Arizona republican., 1906-03-16
A Great Engineering Feat in the Heart of the
 Arizona Mountains

Much has been said and written about the big TOnto dam and the res ervoir which will be filled when that structure is built, yet the story seems ever new and the re-teiling. or the bringing out of some new point in con- nection with the work always finds a ready listener who may be instruct ed Officially it is called the Salt river project by the Reclamation Ser vice officials. and the name of Roose- welt has been given to the busy little town of woTkmen which has sprung up at the site, SeVenty-fiVe miles from Phoenix. However, when the dam is built and tle water level in the res ervoir rises to it's highest point, the town will be wiped out, to finger IF memory only, or perhaps De perpetu ated in the official settlement of the engineers in charge of the 2Onstruc- tion work. who have perched their offices and habitations high up on the side of the canyon. beyond the rea:h of the impounded waters.
 Locally the Tonto basin ras been known for years and q basin il iS m reality; high rock cliffs bounding Salt river on the one hand and TOnro creek on the other to form the con- taininE walls while just below the junction of the two streams Is a pre- cipitous box canyon. So narrow and tortuous is this canyon thu- in times of flood il has acted as a natural dam and held back vast body of water in the basin while the stry-m welt tumbling down in gradually increased solume. Only 210 feet wide is thIs canyon at the bottom, and-acTo5S it is being built the big masonry sITuCt i.'c to hold back the combined flow of the liver and its tributary creek, while eventually a mile-wide la<e will take the place of the present narrow streams
 Picture a big with widely spread arms. the one representing Salt river and the other Tonto creek, whiic the stem is the combined streams, and there is the Tonto reservoir. Cxt'.rd the one arm for sixteent mIles and the Cther for nine miles ana there !s the lake. twenty-five miles from end io end. formed by the dam and impcmIG ing the largest artificial body uf water in the world
 To carry comparisons .t little fur ther in order to get a popular idea of the immensity of the structure which busy wOrkmen are now engaged in rearing, imagine a wall of masonry more than half as nigh as the Wash 1ngtOn monument at the capital city of the nation. Or fancy a structure in the heart of the Arizona mountains which would overtop almost any sky sCraping office building in the coun- try. It would take two ordinary eight or ten-stOry buildings, one atop the other, to equal the height of this dam. Four of our own Fleming blocks stacked up like checkers and set be- side the completed dam would scarcely reach to the level of the roadway which will run across the crest.
 Now to go into actual figures con corning this great engineering work The Tonto dam will be "builded upon a rock" for it's foundation will go down to the solid mountain bed. thirty feet below the surface From this point it will tower 265 feet, of which 2S5 feet will be above low water mark. It will be 165 feet thick through the base. or from heel to toe, and will have d slope on the down stream side until only sixteen feet thick at the crest. On the upstream side the wall will be about one foot out of plumb and that side will present a slight arch against the force of the impounded water Into the solid rock on each side of the canyon will extend the ends of the dam and the whole struc- ture will be built of blocks of stone laid in cement; cyclopean rubble con struction, the engineers call it, the blocks varying up to ten tons in weight and being laid with overlap ping joints.