50 BULLETIN 1017, U. S. DEPARTMENT OF AGRICTJLTTIRE. 



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. These 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 ma} T 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 Wahpeton the capacity of the 

 Red River channel is sufficient to carry the average summer run-off 

 of the watershed. Below the mouth of the She} T enne 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 being 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 



» "The Floods of the Red River Valley," Elwyn F. Chandler. The Quarterly Journal of 

 the University of North Dakota, Vol. VIII, No. ::. April, 1918. 



