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General authority for the construction of the Kittitas division is contained in a contract, dated December 19, 1925, between the United States and the Kittitas Reclamation District. The dam was built under a separate contract dated March 16, 1928, and awarded to C. F. Graff, of Seattle, Wash. The contractor commenced construction, but later, due to financial difficulties, relinquished the job to one of the sureties, Hans Pederson, who completed the work on October 11, 1929.
On September 20, 1928, the gates of the Kachess and Keechelus Reservoirs were closed and work was started on the building of two cofferdams. The upper cofferdam was first built as a rock-filled crib with timber sheeting extending a few feet into a 10-foot stratum of gravel and boulders. The lower cofferdam consisted of a rock-filled section. Notwithstanding the use of additional reinforcements consisting of sack dams, both cofferdams leaked badly through the gravel stratum. To unwater the foundations it became necessary to drive interlocking steel-sheet piling and to cover the cofferdams with clay blankets. The water in the river was first diverted by means of a 12-foot-wide by 9-foothigh timber flume placed on the north side of the river at elevation 2,142.5. Later the river was diverted through a temporary opening left in the dam. As construction progressed further, the opening was closed and the river allowed to pass through the sluice gates.
The foundation was excavated into solid rock to a depth of 3 to 4 feet, and the cut-off trench for the dam was excavated to an additional 5 feet. The excavated material was removed by stiff-leg derricks.
Grout holes were drilled on the center line of the cut-off trench at 5-foot centers. Drill holes were 25 feet deep in the river channel and tapered off to 10 feet on either river bank. Where the exposed foundation showed signs of seams, additional grout holes were drilled. In the south half of the spillway section, downstream from the cut-off trench, 20-foot grout holes were drilled on 10-foot centers,
both ways. The maximum amount of grout needed in any one hole was 38% cubic feet. The average requirement of grout per hole was 4.75 cubic feet. Before actual grouting was started, the foundation was covered with a 5-foot layer of concrete. When the concrete had partly set, the grout pipes were loosened and slightly raised above the top of the rock foundation. Grout under a maximum air pressure of 100 pounds per square inch was then forced into the seamy rock and into voids that existed between the original rock and the concrete blanket.
Concrete in the proportion of 1:2.75:6.25 was used for the interior portion of the dam. A richer mix of 1.5:2.75:6.25 was used in a 3-foot thickness at the exterior surface. This procedure was easily and quickly obtained by the addition of one sack of cement to the batch of the cubic-yard mixer. The concrete was chuted in place from a tower located on the south bank of the river. A concrete mix of 1:2.4:3.6 was used in the reinforced walls and slabs.
A concrete testing laboratory, established at Ellensburg, Wash., made numerous tests on strength, permeability, and economy of the mixes of concrete to be used in the dam. The sand and gravel used in the concrete was purchased from the Pioneer Sand & Gravel Co. and shipped from Steilacoom, Wash. The height of concrete pours varied from 4 to 10 feet. Keys were provided in all construction joints. Metal-lined forms were used on concrete surfaces exposed to view.
The center portion, or spillway section, of the dam was constructed first and the abutments later. The drum gates were assembled in place. Alignment of the steel castings making up the gate hinges was obtained by placing the anchor-bolt nuts on each side of the casting. After the erection of the structural-steel sections of the gate, it was possible to set and grout the cast-iron wall plates to member correctly with the drum-gate side seals and to concrete around the gate hinges and seal castings.
Main items of the contractor's equipment consisted of one y-yard steam shovel; forty 1%-yard side dump cars; two steam dinky locomotives; one guy and two stiff-leg derricks; a stationary air compressor, 1,190 cubic feet per minute; one 200-horsepower motor; and one 1-cubic-yard concrete mixer.
For convenience in shipping materials a spur track was constructed from the Northern Pacific Railroad yards at Easton to the dam site. From 40 to 80 men were employed on the construction. The accompanying tabulation gives a detailed analysis of the cost of the work.
Cost of Dam.—The accompanying table no. 1 shows the detail cost of Easton Dam, not including the cost of preliminary investigations, etc.
2, 233 |
146 7, 592
Right-of-way and lands......... ....... Acres...... 403. 37
.......do. ...... 263. 89 Diversion and care of river .........
Lump sum.. (1) ........ Excavation, earth and loose rock.
Cubic yards. 511 Excavation, solid rock..
...do...... 532 ....do. ..........
..do..... 6, 483 4. 30 Loading, hauling, dumping, etc.
23, 718 Backfill.
. 43 Stripping for dike. .....
103 Dike embankment...
487 1. 20 Riprap...................
3.75 Drilling grout holes. .......
Linear feet. 2, 233
pipes in grout holes.
Cubic feet.. 509 1.70 Concrete below elevation, 2,135.......
Cubic yards. 1, 648 2. 90 Concrete above elevation 2,135, spillway and ...do...... 2,881
4.80 abutments. Concrete piers and stairways..
802 8.75 Concrete in fishway ........
..do... 161 | 10. 20 Concrete in headworks..........
215 10. 20 Concrete in railing post. ......... ..........do...... Placing reinforcement bars ....... ........ Pounds.... 60, 664
..017 Installing and painting structural steel, drum ...do...... 224, 679 .037
gates, pier plates, hinges, and seat castings.
6.80 Installing copper expansion strips .............. Linear feet. 585 Installing electrical conduits .........
904 .50 Installing and painting cast-iron slide gates, hoists, Pounds .... 34, 182 .06
and miscellaneous metal.
7,018 1,639 2, 194
157 1, 031 6, 740
828 1, 109
278 1, 373 20, 743
11, 152 2, 467 3, 303
435 2, 404 27, 483
Scale of Foet NOTE: Axis of Doris parallel to and
18 Riprop B Feet West of Bose Line shown on
EL. 2184 5
491 Gate Hoist .....
-6601 1:6 Drum Oate
34 Risers 9.25'5" SECTION THRU
133 Treods99 26-9* FISH LADDER
in 10:00 --Fish Ladder
EL 2155.09 - Trash Bors @ 4'ers.
16' Gate Valve -20' 20' CI Gate
H.W. Bl. 2:47 (Tross Rack not shown)
48.6.0'CI Sluice Gote
Low Water El. 2137
Sond and Grovel .
Moles 5 crs.
-Excavate to Sound Rock
SECTION THRU LEFT PIER
SECTION THRU SPILLWAY
591 bote Moist
2-12 11'Radial Gates -Air Intakes for Strice Gates
Northern Pacific Ry A
21 Std. Pipe Real
Stop Plank Crooves 2:29 Water Surface
El 2659.0 16 Balanced Valve
SECTION THRU HEADWORKS
Opening Trash Rock 21 22
116 Trousse 9.7"0"
This Drawing Supersedes Dwo No. 33-D-166 Boulders 227124 NL -Sluiceways.
DEPARTMENT OF THE INTERIOR
BUREAU OF RECLAMATION Quartzite
VAKIMA PROJECT-WASHINGTON Assumed Foundation
-Grouted Mofes 5'ers
DIVERSION DAM AND HEADWORKS
GENERAL PLAN AND SECTIONS No.1
23222 Ke 2014 (987 33-D-332
General plan and sections.
WIND RIVER DAM
RIVERTON PROJECT, WYOMING
BY I. B. HOSIG, ENGINEER, BUREAU OF RECLAMATION
In the vicinity of the diversion dam the Wind River Valley has an average fall of 25 feet per mile. The recently workedover portion is 25,000 feet wide and is bordered by sandstone bluffs 40 to 100 feet high. The low-water channel is 120 feet wide and 2.5 feet deep and 8 feet to 10 feet lower than adjacent ground. Low-water surface is at elevation 5,552.0. Bedrock of rather soft sandstones and shales is generally at elevation 5,546 or higher, except in an old channel near the south abutment, where it is about elevation 5,536. Overlying the bedrock is a 7- to 15-foot thickness of granitic and andesitic cobblestones. These constitute the flood stage saltation load of the river. Except in the present stream bed these cobblestones are covered with 1 to 3 feet of sands carried higher in the river cross-section or brought in by winds and intermittent side streams.
THE RIVERTON PROJECT, 100,000 acres irrigable, is located in Fremont County, west central Wyoming. The Wind River is a part of the Bighorn and Yellowstone River systems and drains the south slope of the Shoshone Mountains, and the northerly portion of the east slope of the Wind River Range, the latter a part of the Continental Divide. The drainage basin has an area of 1,860 square miles at the diversion dam. Of this area, a considerable portion has Alpine topography with peaks as high as 13,800 feet above sea level.
The average annual run-off is about 900,000 acre-feet, 80 percent of which comes from mid-May to early August, principally from melting snow. The maximum observed discharge is 12,300 second-feet, occurring in June 1906.
While the irrigation demand synchronizes reasonably well with the flood wave, the full use of the water supply requires some seasonal storage as well as carry-over storage. The seasonal storage is required in late August and early September to finish off the potato, bean, and sugar-beet crops. Storage capacity of 155,000 acre-feet is now under construction at Bull Lake; and the Pilot Butte Reservoir, completed in 1926, provides 31,550 acre-feet of storage capacity.
The entire valley is youthful geologically. The irrigable lands are located, in part, on terraces of the main stream where there is a subsoil of cobble stones; and, in part, on the lower reaches of tributaries from lower lying lands of the drainage basin. Here the soils are mostly colluvial and aeolian in character and bedrock is not far removed. The main canal has an initial capacity of 2,200 second-feet. At mile post 9.25 a branch takes off the Pilot Butte Reservoir and the Pilot Canal. This is a first development of 20,000 acres on which irrigation began in 1925. A drop of 105 feet from the canal to the reservoir is utilized to produce electric power for use in further construction, especially excavation work with electric draglines, although electrical energy is furnished to nearby towns. The present installation consists of two 750 kilovolt-ampere units. The operation of the plant requires year-round operation of the canal, but the reservoir conserves the water so used for irrigation purposes in the following year.
It was required that the low water surface of the river be raised 17.75 feet to permit of diverting 2,200 second-feet into the canal with none passing down the river; that coarse materials carried by the river in flood be kept out of the canal; and that the diversion structure be able to safely pass a flood of 40,000 second-feet. It was also required that a means be provided for passing the saw logs and railroad tie timbers annually driven down the river by a lumber company operating in the headwater forests; that a fish ladder be provided so that the mountain trout can continue their annual upstream run to spawning grounds; and that a roadway be provided across the valley for the benefit of future work on storage developments. The Wyoming State Highway Department cooperated in the last-mentioned matter, building a steel bridge over the spillway section, and more important, incorporating the highway from rail head at Riverton to the diversion dam in the highway U, S. No. 287, one of the principal entrances to the Yellowstone National Park. This cooperation, while highly valuable to the project, did not begin early enough to be of aid during the building of the dam.
The entire width of valley was not necessary for a flood spillway section, and the dam was divided into two parts, a concrete spillway section and an earth dike. A balance between costs incident to height of headworks, bridge piers, and height of earth dike against costs incident to length of spillway section and highway bridge fixed the relative lengths of the two sections at 650 feet and 1,650 feet, respectively. The spillway section is 28 feet wide with a fore apron 24.75 feet wide, and was designed to rest on rock. A gravity ogee section was adopted as against the Ambursen cellular type in spite of slightly less favorable cost estimates, principally because of the greater suitability of the solid section to the rigors of the northern mountain climate. The fore apron is intended to contain
the hydraulic jump and prevent undermining of the main section. The dike section has a maximum height of 25 feet with a 5-foot freeboard at maximum flood stage.
Examination of the cobblestone bed under the dike section made it appear certain that an impervious sheetpiling cut-off would be very difficult to construct because of the cobblestones which ranged up to 18 inches in diameter. Excavation for a puddle trench was also considered very expensive because of trouble with ground water. It was finally decided that the dike section with a moderate cut-off trench near the upper third of the base would be satisfactory. Absolute imperviousness was not necessary and piping was not feared in view of the coarseness of the cobblestone bed. Events have proven the correctness of this conclusion as no piping has occurred in 13 years of operation.