On the Wisconsin River Improvement. 151 



below convex to the axis of the stream. In connection with 

 the work, observations were made of the movements of sand 

 bars, and the effect of the work upon them. The movement 

 at Portage was from 3 to 5 feet per day which seemed to be 

 the average upon the river unless disturbances occured. At 

 Dekorra the effect of dams caused a movement of from 7 to 

 14 feet in twenty-four hours, and at Lone Rock from 6 to 2Q 

 feet in twenty- fours hours. The bars moved along at this rate 

 until reaching the dams, and then receded as rapidly and dis- 

 appeared, the sand being deposited behind the dams. From 

 the result of the work it would appear that it is only necessary 

 to contract the stream proportionate to the required depth^ 

 everything else depending upon the stability of the dams, of 

 which he has not the slightest doubt, as he considers the test 

 which they withstood, when in an early stage of progress, the 

 water poured over the same in an entire sheet, as much severer 

 than any resulting from high water. Concerning the stability 

 of the channel produced, the question arose as to whether high 

 water with increased pressure and velocity would not continue 

 excavating the same until banks and dams would slide in, and 

 the channel become useless ; this gave rise to an examination 

 of the river where the same is confined to a narrow channel, 

 so that its depth is from 6 to 8 feet at low water ; at such pla- 

 ces the bottom is found to be composed of coarser material and 

 gives considerable resistance to the thrust of a pike ; the bottom 

 always remains the same excepting during the passage of a 

 sand bar during a freshet. 



For my own part I think the canal project by far the mo& 

 preferable. As the work will be principally excavation in 

 sand and loam it can be done with proper machinery at a 

 comparative small cost. When once completed it can be 

 maintained at small cost. The banks as proposed will be 

 above high-water mark in the river and consequently not 

 be liable to damage from floods. No estimate need be made 

 for feeders. The Wisconsin river will constitute a natural 



