National Ocean Service (Continued) 
Great Lakes Annual Maximum and Minimum Levels provides annual compila- 
tions of the historic tabulation of water level elevations during stages of 
highest and lowest water levels for each year at each of 54 water level gages 
located around the five Great Lakes. The maximum stage data include the month 
of highest level and the mean elevation for that month, the day of the month 
with the highest level and mean elevation for that day, the day and elevation 
for that day, and the day the elevation of the highest hourly level during the 
year; the minimum stage data include the same information but for the lowest 
levels. The monthly records on file are available for the 54 Great Lakes 
observation stations, with some records dating back to 1901. Furthermore, 
annual summaries and an index of the stations are available. 
Benchmark Descriptions and International Great Lakes Datum Elevations 
describes the locations for approximately 3,000 benchmarks in the Great Lakes 
area, with published elevations on the International Great Lakes Datum (1955). 
Response Format: Tabulations 
Qualified Users: No limitations (free of charge except benchmark 
description and International great lakes datum 
elevation) 
Point of Contact: Water Level Section, N/OMS 124 
National Ocean Service 
Room 626, WSC-1 
6001 Executive Boulevard 
Rockville, MD 20852 
(301) 443-8443 
I1II-10 
