The Clifton clarion., 1886-12-08
RESERVOIRS.
pr J. II. MARITIME ,u, c. E.

The third source of danger, viz: the flow of water over the top of
 the dam is obviated by making it several feet higher than the sur rounding land, so that any surplus
 water may escape from the pond
 by flowing over the land instead of over the dam. In addition, a channel should be cut around the dam to the ravine again, care be- ing taken to prevent its cutting down.
 In many cases a siuice gate in
 the dam itself will be very advan- tageous, rendering it possible to drain the pond or draw off a sur plus of water in time of food.
 This gate should be placed on
 level with the pond bottom, in fact, should be put from two to four feet lower than the bottom to pre- vent the possibility of being under mined. The construction of such a sluice way requires unusual care and skill, and if these be not avail able 1t will be better to omit it, as from tho great pressure of the water above and the liability to leak around it, it is difficult to make It permanent. Such a job should only be undertaken by one who is fully competent and under stands his business, for should a leak occur and the dam wash away immense damage to life and prop erty below will be the almost in evitable result. Still, it can be, and often is done. A sluioe box of four by six feet will be generally sufficient, as with the pressure above an immense body of water will pass through it. If the reser- voir is deep the pressure of the water, amounting sometimes to many tons, against the sluice-gate necesitates powerful mechanism to raise the gate. A long rod working 1n screw iu the gate and reaching to the top, will an swer very we'll, o. ratchet and cog wheels may be used with suit able leverage. But whether sluice- gate be built in the dam or not canal should always be cut on the surface to carry surplus water around the dam into the ravine below, and care must be taken to prevent its cutting down. Such a waste canal is absolutely essential to the safety of the reser voir.
 As to the slope of the enbank- ment, two feet horizontal to one perpendicular will do very well, but three to one will be still bet ter. Remember that in dealing with earth and water you cannot be too careful in the execution of the work-the "I-guess-that will do" principle wont pay. As the damsis built the loose soil scraped from the foundation in the begin ming may be placed over the slope without injury, being upon the surface of the bank.
 A dam built as herein described will be found reliable, and may all, or nearly so, be constructed by common labor, and of the cheapest materials. Dams in running streams intended simply to raise water enough to flow into canals may be built of brush, rock, trees, etc, in beaver style, and will an swer very well, but never for res ervoir dams intended to be water tight.
 When the sides or bottom of a ravine are rocky it may be nec- essary to build of masonry, but in such a case it will not be safe for common mason to undertake the l work. It will be much better to | place the undertaking in the care of an experienced engineer, one who had made such work study, | and in the end it will be found | much the much more economical | course.
 We might give many details needed for dam of masonry work i but not enough in an ordinary newspaper article to be of much | practical benefit. Every location would be different in its eircum- stances and surroundings from an- other and require more or less diff ference in procedure, to be only | judged by practical man on the ground.
 It is impossible in the limited | space of newspaper article to go into all the details necessary for the successful accomplishment of cuob i,npo,.tant yyorIy hut vpa hon,