Why the Columbia River estuary?

Although the Columbia River is distinct among the LMER sites around the country, it represents a distinct class of systems (river estuaries typified by estuarine turbidity maxima) of great importance throughout the world (ETMs around the world). The Columbia River and its estuary exemplify some of the many ways that man has modified the structure of land-margin ecosystems and the fundamental processes that sustain them. Despite the large size of the Columbia River and its watershed, upriver impoundments behind dams, land and water use, and diking, filling and dredging in the lower river and estuary have substantially altered the river system (see Nch'i-Wana). This manipulation of the river has changed patterns and magnitude of flow, greatly reduced the load of sediments carried to the estuary by the river, changed the river's chemistry, and altered the various ETM processes that transform organic matter into the estuary's food web. While the estuary and lower river are certainly not free of pollution effects (especially pesticide residues in higher trophic level organisms), it is still relatively free of any indications of eutrophication and hypoxia that have plagued other large estuaries.

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