50 BULLETIN 1017, U. S. DEPARTMENT OF AGRICULTURE. 
and nearly level the flood water has very little current. Also, owing 
to the wide extent of the flat, level topography the flood depth is not 
great even when very large quantities of water overflow. The"se floods 
cause no damage to the land itself and a few generations ago, before 
agricultural development had begun in the valley, the floods were of 
no consequence. At present an extreme flood such as that of 1897 
(see PL III, fig. 1), would damage much property, interfere with 
transportation, destroy live stock, and might cause loss of human life. 
Thus without increase in height or frequency of floods the possibilities 
of serious damage increases as the country develops and as population 
increases. A flood late in March may delay the preparation of the 
land and seeding long enough to greatly reduce yields, particularly 
of wheat, or may make it impossible to sow the lower portions of the 
fields at anything like the proper date. These spring floods are also 
important carriers of rank growing weeds of the river valleys. 
A feature of the Red River which has an important bearing on 
spring floods is its northward flow through a region of low winter 
temperatures and heavy ice. Spring thaws begin in the upper por- 
tions of the watershed and move gradually downstream, causing run- 
off from large areas to reach lower portions of the river when the 
winter ice is breaking up and beginning to move along the lower 
channel. The ice lodges against trees and other obstructions which 
partially fill the high-water channel of the stream. (See Plate III, 
figs. 2 and 3.) This retards the current and reduces materially the 
discharge capacity of the stream. Chandler 9 states, relative to re- 
tardation of flow by ice. that it has been found by measurements that 
during early spring floods "on some days * * * the water has 
been 2, 3, and even 6 and 7 feet higher than would have been neces- 
sary to discharge the same number of gallons per day later in the 
season when there is no ice retardation * * *." 
SUMMER FLOODS. 
Throughout its entire length below Tvahpeton the capacity of the 
Red River channel is sufficient to carry the average summer run-off 
of the watershed. Below the mouth of the Sheyenne River the 
capacity is greater than is necessary for average flow and is sufficient 
to carry the most extreme summer run-off likely to be caused by 
storm precipitation. Above the mouth of the Sheyenne River maxi- 
mum summer run-off slightly. exceeds the capacity of the waterway 
usually considered as bein£ the stream channel but it does not over- 
flow the outside high banks of the actual high-water channel of the 
river. At and above Fargo some flooding occurs within the high 
banks of the channel during summer months, seriously affecting 
highway traffic, city water, sewer facilities, and property on low 
9 "The Floods of the Red River Valley." Elwyn F. Chandler. The Quarterly Journal of 
the University of North Dakota, Vol. VIII, No. .°>. April, 1918. 
