Ft.

-1

0

+ 1

+ 2+ 3+ 4+ 5

M.

-0.3

0

+ 0.3

+ 0.6

+ 0.9+ 1.2+ 1.5

2014

APR

1973

MAY

1973

JUN

1952

JUL

1947

AUG

1947

SEP

1947

OCT

1945

NOV

1945

DEC

1945

2015

JAN

1946

FEB

1952

MAR

1952

APR

19731935

MAY

19731935

JUN

19521935

JUL

19471934

AUG

19471934

SEP

19471934

OCT

19451934

NOV

19451934

DEC

19451934

2016

JAN

1946

1935

FEB

1952

1936

MAR

19521935

APR

19731935

MAY

19731935

JUN

19521935

JUL

19471934

AUG

19471934

SEP

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

2014

APR

1985

MAY

1986

JUN

1986

JUL

1986

AUG

1986

SEP

1986

OCT

1986

NOV

1986

DEC

1986

2015

JAN

1987

FEB

1987

MAR

1986

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

2016

JAN

19871935

FEB

1987

1936

MAR

1986

1934

APR

19851934

MAY

1986

1934

JUN

1986

1934

JUL

1986

1934

AUG

1986

1934

SEP

1986

CHART DATUM 569.2 FEET (173.5 METERS) 1934

Ft.

-1

0

+ 1

+ 2+ 3+ 4+ 5

M.

-0.3

0

+ 0.3

+ 0.6

+ 0.9+ 1.2+ 1.5

2014

APR

1986

MAY

1986

JUN

1986

JUL

1986

AUG

1986

SEP

1986

OCT

1986

NOV

1986

DEC

1986

2015

JAN

1986

FEB

1986

MAR

1986

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

2016

JAN

19861936

FEB

19861926

MAR

1986

1934

APR

19861926

MAY

1986

1934

JUN

1986

1934

JUL

1986

1934

AUG

1986

1934

SEP

1986

1934

CHART DATUM 572.3 FEET (174.4 METERS)

ELEVATIONS REFERENCED TO THE CHART DATUM OF EACH 

Superior

601.90

183.46

601.77183.42

602.40

183.61

1986

599.54182.74

1926

601.15183.23

MichHuron

579.43

176.61

579.00

176.48

581.10

177.12

1986

576.05175.58

1964

578.38176.29

St.

Clair

575.20

175.32573.92174.93576.77

175.80

1986

571.03174.05

1934

573.82

174.90

Erie

572.21174.41

570.83173.99573.75174.88

1986

568.24

173.20

1934

571.10

174.07

Ontario

245.96

74.97

244.13

74.41

247.28

75.37

1952

242.59

73.94

1935

244.98

74.67

MARCH MEAN LAKE LEVELS

(IGLD 1985)

* 2016 Ft.

M.

2015 Ft.

M.

** MAX.

Ft.

M.

Yr.

** MIN.

Ft.

M.

Yr.

** AVG. Ft.

M.

* provisional** Average, Maximum and Minimum for period 1918-2015

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, on a weekly basis publishes online the Great 

Lakes, Connecting Channels and St. Lawrence River Water Levels and Depths, 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

March 2016

According to preliminary precipitation estimates, precipitation over the Great Lakes was above average in March. 

Precipitation to Lake Superior was about 6% above average, while precipitation to Lakes Michigan-Huron and Erie

was 87% and 57% above average. Precipitation to Lake Ontario was 18% above average. The net basin supply to 

all of the Great Lakes was above average, with the exception of Lake Ontario, which had close to average net basin 

supply. The tables below list March precipitation and water supply information for the Great Lakes basin.

All lakes with the exception of Lake Superior rose from February to March. Lake Superior’s March mean level was 

about 1 inch lower than its February mean level. Mean lakewide average water levels in March were all above their 

long term average (LTA) March levels and above last year’s March levels. Lakes Superior and Michigan-Huron levels 

were 9 and 13 inches, respectively, above their LTA March levels. Lakes St. Clair, Erie, and Ontario were 17, 13, 

and 12 inches, respectively above their LTA March levels.

PRELIMINARY PRECIPITATION (INCHES)

BASIN

March 12-Month Comparison

2016

Average

Diff. % of 

Average

Last 12 

Months

Average

Diff. % of 

(1900-2012) (1900-2012) Average

Superior 1.84 1.73 0.11 106 31.65 30.43 1.22 104

Michigan-Huron 3.98 2.13 1.85 187 35.38 32.48 2.90 109

Erie 4.34 2.76 1.58 157 38.09 35.59 2.50 107

Ontario 3.16 2.68 0.48 118 37.57 35.83 1.74 105

Great Lakes 3.31 2.17 1.14 153 35.08 32.68 2.40 107

 LAKE

March Net Basin Supplies1(cfs) March Outflows2(cfs)

2016

Average

(1900-2008) 2016

Average3

(1900-2008)

Superior 82,000 46,000 85,000 66,000

Michigan-Huron 337,000 183,000 198,000 172,000

Erie 84,000 72,000 234,000 197,000

Ontario 72,000 75,000 285,000 238,000

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