the United States side of the Lakes was obtained from the Federal Power 
Commission at Chicago; this list included public utilities, industries, 
and municipal plants. For information on the Canadian side, the Hydro- 
Electric Power Commission of Ontario was contacted. 
The pertinent water treatment plants and power plants were then con- 
tacted individually. In some cases personal visits were possible, but 
usually contact was by mail. Each potential data source not visited by 
project personnel was sent a letter outlining the project, its aims and 
purpose, and the type of cooperation sought. Included with the letter 
was a three-page questionnaire designed to facilitate the agency's 
reply. The yuestionnaire, which is reproduced in Figure 1, is a form on 
which each observation could be entered, whether hydrographic or meteor- 
ological. Space for pertinent information concerning the observation 
was also provided. It will be noted that a good deal of the information 
reyuested on the questionnaire, i.e., time of observation, type of instru- 
ment or process, instrument sensing element, and name of observer, are 
items which were not required under the terms of the study, but were con- 
sidered pertinent and hence ascertained whenever possible. Information 
relating to these items was not determined for all cooperating agencies, 
and is not included in this report. That which is known is on file with 
the Great Lakes Research Institute. 
it should be pointed out here that rigid adherence to a strict 
policy in contacting and obtaining information from the various agencies 
was not possible; that is, in some cases the use of questionnaires was 
impractical, in others they served to collect information that otherwise 
would likely have been overlooked. 
The water treatment plants and power plants constituted the bulk of 
the hydrographic data sources from which any great variety of data were 
available. However, a number of additional agencies contacted also were 
able to make significant contributions. Specific reference to these 
agencies is made in section 3 of this report. 
During the course of the investigation, items of pertinent litera- 
ture appeared from time to time, and have been included in the Biblio- 
graphy (Appendix I). Also included in the Bibliography are selected 
references from a bibliography of the Great Lakes (Van Oosten, John. 
Great Lakes Fauna, Flora, and their Environment. A Bibliography. Great 
Lakes Commission, Ann Arbor, Mich., 1957). Selection of these references 
was based upon applicability to the interest area of the project. 
Contained within Van Oosten's bibliography are 138 papers from Lake 
Erie on subjects within the interest area of this project, 57 from Lake 
Michigan, 22 from Lake Superior, 19 from Lake Ontario, 13 from Lake 
Huron, and 42 pertinent to all the Great Lakes. Of these, there are 
certain papers which cover comparable subjects at different times and 
which have promise of providing direct material upon possible changes in 
the Great Lakes. 
