PHENOMENA AFFECTING IMPROVEMENT OF THE LOWER COLUMBIA ESTUARY AND ENTRANCE

John B. Lockett

Abstract


This paper describes work undertaken to improve the lower Columbia Estuary and Entrance for navigation and discusses past concepts of phenomena controlling the regimen of this area as related to these improvements. Recent advances in technology have given birth to a new concept of tidal hydraulic phenomena which emphasizes the relation of salinity intrusion and littoral movement to the degree of shoaling experienced in estuarine areas. The findings of prototype measurements undertaken in 1959 along the lower Columbia, and other endeavors to expand the knowledge of controlling phenomena, including statistical wave studies, analyses of offshore changes, studies of attrition and accretion of adjacent shorelines, and comprehensive investigations of the distribution of Columbia River sediments are reviewed in the light of this new concept. Authorization, construction and verification of the comprehensive lower Columbia Estuary hydraulic model are discussed, as well as tests proposed for identification of controlling phenomena and for development of the most effective and economical plan of improvement. Finally, the paper summarizes the extent of present knowledge and outlines considerations for the future under conditions of controlled upland discharge resulting from contemplated headwater reservoir operation.

Keywords


Columbia Estuary; navigation; sediment transport

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