44 
BULLETIN 1017, U. S. DEPARTMENT OE AGRICULTURE. 
of annual run-off to annual precipitation was computed. The data 
for the area above Grand Forks are shown in figure 16. On that 
watershed the run-off in 1897 was maximum both in depth (3.2 
inches) and in percentage of annual precipitation (14.3 per cent). 
In 1916, when maximum recorded annual precipitation occurred, 
the run-off (3.1 inches) was nearly maximum, but the percentage 
of precipitation (11.2 per cent) that appeared as run-off was less 
Depth in Inches 
5 10 15 20 25 
188? 
™ r- 1 J — ■ • J — L ■— ' — I 
mK — J 1 1 , 
— 1 1 -l ' 
1884 
B 
IHHb 
_ 1 1 1 , 
1 1 1 ' 
1886 
188/ 
3 
1888 
■ 1 
1889 
1890 
] 
1891 
1892 
h 
1893 
1894 
IHHb 
1896 
I 
1 1 1 1 
189/ 
1898 
1899 
1900 
1901 
I9U2 
1903 
1904 
1905 
1 1 1 i 
1 1 1 1 
-' 1 1 1 1 
= 
IbUb 
1907 
1908 
1909 
1 1 1 
b ' I ' — u 
1910 
!9l 1 
■ 
i i i i 
1912 
■ 
1913 
1914 
1915 
1916 
) 
1917 
1918 
1919 
T 
Si 
41 
30 
Depth in inches 
5 10 15 20 25 
1916 11.2 
1882 11.7 
1896 
1905 
1901 
1891 
1884 
1906 
1914 
1900 
1915 
1919 
1912 
1902 
1909 
7.7 
7.1 
6.5 
3.1 
6.7 
9.6 
3.7 
46 
6.5 
5.7 
2.2 
7.6 
6.3 
1897 14.3 (Max) 3.2 
1911 l.8(MinJ0.4 
1904 10.. 
1908 
1903 
1887 
1892 
1899 
1893 
1890 
1898 
1918 
1913 
1895 
1894 
1886 
1883 
1885 
1807 
1888 
1889 
1917 
1910 
73 
7.3 
3.7 
10.5 
6.8 
10.3 
3.0 
5.1 
2.6 
3.6 
3.1 
6.7 
6.4 
11.7 
9.6 
10.3 
10.5 
3.3 
9.0 
9.9 
2.4 
1.6 
1.6 
0.8 
2.2 
1.4 
2.1 
0.6 
1.0 
0.5 
0.7 
0.6 
1.3 
1.2 
2.2 
1.8 
1.9 
1.8 
0.5 
1.2 
1.2. 
MEAN 7.0 
1.5* 
30 
27.8 
27.4 
27.2 
26.9 
26.0 
25.6 
25.3 
25.0 
24.2 
23.8 
23.1 
23.0 
22.6 
22.5 
22.3 
22.3 
22.2 
22.1 
21.8 
21.8 
21.8 
21.0 
20.6 
20.4 
20.3 
19.8 
19.6 
19.5 
19.5 
19.3 
18.8 
18.7 
18.7 
18.5 
17.1 
153 
13.4 
12.0 
I 21.5 
Fig. 
16. — Annual precipitation and run-off on Red River of the North watershed above 
Grand Forks, N. Dak. 
than for 1897. The run-off during 1897 was increased by the heavy 
precipitation of 1896, by maximum depth of snow on the ground 
in March, 1897, and by extremely heavy monthly and storm pre- 
cipitation during July, 1897. 
Probable future maximum run-off as estimated from a study of all 
available data for the four watersheds mentioned above is indi- 
cated in Table 11. It is improbable, however, that run-off equiva- 
