RESERVOIRS AND PONDS. 77 



barrels of some 550 pounds and could be furnished at 

 $25 a ton. The sand free from any loam could always 

 be secured at or very near the pond, and the whole mixed 

 at the job and applied as fast as mixed. It would be 

 safe to estimate that the paying pitch for this kind of 

 work would not exceed three cents a square foot should 

 the entire coating run an inch thick when laid. Treated 

 in this way a pond will not leak and the only loss of 

 water will be from evaporation, which varies from 50 to 

 100 inches annually. This loss reduces the amount for 

 irrigation or other purposes that can be depended upon 

 by about 30 per cent. The more humid the section the 

 less the loss. 



Gates and Spillways. In all large reservoirs it 

 is necessary to provide a conduit or culvert to convey the 

 water to the supply ditch leading from the reservoir. 

 This may be built of masonry work the proper size to 

 carry the amount of water the ditch will accommodate, 

 and should be laid up with water lime or cement. As 

 we have said, this should be built the first thing before 

 the walls of the reservoir are commenced. The gate 

 should always be put on the inside end. A very simple 

 and easy gate to operate, say up to eight or nine feet sur- 

 face, is what is called the paddle gate. The end of the 

 sluice that the gate goes on should be made as follows : 

 Extend the bottom into the pond eight or ten inches, 

 pull the top back so the sides will describe an angle of 

 fifty-five degrees to the bottom line, make the face straight 

 and smooth, put two pieces of 3x6 timber on top of the 

 wall and let them run back under the dirt work. Cut 

 the paddle or gate about two inches larger than the 

 aperture. Bolt two cleats near the ends and let them 

 extend four inches above. Then bolt on a handle or 

 lever in the center three by four inches, and eight feet 

 long ; bolt a roller crosswise to the cleats and handle 

 close down to the top of the gate, and make some convex 



