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Introduction
These pages were originally published as a
technical report in 1993 and present a tabulation of some
of the geographic, oceanographic, and hydrological parameters for 141 coastal
embayments in the Bay of Fundy, Scotian Shelf and southern Gulf of St. Lawrence.
The project was called "Classification of Estuaries, Inlets and Coastal
Embayments" or CEICE for short.
The basic presentation consists of a map and a table of
variables including:
- Geographic parameters - area at high water (HW) and chart datum (CD),
perimeter, axis length, volume at chart datum, maximum depth in the inlet,
width and area at the mouth of the inlet, and watershed area;
- Oceanographic parameters - mean and large tidal range, mean tidal volume,
tidal current at the mouth of the inlet and an estimate of the flushing time;
- Hydrological parameters - monthly mean freshwater discharges into the
inlet and their standard deviations.
Data Files
The two major data sources in CEICE are the maps of coastlines and bathymetry.
An embayment identifier (BAY_ID) identifies individual embayments. Additional
parameters from other sources (i.e. tidal range) are added to the database record
to permit the calculation of other variables. As an example, surface area and
cross-sectional area are used with the tidal range to compute a mean tidal
current across the section.
Base Maps
At the time this report was produced, there was virtually no digital bathymetry
for the inshore regions of Nova Scotia, New Brunswick and Prince Edward Island.
In order to obtain the necessary bathymetric contours, bathymetric charts from
the Canadian Hydrographic Service were digitized as a series of ASCII files.
Fifty-seven different charts were used with scales from 1:10000 (Halifax Inlet)
to 1:200000 (Minas Basin, Chignecto Bay, Baie de Chaleur). The majority of the
maps fell within the range of 1:20000 to 1:60000. Metric charts were selected
when available, but charts with contour intervals in both fathoms and feet were
also used. In some cases a single basemap consists of a number of bays (e.g.
Barrington Passage and vicinity) which are reported in the database separately.
Earth and Oceans Research Ltd converted
the ASCII files using AUTOCAD where they were plotted at full scale and overlaid
over the original charts. Any digitizing errors were corrected using AUTOCAD.
In some cases, for example Lennox Passage, the shoreward end of the embayment was
artificially closed off. A comment on the data page for a particular embayment
will make note when this has occurred.
Embayment Description
A map and a data sheet of the physical parameters are provided for each bay.
All parameters are specified to one decimal place, which is simply a result of
the computations. These should be rounded off as appropriate.
The title includes the embayment name,
NAFO fishing zone, Canadian Hydrographic chart number from which the bathymetric
contours were derived and a bay identification number. The bay number normally
consists of two uppercase letters. A third lower case letter denotes that the
bay is a sub-area of a larger area.
A description of the rest of the parameters is as follows;
| Area(CD) |
Surface area (km2)
at the 0 contour (chart datum) |
| Area(HW) |
Surface area (km2) at the coastline (high water) |
| Perimeter |
Distance (km)
along the perimeter of the coastline |
| Volume(CD) |
Volume below the
0 contour (chart datum) |
| Axis Length |
Distance (km) from
head to open boundary - measured from CHS chart |
| Max. depth |
Maximum depth
(m) reported on the CHS chart |
| Section width |
Total width (km)
across the open boundary(s) |
| Section area |
Cross-sectional
area (m2) across the section |
| Tidal range |
Tidal range (m)
for mean and large tides compiled by CHS. |
| Tidal Volume |
Based on mean
tidal range, defined as; |
| Tidal Current |
Computed from
Tidal Volume passing through section over half a tidal cycle referred
to the M2 tide (T = 12.42 hours) |
| Flushing time |
The estimated time
in hours that it takes for a tracer to be reduced to approximately a
third of its initial concentration. It assumes complete mixing of the
incoming tidal volume with the surrounding embayment volume and the
subsequent complete removal from the bay of the tidal volume. One would
normally expect the actual flushing time to be somewhat longer.
Specifically, the flushing time is defined as; |
| Tidal / Freshwater Ratio |
Ratio of the tidal
volume to the equivalent amount of freshwater entering the system during
one-half tidal cycle. The freshwater amount is based on an average
annual discharge. |
| Watershed area |
Drainage area
(km2) for an embayment |
| Freshwater Discharge |
Estimated monthly
discharge based on;
- gauged rivers in inlet adjusted by watershed areas not gauged
- gauged rivers from nearby inlets adjusted by ratio of watershed
areas in the two inlets
Standard deviation is given as a % of the
monthly mean |
Acknowledgements
This project was conceived by Dr.
R.W. Trites over 20 years ago.
The original citation on which
these pages are based is:
D. Gregory,
B. Petrie, F. Jordan, and P. Langille. 1993. Oceanographic, geographic and
hydrological parameters of Scotia-Fundy and southern Gulf of St. Lawrence inlets.
Can. Tech. Rep. Hydrogr. Ocean Sci. No. 143: viii + 248 pp.
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