RESERVOIRS AND PONDS. 



79 



Plank ii}) the sides with two-inch plank and fill in 

 lii-t \veen the sides of the bentwork level with gravel, and 

 put plenty of gravel on that part of brush above the 

 bentwork. 



A Hydraulic Embankment. A novelty in the 

 way of reservoir construction is that of the great dam 

 built by a local water company at Santa Fe, New Mexico. 

 By means of a gigantic hydraulic plant, the sides of a 

 cailon were torn down and the detached material thus 

 obtained was carried through a fourteen-inch main and 

 deposited on the embankment under a pressure of 140 

 pounds to the square inch. The action of the water 

 both cemented and puddled it there. Immediately above 

 the site the banks of the stream separate so as to include 



FIG. 20. CROSS SECTION OF HYDRAULIC RESERVOIR. 



a reservoir of a somewhat oval shape 1600 feet long and 

 500 feet in average width, and of an average depth of 30 

 feet. As shown by the cross section in Fig. 20, the dam 

 is 85 feet in hight at the middle of the stream and is 300 

 feet wide at the bottom. Its entire length is over 1000 

 feet. Its careful construction and the precautions taken 

 to render the dam impervious' to water are shown by 

 the cross section. Under the upper half of the dam the 

 excavation is made to bed rock ; parallel strips of bed- 

 rock surface are broken fresh, and concrete ribs built 

 thereon parallel with the center of the dam. In these 

 concrete ribs, in the composition of which the very best 

 hydraulic cement is used, triple sheet piling is embed- 

 ded and carried up into the puddle. The entire upper 



