and the third comprising the streams flowing to Lake Superiorthe St. Louis and its tributaries and minor streams. In the first group data for the Mississippi are given first and then data for each important tributary from the source downward. In the second group data for Red River are followed by data for its more important tributaries, which in turn are followed by the data for Rainy River and its tributaries. In the third group data for the St. Louis are followed by data for its important tributaries, and these are followed by data for the minor streams flowing directly into Lake Superior, beginning at the upper end of the lake. For each main river and principal tributary are given, so far as available, the following data: General information concerning areas drained, presented under the headings: Source, course and tributaries Topography, geology, and forestation Rainfall and runoff Floods Navigation Regulation of flow. Natural control of lakes and swamps Artificial control by reservoirs Log driving Drainage Specific information; presented under the headings: Gaging station records (for each station maintained) Station description Table showing daily discharge Table of monthly estimates Developed water power: Description of each plant with estimate of available power at the given head for (a) lowest monthly record, (b) average of lowest monthly record for each year, (c) average of lowest of 6 high-water months for each year. Undeveloped water power: Profile of river showing topography of banks. Description of possible sites and projects and estimate of height of dam necessary to develop. Length of dam and pipe line (if any). Area that would be flooded by proposed dam. Available horsepower at given head for (a) lowest monthly record, (b) average of lowest monthly record for each year, and (c) average of lowest of 6 highwater months for each year. Storage: Description of feasible reservoir sites with capacities as determined from surveys Effect of storage on flow of the river shown by means of mass curves. Sanitary statistics of the river for Towns of 500 inhabitants and more, located on streams, showing source of water supply, and method of sewage disposal. The data pertaining to the drainage basins are followed in the report by certain data which apply to the entire State and which are discussed in the order indicated below: Laws and regulations pertaining to Minnesota streams Federal laws State laws International Treaty for boundary waters Distribution of rainfall in Minnesota Evaporation records at points in North Dakota, Minnesota, Wisconsin, and Iowa Gazetteer of all streams in the State showing source and outlet Bibliography showing published sources of information used in preparing this report. ACKNOWLEDGMENTS. Acknowledgments of aid rendered are due to the organizations, companies, and persons named below: Officials of the United States Engineer Office, St. Paul, for use of unpublished records of run-off, and maintenance of evaporation records. Officials of the United States Weather Bureau, for daily gage heights of the Mississippi at St. Paul, and the Minnesota at Mankato. State Board of Health for cooperation in the Mille Lacs Survey, and for valuable data relative to municipal water supply and sewage disposal. Kettle River Company, Minneapolis, for records of flow and profile of Kettle River. Great Northern Power Co., Duluth, for various records of flow in St. Louis River basin, as discussed in the report. Minnesota & Ontario Power Co., International Falls, cooperation in maintaining gaging station on Rainy River at International Falls. Mr. S. B. Johnson, Ottawa, Canada, Department of Public Works, for cooperation in maintaining gaging station on Rainy River at International Falls and for gage heights of Rainy Lake at Ranier and precipitation records at Fort Francis. Mr. L. P. Wolff, consulting engineer, St. Paul, for records of flow from St. Croix River 1902-1905. Stone & Webster Engineering Corporation for records of flow of St. Croix River for 1905-1912. Consumers Power Co., for cooperation in maintaining gaging station on Blue Earth River near Rapidan. Minnesota Canal & Power Co., Duluth, for records of Kawishiwi River, 1905-1907. Mr. E. B. Banks, city engineer, Superior, Wis., for the profiles of Kawishiwi and Rainy rivers. Crookston Water Works, Light & Power Co., for cooperating in installation of automatic gage on Red Lake River at Crookston. St. Anthony Falls Water Power Co., Minneapolis, for winter records of the Mississippi at Minneapolis. Mr. R. D. Thomas for data on power development on the Mississippi at Minneapolis. Various managers and owners for descriptions of power plants. The Minnesota Forest Service for information regarding forestry and log driving. The United States Forest Service for information regarding forestry on the Superior National Forest. METHODS OF COLLECTING AND COMPILING DATA. STREAM GAGING RECORDS.' "The description of the methods used in compiling the records of stream flow presented in this report is taken chiefly from Water-Supply Paper U. S. Geol. Survey No. 261, pp. 18-27. FIELD METHODS OF MEASURING STREAM FLOW. Three distinct methods are used to determine the flow of water in open channels: (1) By measurements of slope and cross section and the use of Chezy's and Kutter's formulas; (2) by means of a weir or dam; (3) by measurements of the velocity of the current and the area of the cross section. Only the third method is here described as the other methods are not used in the work in Minnesota. Streams in general may present throughout their courses, to a greater or less extent, all gradations from permanent and semipermanent to varying conditions of flow. In accordance with the situation of the measuring section with respect to the physical conditions, current-meter gaging stations may in general be divided into four classes: (1) including stations located at points where the conditions that control the flow at the gage are comparatively permanent; (2) those located where conditions change only during |