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Phoenix, AZ, United States

Geisbush J.,Central Arizona Project
Pipelines 2015: Recent Advances in Underground Pipeline Engineering and Construction - Proceedings of the Pipelines 2015 Conference | Year: 2015

The Central Arizona Project (CAP) operates and maintains three (3) 21-foot diameter pre-stressed concrete non-cylinder pipes (PCP) as part of the aqueduct system that delivers almost 1,950 million gallons of Colorado River water per day, to Maricopa, Pinal, and Pima Counties in central and southern Arizona. The pipelines, installed in the late 1970's, have experienced pre-stressing wire breaks and have been repaired several times since the early 1990's. The wires have broken primarily due to defects in the wire. One of the pipes, the Centennial Wash Siphon, conveys water beneath Interstate-10 and the Centennial Wash, about 80 miles west of Phoenix, AZ. The siphon is upstream of CAP's first customer turnout, and as such is critical in the aqueduct's conveyance and delivery system. An internal electromagnetic inspection in January 2013 discovered several pieces of the pipe comprising the siphon had many broken prestressing wires, prompting a closer inspection and assessment of the siphon. The case study described herein examines inspections, assessment, monitoring, and subsequent repair using post-tension tendons of the Centennial Wash Siphon. This paper further discusses the ongoing efforts of monitoring, assessing, repairing, and maintenance practices for the largest prestressed concrete pipes in the world. A brief history of the siphons includes manufacturing of the 252-inch diameter prestressed concrete pipes, installation of the pipelines, and early investigations and repairs. The focus of this paper is on the assessment and monitoring since the last repairs in 2006, specifically newer technologies that have emerged to assist CAP in monitoring and making decisions in the repair methods and locations. Relevant points include a discussion on the excavation of the pipes requiring repair, the repair work (post-tension tendons), and maintenance practices. A brief discussion will follow on new technology recently installed in all three of CAP's prestressed concrete siphons. © 2015 ASCE. Source

Rodrigues D.B.B.,University of Sao Paulo | Gupta H.V.,University of Arizona | Serrat-Capdevila A.,University of Arizona | Oliveira P.T.S.,University of Sao Paulo | And 3 more authors.
Journal of Water Resources Planning and Management | Year: 2014

The United States and Brazil both deal with water-related problems associated with being large territorial areas having uneven distribution of water resources and population. Water transfer projects have been widely considered to be feasible solutions to the mitigation of local water shortages. This paper contrasts American and Brazilian water allocation systems and water transfer projects, located in the Colorado and Piracicaba River basins, seeking potential exchanges between these two water management systems and analyzing their adaptability to trends in water demand and climate. This evaluation indicates that the American system could potentially benefit from some of the principles present in Brazilian framework, including (1) participatory approach involving government, users, and citizens; (2) recognition of the economic value of water; and (3) prioritization of drinking water supply during shortage times. In turn, the Brazilian system could benefit from certain characteristics of American water management, including reduced bureaucracy and a more efficient decision and operation process. Interestingly, both countries have found it useful to employ soft-path solutions to ensure system adaptability to future water demand and supply. © 2014 American Society of Civil Engineers. Source

Geisbush J.,Central Arizona Project
Pipelines 2013: Pipelines and Trenchless Construction and Renewals - A Global Perspective - Proceedings of the Pipelines 2013 Conference | Year: 2013

The Central Arizona Project (CAP) owns, operates, and maintains 73 acoustic, ultrasonic, transit-time flowmeters measuring flow through 103 pipes - either measuring flow from pumping plant discharges, measuring water delivered to customers, or measuring flow for groundwater recharge credits. Flowmeters are essential to CAP's operations, water accounting, and customer billing. The CAP performed an analysis of each of its acoustic transit-time flowmeters in an effort to: (1) identify existing or potential problems with the accuracy of the flowmeters and make recommendations for corrective action; (2) review and improve maintenance procedures; and (3)examine the long-term viability of the flowmeters. Justification for the study was derived from the following difficulties: ≤ Inconsistent losses reported in monthly water balance studies ≤ Occasional discrepancies between CAP flowmeters and some customer's own metering systems. The desired outcomes of the investigation are to: ≤ Improve the accuracy and reliability of CAP's flowmeters by developing guidelines that are consistently applied in the maintenance and operation of the flowmeters ≤ Identify which flowmeters have reached, or are nearing, the end of their useful life and develop a program to replace those identified flowmeters This paper reviews the replacement project that resulted from the initial investigation. © 2013 American Society of Civil Engineers. Source

Randolph R.D.,Central Arizona Project | Howard A.,562 S Yank St
Pipelines 2010: Climbing New Peaks to Infrastructure Reliability - Renew, Rehab, and Reinvest - Proc. of the Pipelines 2010 Conference | Year: 2010

Twenty-one foot diameter buried steel pipe were constructed on the Central Arizona Project by the US Bureau of Reclamation and the Central Arizona Water Conservation District. The project conveys water from the Colorado River through Phoenix to Tucson, Arizona. The 336 mile long project included open canals, tunnels, pumping plants, pipelines, and inverted siphons. The first section of the project included seven 21-foot inside diameter siphons. Six of the siphons were constructed of precast prestressed concrete pipe. These siphons were fabricated and installed in 1975 through 1978. Investigations in the early 1990's revealed distress to the mortar coating and prestressing wire. Two of the siphons were replaced by new parallel 21-foot diameter steel pipe. The installations were the largest buried steel pipe ever designed by Reclamation. The size of the pipe and the depth of burial presented unique construction challenges and several modifications were made during construction. Pipe wall thickness, interior bracing, the Arizona heat, dewatering, and backfilling all presented challenges during installation. Subsequent interior inspections found no structural distress but found problems with the interior lining that required remedial work. Details of the design of the pipe and installation are discussed in a companion paper. © 2010 ASCE. Source

Gastelum J.,Central Arizona Project | Sheng Z.,Texas AgriLife Research Center | Michelsen A.,Texas AgriLife Research Center
World Environmental and Water Resources Congress 2012: Crossing Boundaries, Proceedings of the 2012 Congress | Year: 2012

During the last 20 years, water resources datasets have been compiled in the Mesilla Basin: groundwater level monitoring data across the Mesilla aquifers, piezometric measurements along three cross sections located across the Rio Grande, seepage survey of the Rio Grande reaches between Leasburg Dam in New Mexico and El Paso, Texas, and groundwater pumping in the Canutillo wellfield located northwest of El Paso. Groundwater contour level maps have been generated for three different time periods. Daily groundwater level graphs for five different years from piezometers of the cross section A-A' were evaluated. The impact of groundwater pumping was evaluated at the Canutillo well field cross section. Seepage data was reviewed to identify how gains or losses have been behaving since the beginning of surveying efforts. Overall, this study provides with fresh analysis of groundwatersurface water interactions in the basin, aimed to contribute to enhancing the understanding of surface-groundwater interactions. © 2012 ASCE. Source

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