Volume 1 - Main Report

6.1.4 Physical Oceanography
Two physical oceanographic survey campaigns were conducted in Deception Bay:
August to September 2006 and August to September 2012. Tides and water levels,
waves, flow and currents, physicochemistry and water quality were characterized for
these two periods in order to describe the oceanographic conditions in Deception
Bay.
6.1.4.1 Tides and Water Level
6.1.4.2 Waves
There are few records of the water level in the Deception Bay region. The tidal
characteristics established based on the water levels measured during the 2012
survey campaign are used to describe the tide at the study site (Figure 6.7). The tide
that enters Deception Bay is semi-diurnal, meaning that it presents two complete
oscillations per day, i.e. two high waters (high tide) and two low waters (low tide).
Each oscillation extends over an average period of 12 hours and 25 minutes.
Tidal Characteristics
Harmonic analysis of the water levels measured in 2012 (GENIVAR, 2012a) allows
the establishment of a series of hourly values, which is used to establish the tidal
characteristics (Table 6.8). The tidal range of 3.9 m for mean tides and 5.7 m for
large tides is relatively large. The mean water level is 2.9 m and the higher high
water large tide (HHWLT) is 5.8 m (Table 6.8).
Storm Surge Observed in Deception Bay
The analysis of the atmospheric component of the water levels measured indicates a
mean variation of around 20 cm and a significant rise of the mean water level around
mid-September 2012 (Figure 6.8). This rise of around 60 cm is due to the passage of
a major depression. On September 13, the winds reached more than 30 km/h and
the barometric pressure was below 98 kPa (Table 6.9). The combination of the
passage of a depression associated with high winds and large tides causes extreme
tidal events.
The wave measurements taken in 2006 (Figures 6.9 and 6.10) show that the
significant height (H s ) never exceeded 0.8 m. Assuming a Rayleigh distribution, it is
possible to apply a conversion factor of 1.87 for H max /H s (Komar, 1998) in order to
determine the maximum height of the waves. This was estimated at 1.5 m during the
measuring period.
Canadian Royalties Inc.
GENIVAR
101-53046-02 November 2012
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