110 
H. Non-tabulated Data 
Information relating to river discharge has not been included in the 
tabulations. Discharge figures for major streams and rivers tributary 
to the Great Lakes are obtained from gaugings in both the United States 
and Canada. In the United States, the responsible agency is the U. S. 
Geological Survey. Records pertinent to the Great Lakes basin are pub- 
lished yearly in the publication Surface Water Supply of the St. 
Lawrence River Basin. 
In Canada, discharge records are obtained by the Canada Department 
of Northern Affairs and National Resources, Water Resources Branch. 
Records are published yearly in Water Resources Papers, which are very 
similar to those issued by the U. S. Geological Survey. 
Both of the above publications are generally two to three years in 
arrears. More recent data, if desired, are available from individual 
U. S. Geological Survey offices in the United States, or from the De- 
partment of Northern Affairs and National Resources, Water Resources 
Branch, Ottawa, Ontario. 
There are several sources of meteorological data that are not shown 
in Table 1. Principally, these are data collected by commercial vessels 
operating on the Lakes. These have not been listed in Table 1 since the 
data are obtained in varying quantities and locations during the year. 
There are approximately 3/7 commercial lake vessels operated by 
United States companies and about half that many Canadian commercial 
vessels that make meteorological measurements when operating more than 
four miles from shore. These data are transmitted by radio to collection 
agencies in Canada and the United States for use by marine meteorological 
personnel and for dissemination over meteorological communications net- 
works. 
In addition, there is a smaller number of research and other special 
purpose vessels which take meteorological data at whatever time they may 
be conducting operations. This group is comprised of fisheries investi- 
gations vessels, U. S, Lake Survey vessels such as the "Williams", the 
paper mill cruiser operated in northeastern Lake Superior by Colin A. 
MacMillan of the Marathon Paper Company, and the U. S. Coast Guard cut- 
ter "Mackinac.'"' The latter vessel makes six-hourly reports to the U. S. 
Weather Bureau at Cleveland, Ohio, whenever operating farther than four 
miles from shore. 
Table 2. Inland Data Sources 
Table 2 lists all meteorological data sources that were inland from 
the sources listed in Table 1. An inland source was defined to be suit- 
able for inclusion in Table 2 if it was more than two miles from the 
nearest Lake shoreline. As was indicated earlier, an irregular area 
surrounding the Lakes was specified to be important as far as the meteor- 
ological effects on the Lakes are concerned. This “area of influence" 
was selected as the drainage basin of the Great Lakes. The basin has 
been determined by the U.. S. Lakes Survey (see Fig. 7, p. 112). 
