Project Name: Large Diameter Water System Rehabilitation & Replacement

Includes project:

The City owns approximately 320 miles of 16-inch to 48-inch large diameter water mains ranging from new installations to assets more than 75 years old. As of 2009, approximately 95 percent of the City’s water system infrastructure is ductile or cast-iron pipe. There is limited information about the actual condition of the large water mains, except where sections have been repaired or replaced. In order to determine the remaining service life of the water mains, the Department plans to assess the condition of its critical lines. The results will be used to develop a rehabilitation, repair and replacement program for large water mains. A planning phase will assess the condition of the large water mains. DWM has a calibrated hydraulic model of the water transmission and distribution system and a Criticality Assessment model. These models will be used in conjunction with a database of water main maintenance work orders to develop a priority list of large water mains to be assessed. The Department will then perform an assessment to determine the wall thickness, location of leaks and other water main problems.

Approximately 30 miles per year of the large water mains will be assessed. Subsequent phases will include design and construction. The results of the condition assessment will be used to prepare detailed designs for the rehabilitation, repair and replacement of large water mains.

The scope of this project includes:

• Updating DWM Criticality Analysis model including fire flow analysis
• Developing a priority list of large water mains requiring a condition assessment
• Performing condition assessment of large diameter water mains
• Preparing a priority list of critical projects
• Reviewing and updating standard design details and specifications for large watermains

Justification:

• Reduces cost and effort for corrective and emergency maintenance
• Enhances operational reliability and efficiency of the water distribution network
• Ensures continued compliance with state and federal rules and regulations

Project Type: Water Distribution
Project Start: 7/1/2015
Proposed Construction Start: TBD
Scheduled Completion: 09/02/2024
Project Budget: $12,000,000
Council District(s): Citywide
NPU(s): Citywide
Project Status / Phase: Active / Planning