National Ocean Service 
Office of Oceanography and Marine Services 
National Oceanic and Atmospheric Administration 
US Department of Commerce 
6001 Executive Boulevard 
Rockville, MD 20852 
(301) 443-8443 
Kind of Data 
Telemetered Water Level Data, Great Lakes 
Hourly Water Levels, Great Lakes 
Daily Mean Water Levels, Great Lakes 
Great Lakes /-day Water Levels 
Great Lakes Data: Monthly Mean Elevations and Monthly Mean Discharge 
Great Lakes Annual Maximum and Minimum Levels 
Benchmark Descriptions and International Great Lakes Datum Elevations 
Location: Great Lakes 
Description of Data: Telemetered Water Level Data, Great Lakes, is a biweekly 
compilation of provisional up-to-date telemetered water level data, hourly 
values, and daily mean in feet received from 23 key stations located around 
the Great Lakes. The elevations are referred to the International Great Lakes 
Datum (1955). 
Hourly Water Levels, Great Lakes, is a monthly tabulation of hourly water 
level data in feet for the month at each of 54 water level gages located 
around the Great Lakes. The data include the mean water level elevations in 
feet for each day of the month and the maximum and minimum levels for the 
month. The elevations are referred to the International Great Lakes Datum 
(1955). Monthly records are on file for each water level gage, with some 
records dating back to 1860. Furthermore, annual summaries and an index of 
stations are available. 
Daily Mean Water Levels, Great Lakes, is a monthly tabulation of daily 
average water level data in feet for each of 54 gages located around the Great 
Lakes. The elevations are referred to the International Great Lakes Datum 
(1955). Records are on file for each water level gage, and a data summary 
sheet is available. 
Great Lakes 7-day Water Levels is a weekly tabulation of the latest /-day 
daily average water level data in feet and meters for 13 selected gages in the 
Great Lakes. Records are available back to 1969. 
Great Lakes Data: Monthly Mean Elevations and Monthly Mean Discharge is 
a compilation of recorded monthly mean lake elevations in feet and monthly 
mean discharge in cubic feet per second of the major rivers, including St. 
Mary River, St. Clair River, Detroit River, Niagara River, and St. Lawrence 
River, connecting the Great Lakes. NOAA compiles the monthly elevation data, 
and the US Army Corps of Engineers compiles the discharge data. 
ILi-9 
