CYPRESS CREEK DRAINAGE DISTRICT, ARKANSAS. 7 
whose backwater enters the district through the gap in the levees 
at the mouth of Cypress Creek, damaging not only the district itself, 
but a large area in Chicot County, Arkansas, and northern Louisiana, 
since such water, once behind the Mississippi River levee, must flow 
south to the Red River. The drainage problem, then, is not only 
to provide the necessary outlets and laterals to care for the run-off 
from the 658 square miles tributary to the district, but to so design 
and locate these outlets that the drainage water now entering the 
Mississippi River through the levee gap will be diverted, thus making 
it possible to close this gap. With the construction of these outlets 
and the closing of the levee gap the reclamation of the district will 
be assured. 
RUN-OFF. 
No phase of the preliminary study of a drainage project has a more 
vital bearing upon the success of the undertaking than the determi- 
nation of the rate of run-off for which provision must be made. Obvi- 
ously, precipitation is the most important element to be considered 
in the study of run-off, although certain other factors have more or 
less effect upon the rate of run-off. These are the size, shape, and 
topography of the watershed; the character of soil and vegetation; 
the rate of evaporation; the climate and seasons; and the water stor- 
age capacity of the soil, stream channels, and other natural reservoirs. 
RUN-OFF INVESTIGATIONS MADE. 
RAINFALL. 
Southeast Arkansas is characterized by high humidity and heavy 
rainfall. The rainfall records of the United States Weather Bureau 
for Arkansas City and Pine Bluff have been carefully examined, the 
former station being the only one in the Cypress Creek drainage dis- 
trict. The records for Pine Bluff, however, may be taken as indi- 
cating rainfall conditions on the upper portion of the Cypress Creek 
watershed. 
The average annual rainfall for Arkansas City, including the year 
1912, is 45.23 inches, and for Pine Bluff, 49.63 inches. The records 
for Arkansas City for the years 1897 to 1911, inclusive (not including 
the years 1907 and 1908, for which records are incomplete), show the 
greatest annual rainfall to have been 70 inches, in 1911, and the mini- 
mum to have been 26,83 inches, in 1901. At Pine Bluff the maxi- 
mum annual rainfall for the same period was 82.89 inches, in 1905, 
and the minimum 37.21 inches, in 1901. The greatest monthly rain- 
fall recorded at Arkansas City was 15.42 inches in December, 1911, 
and at Pine Bluff, 15.71 inches in May, 1905. 
Some of the heaviest storm periods at Arkansas City during the 16 
years preceding 1913 were as follows: December 7-16, 1911, 9.7 inches; 
