Arizona republican., 1908-04-01

end of the dam, but not interferinI
 with the solid anchorage of tha
 structure into the side of the canyon
 This tunnel is of an average height O eight feet and is twelve feet wide.
 runs from a point about 15O feet abov
 the upstream face of the dam to point below the power house-a tota length of 500 feet. Protecting the up per end of the tunnel will be a stee and concrete grizzly. arched above fol
 many feet to withstand the pressure o
 the water and to prevent the entrance
 of brush or debris into the tube. The l tunnel has a fall of a foot and q half sufficient to drain it when the water is
 shut out. To close this opening Into
 the reservoir two sets of gates are cast | solid q foot thick, six feet wide and ten feet long. They are 10 be set in
 a casting of bronze to resist the wear and pressure which will come upon them when the reservoir is full of
 water. One set will be in service
 while the duplicate series will be
 ready for an emergency or the repair
 of the others. They will be operated DE HNHfdulic poWeT-
 Another outlet from the reservoir will be penstcck through the dam at the ninety foot level. This will be l used for power purposes when there l is that much water in storage and will
 give a sixty foot fall.
 Salt River was known to be cratic
 but it has seemed as if since the be- ginning of construction work on the big dam the river has been develop ing floods at most unexpected and in- Opportune times. and of tremendous volume. For two years now the work of building has been under way but it is only within the past six months that appreciable progress has been made on the structure. Preparation and excavation for the foundation proved tedious work Golfer dams were ineffective and time after time the partly made excavation was flood ed and filled so that the cleaning out process had to be repeated. Finally a good start was made and eventually the foundation of the face of the dam for thickness of forty feet was laid all the way across the canyon This proved an effective barrier to the water until a flood mightier than might have been expected at that time poured over it. filling the excava- ton behind and again delaying the work. The falling river found the men again at their task, and after several like interruptions. the founda- tion was at last completed for the whole thickness of the dam, or 165 feet from face to toe.
 once having reached the surface. the work could be prosecuted more wig orously and to better advantage. Now the structure begins to show as one after another the big blocks of stone, each of many tons weight, are placed in position with their cement binding. Cableways stretched across the canyon at dizzy height carry materials from the mountain sides. the stone being quarried from the site of the spillways so that two purposes are served in the one work. Derricks set up on the completed portion of the stone work help along the construction as the big blocks are scrubbed and critically ex- amined for cracks and flaws before being lowered into place.
 While the foundations were being laid. the rivers ordinary flow was di- verted through the sluicing tunnel. So long as there were no floods the work went forward at good speed and for two-thirds the length of the dam. the stone work was carried up as fast as consistent with thoroughly good con- struction. The other third. on the north end of the dam. was left a few feet above datum in order to provide a spillway for floods and also over which to divert the river when the tunnel had to be closed to permit the gates to De set. The south two thirds of the structure is now nearing forty-five feet in height on the upstream face, sloping back to about fifteen feet low CT on the down stream face. The dam is built of solid blocks of stone throughout and is not of two walls fill ed in loosely as is wrongly supposed by some persons.
 There will be in the Roosevelt dam a total of 3OO.OOO cubic yards of masonry and of this amount, over 60,000 yards have been laid at this writing, or a lit- tie over 20 per cent of the masonry is laid. While the dam gradually be- comes thinner as it hears the top. be- ing finally sixteen feet thick at the crest, it gets longer as the sides of the canyon widen, so that its length at the level of the spillways will be about zoo feet. The spillways. one at each end of the dam, will be over the solid rock of the canyon and will be twenty-five feet deep and 200 feet wide. Each will be spanned by bridge of reinforced concrete. con- meeting the ends of the dam with the mountain sides and serving as a road way across the top of the structure. The dam will tower in all 2S0 feet above bed rock. or about 250 feec above the surface of the river.
 Orders have gene forth for the re- moval of the buildings of the town of Roosevelt to a point higher up on the mountain side. out of reach of the water which will flood the present