OVERFLOW OF RED RIVER OF THE NORTH. 71 



thorough drainage of small areas. Although a large amount of local 

 drainage is necessary in the watershed, plans for it are not discussed 

 here. This work should be taken up under State drainage laws. 



RESULTS OF IMPROVEMENTS. 



Lake Traverse and the Bois de Sioux River constitute the outlet 

 for 1,200,000 acres or 1,875 square miles of land, of which 1,345 square 

 miles are in Minnesota, 170 square miles in North Dakota, and 360 

 square miles in South Dakota, as indicated in Table 1. Run-off from 

 the higher parts, 1,087,630 acres, of this watershed now causes con- 

 siderable flooding over an area of 112,370 acres of lower-lying lands 

 divided among the three States as follows : Minnesota, 31,140 acres ; 

 North Dakota, 75,160 acres; South Dakota, 6,070 acres. This lower 

 land is all directly tributary to Lake Traverse and the Bois de Sioux 

 River below the location that has been suggested for the detention 

 reservoir and dam. 



The proposed improvements are designed to control the run-off 

 from the upper watershed of 1,335 square miles above the proposed 

 dam, (1) by storing in the reservoir all the run-off from this water- 

 shed during March and April; (2) by storing during other periods 

 after May 1 the flow into the reservoir in excess of the 1,000 second- 

 feet which would be discharged through the control outlet; (3) by 

 storing all the run-off that occurs during any period of 15 days dur- 

 ing the summer when the run-off from territory below the dam fills 

 the channels farther down. The channel capacities and provision 

 for control of run-off are so planned that when operating in con- 

 junction with properly designed and constructed local drainage, the 

 flow of water over the entire Lake Traverse-Bois de Sioux water- 

 shed can be so regulated that no serious damage will result from 

 flooding or lack of drainage. As a result of the construction of the 

 proposed improvements 112,370 acres will be protected from overflow 

 and given good outlet drainage. The Lake Traverse-Bois de Sioux 

 project is complete within itself. While it may, if desired, be in- 

 cluded as a part of the larger Red River project, it can be prosecuted 

 entirely independently of any other improvements. 



COST ESTIMATE. 



A statement of the necessary construction work together with the 

 estimated cost of the various items follows : 



Browns Valley levee and railroad embankment $39, 970 



Dam, earth embankment . 107,950 



Spillway 66, 960 



Control sluiceway 67, 960 



Approach to outlet 25, 700 



Main ditch 394, 770 



