OVERFLOW OF RED RIVEB OF THE NORTH. 61 
precipitation without overflow. Three conditions make additional 
surface drainage necessary: (1) Flat or nearly level land sin face 
without natural drainage channels; (2) depressions in which water 
collects and stands because of lack of outlet; and (3) natural chan- 
nels too small to serve properly the areas they drain. Heavy soils 
or other conditions make unclerdrainage necessary in many local it ies. 
The north shore line of Lake Traversers not well defined (see fig. 3, 
sheets 2 and 3), and during high stages the lake overflows the land 
several miles to the north. Much of this land has been or is now 
cultivated and the remainder is used to some extent as hay land. 
The present channel of the Bois cle Sioux is entirely inadequate to 
carry the water that comes to it from Lake Traverse (see PL V, fig. 1) . 
The cross sections (fig. 4) show that near Lake Traverse the stream 
has practically no channel. As one goes downstream the size of the 
channel gradually increases until at Breckenridge it is large and well 
defined. The Mustinka River, which drains 852 square miles, rises in 
the hills near Fergus Falls and flows south about 25 miles and then 
west and southwest to Lake Traverse. Practically all of the water- 
shed of the Mustinka in Traverse County (see fig. 1) has been drained 
by ditches spaced approximately 1 mile apart. In that county the 
channel of the Mustinka has been dredged and straightened for a con- 
siderable portion of its course. The Rabbit River drains approxi- 
mately 300 square miles lying north and west of the Mustinka. It 
enters the Bois cle Sioux about 10 miles south of Breckenridge (see 
fig. 3, sheets 3 and 4) . As shown in fig. 1, a considerable portion of its 
watershed has been drained by open ditches spaced 1 mile apart. 
From a point about 4 miles south of White Rock, S. Dak., north to 
Fairmount, N. Dak., there is a strip of land along the Bois de Sioux 
which is frequently overflowed. From Fairmount north to Brecken- 
ridge the lands are occasionally overflowed. At times serious damage 
is caused by Avater from the Wild Rice River in North Dakota break- 
ing out of its banks, flowing east, and flooding the land between its 
channel and the Bois de Sioux. Similar conditions exist on the Rab- 
bit River and Otter Tail River, which flood land southeast of Breck- 
enridge. 
As the channel of the Bois de Sioux is too small to remove the 
water which comes to it when heavy rains occur, much land is flooded 
and the drainage of the higher-lying lands is obstructed. The flood 
water drains off slowly through the inadequate watercourse or remains 
on the land until evaporated. In years when heavy rains occur dur- 
ing the summer months, the crops are seriously damaged or com- 
pletely destroyed. This damage becomes more serious if preceded by 
a wet spring. Floods .are frequently caused by the melting of snow 
in the spring. These spring floods cause some damage by interfering 
with farming operations and prevent planting at the proper time. 
