78 IRRIGATION FAHMIXG. 



boxes in the timbers on top of the wall to receive them. 

 Put some strap iron over these gudgeons so the water 

 will not lift the gate out of place. Put a pulley in the 

 top end of the handle and set a post on the top of the 

 embankment. Fasten one end of the rope to the post 

 and pass it through the pulley and back to the post. 

 The action^of the water will always close the gate, and to 

 open it take hold of the loose end of the rope, and pull 

 back and snub it to the post. 



If the reservoir is so situated that it will catch any 

 amount of surface or storm water it must be provided 

 with an ample spillway large enough to take off the sur- 

 plus water, so that in no emergency can the water rise 

 over the crest of the dam; and the spillway must be pro- 

 vided with large and ample aprons, so the momentum of 

 the water pouring over the spillway will not cut out the 

 bottom below the dam and undermine it. More dams 

 are lost from the action 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 waste way. This should 

 be built of timber bents boarded up with two-inch plank. 

 Make a water-tight bottom under the wasteway. 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 ;it 

 least six feet wider than the wasteway. Then com- 

 mence 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 center 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. 



