OVERFLOW OF RED RIVER OF THE NORTH. 59 



ful whether the design has been proper in all cases. The upland 

 soils are of a lighter, more porous character, and the question of suc- 

 cessful tile drainage is one of proper design and construction rather 

 than of practicability. 



The very dense soil of the lowlands takes water slowly. During 

 wet seasons the soil often remains completely saturated and even sub- 

 merged for considerable periods. The light slope of the land retards 

 the surface flow and crops frequently are damaged through the pres- 

 ence of this excess water. Tile drains, properly placed, provide di- 

 rect channels to the outlet. They rapidly remove the free water 

 from the soil, thus quickly renewing its capacity for absorption and 

 in time increasing the porosity of the soil above the drains, thereby 

 accelerating percolation and the removal of excess water. Surface 

 evaporation is decreased during dry periods, especially on cultivated 

 lands. The net result of tile drainage, therefore, is a reduction of 

 the bad effects of excessive moisture during wet periods and of defi- 

 cient moisture at times of drought. In the uplands are many areas 

 too wet to be cultivated that can be made arable by tile drainage. As 

 the development of farming progresses, more and more of this higher- 

 lying land will be improved by this means. 



RECOMMENDED PLAN OF DRAINAGE. 



The surveys and investigations revealed clearly that the securing 

 of adequate drainage for the wet and overflowed lands in the valley 

 of the Red River of the North requires that floods be either con- 

 trolled or reduced in stage as much as possible and that adequate 

 drainage ditches be provided to remove excess water rapidly from 

 those lands which have insufficient natural drainage. 



It was found that in the watershed of Lake Traverse and the Bois 

 de- Sioux River (see fig. 1), the conditions affecting drainage and 

 flood control were such that the improvements in this section of the 

 valley must be constructed as one project. However, in preparing 

 the plans the effect of the recommended improvements upon the flood 

 situation in the lower valley was given careful consideration. The 

 work in the valley separates into three projects, which can be carried 

 out separately or as one large project. These are the Lake Traverse- 

 Bois de Sioux, the Red Lake-Red Lake River, and the Red River of 

 the North projects. 



LAKE TRAVERSE— BOIS DE SIOUX PROJECT. 



SUMMARY OF RECOMMENDED WORKS. 



The improvements recommended in the Lake Traverse-Bois de 

 Sioux watershed are, briefly, the following: 



1. A detention reservoir to be formed in Lake Traverse by the 

 construction of an earth clam provided with spillway and outlet con- 



