— 34 - 



must be extracted, but it will be noticed that this direc- 

 tion cuts a shallow place near the Argentine coast, where 

 probably rocks will be found. 



For this reason it is believed that it is more convenient to 

 adopt a direction partly straight and partly curved, follow- 

 ing the thalweg of the river giving at the same time a width 

 of BO instead of 50 meters to the channel. It is almost sure 

 that adopting this direction no rock will be met with and 

 the cube to be dredged will be reduced at the same time to 

 30.000 m 3 . 



As the bars of «Yuqueri Grande» and of «Corralito form 

 in reality one single bar, being the first one, as explained 

 before, a consequence of the second, it has been agreed upon 

 to give the name of «Yuqueri Grande » to the whole part 

 which bed is gravel or small stone, and that of «Corra- 

 lito» to the part where the bed is completely of a rocky 

 nature, 

 corraiito bar. Immediately upstream the «Corralito:> bar is found, the 

 formation of which is compact stone in the middle of which 

 exists a narrow channell. When taking the level of the wa- 

 ter surface in the jDart above and below the bar, when the 

 height of the river water was 0,62 meters a difference of 0,40 

 meters was found over a distance of 2237,20 meters, that is 

 to say a slope of 0,183 meters per kilometer. 



The corresponding mean velocity observed at the surface 

 was 0,92 meters the greatest velocity, 1,26 meters per second. 

 Other observations made when the height of the river was 

 2,50 and 3,80 meters gave as a result velocities of 1,382 and 

 1.3118 meters per second. 



In order to navigate the «Corralito2> channel, the following 

 buoys, all near the Argentine shore, will be placed when 

 goiiiLi 1 upstream, three at the beginning and four ai the end. 



in the plan of the works for deepening permanently this 

 partof the river for navigation with vessels drawing '.> feet, 

 a direction in a straight line has been adopted, which follows 

 as much as possible the existing channel and reduces the 

 excavation to be executed to a minimum. 



Thecubeaf the material which niiist be broken up and 

 excavated is 17. Too meters. The marking of this bar and 

 that of Yuqueri Grande must be done with buoys pro- 



