Ft.

-1

0

+ 1

+ 2+ 3+ 4+ 5

M.

-0.3

0

+ 0.3

+ 0.6

+ 0.9+ 1.2+ 1.5

2011

MAR

1952

APR

1973

MAY

1973

JUN

1952

JUL

1947

AUG

1947

SEP

1947

OCT

1945

NOV

1945

DEC

1945

2012

JAN

1946

FEB

1952

MAR

19521935

APR

19731935

MAY

19731935

JUN

19521935

JUL

19471934

AUG

19471934

SEP

19471934

OCT

19451934

NOV

19451934

DEC

19451934

2013

JAN

1946

1935

FEB

1952

1936

MAR

19521935

APR

19731935

MAY

19731935

JUN

19521935

JUL

19471934

AUG

19471934

CHART DATUM 243.3 FEET (74.2 METERS)

Ft.

-1

0

+ 1

+ 2+ 3+ 4+ 5

+ 6

M.

-0.3

0

+ 0.3

+ 0.6

+ 0.9+ 1.2+ 1.5+ 1.8

2011

MAR

1986

APR

1985

MAY

1986

JUN

1986

JUL

1986

AUG

1986

SEP

1986

OCT

1986

NOV

1986

DEC

1986

2012

JAN

1987

FEB

1987

MAR

1986

1934

APR

19851934

MAY

1986

1934

JUN

1986

1934

JUL

1986

1934

AUG

1986

1934

SEP

1986

1934

OCT

1986

1934

NOV

1986

1934

DEC

1986

1934

2013

JAN

19871935

FEB

1987

1936

MAR

1986

1934

APR

19851934

MAY

1986

1934

JUN

1986

1934

JUL

1986

1934

AUG

1986

1934 CHART DATUM 569.2 FEET (173.5 METERS)

Ft.

-1

0

+ 1

+ 2+ 3+ 4+ 5

M.

-0.3

0

+ 0.3

+ 0.6

+ 0.9+ 1.2+ 1.5

2011

MAR

1986

APR

1986

MAY

1986

JUN

1986

JUL

1986

AUG

1986

SEP

1986

OCT

1986

NOV

1986

DEC

1986

2012

JAN

1986

FEB

1986

MAR

1986

1934

APR

19861926

MAY

1986

1934

JUN

1986

1934

JUL

1986

1934

AUG

1986

1934

SEP

1986

1934

OCT

1986

1934

NOV

1986

1934

DEC

1986

1964

2013

JAN

19861936

FEB

19861926

MAR

1986

1934

APR

19861926

MAY

1986

1934

JUN

1986

1934

JUL

1986

1934

AUG

1986

1934

CHART DATUM 572.3 FEET (174.4 METERS)

ELEVATIONS REFERENCED TO THE CHART DATUM OF EACH 

Superior

600.26182.96

600.20

182.94

602.46

183.63

1986

599.61

182.76

1926

601.28183.27

MichHuron

576.15

175.61

577.30

175.96

581.07

177.11

1986

576.08175.59

1964

578.38176.29

St.

Clair

572.64174.54

574.11

174.99576.77

175.80

1986

570.51

173.89

1926

573.43174.78

Erie

570.41

173.86

572.08174.37573.43174.78

1987

568.18173.18

1936

570.80

173.98

Ontario

244.49

74.52

246.03

74.99

246.95

75.27

1952

242.06

73.78

1936

244.75

74.60

FEBRUARY MEAN LAKE LEVELS

(IGLD 1985)

* 2013 Ft.

M.

2012 Ft.

M.

** MAX.

Ft.

M.

Yr.

** MIN.

Ft.

M.

Yr.

** AVG. Ft.

M.

* provisional** Average, Maximum and Minimum for period 1918-2011

1985

1985

1973 1973

1936

1934

1926 1934

LAKE ONTARIO

LAKE ERIE

LAKE ST. CLAIR

LEGEND

LAKE LEVELS

RECORDEDPROJECTEDAVERAGE **MAXIMUM **MINIMUM **

The levels on the hydrographs are shown inboth feet and meters above (+) or below (-) Chart Datum. Chart Datum, also known as Low Water Datum, is a reference plane on each lake to which water depth and Federal navigation improvement depths on navigation charts are referred.All elevations and plots shown in this bulletin are referenced to International Great Lakes Datum 1985 (IGLD 1985). IGLD 1985 has its zero base at Rimouski, Quebec near the mouth of the St. Lawrence River (approximate sea level).
 Information 

Recorded water levels in this bulletin are derived from a representative network of water level gages on each lake 

(see cover map). Providers of these data are the U.S. Department of Commerce, NOAA, National Ocean Service, 

and Integrated Science Data Management, Department of Fisheries and Oceans, Canada. The Detroit District, 

Corps of Engineers and Environment Canada derive historic and projected lake levels under the auspices of the 

Coordinating Committee on Great Lakes Basic Hydraulic and Hydrologic Data. 

This bulletin is produced monthly as a public service. The Corps also publishes the "Great Lakes, Connecting 

Channels and St. Lawrence River Water Levels and Depths,” weekly, which provides a forecast of depths in the 

connecting rivers between the Great Lakes and the International Section of the St. Lawrence River. This Monthly 

Bulletin of the lake levels for the Great Lakes may be obtained free of charge by writing to the address shown on 

the front cover, by calling (313) 226-6442 or emailing hhpm@usace.army.mil. Notices of change of address 

should include the name of the publication. This information is available on the internet at 

http://www.lre.usace.army.mil/glhh. 

Great Lakes Basin Hydrology

February 2013

The overall Great Lakes basin received near average precipitation for the month of February but received below 

average over the last 12 months. Lake Superior was the only basin to receive below average precipitation in 

February while the other lakes received near or above average precipitation. All of the lakes have received below 

average precipitation over the past 12 months. Similar to precipitation, all of the water supplies to the Great Lakes 

were above average last month, with the exception of Lake Superior. The outflows from each of the Great Lakes 

were below their averages for February. The tables below list February precipitation and water supply information 

for all Great Lakes basins. 

A comparison of monthly mean lake levels for February to long-term average (1918-2011) shows Lakes Superior 

and Michigan-Huron were 12 and 27 inches below average, respectively. Lake Michigan-Huron’s February water 

level rose 2 inches from January’s level, bringing it 1 inch above the previous February record low set in 1964. 

Lakes St. Clair, Erie, and Ontario were 9, 5, and 3 inches below average, respectively, last month. Boaters should 

be aware of hazards to navigation due to continued below average water levels on all lakes. 

 

PRECIPITATION (INCHES) 

BASIN 

February 12-Month Comparison 

2013 Average Diff. % of 

Average 

Last 12 

months 

Average Diff. % of 

(1900-2008) (1900-2008) Average 

Superior 1.08 1.45 -0.37 74 27.66 30.51 -2.85 91 

Michigan-Huron 1.86 1.74 0.12 107 30.13 32.44 -2.31 93 

Erie 2.09 2.09 0.00 100 31.16 35.40 -4.24 88 

Ontario 2.80 2.37 0.43 118 31.50 35.71 -4.21 88 

Great Lakes 1.77 1.78 -0.01 99 29.87 32.64 -2.77 92 

 

 LAKE February WATER SUPPLIES1

 (cfs) February OUTFLOW2 (cfs) 

2013 Average3

(1900-2008) 2013 Average3(1900-2008)

Superior 7,000 9,000 55,000 67,000 

Michigan-Huron 138,000 88,000 142,000 157,000 

Erie 64,000 38,000 186,000 192,000 

Ontario 51,000 37,000 218,000 227,000 

Notes: Values (excluding averages) are based on preliminary computations; cfs denotes cubic feet per second. 1

 Water supply is the net result of precipitation falling on the lake, runoff from precipitation falling on the land which flows to 

the lake, and evaporation from the lake. Negative water supply denotes evaporation exceeded runoff and precipitation. 2

 Does not include diversions. 

3

 Lake Ontario average water supplies and average outflows are based on period of record 1900-2005