OVERFLOW OF RED RIVER OF THE NORTH. 15 
and papers by early settlers, traders, and explorers ; and photographs 
and old newspaper accounts of floods. The investigation of drainage 
development was aided by maps and records of the States, counties, 
and districts prosecuting such projects. Records and maps compiled 
by the various agencies of the Federal Government furnished valu- 
able data concerning precipitation, run-off, temperature, geography, 
and geology. 
MAPS AND PROFILES. 
The detail map (fig. 3, sheets 1 to 20) was made up as far as possi- 
ble from data taken in the field, but as the field work was for the 
most part done along the main watercourse it was necessary to de- 
pend on other maps for information concerning backlying areas. 
The portions of the map (fig. 3) based on the surveys represent true 
conditions perhaps more accurately than do the other portions. Fea- 
tures of the map not determined by survey were taken from the best 
maps available, the data being carefully coordinated and adjusted. 
The surface elevations shown are considered equal in accuracy to 
the general leveling along the river, with the exception of those a 
mile or more back from the river on the east side from Breckenridge, 
Minn., to the north line of Marshall County. While these latter ele- 
vations are as nearly correct as could be determined from the avail- 
able data and are considered satisfactory for the purpose of this in- 
vestigation, there is some doubt as to the degree of accuracy, and they 
should not be used in preparing plans for local drainage projects 
without being carefully checked. The ' General Land Office and 
Geological Survey plats were freely used in connection with notes of 
the survey work. War Department maps of Lake Traverse fur- 
nished considerable data in that vicinity. For territory not covered 
by Federal Government agencies, State, county, railroad, and various 
other maps were used. The locations of artificial drainage s}^stems 
were supplied from local drainage plats, county and State maps, 
and drainage district records. Surface elevations, in addition to 
those taken directly in the field, were obtained from the Geological 
Survey maps and from ties to other surveys of which plats showing 
surface elevations were available. 
A profile of the watercourse showing stream-bed and bank eleva- 
tions, bridges, high-water marks, etc., was drawn, and selected cross 
sections of the river were plotted. The profile and cross sections 
(figs. 2 and 4) were prepared from data obtained in the field. 
PRECIPITATION AND RUN-OFF RECORDS. 
. An extended study was made of precipitation records with the 
view of determining past and probable future intensity and distri- 
bution of precipitation as factors influencing run-off. The results 
