OVERFLOW OF RED RIVER OF THE NORTH. 13 



The elevations of the United States Coast and Geodetic Survey 

 bench marks are the result of the latest (1912) adjustment of the 

 precise leveling done by that survey in 1906. At that time the eleva- 

 tions of some of the United States Geological Survey bench marks 

 were redetermined by this precise leveling and the others in the 

 vicinity were adjusted to agree. Since then, the leveling of the 

 Geological Survey in the valley has been based upon the Coast and 

 Geodetic Survey elevations, so that at the present time the elevations 

 of all bench marks of both surveys, as used in this investigation, 

 accord with the latest adjustment of the precise leveling results. 



Most of the leveling was done with wye levels. A small part 

 along the Bois de Sioux was done with transits. All levels were re- 

 quired to check within the usual limits of error for wye level work. 

 Base-level lines were run for the entire length of the Bois de Sioux 

 and Red Rivers within the United States, and elevations at frequent 

 intervals were taken of the river bed and banks. From the site of 

 the proposed detention dam northward as far as Wahpeton all land 

 that is affected by floods was covered by the level parties, elevations 

 for the most part being taken along section lines. These areas are 

 shown on sheets 2, 3, and 4, figure 3. Over the remainder of the val- 

 ley the leveling was confined to the immediate vicinity of the river 

 channel and to ties to various bench marks and points of former 

 surveys. 



CROSS SECTIONS. 



Cross sections of the Bois de Sioux and Red Rivers were taken 

 along the whole length at intervals of approximately one mile, and 

 at all bridges (see fig. 4)'. The valley was cross-sectioned at the 

 sites of the proposed levee at Browns Valley and the detention dam 

 near White Rock. Test borings were also made at the latter point. 

 A few cross sections of the Otter Tail, North Dakota Wild Rice, 

 Sheyenne, and Red Lake Rivers were taken. 



HIGH-WATER DATA. 



Special effort was made to locate all reliable high-water marks, 

 both those left by the water or ice on trees, bridges, etc., and those 

 which were set by observers as permanent records. The field parties 

 were constantly on the lookout for reliable information as to high 

 water and from time to time special field trips were made by en- 

 gineers for this purpose. The elevations of all authentic high-water 

 marks found were taken, and are shown on figure 3, sheets 1 to 20. 



STREAM GAUGING. 



Staff stream gauges were established at Haggart and Valley City, 

 N. Dak., on the Sheyenne River; at Wild Rice, N. Dak., on the 

 Dakota Wild Rice; and near Fairmount, N. Dak., on the Bois de 



