24 
BULLETIX 1017, U. S. DEPARTMENT OF AGRICULTURE. 
until in 1921 about 50 were maintained within the Red River water- 
shed (see fig. 1). Daily precipitation records are available for 
twenty or more stations for the period 1892 to 1919. 
DISTEIBUTIOX OF PRECIPITATION. 
In making the study of precipitation data the contributing area 
south of the international boundary was divided into seven areas as 
indicated in figure 5. This facilitated the determination of the pre- 
cipitation on watersheds of various tributary streams and on areas 
above certain stream-gaging stations; it also made evident the rela- 
tions between size of watershed and intensity of precipitation. 
CANADA 
SOUTH DAKOTA (\ ^ Morrfs 
Fig. 
-Outline watershed map of Red River of the North, showing subdivisions for 
precipitation studies. 
The precipitation records were considered in four classes — annual, 
monthly, and storm periods, and the period during which snow is 
stored. The annual, monthly, and storm precipitations were com- 
puted from the records for each area and weighted averages were 
computed for certain larger areas which comprise two or more of the 
subareas. The records prior to 1892 are too meager to afford satis- 
factory basis for estimating the distribution of precipitation over 
these areas. 
