RESERVOIRS AND PONDS. tOt 



about 2>oo degrees, and spread much in the same way 

 as the asphalt coating is applied upon streets. This 

 mixture could be used while hot as a mortar and 

 spread with a trowel or with a flat shovel. If spread 

 smoothly and evenly while hot, and with as much 

 pressure as possible to make it compadl, it would soon 

 set and form a coating that would give more or less 

 with the settling of the ground, that would be abso- 

 lutely water-tight and that would not deteriorate un- 

 der the changes of temperature. The paving mixture 

 itself comes in 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 

 paving 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 an- 

 nually. 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 reser- 

 voir. This may be built of masonry work the proper 

 size to carry the amount of water the ditch will accom- 

 modate, 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. 



