Wellton-Mohawk Irrigation System, Wasteway No. 1, Wellton-Mohawk Canal, North side of Wellton-Mohawk Canal, bounded by Gila River to North & the Union Pacific Railroad & Gila Mountains to south, Wellton

Source document Quoted word for word from HAER AZ-68-F. Not written, edited or summarised by this site.

Wasteway No. 1 is located on the north side of the Wellton-Mohawk Canal, ap- proximately 2 miles downstream from the Wellton-Mohawk check and turnout (head), Wellton vicinity, Yuma County, Arizona. The Union Pacific Railroad lies about 200 m to the south, and the Gila River borders the irrigation feature to the north. Wasteway No. 1 lies within the SW 1A of the SW 14 of the SW 1A of Section 3, Township 8 South, Range 21 West, on the Laguna Dam, Arizona, 7.5-min- ute U.S. Geological Survey (USGS) quadrangle (photorevised Universal Transverse Mercator Coordinates: Zone 11, N E

Source document Quoted word for word from HAER AZ-68-F. Not written, edited or summarised by this site.

Construction of the Wellton-Mohawk Division of the Gila Project began in and was essentially completed in With the completion of the irrigation tem, Colorado River water was delivered to previously arid lands in the lower Gila River valley. A wasteway allows for the rapid discharge of water from the system. Wasteway No. 1 is the largest wasteway on the system, and its use of an automatic float system to regulate discharge makes it unique to the Wellton-Mo- hawk Division. Although not individually eligible for listing in the National Register of Historic Places, Wasteway No. 1 contributes to the function and sig- nificance of the Wellton-Mohawk irrigation system (Thompson and Sterner Report Prepared by: Scott Thompson, Senior Historian Statistical Research, Inc.

Tucson, Arizona Date: September Wellton-Mohawk Irrigation System, Wasteway No. 1, Wellton-Mohawk Canal HAER No. AZ-68-F (page 2) I. PHYSICAL HISTORY A. Date of Construction Wasteway No. 1 was constructed between and B. Architect The Office of the Chief Engineer, Bureau of Reclamation, Denver, Colorado, designed Wasteway No. 1. C. Original Owner The U.S. Department of the Interior, Bureau of Reclamation (Reclamation) owns Wasteway No. 1. How- ever, the Wellton-Mohawk Irrigation and Drainage District (WMIDD), a state-chartered agency that was established as the local water users organization that would administer the irrigation project, is respon- sible for operating and maintaining the feature. D.

Builder On July 29, the Fisher Contracting Company of Phoenix, Arizona, was awarded a contract to con- struct the Wellton-Mohawk check and turnout off the Gila Gravity Main Canal. In addition, contract spec- ifications called for the contractor to complete the Wellton-Mohawk Canal and all structures attendant to Pumping Plant No. 1. Wasteway No. I was one of the structures built under this contract.

Construction of the check and turnout began in September and work on the wasteway commenced in early I All requirements of the contract were fulfilled on February 6, Total contract earnings for the project amounted to (Reclamation 1949a:38, On March 29, the Western Contracting Company was awarded a contract for to furnish and install radial gates and hoists at certain structures along the Wellton-Mohawk Canal from the turnout off the Gila Gravity Main Canal to the turnout for the Wellton Canal at Mile (Reclamation 195 I The Pacific Coast Engineering Company of Alameda, California, fabricated the gates and hoist mech- anisms (Dayton The actual installation was subcontracted to Harless and Cheney of Phoenix, Arizona, and work commenced in September Striking employees at the plant that fabricated the hoist mechanisms delayed delivery of the parts until January As specified in the contract, Harless and Cheney installed two x top-seal radial gates and connections to operating float mech- anisms for Wasteway No.

1. The contract was completed and accepted on April 25, (Dayton Reclamation 1952a:8). Wellton-Mohawk Irrigation System, Wasteway No. 1, Wellton-Mohawk Canal HAER No. AZ-68-F (page 3) E. Original Plans and Construction Reclamation's Office of the Chief Engineer, Denver, Colorado, produced the original architectural and engineering drawings for Wasteway No. 1. Dates on the drawings range from January to May The Fisher Contracting Company constructed Wasteway No. 1 and all work was accepted by Reclamation on February 6, 1951(Reclamation1951:7). The contracting firm of Harless and Cheney of Phoenix, Ari- zona, installed the float-operated radial gates.

The contractor completed the installation and adjusted the operating mechanism in February Two months later, Reclamation accepted all work under the contract (Dayton 7). II. ARCHITECTURAL AND ENGINEERING INFORMATION Wasteway No. 1, one of several wasteways on the irrigation system, is located on the north side of the Wellton-Mohawk Canal approximately 2 miles downstream from the canal's head (Figure 1). The waste- way is a protective structure designed to reduce water levels within the conveyance system in the event of internal flooding (either natural or mechanical) or for maintenance or inspection reasons. It allows for the rapid removal of large quantities of water in emergency overflow situations or when a section of canal needs to be dewatered for maintenance. Wasteway No.

1, which is unique to the Wellton-Mohawk irri- gation system, incorporates an automatic float system to regulate discharge. The float system can be over- ridden and operated manually. The bulk of the structure is constructed of reinforced concrete. It is symmetrical in plan with two weir well inlets, two weir wells, two float wells, two radial gates, and an outlet for the discharge of excess water (Figure 2). The two weir-well inlets are located on either side of the main structure on the slope of the canal bank and are constructed of reinforced concrete. Twelve-inch-diameter concrete pipes connect the inlets to their respective weir wells. Each weir well measures x wide and deep. A funnel-shaped, adjustable weir sits inside the weir well.

The weir is connected to a down pipe that empties into the adjacent float well (Figure 3). Each float well is x wide and deep and houses a hollow, metal float. The float is connected to a hoist mechanism by means of a steel cable. Wasteway No. 1 employs two top-seal radial gates to control water surface elevations on the lower sec- tion of the Wellton-Mohawk Canal. A top-seal radial gate is used when water levels would otherwise be above the top of the gate. By building a breast wall above the gate and equipping the gate with top, side, and bottom seals, the gate can restrict the flow of water through the wasteway when it is in the closed position. The gates are housed in concrete compartments about 16' x 10' wide and 17' deep.

Each radial gate measures x and is constructed of steel with a curved faceplate and four arms (Figure 4). Water from the canal is against the convex side of the radial gate. The gates are designed to operate auto- matically using a float control to maintain water-surface levels in the canal. Two steel cables are attached to the top comers of each radial gate. The cables connect to a concrete counterweight by way of a hoist mechanism mounted on the wasteway deck above the gate compartment. The hoist mechanisms for the floats and radial gates are described below. Wellton-Mohawk Irrigation System, Wasteway No. 1, Wellton-Mohawk Canal HAER No. AZ-68-F (page 4) The wasteway deck is mostly concrete with metal grates covering the weir well, float well, and radial gate compartments.

The radial-gate hoist mechanisms are mounted on the concrete deck above the gates and consist of four gate cable drums (two for each gate) and four pulley sheaves (two for each counterweight). The gate drums are anchored to concrete pedestals, and the sheaves are mounted on metal plates anchored to the concrete deck. Two float cable drums (one for each float) are mounted on metal plates directly above the float-well compartments. All of the drums and sheaves are made of cast iron. The float drums and gate drums on both the right- and left-hand sides of the wasteway structure are arranged in line (Fig- ure 5). A metal shaft runs through the centers of the float and gate drums, so that all the drums tum to- gether (Figure 6).

The shaft also connects the hoist mechanisms to a worm gear reducer positioned on the centerline of the deck. The worm gear reducer has a hand crank that allows WMIDD personnel to raise or lower the radial gates manually. (Note: Since the radial gates and floats are quite heavy, the worm gear reduces the rotational speed of the shaft that passes through the gate and float drums while increasing torque, thus allowing for manual operation of the gates when necessary.) In addition to the gate hoist mechanisms, there are three hand wheels on each side of the deck. The larger of the three adjusts the elevation of the funnel-shaped weir inside the weir well. The other two hand wheels operate the drain openings inside the weir well and float well.

A service road runs parallel to the canal and the WMIDD has installed protective barriers at each comer of the wasteway deck. The barriers consist of two metal posts connected by steel cables (see Figures 5 and 6). Across the road from the deck is the outlet for Wasteway No. l. The outlet consists of a twin rectangular box section and a discharge chute with baffle blocks for diffusing the flow of water. The entire outlet structure is constructed of reinforced concrete. Water discharged through the wasteway enters a human- made drainage that empties into the Gila River. Wasteway No. 1 operates automatically to discharge excess water in the upper sections of the Wellton- Mohawk Canal. Water from the canal enters the inlets and flows into the weir wells through 12"-diameter concrete pipes.

Reclamation (l has described how an automatically controlled wasteway oper- ates once water enters the system: In this type of installation the gate and float are counterweighted to such a degree that the effect of buoyancy on the float will cause the gate to be raised or lowered. The water sur- face is controlled by the height of the adjustable circular weir. When the water surface upstream from the gate rises above the weir, water passes over the weir into the float well. The water in the float well rises if the water passing over the weir exceeds the amount of water passing through the orifice plate and out the drain As the water in the float well rises, partially submerging the float and causing it to lose effective weight, the gate will start to rise.

As the gate rises the float also rises again, increasing its ef- fective weight and bringing the system back into balance. In other words, when the water level in the canal rises above a predetermined point, water flows into the float wells causing the floats to rise. This series of events starts the hoist mechanisms and raises the gates. Wellton-Mohawk Irrigation System, Wasteway No. 1, Wellton-Mohawk Canal HAER No. AZ-68-F (page 5) Wasteway No. 1 appears to be well maintained and operating as designed. All of the hoist mechanisms and gates are original. The irrigation feature is over 50 years old and the concrete shows normal signs of surface deterioration. Nevertheless, the wasteway is in good condition. III.

REFERENCES CITED Bureau of Reclamation (Reclamation) 1949a Annual Project History, Gila Project, Yuma, Arizona. Vol. XIV. U.S. Department of the Interior, Bureau of Reclamation, Denver. On file, Bureau of Reclamation, Yuma Projects Office, Yuma, Arizona. Wellton-Mohawk Canal Sta. Wasteway No. 1, Float Operated Radial Gate In- stallation. Drawing U.S. Department of the Interior, Bureau of Reclamation, Denver. Drawing on file, Bureau of Reclamation, Yuma Projects Office, Yuma, Arizona. Annual Project History, Gila Project, Arizona. Vol. XVI. U.S. Department of the Interior, Bureau of Reclamation, Denver. On file, Bureau of Reclamation, Yuma Projects Office, Yuma, Arizona. 1952a Annual Project History, Gila Project, Arizona. Vol. XVII. U.S.

Department of the Interior, Bureau of Reclamation, Denver. On file, Bureau of Reclamation, Yuma Projects Office, Yuma, Arizona. Operating Instructions, Radial Gates and Radial Gate Hoists. U.S. Department of the In- terior, Bureau of Reclamation, Design and Construction Division, Denver. Dayton, Marshall Unit Record of Construction on Radial Gates and Gate Hoists for Wellton-Mohawk Canal Station to Station Specifications No. Wellton-Mohawk Division, Gila Project, Arizona, Lower Colorado River District, Yuma, Arizona. U.S. Department of the Interior, Bureau of Reclamation, Lower Colorado River District, Yuma, Arizona. On file, Bureau of Reclamation, Yuma Projects Office, Yuma, Arizona. Thompson, Scott, and Matthew A.

Sterner Inventory and Documentation of the Irrigation System of the Wellton-Mohawk Division of the Gila Project. Technical Report Statistical Research, Tucson. Wellton-Mohawk Irrigation System, Wasteway No. 1, Wellton-Mohawk Canal HAER No. AZ-68-F (page 6) ~ I !il ~ -~ ~~ -- ., \ ~ ~ !il !il N Grid 0 ==:::::imeters 250 500 750 Scale Universal Transverse Mercator coordinate system and grid Datum: North American Zone 11 N Ellipsoid: Clarke Unit: meter Base data: Laguna Dam and Fortuna 7.5-minute USGS quadrangles (both photorevised in Figure 1. Project location Laguna Dam, Arizona, and Fortuna, Arizona, 7.5-minute USGS quadrangles [both photorevised ~ ~ 0 ::: ~ 0 ::i- p.o =< ~ (JQ ~ ::; ::: C/J '-< [/) (D" s ~ p.o [/) Cl> =< p.o '-< z 9 >- tTJ " ~~ z 2.. 0 .

0 >9 ~~ (XJ ' 0::i- i p.o "Tj =< Figure 2. Construction of Wasteway No. 1 on Wellton-Mohawk Canal, showing location of weir-well inlets, May 17, >O Note the two funnel-shaped, adjustable, circular weirs to the right of the main structure (photograph courtesy of Reclamation). p.o n (JQ p.o Cl> --l p.o - Wellton-Mohawk Irrigation System, Wasteway No. 1, Wellton-Mohawk Canal HAER No. AZ-68-F (page 8) . : .. . . . ::- ... ,.. . ~ ,_ ~ ,: . . ~ : "' .. .. G 'r . .. . '-. ~" ,, . . ( ~ 0 ; Figure 3. Section drawing of weir well and float well, Wasteway No. 1 (Reclamation Wellton-Mohawk Irrigation System, Wasteway No. 1, Wellton-Mohawk Canal HAER No. AZ-68-F (page 9) .L. 20 . _J c .. - ~ . -_: .- ,:, .,o;f:. '-. . '~ -:: ,l---4---i!---~ /_ '-" , ~ I .. ~ ' ' 1 . ~ . ,---to"-o'x5'.0" TOP 5 .4_ !

/?Aui/11- 64/ - -9 -3f f?odiv.:; - - - - ' I '6 t FLOW .' u ' .. ' . I : ' ' " ' ~-- 5 C//O;Y C-C Figure 4. Section drawing of top-seal radial gate, Wasteway No. 1 (Reclamation Wellton-Mohawk Irrigation System, Wasteway No. 1, Wellton-Mohawk Canal HAER No. AZ-68-F (page l 0) Figure 5. Float drums and gate drums on wasteway deck, October Wellton-Mohawk Irrigation System, Wasteway No. 1, Wellton-Mohawk Canal HAER No. AZ-68-F (page 11) Figure 6. Hoist mechanism for Wasteway No. 1, October Note shafts connecting the drums to the worm gear reducer.