Wellton-Mohawk Irrigation System, Pumping Plant No. 1, Bounded by Gila River & Union Pacific Railroad, Wellton

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

Pumping Plant No. 1 is located on the Wellton-Mohawk Canal, Wellton vicinity, Yuma County, Arizona. The plant is bounded by the Gila River to the east and the Union Pacific Railroad to the west. The pumping plant lies within the SE 114 of the NW 1/4 of the SW 114 of Section 21, Township 8 South, Range 20 West, on the Ligurta, Arizona, 7.5-minute U.S. Geological Survey (USGS) quadrangle. Universal Transverse Mercator Coordinates: Zone 11, N E

Source document Quoted word for word from HAER AZ-68-A. 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. The Wellton-Mohawk Canal was the first of several main canals constructed in association with the Wellton-Mohawk Division of the Gila Project. Engineers with the U.S. Department of the Interior, Bureau of Reclama- tion designed the gravity-fed system to carry water up the Gila River valley, op- posite the river's flow. This required the construction of three pumping plants along the Wellton-Mohawk Canal to lift the water approximately Pumping Plant No.

1 is an integral part of the Wellton-Mohawk irrigation system and is eligible for listing in the National Register of Historic Places under Criteria a and c (Thompson and Sterner It is eligible under Criterion a for its role in regulating the flow of Colorado River water in the canals for distribution to lands under cultivation. The pumping plant is a major feature on the system and is sig- nificant under Criterion c for its design and operational characteristics. Report Prepared by: Scott Thompson, Senior Historian Statistical Research, Inc. Tucson, Arizona Date: September Wellton-Mohawk Irrigation System, Pumping Plant No. 1 HAER No. AZ-68-A (page 2)

Physical History

Pumping Plant Nos. 1, 2, and 3 are located on the Wellton-Mohawk Canal. Each plant is similar in design and construction and consists of a reinforced-concrete superstructure that houses several centrifugal-type pumping units. The information in this section pertains to the physical history of Pumping Plant Nos. 1, 2, and3. A. Date of Erection Construction of Pumping Plant Nos. 1-3 began in February and all work was completed and ac- cepted on April 24, The pumping plants began service shortly after that. B. Architect The Office of the Chief Engineer, Bureau of Reclamation, Denver, Colorado, designed the three pumping plants (Dayton C. Original Owner The U.S. Department of the Interior, Bureau of Reclamation (Reclamation) owns Pumping Plant Nos. D.

Original and Subsequent Occupants In October Reclamation transferred operation and maintenance of the pumping plants to the Wel- lton-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 (Beck et al. 1960:Appendix XI:2). E. Builder On November 9, United Concrete Pipe Corporation of Baldwin Park, California, was awarded the general contract to construct Pumping Plant Nos. Notice to proceed with the contract was issued on December 28, The following companies acted as subcontractors on the project: Casey and Case Contracting Company of Los Angeles, California, installed 251 cast-in-place concrete piles for the foun- dation of Pumping Plant No.

3; Allison Steel Corporation of Phoenix, Arizona, fabricated and erected the structural steel used to construct the pumping plants; Asbestos Engineering and Supply Company placed the roofing on the three plants; and Montgomery Company, Inc., installed all of the permanent Wellton-Mohawk Irrigation System, Pumping Plant No. 1 HAER No. AZ-68-A (page 3) mechanical equipment (e.g., electrical wiring, pump motors, pumps, ventilating systems). Reclamation awarded contracts for the pumps and pump motors to the following companies: Worthington Pump and Machinery Company of Harrison, New Jersey, manufactured the vertical-shaft, centrifugal pumps in- stalled at each plant; Electric Products Company of Cleveland, Ohio, built the synchronous motors for Pumping Plant Nos.

1 and 3; and Electric Machinery Manufacturing Company of Minneapolis, Minne- sota, supplied the motors for Pumping Plant No. 2 (Dayton F. Original Plans and Construction The original architectural and engineering drawings for Pumping Plant Nos. 1-3 were produced by Rec- lamation's Office of the Chief Engineer, Denver, Colorado. Dates on the drawings range from June to December United Concrete Pipe Corporation of Baldwin Park, California, was awarded a con- tract for to construct Pumping Plant Nos. II. CONSTRUCTION OF PUMPING PLANT NOS. 1, 2, AND 3 The Wellton-Mohawk irrigation system is a significant engineering achievement with its miles of canals and laterals, pumping plants, and appurtenant structures that regulate the delivery of water and protect system components.

Reclamation engineers designed the system to carry water up the Gila River valley for final delivery to individual farms. The system can best be described as gravity fed, using large and small pumping stations only when elevation corrections are necessary. Pumping Plant Nos. located approximately 5 miles apart on the Wellton-Mohawk Canal, are major features of the system and regulate the flow of Colorado River water in the canals for distribution to farms in the division. They have a com- bined lift of about and are designed to supply a peak demand of cubic feet per second (Dayton The pumping plants are virtually identical in construction and operation, the main dif- ference being the number of pumps at each plant.

Each plant has an accompanying electrical substation to maintain a constant source of power to the system. Water is discharged at the new canal level through a discharge pipe. Each pipe is associated with an individual pump. The number of pumps discharging water at any given time is dependent on the volume of delivery required downstream. A.

Chronology of Construction During calendar year Reclamation conducted preconstruction surveys for canal structures of the Wellton-Mohawk Division of the Gila Project (including laterals, floodways, protective dikes, and drain- age features) and investigated borrow areas for compacted-earth lining and sources of concrete aggregates (Reclamation Construction of the Wellton-Mohawk Canal began in September and all work was completed and accepted by Reclamation on April 25, The Fisher Contracting Com- pany of Phoenix, Arizona, completed the canal to Pumping Plant No. 1, and the Morrison-Knudsen Com- pany, Inc., of Los Angeles, California, constructed the Wellton-Mohawk Canal and all associated struc- tures downstream of Pumping Plant No. 1 to Pumping Plant No.

3 (Reclamation :7, Wellton-Mohawk Irrigation System, Pumping Plant No. 1 HAER No. AZ-68-A (page 4) Concomitant to the construction of the Wellton-Mohawk Canal, the United Concrete Pipe Corporation of Baldwin Park, California, was awarded the contract for the construction of Pumping Plant Nos. Field operations commenced on January 25, and all work under the contract was completed on April 24, (Reclamation 1952a:7). Construction operations were headquartered at a temporary con- struction camp located at Ligurta, a former railroad siding on the Southern Pacific Railroad (now Union Pacific Railroad).

The camp consisted of an office for the supervisory personnel, a maintenance garage, a carpenter shop, a storage building, and a cleared area for storing equipment and materials (Dayton Concrete for the project was obtained from the concrete batching plant operated by the Morrison-Knud- sen Company, Inc., for construction of the Wellton-Mohawk Canal. The contractor set up an aggregate processing plant and concrete batching plant in the Little Ligurta Wash in the SW 114 of Section 7, Town- ship 9 South, Range 19 West, on the Ligurta, Arizona, 7.5-minute U.S. Geological Survey (USGS) quadrangle (Dayton Because Pumping Plant Nos.

1-3 are very similar in terms of design and construction, the contractor es- tablished the following procedure for constructing the three plants: An operation was started at Pumping Plant #1 and as soon as completed, the men and equipment were moved to Pumping Plant #2 and the same operation completed and then on to Pumping Plant #3. As soon as the first operation (excavating for pump house site) was completed at Pumping Plant #1, the second operation started (setting forms for cut- off walls). The steel gang placed the reinforcement steel, the carpenters the forms, the forms were checked for line, grade, cut-outs, etc. and then the concrete crew placed the concrete. As each gang finished it's [sic] part of the work, they progressed to the next pumping plant and so on [Dayton 1953:1a-lb].

The contractor began excavating operations at Pumping Plant No. 1 on February 15, Excavation at Pumping Plant Nos. 2 and 3 commenced in March. Following the structure excavation, the contractor placed the substructure concrete at each site (Figure 1). The foundations for Pumping Plant Nos. I and 2 were placed on original material consisting of sand and gravel. However, test bores conducted by Recla- mation revealed that the Pumping Plant No. 3 site was undermined with expansive clay layers. To mini- mize the possibility of ground heaving, Reclamation issued a change order for the construction of 251 cast-in-place, reinforced-concrete piles to serve as the foundation for Pumping Plant No. 3.

Casey and Case Contracting Company, of Los Angeles, California, installed the concrete piles under subcontract to the United Concrete Pipe Corporation (Figure 2). Workers placed a layer of loose gravel around the piles. Steel reinforcement bars that extend from the tips of the piles were then anchored into the concrete base slab (Dayton 5a, Upon completion of the plant foundations, workers proceeded to construct the intakes, discharge pipes, afterbay structures, and superstructures at the three plants (Figures 3 and 4). United Concrete Pipe Corpo- ration, the general contractor, fabricated the 72" reinforced-concrete discharge pipes for the pumping plants at its concrete plant in Baldwin Park, California (Dayton (Figure 5).

The discharge pipes are connected to the pumping units and extend underground from the plant building to the afterbay structure. Each discharge pipe outlet is fitted with a 72"-diameter, steel flap gate that closes when the pump unit is off to prevent a reverse flow of water into the pump from the canal. The flap gate is designed to auto- matically swing open when the pump fills the discharge pipe with water. A hydraulic gate-check cylinder located atop the afterbay structure (Figure 6) is linked to the flap gate and prevents the gate from Wellton-Mohawk Irrigation System, Pumping Plant No. 1 HAER No.

AZ-68-A (page 5) slamming when the pump shuts off (Reclamation The number of hydraulic gate-check cylinders at each afterbay structure corresponds to the number of discharge pipes with flap gates. By the end of the plant buildings were virtually complete with the main pumps and motors in place and the installation of power and control circuits in progress (Reclamation :8) (Figures 7 and 8). On April 24, Reclamation accepted all work on Pumping Plant Nos. 1-3 (Dayton 1953:vi). The plants became operational soon after that. B. Pumping Plant Operations Reclamation engineers designed the pumping plants for "normally unattended operation" (Dayton 3).

When the pumping plants went into operation, the remote control point was located at the Gila Sub- station, near the terminus of the Gila Gravity Main Canal, approximately 13 miles west of Pumping Plant No. 2 (Section 1, Township 9 South, Range 22 West, Gila and Salt River Baseline and Meridian, on the Fortuna, Arizona, 7.5-minute USGS quadrangle [photorevised From this station, an operator could control water levels and plant operations. Float switches in the canal (immediately upstream from the plants) "automatically shut down one or more plants for high or low water levels in any of the canal sections" (Reclamation At present, the WMIDD operates the three pumping plants remotely from its headquarters in Wellton using a supervisory control and data acquisition (SCADA) system.

The SCADA system allows the remote plant operator to monitor canal elevations on the intake and discharge sides of the pumping plants, to start and stop the pumping units, to monitor running pumps for temper- ature and rate of flow, and to control the regulating valve in Pump Unit 1 at each plant (Dewey and Macaluso All of the pumping units at the plants can be operated on-site (Kenneth Baughman, personal communication Starting any of the indoor pumping units requires a vacuum priming pump, no matter if the plants are operated on-site or remotely. A single vacuum priming pump is located near the Unit l pump at each plant. The priming pump draws the air out of the idle unit's empty draft tube, scroll cage, and discharge line.

The resulting vacuum pressure raises the water level in the draft tube and pumping chamber from the static level in the canal forebay to about mid level on the pumping chamber im- peller. The raised water level then contacts an electrically-operated float switch on the pump casing which allows the unit motor to start [Dewey and Macaluso The vacuum priming pumps at the three plants are original (Kenneth Baughman, personal communication Pump Unit 1 at each plant has a SCADA-operated throttling valve.

This valve can reduce the dis- charge capacity of Pump Unit 1 by up to 50 percent and serves to regulate the plant discharge to meet downstream water demands (Dewey and Macaluso Immediately downstream from the afterbay structure at each pumping plant is a water stage float well, or stilling well, for collecting canal water surface readings. The stilling wells contain SCADA devices for monitoring discharge rates at each pumping plant. Wellton-Mohawk Irrigation System, Pumping Plant No. 1 HAER No. AZ-68-A (page 6) Electricity for powering the pumping plants and other operations on the irrigation system is supplied by Reclamation's power plants at Parker Dam and Davis Dam on the Colorado River (Reclamation 1953a:5). A 34.5-kilovolt switchyard was constructed adjacent to Pumping Plant No.

2 for distributing power to the three pumping plants. Separate transformers were installed at each pumping plant (Dayton At present, the pumping units and major equipment at Pumping Plant Nos. 1-3 receive power through an on- site transformer/switchyard adjacent to each plant. Should the power supply be interrupted, an auxiliary transformer and lead-acid batteries (located on the pump-room level at each plant) will provide direct current power for emergency lighting and the communications and control equipment (Dewey and Macaluso C. Additions and Alterations On August 12, heavy rains produced flood conditions, causing runoff to breach the protective dikes, to flow into the Wellton-Mohawk Canal, and then to flood the pump room of Pumping Plant No. 2.

The flood forced the emergency shut down of the plant. Within 72 hours, however, the damage had been re- paired, and water was delivered to the downstream section of the canal. The water entered through two large, louvered vents on the intake side of the control room wing. To prevent similar incidents in the future, the WMIDD constructed a concrete flood protection wall around the vent openings (Black and Cash Pumping Plant Nos. 1-3 were designed to employ six, five, and four pumping units, respectively. When the plants began operations in only Units 1-4 had been installed in Pumping Plant No. 1, and Pumping Plant Nos. 2 and 3 were equipped with Units During construction, workers laid discharge pipes and provided space for the additional units (see Figure 3).

In September Reclamation installed the remaining pumps and motors at each plant (Dewey Around the WMIDD installed a spillback in the afterbay of each pumping plant as part of the ca- pacity control system. The spillback regulates discharge by redirecting excess water to the forebay by means of an underground return bypass. A concrete box, offset from the spillback inlet, contains a gate for regulating the return flow of water into the forebay (Beck et al. 1960:Appendix XI:3-4). As originally constructed, the plants had two ventilation fans on the pump-room level to circulate air through ducts in the subbasement. In addition, louvered vents on the upper facades of .each plant were designed as a natural cooling system.

However, during the hot summer months the vents and fans proved ineffective in lowering the temperature inside the plants. In WMIDD maintenance crews installed large evaporative coolers to improve the cooling system at each plant. The evaporative-cooling units are . located on the intake side of each plant, adjacent to the control room wing (Figure 9). They draw air into the subbasement level that then flows, via grates, into the pump room and motor-room levels to cool the pumps and motors (Austin and Steele (Note: The flood protection wall at Pumping Plant No.

2, constructed in was removed to accommodate this new cooling system.) In WMIDD per- sonnel removed the corroded, sheet-metal duct work for the evaporative coolers and installed black, cor- rugated, high-density-polyethylene plastic pipe (Dewey and Macaluso Wellton-Mohawk Irrigation System, Pumping Plant No. 1 HAER No. AZ-68-A (page 7) Beginning in the WMIDD embarked on a program to increase the number of pumps at the three plants to regulate the discharge more effectively. At Pumping Plant No. 3, three outdoor, vertical turbine- type pumping units were installed beside the forebay (Goddard and Yocom 1972:Appendix VI:3).

The turbine pumps pull water from the canal forebay and deliver it to the canal afterbay through a single, buried 60"-diameter discharge pipe (Dewey The discharge-pipe outlet is adjacent to the original afterbay structure. Outdoor regulatory pumping units at the other two plants were installed and operable by April (McEwan and Hunter 1975:Appendix IV:2) (Figure The outdoor pumping units elim- inate any spillback, thus obviating the need for a spillback system. Once the regulatory pumps were in- stalled, the WMIDD closed the spillback gates at each of the plants (Kenneth Baughman, personal com- munication In the WMIDD installed air-conditioning units in the plant control rooms (Robertson In the WMIDD rehabilitated and reconstructed the electrical switchyards at each pumping plant.

This included the installation of a new power transformer at each site. Pumping Plant No. I receives an uninterrupted supply of power from the adjacent transformer/switchyard through a buried transmission line. Overhead transmission lines between the switchyards and plant structures provide power to Pumping Plant Nos. 2 and 3. The following year, the WMIDD modernized Pumping Plant No. 2 for more-efficient operation and maintenance by retrofitting the control room with new switchgear, cabinets, cable trays, electrical conduit, and SCADA system upgrades (Dewey and Macaluso 7). III. ARCHITECTURAL AND ENGINEERING INFORMATION Pumping Plant No.

I, located on the Wellton-Mohawk Canal (Figure is one of three pumping plants in a series that has a combined lift of about The plant is similar to its counterparts in both plan and construction. Each plant structure consists of three levels: an intake level, a pump-room level, and a motor-room level. A control room for operating and monitoring the pumping units on-site is housed in a wing adjacent to the motor room. The pumping plant is a concrete structure with a generally L-shaped plan. The two uppermost levels of the plant measure x in plan with a wing that forms an "L" that measures x The intake level, or substructure, measures x The lower structures that lie below grade are constructed of reinforced concrete.

The superstructure, which makes up the motor-room level, is constructed of structural steel framing with reinforced-concrete walls. As originally constructed, the roof consisted of a wood plank decking, overlaid with insulation board and topped with four-ply, coal-tar-felt built-up roofing (Dayton As part of the periodic maintenance schedule, WMIDD workers have replaced the outer layer with modern roll-roofing material (Kenneth Baughman, personal communication The following sections describe the plant interior and exterior. Wellton-Mohawk Irrigation System, Pumping Plant No. 1 HAER No. AZ-68-A (page 8) A. Description of Intake Level The intake level lies below grade and is constructed of reinforced concrete.

There are six intake structures through which water in the canal forebay enters the system. The number of intakes corresponds to the number of pumping units in the plant. A 24"-wide concrete pier stands in the center of each intake opening. Together, the six piers support the pump-room floor above. Precast-concrete suction tubes with 90 bends extend from the rear of the intake structures to allow water to be drawn up by the pumps. Surrounding the intake structures on the south, east, and west are a series of compartments with rein- forced-concrete interior walls and concrete floors. The compartments are connected by openings and are known collectively as the subbasement.

The compartment along the south wall serves as an air duct for transferring conditioned air from the evaporative-cooling system to the pump and motor rooms via floor grates. The subbasement floors are sloped to allow collected water to flow into floor drains. Two drainage sumps are located near the west wall of the subbasement structure. Maintenance personnel use ladders that extend downward from the pump-room level to access the subbasement. B. Description of Pump-Room Level The pump-room level lies below grade and is constructed of reinforced concrete. Six vertical-shaft, cen- trifugal-type pumps, manufactured by the Worthington Pump and Machinery Company, are mounted on concrete support pedestals.

Each pump has a capacity of 224 cfs and is connected to a discharge pipe that conveys water to the afterbay. The pumps are separated by load-bearing, reinforced-concrete partitions that extend from the floor to the ceiling. (Note: In addition to the six indoor units, Pumping Plant No. 1 has three outdoor, vertical turbine-type pumping units. Each of the outdoor units is powered by a horsepower electric motor and has a capacity of 55 There are two power distribution cabinets along the north interior wall. Two concrete staircases-located along the north wall directly across from Units 1 and 6-lead to exterior doors that provide access to the operating deck above the intakes.

Immediately east of the pumps is the service-bay area that houses a battery bank and transformer that supply direct current power to the control equipment and emergency lighting. The vacuum pump for Priming Unit 1 is mounted on the floor adjacent to the concrete partition that separates the service-bay area from Unit 1. Two ventilation fans associated with the evaporative-cooling system are located along the north wall of the service bay. There is a sump pump along the west wall on this level for pumping water from the subbasement to the forebay. Access between the pump-room and motor-room levels is by way of two concrete stairways: one is lo- cated in the southeast comer of the plant structure, the other in the southwest comer. Wellton-Mohawk Irrigation System, Pumping Plant No.

1 HAER No. AZ-68-A (page 9) C. Description of Motor-Room Level The motor-room level sits above grade and has a steel-frame construction with precast, reinforced-con- crete walls. The floor is finished concrete. There are eight pairs of steel columns along the length of the motor-room level. Seven pairs are evenly spaced, set on center along the section of the building that houses the electric motors. Each pair of columns supports a steel I-beam. These primary beams join smaller, steel secondary beams that run perpendicular to the larger beams. The primary and secondary beams support the wood-plank roof deck. The reinforced-concrete walls of the superstructure are an- chored to the steel columns and the ends of the secondary support beams.

Construction crews cast the walls on-site in sections, raised them into place, then anchored them to the steel frame. The main entrance to the motor room is through the large, folding double doors on the east side of the plant. Just inside the doors is the service bay, which measures about 40' x 30' in plan. The service bay flows uninterrupted into the area where the electric motors for Pump Units 1-6 lie in a line from east to west. Each motor is rated at 1, 100 hp. The Electric Products Company of Cleveland, Ohio, manufactured the motors in use at Pumping Plant No. 1. All motors are original. There is a 15-ton overhead traveling crane capable of lifting a fully assembled pump motor. Maintenance crews use the crane for removing a motor when servicing a pump.

The crane operates on a runway above the motor floor that travels the length of the motor room. Two steel beams, each running the length of the building and attached to the steel columns, provide support and act as a track for the crane bridge. The trolley hoist has a variable-speed, motor and has a hook travel of The trolley is driven by a motor. A separate motor drives the crane bridge along the runway. Crane operation is controlled from the floor using pendant cords suspended from the controllers. A walkway runs the entire length of the bridge, providing access to the drive mechanism and trolley. The walkway is accessible from a ladder located at the west end of the motor-room floor. Cyclops Iron Works manufactured the crane assembly for (Dayton 1953:IV). D.

Description of Control Room The control room is located off the motor room in the wing portion of the superstructure and contains the switchgear for operating the pumps and motors and other equipment for providing instrumentation and metering data (Dayton The wing that houses the control room is rectangular in plan and mea- sures 41 x A reinforced-concrete interior wall with double doors separates the control room from the service bay. The doors are sash type with a glazed upper section. Two steel I-beams, each about 16' long, are attached to the north and south interior walls of the control room just beneath the ceiling. Shorter lengths of steel I-beams are bolted perpendicularly to the primary beams to form a grid that sup- ports the wood-plank roof deck.

Banks of metal cabinets contain the switchgear for controlling the pumping units. The switchgear in Pumping Plant No. 1 is original, augmented by spare parts from the equipment removed from Pumping Wellton-Mohawk Irrigation System, Pumping Plant No. 1 HAER No. AZ-68-A (page 10) Plant No. 2, which was replaced with new equipment in (Kenneth Baughman, personal communica- tion E. Description of Exterior, North Facade Metal trash racks cover the intake to the indoor pumping units and prevent plant matter and other debris from interfering with pumping operations. Pumping Plant No. 1 is outfitted with a trash-rack rake and hoist on the intake side of the structure. The rake is used to keep the trash rack clear of debris that would otherwise restrict the flow of water through the intake.

(Although each plant has trash racks on the intake side, only Pumping Plant No. 1 is equipped with a trash rake and hoist mechanism.) A motor-op- erated, geared trolley hoist attached to the bottom flange of a 12" I-beam handles the rake. The I-beam is attached to the superstructure below the motor room windows (see below). The rake, which consists of a series of metal teeth, functions by rolling down the face of the trash rack "with the teeth turned parallel with the rack, thus overriding any obstacle. At the moment of pull up, they rotate, penetrating into the trash rack; they rake it clean on the upward movement, carrying the trash up to a position on the apron of the trash rack where the rake can be unloaded" (Reclamation ).

Stop-log slots, covered by metal grates, are found on the concrete operating deck above the trash racks. As originally designed, 6" x 6" timber stop logs were used to seal off the pump suction tube opening when a pumping unit was taken out of service for maintenance, repair, or inspection. In the the WMIDD fabricated aluminum stop logs resembling large doors to block the flow of water into the suction tube openings (Mages et al. Ten windows are in use along the north facade, or intake side, of the plant superstructure. There are six multipane, metal-frame industrial windows on the motor-room level and four windows of identical type on the pump-room level. Each window is high x wide. Six louvered vents, each of which measures about 2' x 2', are in place directly beneath the roof line.

There are two entrances to the pump room, one on either side of the industrial windows. Exterior access to these doors is by means of a concrete operating deck above the trash racks. There are three three-pane, metal-frame windows on the north facade of the control room wing. Each window measures high x wide. A small, louvered vent is in use on the north facade of the control-room wing, at the pump- room level. The two large, louvered vents located above the grade line on the control-room wing are now part of the evaporative-cooling system and are no longer visible. In addition to the six indoor pumping units, there are three outdoor, vertical turbine-type pumping units located beside the forebay near the west end of the pumping plant.

Each outdoor unit has a capacity of 55 cfs and is powered by a electric motor. Wellton-Mohawk Irrigation System, Pumping Plant No. 1 HAER No. AZ-68-A (page 11) F. Description of Exterior, West Facade There is a single multipane, metal-frame window on the west facade of the superstructure at the motor- room level. The window measures x A louvered vent is in place above the window and just below the roof line. The vent is about 2' x 2'. There is a three-pane, metal-frame window on the west facade of the control-room wing that measures x G. Description of Exterior, East Facade The main folding double doors on the east facade of the plant provide access to the motor-room level and are made of metal, with a divided, glazed section. Each door is high x wide.

There is an ap- proximately 2' x 2' louvered vent above the doors and below the roof line. On the north end of the east facade there is a metal door with a glazed section that serves as an entrance to the control room. H. Description of Exterior, South Facade Along the south facade on the motor-room level are eight multipane, metal-frame industrial windows. The windows are high x wide. Six louvered vents are in use and are positioned high on the ex- terior wall just below the roof. Each vent measures approximately 2' x 2'. I. Description of Afterbay Section At Pumping Plant No. 1, water is lifted from the canal forebay about 31' in elevation and then discharged into the afterbay.

The afterbay section consists of seven discharge channels: six for the discharge pipes connected to the indoor pumping units and one for the discharge pipe associated with the three outdoor, turbine-type pumps. A concrete deck with six hydraulic gate-check cylinders sits atop the discharge chan- nels. Each hydraulic gate-check is linked to a flap gate and prevents the flap gate from slamming shut when the pump corresponding to that discharge pipe is not in operation. Stop-log grooves, covered by metal grates, are found on the concrete deck of the afterbay structure. Ini- tially, WMIDD personnel used 6" x 6" timber stop logs to seal off the discharge openings in the afterbay structure so that they could service the flap gates.

Beginning in the the WMIDD fabricated alu- minum stop logs resembling large doors to block the flow of water, allowing maintenance crews to ser- vice a flap gate while the others are in operation (Mages et al. Reclamation Wellton-Mohawk Irrigation System, Pumping Plant No. 1 HAER No. AZ-68-A (page 12) J. General Description of Plant Exterior The grade line around the plant superstructure varies. It generally slopes upward along the west elevation toward the outlet side. On the east side of the plant, the ground elevation is level with the motor-room floor. The service yard around the pumping plant has a bituminous surface and the side slopes are sparsely covered with desert vegetation to minimize the effects of erosion. K.

Current Condition of Plant WMIDD employees perform routine maintenance and cleaning at Pumping Plant No. 1. The interior and exterior are well maintained and in good condition. The plant has been in service for over 50 years, and the concrete structures (e.g., walls and floors) show signs of normal surface deterioration. Nevertheless, the overall condition of the concrete structure appears to be satisfactory. IV. REFERENCES CITED Austin, R. D., and T. L. Steele Review of Maintenance Pro gram, Irrigation Structures and Facilities. U.S. Department of the Interior, Bureau of Reclamation, Boulder City, Nevada. Beck, M. E. Day, and Fred Engstrom Condition of Major Irrigation Structures and Facilities, Region 3, U.S.

Department of the Interior, Bureau of Reclamation, Office of Assistant Commissioner and Chief Engineer, Denver. Black, C. M., and N. W. Cash Condition of Major Irrigation Structures and Facilities, Yuma, Gila and Parker-Davis Proj- ects, Region 3, U.S. Department of the Interior, Bureau of Reclamation, Denver. Bureau of Reclamation (Reclamation) 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. Annual Project History, Gila Project, Yuma, Arizona, Vol. XV. U.S. Department of the Interior, Bureau of Reclamation, Denver. 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. Wellton-Mohawk Irrigation System, Pumping Plant No; 1 HAER No. AZ-68-A (page 13) 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. Wellton-Mohawk Pumping Plants No. 1, 2, and 3 and Switchyards, Designers' Operating Criteria, Gila Project. U.S. Department of the Interior, Bureau of Reclamation, Design and Construction Division, Denver. Gila Project. U.S. Department of Interior, Bureau of Reclamation, Boulder City, Nevada. Pamphlet on file, Arizona State Library, Archives, and Public Records, Phoenix.

Dayton, Marshall Unit Record of Construction on Earthwork, Tunnel, Canal Lining, and Structures, Wellton- Mohawk Canal Station to Station Specifications No. Wellton-Mo- hawk Division, Gila Project, Arizona. U.S. Department of the Interior, Bureau of Recla- mation, Lower Colorado River District, Yuma, Arizona. On file, Bureau of Reclamation, Yuma Projects Office, Yuma, Arizona. Unit Record of Construction of the Wellton-Mohawk Pumping Plants Nos. 1, 2, and 3, Spec- ifications 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.

Dewey, Timothy Review of Operation and Maintenance Program, Examination Report, Wellton-Mo- hawk Pumping Plants, Wellton-Mohawk Division, Gila Project, Arizona. U.S. Department of the Interior, Bureau of Reclamation, Lower Colorado Regional Office, Boulder City, Nevada. Dewey, Timothy, and Frank Macaluso Examination Report, Review of Operation and Maintenance, Wellton-Mohawk Pumping Plants, Gila Project, Wellton-Mohawk Irrigation and Drainage District, Arizona, Lower Colorado Region. U.S. Department of the Interior, Bureau of Reclamation, Lower Colorado Regional Office, Boulder City, Nevada. Goddard, T. W., and L. J. Yocom Condition of Major Water System Structures and Facilities, Region 3. U.S.

Department of the Interior, Bureau of Reclamation, Office of Design and Construction Engineering and Re- search Center, Denver. Mages, C. B., T. R. Haider, and L. J. Yocom Review of Maintenance Program, Examination Report, Wellton-Mohawk Pumping Facilities. U.S. Department of the Interior, Bureau of Reclamation, Denver. McEwan, John S., and Frank A. Hunter Review of Maintenance Program, Irrigation Structures and Facilities. U.S. Department of the Interior, Bureau of Reclamation, Lower Colorado Region, Boulder City, Nevada. Wellton-Mohawk Irrigation System, Pumping Plant No. 1 HAER No. AZ-68-A (page 14) Robertson, James Review of Operation and Maintenance Program, Examination Report, Wellton-Mohawk Pumping Plants. U.S. Department of the Interior, Bureau of Reclamation, Denver.

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, Pumping Plant No. 1 HAER No. AZ-68-A (page 15) Figure 1. Workers placing reinforcement steel in base slabs of Pumping Plant No. 1, May 24, (photograph courtesy of Reclamation). Wellton-Mohawk Irrigation System, Pumping Plant No. I HAER No. AZ-68-A (page 16) Figure 2. View of Pumping Plant No. 3 foundation site, showing completion of cast-in-place concrete piles, August 11, (photograph courtesy of Reclamation). Wellton-Mohawk Irrigation System, Pumping Plant No. 1 HAER No. AZ-68-A (page 17) LO en M' C\I ~ (ti ... :I ..0 Q) LL ""' I/) Q) c.. c..

Q) (ti ..c -- "C Q) 0 c: C\I ci z c: (ti c. - C'l (ti c: E c.~ E cc~ :I c. - -( t i > 0- 0 ~ .52 t:: - E :Io 0 0 ..c ... c.. .sL c, 0 ct! 0 Eo -0 ..c c.. c: - 0 Q) I/) > (ti ..0 I Q) ~ Q) I/) -I /) ... E -0 C'l c: ~Q) w ... cv:i ~ :I C'l u:: Wellton-Mohawk Irrigation System, Pumping Plant No. I HAER No. AZ-68-A (page 18) Figure 4. Erecting forms for outlet-transition wing walls at Pumping Plant No. 2, September 18, (photograph courtesy of Reclamation). Wellton-Mohawk Irrigation System, Pumping Plant No. 1 HAER No. AZ-68-A (page 19) LO ~ >. ttl :a: "O c: ::I Cl ~ -0 c: IJ) c.C a.: ,S: ... 0 ttl .c: >. 0 - IJ) Cl> "O t:: -0 ::I 0 IJ) 0 ]! ' . '5 r: 0 Cl M' .S .o 0 .c: z a. c: 1 c: 0 . +:: a. ttl oi E c: a. al E er: ::I'-" I - a.

0 c: 0 +:: 0 ::I IJ) c: 0 (.) LC) Cl> ::I Cl u::: Wellton-Mohawk Irrigation System, Pumping Plant No. 1 HAER No. AZ-68-A (page 20) Figure 6. Discharge area of Pumping Plant No. 1 with hydraulic gate-check cylinders on top of afterbay structure, October Wellton-Mohawk Irrigation System, Pumping Plant No. 1 HAER No. AZ-68-A (page 21) I/) O'> 0 N > "3 c: 0 0 0 () Cl> c. a: Cl> ~CJ c: 0 () "C Cl> c: ::> .0 > "C Cl> E 0 't: Cl> c. ~ 0 :s: 0 z c: C\l a. Cl c: c. E ::I a. C\l ::I ::I Cl> c. ::I (/) "C Cl> ~ c. E 0 () ::I Cl u::: Wellton-Mohawk Irrigation System, Pumping Plant No. 1 HAER No. AZ-68-A (page 22) Figure 8. Electric motors for powering the pumps at Pumping Plant No. 2, October 23, (Reclamation photograph courtesy of WMIDD). Wellton-Mohawk Irrigation System, Pumping Plant No. I HAER No.

AZ-68-A (page 23) Q) "O Q) $9 c: c: 0 Cl c: ~ E . 0 0 0 ,_ 0 N 0,_ ..c c: 0 0 CJ CJ ....oO- C') c: . 0 ._ Q) ~z "O 2 a: - Cl c: c: :I - Cl 0. c: E =:I 0 a.. 0 CJ I Q) > ,_ 0 0. > w a) ,_ Q) :I C') u::: Wellton-Mohawk Irrigation System, Pumping Plant No. I HAER No. AZ-68-A (page 24) i.ri 0 0 ... N cu -- ..c 0 0 ( .) 0 -a: z c: co Cl c: o.. E ::i a. co ~ co >- co ..c ~ -0 cu - cu "O u; cu ..c IJ) c: ::i Cl o..c: E ::i a. - 0 "O ::i 0 ci ~ ::i Cl ii: Wellton-Mohawk Irrigation System, Pumping Plant No. I HAER No. AZ-68-A (page 25) 'P - "" .t, \, " ~" . ; :i ~ :'1 ~ \. ._; . \\. We.II I L .. ---;(iils I ( I i,. I ~7 i \_ I& ' j / ' Figure 11. Project location Ligurta, Arizona, 7.5-minute USGS quadrangle).