Roosevelt Dam

(Fig.51, See Also Frontispiece).

The dam is situated on the Salt river 75 miles E. N. E. of Phoenix, 40 miles from the railroad at Globe and 60 miles from the railroad at Mesa. A highway was built down the valley of the Salt river to the latter city and most of the freight was hauled over that route. The lowest bid received from cement manufacturers for cement delivered at the dam site was $4.89 per barrel. The Reclamation Service found cement materials at the dam site and there built and operated a cement mill with a capacity of about 400 barrels per twenty-four hours. This mill furnished all the cement for the dam, and a large quantity for use on other parts of the project.

Cost of manufacturing 107,589 barrels of cement in 1908

Cost per bbl.

Office salaries, superintendent, chemist, etc................

... $0.049

Operating labor...........

0.291

Maintenance labor..........

... 0.055

Maintenance material.................................

... 0.085

Clay digging.........................................

0.054

Clay hauling..........

0.078

Limestone quarry..........

0.121

Supplies.............

0.051

Fuel wood for drying clay..........

0.067

Fuel oil....

0.922

Power................

0.122

Depreciation about.................

0.80

Total............................................

$2.696

Owing to the many interruptions to the work, and to limited storage capacity, the average operating costs for the entire period were higher. The cement mill, machinery, installation, complete cost $249,447.92. Owing to the remote location, length of service, cost of hauling and handling the salvage was very small, not over 5 per cent. The total cost of operation, for the entire period of about five years and three months, including depreciation of plant, was $1,063,542.36. The total output of 338,452 barrels cost $3.14 per barrel.

On January 10, 1905, a contract was let for 50,000 barrels (42 gal.) of fuel oil at $3.48 per barrel delivered at the mill, of which about 20 cents represented the price of oil in Southern California, about $1 freight to Mesa, and the rest for 60-mile haul in tank wagons. In October, 1908, a contract was made for an additional 33,000 barrels at about $4.34 per barrel, about 50 cents of the increase being in the price of oil at the fields. One barrel of oil burned a trifle over four barrels of cement. The saving to the Reclamation Service from building and operating the mill was $1.75 per barrel upon very nearly the entire output of the mill, although a small quantity of cement was hauled toward the railroad and used in territory where outside cement might have competed.

In addition to furnishing the cement the Reclamation Service also furnished the sand. Natural sand from the river would have involved a very expensive haul, and the deposits would have been inaccessible as soon as any water was stored or in case of a freshet. A plant was erected for crushing sand from rock, which was done throughout the work with entirely satisfactory results. The total plant charge was a trifle more than $31,000, and the total cost of producing sand, including quarrying the rock, crushing, plant maintenance and depreciation, and overhead charges, was about $1.50 per cu. yd.

To furnish power for construction purposes there had been constructed a 225 sec. ft. capacity canal 19 miles long taking water from the Salt river and delivering it to a 1000-kw. wheel in a temporary power house at the dam site. This canal is a feature of the completed project. Power was sold to the contractor at 1/2 cent per h.p.-hour.

With cement, sand and power furnished as above the following prices were bid for the construction of the dam:

Excavation, class 1, sand and gravel in bottom, cu. yd. at..........

$1.75

Excavation, class 2, rock below river level, cu. yd. at...

5.00

Excavation, class 3, rock above river level, including all waste material from spillways at.........................................

1.50

Rubble masonry in dam at.....................................

3.15

Rubble masonary in Wing walls at....

4.75

Coping masonry, concrete in bridge piers, concrete bridges (three 60-ft. spans each), 2 at.....................................

$7,500.00

(For accounts of the progress of the work and some of the difficulties encountered see Engineering News, Sept. 10,1908, Engineering Record, Dec. 31, 1910.) Some of the foregoing quantities were exceeded during construction, excavation Class 3 very largely, owing to the amount of waste in the spillways; and the masonry in the dam somewhat, owing to increasing the height of the dam 10 ft. after the contract was let. Around one end of the dam a tunnel was driven, lined and provided with gates. This tunnel, known as the sluicing tunnel was with floor at river level, and up to its capacity diverted the river during construction. Experience with these gates indicated the desirability of relieving them of the high operating head. For this purpose a second outlet tunnel was driven on the other side of the river at elevation about 125. Three lines of 5-ft. cast-iron pipe are placed through the dam, converging to a 9-ft. diameter tunnel and continuing some 100 ft. through the rock abutment to two outlets. On the upstream ends of the 5-ft. pipes are three 58-in. balanced valves. The frontispiece shows water discharging from this tunnel.

The cost of the dam and appurtenances to Dec. 31, 1911, nearly a year after completion, was as follows:

Roosevelt dam (as given in detail below)....

$3,126,430.06

Sluicing tunnel, 108 sq. ft. section, 450 ft. long, excavation lining, reinforced concrete screen tower 78 ft. high, etc............

125,410.04

Hydraulic gates, including contract with manufacturers.............

128,832.18

Gate chamber, setting, accessories and design (for a description of these gates see Engineering News, May 30,1907)........

249,841.27

Reservoir..................

23,356.06

Second outlet tunnel, including three 58-in. balanced valves ($13,890), 270 ft. 5-ft. cast-iron pipe, 100 ft. of tunnel driven and lined, apparatus for operating, and for measuring discharge............

55,713.49

Roadway approach to east end of dam......................

13,530.55

Total.................................................

$3,594,282.37