Forecasting the Wave-Current Interactions at the Mouth of the Columbia River, Or, Usa

Abstract

An operational wave forecast of the area near the mouth of the Columbia River is presented. This region is known for its large waves and strong tidal currents. The forecast is forced with full directional spectra obtained from a refined WaveWatchIII forecast of the Pacific Northwest, and tidal current inputs are obtained from an estuarine circulation forecast of the Columbia River. The forecast has been operational since August 2011 providing short-term predictive wave information at the mouth of the Columbia River. Results from a 6-month period are promising, with a normalized root-mean-squared error (NRMSE) of 16% at the location of an inshore buoy, which is located outside the zone of tidal influence in 25 m water depth. Near the river mouth and in the channel, wave heights are heavily dominated by the tidal currents which significantly increase wave heights on ebb tides. Hindcast results shows that the model is able to predict the general effect of the tidal currents with a NRMSE of 30% in wave heights at the river mouth. Despite some of the model limitations, it still provides valuable information to navigators and bar pilots since it includes the effects of the tidal currents.

Surface wave breaking over sheared currents: Observations from the Mouth of the Columbia River

“…The inlet entrance is roughly 3.5 km wide, and has been engineered with two jetties at the mouth (a third jetty was also constructed inside the river mouth), and a dredged shipping channel is maintained out the west facing inlet, turning southward. Previous studies have shown strong wave‐current interactions at this site, using both remote sensing data [ Gonzalez and Rosenfeld , ] and model simulations [ Kassem and Ozkan‐Haller , ]. Field measurements of waves and wave breaking have historically been sparse.…”

Wave breaking turbulence at the offshore front of the Columbia River Plume

“…The Columbia River plume has been studied by many previous authors, in particular Kilcher and Nash [] who describe the shear‐driven interfacial mixing as the plume spreads offshore and McCabe et al [] who describe the salt fluxes of the spreading plume in a Lagrangian frame. The transformation of waves at the Columbia River mouth has also been studied by previous authors, in particular Gonzalez and Rosenfeld [] who describe the refraction and focusing of waves in the presence of the opposing currents and Kassem and Ozkan‐Haller [] who show increased wave heights and steepness in the presence of the opposing currents. In contrast to the previous works, our study is limited to an assessment of the wave‐driven processes at the edge of the river plume as it spreads offshore during ebb tides, in particular where the vertical and lateral processes collide.…”

Analytical approximation and numerical simulations for periodic travelling water waves

“…Moreover, the case γ = 0 gives rise to a large number of rotational waves, which display a variety of different characteristics. This mechanism describes waves where wavecurrent interactions cause significant increase of the wave amplitude in little time; such a case appears at the Columbia River entrance, where tidal currents cause a doubling in the wave height; see [36,37].…”