60 BULLETIN 1017, U. S. DEPARTMENT OF AGRICTTLTUPvE. 



trol and extending across the watercourse and the adjacent lowland 

 near White Rock, S. Dak., and also an earth levee at the south end of 

 the lake, near Browns Valley, Minn. 



2. A new channel for the Bois de Sioux from the clam in Lake 

 Traverse to a point near Wahpeton, N. Dak., where the natural chan- 

 nel will carry the water without flooding. 



3. A system of ditches to provide for the drainage in the areas to 

 be reclaimed by the project. 



In addition it will be necessary to replace some of the present 

 bridges with larger ones and to construct new ones at points where 

 the operations would otherwise interfere with transportation. 



These improvements are designed to relieve flood conditions, make 

 possible the reclamation of the wet lands along the Bois de Sioux, 

 and provide outlets for the drainage necessary to the development 

 of this area. 



DESCRIPTION OF WATERSHED. 



Lake Traverse and the Bois de Sioux River, with their tributary 

 watershed, include the south end of the bed of the glacial Lake 

 Agassiz and the land adjacent to its shores. The nature of the topog- 

 raphy and soil is a result of glacial action and subsequent natural 

 processes as previously discussed. The soil is alluvium, composed of 

 clay mixed with varying quantities of fine sand and organic matter, 

 with occasional bowlders occurring in the vicinity of White Rock. It 

 is fertile, and when drained and cultivated produces good crops of 

 wheat and other small grains, potatoes, grasses, and vegetables and 

 fruits adapted to the climate. 



That part of the watershed lying in North and South Dakota, to- 

 gether with a strip approximately 30 miles wide just east of the 

 Bois de Sioux and Lake Traverse in Minnesota, is prairie land. 

 The only timber occurs in strips, varying in width from 100 feet to 

 one-half mile, along the principal streams. The land is flat and rises 

 in a gentle slope on both sides. Practically all the prarie land has 

 been cultivated. 



The eastern portion of the watershed, in Minnesota, was originally 

 covered by forests. The topography is quite rough and there are 

 many depressions, in some of which are found lakes while others are 

 simply marshes. Over much of the area the timber has been cut and 

 the lands cleared, until at present probably less than 10 per cent of 

 this area is forested. The total area of the watershed above the 

 junction of the Bois de Sioux with the Otter Tail, at Breckenridge, 

 Minn., is 1,875 square miles. 



Owing to the flatness of the land surface and to the limited quanti- 

 ties of water which the drainage channels have carried, the latter are 

 poorly developed and are not large enough to carry off the excess of 



