A Calculation of Flushing Times and Pollution Distribution for the Columbia River Estuary PDF Download

Author: Victor Thomas Neal
Publisher:
ISBN:
Category : Columbia River Estuary (Or. and Wash.)
Languages : en
Pages : 164

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Book Description
The probable pollution distribution and flushing times have been calculated for the Columbia River Estuary, a coastal plain estuary. The pollution distribution was determined by the fresh water fraction and by the diffusion equation. The flushing times were calculated by the modified tidal prism method and by the fraction of fresh water, These methods are explained and discussed in the study. The widely varying river flow and resulting salt water intrusion were considered, as well as the varying semi-diurnal tidal range. These changing factors cause a complex variation in estuarine classification from well-mixed to stratified. The data used was taken principally from the U.S. Corps of Engineers current measurement program of 1959. The data show a stronger flow on the north side of the estuary during flood tide and a stronger flow on the south side during ebb tide. Due to this fact, the estuary was also treated as two separate channels in calculating the pollution distribution. The results of the various calculations for combinations of conditions are given in this study. A comparison of the different methods is also summarized. The estuary has been found to have a relatively short flushing time, even under low river flow conditions. The variation in strength of flow from the north side to the south side has been shown to produce pollution distributions not normally expected in an estuary.