RESERVOIRS AND PONDS. I03 



not cut out the bottom below the dam and undermine 

 it. More dams are lost from the a(5lion of the water 

 on the lower side than on the upper side. 



The first step to be taken in building storm reser- 

 voirs is to build a substantial wasteway. This should 

 be built of timber bents boarded up with two-inch 

 plank. Make a water-tight bottom under the waste- 

 way. This can be done either with lumber or brush. 

 If made of brush, cut willows and tie them in bundles 

 six or eight inches in diameter ; the length of the whips 

 should be ten or twelve feet. Tie two bands around 

 them three or four feet apart. Commence with the 

 brush at least thirty feet below the center line of the 

 dam and lay the bundles butt end down-stream, close 

 together in tiers at least six feet wider than the waste- 

 way. Then commence with another tier, putting them 

 back three feet up-stream, and so on, until they reach 

 into the reservoir fifteen or twenty feet above the cen- 

 ter line. Put onto the brush a light coat of gravel so 

 as to fill up all the cracks, and then erect the bentwork 

 on this bottom. Plank up the sides with two-inch 

 plank and fill in between 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 construdtion is that of the great dam 

 built by a local water company at Santa F^, New 

 Mexico. By means of a gigantic hydraulic plant, the 

 sides of a canon 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 ac5lion 



