Modeling Tidal Water Levels for Canadian Coastal and Offshore waters

Friday, 19 December 2014
Catherine M I Robin1,2, Philip MacAulay3, Shannon Nudds3, Andre Godin4, Bodo de Lange Boom5, Jason Bartlett6, Louis Maltais4, Terese Herron6, Michael R Craymer2, Marc Veronneau2 and Kian Fadaie1, (1)Canadian Hydrographic Service, Fisheries and Oceans Canada, Ottawa, ON, Canada, (2)Canadian Geodetic Survey, Natural Resources Canada, Ottawa, ON, Canada, (3)Canadian Hydrographic Service, Fisheries and Oceans Canada, Dartmouth, NS, Canada, (4)Canadian Hydrographic Service, Fisheries and Oceans Canada, Mont Joli, QC, Canada, (5)Canadian Hydrographic Service, Fisheries and Oceans Canada, Sidney, BC, Canada, (6)Canadian Hydrographic Service, Fisheries and Oceans Canada, Burlington, ON, Canada
IIn 2010, the Canadian Hydrographic Service initiated the Continuous Vertical Datum for Canadian Waters (CVDCW) project, the aim of which is to connect tidal water level datums (high and low water levels, chart datum, etc.) to a national geodetic reference frame over all Canadian tidal waters. Currently, water level datums are tied to a geodetic reference frame at approximately 400 tide stations which have been surveyed with GPS, whereas water levels vary significantly in space even a short distance away from tide stations. The CVDCW captures the relevant spatial variability between stations and offshore by integrating ocean models, gauge data (water level analyses and/or GPS observations), sea level trends, satellite altimetry, and a geoid model.

The CVDCW will enable the use of Global Navigation Satellite System technologies (primarily GPS) for hydrographers and navigators. It will also be important for other users including oceanographers, environmental and climate scientists, surveyors and engineers. For instance, it will allow easier integration of hydrographic and terrestrial data, provide a baseline for storm surge modeling and climate change adaptation, and aid with practical issues such as sovereignty and the definition of the coastline. Once high and low water surfaces are complete, they will define a large portion of the vertical link between land and ocean, helping to delineate flooding thresholds and inter-tidal ecosystem zones and boundaries. 

Here we present an overview of the methodology using a set of prototype model results, and will outline features of interest for studies in coastal stability, climate change adaptation, and sea level change.