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Return to Coast Pilot index (1) Chart Datum, St. Clair River.- Depths and vertical clearances
under overhead cables and bridges given in the chapter are referred to the sloaping
surface of the river corresponding to a Lake Huron Stage of 577.5 feet (176.0 meters) and
a Lake St. Clair Stage of 572.3 feet (174.4 meters) above mean water level at Rimouski,
Quebec, on International Great Lakes Datum 1985 (IGLD 1985), which elevations are the
planes of low water datum for the two lakes. (See chart datum, Great Lakes System, indexed
as such, chapter 1.)
(2) General Description.- St. Clair River is about 39 miles long from
Lake St. Clair via St. Clair Cutoff Channel and South Channel to the head of the river at
Lake Huron. The lower 11 miles of the river is a broad delta through which numerous
channels flow into Lake St. Clair. South Channel and St. Clair Cutoff Channel form the
main navigation route through the delta and connect with the dredged channel across Lake
St. Clair. The upper river, above Chenal Ecarte, is generally a single deep channel,
except where obstructed by Fawn Island and Stag Island. The banks of the river are clay
and sand and usually quite steep.
(3) Channels.-The channel through St. Clair River has been improved in
places by dredging. The federal project depth in the river is 27 feet.
(4) Fluctuations of water level.-Each year the St. Clair River has a
seasonal rise and fall of about 1 foot, generally in consonance with the seasonal
variations of Lake Huron. High winds may cause rapid fluctuations of up to 2 feet above or
below normal.
(5) Currents,St. Clair River.-The following currents are based on
averages of water flow through through the entire cross section of the river, that is from
bank to bank and from surface to bottom during normal flow conditions. Normal flow
conditions are encountered when there is no wind, Lake Huron is at a stage of 578.9 feet
(176.4 meters) and Lake St. Clair is at a stage of 573.9 feet (174.9 meters) above the
mean water level at Rimouski, Quebec, on the International Great Lakes Datum 1985 (IGLD
1985), that is 1.4 feet (0.4 meter) and 1.6 feet (0.5 meter) above their respective Low
Water Datums. The current encountered at midstream is usually about 1.5 times the average
velocity. Greater Velocities may be expected when the difference between lake levels is
greater, or the lake stages higher.
(6) Currents for the following locations in the St. Clair River are given at high water
flow of 230,000 cubic feet per second (cfs), medium water flow of 188,000 cfs, and low
water flow of 130,000 cfs, respectively.
(7) Algonac: 2.0 mph, 1.6 mph, and 1.3 mph.
(8) Port Lambton: 2.0 mph, 1.7 mph, and 1.3 mph.
(9) Marine City: 2.0 mph, 1.6 mph, and 1.3 mph.
(10) St. Clair: 2.1 mph, 1.8 mph, and 1.4 mph.
(11) Marysville: 1.9 mph, 1.6 mph, and 1.3 mph.
(12) Point Edward: 3.9 mph, 3.3mph, and 2.5 mph.
(13) The rapids section extends from about 1,00 feet above to 200 or 300 feet below the
Blue Water Bridge. During peroiods of sustained high N to NE winds on Lake Huron,
velocities in the upper St. Clair River are increased.
(14) Ice.- The only need for ice breaking in the St. Clair River occurs
when the ice bridge that form across the S end of Lake Huron breaks and the broken mass of
ice travels down the river to the lower end where it meeets the natural ice cover and
forms a massive ice jam. When this occurs, ice can clog the entire 27-foot depth of the
channel and cause serious flooding. (See winter navigation, chapter 3.)
(15) Navigation Regulation.-The State of MIchigan enforces the following
speed limits for recreational craft within its jurisdictional boundaries from the mouth of
the Black River down stream to the mouth of the St. Clair River: slow-no wake for vessels
less than 26 feet long within 200 feet of any shore, dock, or pierhead, and slow-no wake
for vessels 26 feet or longer within 600 feet of any shore, dock, or pierhead.
(16) A vessel traffic reporting system and related navigation regulations have been
established for the connecting waters from Lake Erie to Lake Huron. (See 33 CFR
162.130 through 162.140, chapter 2, for regulations.)
(17) Vessel Traffic Service.-The Canadian Coast Guard operates a Vessel
Traffic Service in Canadian waters from Long Point in Lake Erie through the Detroit and
St. Clair Rivers to De Tour Reef Light in Lake Huron. (See Chapter 3 and the Annual
Edition of Canadian Notices to Mariners for complete information.)
(18) Pilotage.-The waters of St. Clair River are Great Lakes designated
waters; registered vessels of the United States and foreign vessels are required to have
in their service a United States or Canadian registered pilot. Registered pilots for St.
Clair River are supplied by the Lakes Pilots Association. Pilot exchange points are just
below the Ambassador bridge in Detroit River and off Port Huron at the head of the St.
Clair River in about 43 05'30"N.,82 24'42"w. The pilot boat in the Detroit River
, J.W. Westcott II, has a black hull encircled by an orange band and a white cabin with
the words "U.S. Mail" in black letters. Three pilot boats are at Port Huron:
Huron Belle has an international orange hull with an aluminum cabin, and Huron Maid and
Huron Lady each have an international orange hull with a white cabin. (See pilotage,
chapter 3, and 46 CFR 401, chapter 2.)
19-128 omitted
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