Wellton-Mohawk Irrigation System, Pumping Plant No. 2, Bounded by Interstate 8 to south, Wellton

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

Pumping Plant No. 2 is located on the Wellton-Mohawk Canal, Wellton vicinity, Yuma County, Arizona. The facility is bounded by Interstate 8 to the south. The pumping plant lies within the NE 1/4 of the SW 1/4 of the SE 1/4 of Section 1, Township 9 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-B. 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 ca- nals 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.

2 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. 2 HAER No. AZ-68-B (page 2)

Physical History

See AZ-68-A for information pertaining to the physical history of Pumping Plant Nos. II. CONSTRUCTION OF PUMPING PLANT NOS. 1, 2, AND 3 Please refer to AZ-68-A for a chronology of construction and discussions of pumping-plant operations and modifications to the structures. III. ARCHITECTURAL AND ENGINEERING INFORMATION Pumping Plant No. 2, located on the Wellton-Mohawk Canal (Figure 1), is one of three pumping plants in a series that has a combined lift of about Of the three major pumping plants on the irrigation system, Pumping Plant No. 2 has the greatest lift, and the distance from the pumping plant to the discharge outlets is greater than that of its two counterparts.

Eight pumps (five indoor, three outdoor) lift water and dump the water back into the Wellton-Mohawk Canal through six discharge pipes. Like its two counter- parts, the plant structure consists of three levels: an intake level, a pump-room level, and a motor-room level. A wing adjacent to the motor room houses the control room that is used to operate and monitor the pumping units on-site. 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. A. Description of Intake Level The intake level lies below grade and is constructed of reinforced concrete. There are five intake struc- tures that allow water in the canal forebay to enter the plant 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 Wellton-Mohawk Irrigation System, Pumping Plant No. 2 HAER No. AZ-68-B (page 3) opening. Together, the five 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 north, south, and east 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 east 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. A drainage sump is located near the south wall of the subbasement structure. Ladders provide access to the subbasement. B. Description of Pump-Room Level The pump-room level lies below grade and is constructed of reinforced concrete. The floor is finished concrete. Five vertical-shaft, centrifugal-type pumps, manufactured by the Worthington Pump and Ma- chinery Company, are mounted on concrete support pedestals.

Each pump has a capacity of 252 cubic feet per second 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 five indoor units, Pumping Plant No. 2 has three vertical turbine-type pumping units adjacent to the forebay. Each unit is rated at 55 cfs and powered by a 750-horsepower electric motor.) There are two power-distribution cabinets along the west interior wall. Two concrete staircases-located along the west wall directly across from Units I and 5-lead to exterior doors that provide access to the operating deck above the intakes.

Immediately north 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 I is mounted on the floor adjacent to the concrete partition that separates the service-bay area from Unit I. Two ventilation fans associated with the evaporative-cooling system are located along the west wall of the service bay. There is a sump pump along the south 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 northeast corner of the plant structure, the other in the southeast corner. 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 seven pairs of steel columns along the length of the Wellton-Mohawk Irrigation System, Pumping Plant No. 2 HAER No. AZ-68-B (page 4) motor-room level. Six pairs are evenly spaced, set on center along the portion of the building that houses the 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 anchored to the steel columns and the ends of the secondary support beams.

Construction crews cast the walls on-site in sec- tions, 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 north side of the plant. Just inside the doors is the service bay, which measures about 43' x 30' in plan. The service bay flows uninterrupted into the area where the electric motors for Pump Units 1-5 lie in a line from north to south. Each synchronous pump motor is rated at hp. The Electric Machinery Manufacturing Com- pany of Minneapolis, Minnesota, built Units the Electric Products Company of Cleveland, Ohio, manufactured Units 4 and 5. All motors are original. There is a 30-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, 20-horsepower 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 south end of the motor-room floor.

The Crane Hoist Engineering Company manu- factured the crane assembly for (Dayton 1953:III). 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 In the WMIDD installed new switchgear, cabinets, supervisory control and data acquisition (SCADA) system upgrades, cable trays, and electrical conduit in the control room (Dewey and Macaluso Spare parts from the original equipment are kept in storage and used to repair the control-room equipment at Pumping Plant Nos.

1 and 3 (Kenneth Baughman, personal communication The wing that houses the control room is rectangular in plan and measures x A reinforced-concrete interior wall with double doors separates the control room from the service bay. The sash-type doors have a glazed upper section. A dropped ceiling with fluorescent lighting was added as part of the control-room renovation. The ceiling elements are suspended from the primary and secondary steel beams that support the original wood-plank roof deck. Wellton-Mohawk Irrigation System, Pumping Plant No. 2 HAER No. AZ-68-B (page 5) E. Description of Exterior, West Facade Metal trash racks cover the intake to the indoor pumping units and prevent plant matter and other debris from interfering with pumping operations. Unlike Pumping Plant No.

1, Pumping Plant No. 2 does not have a motor-operated trash rake, and the racks must be cleaned manually. Maintenance crews clean the trash racks from the operating deck above the intake to the indoor pumping units. 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. Eight windows are in use along the west facade, or intake side, of the plant superstructure.

There are five multipane, metal-frame industrial windows on the motor-room level and three windows of identical type on the pump-room level. Each window is high x wide. Five 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 west facade of the control-room wing. Each window measures high x wide. A small, louvered vent is in use on the west 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 five indoor pumping units, there are three outdoor, vertical turbine-type pumping units located beside the forebay near the south end of the pumping plant. Each outdoor unit has a capacity of 55 cfs and is powered by a electric motor. F. Description of Exterior, South Facade There is a single multipane, metal-frame window on the south 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 3' x 5'. There is a three-pane, metal-frame window on the south facade of the control-room wing that measures x ".

Wellton-Mohawk Irrigation System, Pumping Plant No. 2 HAER No. AZ-68-B (page 6) G. Description of Exterior, North Facade The main folding double doors on the north 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 approximately 3' x 5' louvered vent above the doors and below the roof line. On the west end of the north facade, there is a metal door with a glazed section that serves as an entrance to the control room. H. Description of Exterior, East Facade Along the east facade on the motor-room level are seven multipane, metal-frame industrial windows. The windows are high x wide. Five 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. 2, water is lifted from the canal forebay about 84' in elevation and then discharged into the afterbay. The afterbay section consists of six discharge channels: five for the discharge pipes con- nected to the indoor pumping units and one for the discharge pipe associated with the three outdoor, tur- bine-type pumps. A concrete deck with five 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 J. General Description of Plant Exterior The grade line around the plant superstructure varies. It generally slopes upward along the south elevation toward the outlet side. On the north side of the plant, the ground elevation is level with the motor-room floor to facilitate the transport of large equipment through the folding double doors.

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. Wellton-Mohawk Irrigation System, Pumping Plant No. 2 HAER No. AZ-68-B (page 7) K. Current Condition of Plant WMIDD employees perform routine maintenance and cleaning at Pumping Plant No. 2. 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 concrete structure is in satisfactory condition. IV. REFERENCES CITED Bureau of Reclamation (Reclamation) 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. Dayton, Marshall 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, 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. 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. 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. 2 HAER No. AZ-68-B (page 8) Figure 1. Project location Ligurta, Arizona, 7.5-minute USGS quadrangle).