Ft.

-1

0

+ 1

+ 2+ 3+ 4+ 5

M.

-0.3

0

+ 0.3

+ 0.6

+ 0.9+ 1.2+ 1.5

2011

JUL

1947

AUG

1947

SEP

1947

OCT

1945

NOV

1945

DEC

1945

2012

JAN

1946

FEB

1952

MAR

1952

APR

1973

MAY

1973

JUN

1952

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

SEP

19471934

OCT

19451934

NOV

19451934

DEC

19451934

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

JUL

1986

AUG

1986

SEP

1986

OCT

1986

NOV

1986

DEC

1986

2012

JAN

1987

FEB

1987

MAR

1986

APR

1985

MAY

1986

JUN

1986

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

SEP

1986

1934

OCT

1986

1934

NOV

1986

1934

DEC

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

JUL

1986

AUG

1986

SEP

1986

OCT

1986

NOV

1986

DEC

1986

2012

JAN

1986

FEB

1986

MAR

1986

APR

1986

MAY

1986

JUN

1986

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

SEP

1986

1934

OCT

1986

1934

NOV

1986

1934

DEC

1986

1964

CHART DATUM 572.3 FEET (174.4 METERS)

ELEVATIONS REFERENCED TO THE CHART DATUM OF EACH 

Superior

601.25

183.26

601.05

183.20

602.89

183.76

1986

599.90

182.85

1926

601.84183.44

MichHuron

577.59176.05

577.66

176.07581.79177.33

1986

576.64

175.76

1964

579.20

176.54

St.

Clair

574.11

174.99574.08174.98577.17175.92

1986

572.34174.45

1934

574.70

175.17

Erie

571.62174.23571.59174.22574.28175.04

1986

569.06

173.45

1934

571.95174.33

Ontario

246.39

75.10

245.73

74.90

248.56

75.76

1952

243.41

74.19

1935

246.19

75.04

JUNE 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 1918-2012

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/Missions/GreatLakesInformation.aspx. 

Great Lakes Basin Hydrology

June 2013

Most of the Great Lakes basin received above average precipitation for the month of June. The Lake Superior 

basin, however, received only 89% of average precipitation and has received 87% of average over the past 12 

months. The Michigan-Huron basin received near average precipitation in June and 103% of average precipitation 

over the past 12 months. The Erie and Ontario basins received 144% and 152% of average precipitation, 

respectively, in June. Overall, the Great Lakes basin received above average precipitation last month. The net 

basin supply of water to each of the lakes was above average in June, and the outflows for all of the lakes were 

below average. The tables below list June precipitation and water supplies for the Great Lakes basin. 

The water levels of all of the Great Lakes continued their seasonal rise in June. Lakes Superior, Michigan-Huron, 

St. Clair, and Erie each rose 5 to 6 inches from May to June, while Lake Ontario rose 9 inches. A comparison of 

June’s monthly mean lake levels to long-term average (1918-2012) shows Lakes Superior and Michigan-Huron 

were 7 and 19 inches below average, respectively. Lakes St. Clair and Erie were 7 and 4 inches below average, 

respectively, last month while Lake Ontario was 2 inches above average. Boaters should be aware of hazards to 

navigation due to continued below average water levels on the upper lakes. 

 

PRECIPITATION (INCHES) 

BASIN 

June 12-Month Comparison 

2013 Average Diff. % of 

Average 

Last 12 

months 

Average Diff. % of 

(1900-2010) (1900-2010) Average 

Superior 2.90 3.27 -0.37 89 26.51 30.46 -3.95 87 

Michigan-Huron 3.21 3.17 0.04 101 33.56 32.44 1.12 103 

Erie 4.99 3.47 1.52 144 36.19 35.43 0.76 102 

Ontario 4.77 3.14 1.63 152 34.80 35.73 -0.93 97 

Great Lakes 3.55 3.23 0.32 110 32.00 32.64 -0.64 98 

 

 LAKE June Net Basin Supplies1

 (cfs) June Outflows2 (cfs) 

2013 Average3

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

Superior 174,000 155,000 72,000 77,000 

Michigan-Huron 213,000 204,000 172,000 192,000 

Erie 90,000 31,000 197,000 216,000 

Ontario 86,000 42,000 232,000 260,000 

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

 Net basin 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 net basin supply denotes evaporation exceeded runoff and 

precipitation. The net total supply can be found by adding the net basin supply and the outflow from the upstream lake. 2

 Does not include diversions. 

3

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