
factors as dissolved oxygen, biochemical oxygen demand, the nitroso-lignin
test (PBI), Sphaerotilus growth, and others.
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