Condition Assessment of Two 21-Ft Diameter Flexible Steel Pipelines: A Case Study at the Central Arizona Project

The Central Arizona Project (CAP) is an aqueduct system that delivers 1.6 million acre-feet of Colorado River water annually from Lake Havasu to approximately 5 million people in Arizona via a series of open channel canals, tunnels, large pipelines, and pumping plants. In the summer and fall of 2018, two critical, 252-inch diameter flexible steel pipelines were dewatered for condition assessments after more than 15 years without an outage. These pipelines convey over 2 billion gallons of water each day, making opportunities for inspection rare and difficult to schedule. Crews must work around the clock during an outage to dewater, inspect, repair, and rewater to quickly put the system back in operation. This paper will present the highlights and challenges of these recent pipeline inspections performed by CAP and Bureau of Reclamation engineers including outage planning, dewatering, inspection procedures, results, and recommendations.