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A three-dimensional, barotropic, finite element model is used to calculate the tidal flows in eastern Juan de Fuca Strait and the southern Strait of Georgia. The harmonics of eight constituents are computed and compared with those from previous finite difference models and those from historical tide gauge and current meter observations. Root-mean-square differences between observed and calculated sea level amplitudes are within 2.0 cm for all constituents, and the phases are within 4.0 ø for all constituents except K2. Horizontal currents from the model are found to reproduce the observed vertical variations in shear except in regions where stratification effects and internal tides exist. In particular, the model representation of currents at six stations in the Canadian Tide and Current Tables (volume 5) is accurate. The pattern of tidal residual currents has much more detail than previous, coatset resolution models, and numerous eddies are predicted. Computed energy flux fields reveal that over a 29-day period only 38% of the tidal power entering Juan de Fuca Strait is transmitted into the southern Strait of Georgia, and of the 39% entering tIaro Strait, 36% is dissipated within the strait itself. 1. Introduction This paper describes the development and validation of a three-dimensional, barotropic, tidal model for eastern Juan de Fuca Strait and the southern Strait of Georgia (Figures 1 and 2). The tides in this region have been previously simulated by a series of finite difference models ICrcart, 1976, 1978; Crean et al., 1988; Stronach, 1991] whose finest resolution of 2 km was restricted by computer limitations. Although nested models with higher resolutions have been developed for regions such as Howe Sound [Stronach et al., 1993], the complicated coastline and numerous narrow channels through the Gulf (Canadian) and San Juan (American) Islands have had only crude approximations. As a consequence, the smaller-scale details of the tidal (and estuarine) flows in this region are not well modeled [oeeBlond et al., 1994] and are still poorly understood. The primary objective of this model is to provide a better resolution for this region and reproduce some of the smaller-scale tidal details. Given the success of finite element models for other sections of the British Columbia coast [Foreman and Walters, 1990; Foreman et al., 1993], a triangular grid was generated for the region and the harmonic, wave equation, finite element method was used to solve the tidal equations. Such a grid offers more flexibility than traditional finite difference grids by locally reducing numerical errors through provision of a better fit of the actual coastline and/or bathymetric features with elements of an arbitrary size, shape, and orientation (within certain regularity constraints). In particular, with the aid of the TRIGRID computer package [Henry and Walters, 1993] it is relatively easy to locally refine a grid by placing smaller elements in regions where the elevation or velocity field is changing rapidly and higher accuracy i...

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Storm surges are a significant concern in the siting and design of structures along the Beaufort Sea coast in that the coastal relief is low and the magnitude of surges in this region is large. Coastal storm surge elevations along the southern Canadian Beaufort Sea coast were documented by surveying log debris lines in the Kugmallit Bayfluktoyaktuk region. Careful attention to site selection and survey technique resulted in estimated errors in surge elevation measurements of less than k0.3 m. The data indicate a local surge maximum has occurred at Tuktoyaktuk at approximately 2.4 m above mean sea level (MSL); lower maximum surge elevations (2 m above MSL) were documented to the north and west of Tuktoyaktuk. There is no evidence that higher surges have occurred during the last 100 years. A surge that occurred in August 1986 measured approximately 1.6 m above MSL at Tuktoyaktuk and decreased to approximately 1.4 m above MSL 20 km to the north and west of Tuktoyaktuk. These surge elevation data provide a basis for the calibration of numerical models of surge and can be used directly in siting and design analysis of coastal structures.