Tidal-Fluvial and Estuarine Processes in the Lower Columbia River: I. Along-channel Water Level Variations, Pacific Ocean to Bonneville Dam

Journal Article · Sun Mar 01 04:00:00 EST 2015 · Estuaries and Coasts, 38(2):415-433

DOI:https://doi.org/10.1007/s12237-014-9819-0· OSTI ID:1173022

Jay, D. A.; Leffler, K.; Diefenderfer, Heida L.; Borde, Amy B.

This two-part paper provides comprehensive time and frequency domain analyses and models of along-channel water level variations in the 234km-long Lower Columbia River and Estuary (LCRE) and documents the response of floodplain wetlands thereto. In Part I, power spectra, continuous wavelet transforms, and harmonic analyses are used to understand the influences of tides, river flow, upwelling and downwelling, and hydropower operations ("power-peaking") on the water level regime. Estuarine water levels are influenced primarily by astronomical tides and coastal processes, and secondarily by river flow. The importance of coastal and tidal influences decreases in the landward direction, and water levels are increasingly controlled by river flow variations at periods from ≤1 day to years. Water level records are only slightly non-stationary near the ocean, but become increasingly irregular upriver. Although astronomically forced tidal constituents decrease above the estuary, tidal fortnightly and overtide variations increase for 80-200km landward, both relative to major tidal constituents and in absolute terms.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1173022
• Report Number(s): PNNL-SA-98787; 400403209
• Journal Information: Estuaries and Coasts, 38(2):415-433, Journal Name: Estuaries and Coasts, 38(2):415-433
• Country of Publication: United States
• Language: English