NASSCO Report: Implementing Advanced Technologies, Asset Management to Help Prioritize and Rehabilitate Pressurized Pipeline Infrastructure
Pressurized pipeline infrastructure (both water and wastewater) throughout the United States is reaching a critical stage of critical condition. The outlook of this infrastructure as recently described in ASCE’s 2021 Report Card (and statewide individual report cards in each successive years) shows that the trend line of system deterioration is getting worse for both water and sewer conveyance systems.
The hardest ones are also those that need to address the systems that are pressurized 24/7/365 with no room for holidays and time off.
There are many challenges associated with pressurized pipeline assessment and prioritization for follow-up renewal. Wastewater force mains and water transmission and distribution systems (combined are referenced herein as pressurized conveyance infrastructure) are inherently challenging to inspect and assess. The challenge is elevated when one needs to take this limited inspection data and evaluate these systems and their relative condition associated with structural integrity, hydraulic performance, reliability, and remaining service life. And do this pipe-by-pipe. This begins with the simple challenge that this critical infrastructure is, for the most part, buried.
The average life span (and thus its remaining useful life) of a single pressure pipe asset depends on several variables including its original design criteria, materials and methods of construction, soil pH, operating pressure (including transients), seismology, supporting foundation, and preventative maintenance. Design engineers often use 50 years as the average life expectancy for most pipe types. However, there are water distribution systems (and a few wastewater force mains), currently in service, that exceed 100 years. The fact is, we currently do not have good data analytics to determine an overall remaining useful life of the nation’s 2.2 million feet of pressure pipe infrastructure that has now surpassed 40 years of supplying drinking water to U.S. consumers. Whether the actual life expectancy is 50, 60, or 70 years, we as an industry need to agree that the remaining useful life of a typical water conveyance asset is approaching zero, and that is certainly something to be concerned about.
The problem with pressure pipelines is one of being a double-edged sword. These systems are not only aging dramatically, but the estimated costs to upgrade and improve this critical national infrastructure are also increasing at astonishing levels. In their recent report to Congress, the EPA determined that the nation’s water utilities in particular will need $313 billion in water distribution infrastructure investments over the next 20 years. This same survey by EPA found that water utilities planned to spend an estimated $78 billion over the next 20 years to satisfy that need. This demonstrates a shortfall of a whopping $235 billion in funding for needed improvements during the next 20 years.
Whether the estimated need for pressure pipeline conveyance system improvements is $300 billion over the next 20 years, $1.0 trillion over the next 25 years, or some something in between, the critical needs must be met first before the longer-term challenges are prioritized. Digging ourselves out of this hole (or sinkhole) will require a large inspection technology toolbox that includes smart data analytics and good business management solutions.
To address these serious, if not alarming, conditions, municipalities and water utilities should consider the need to implement asset management as a good starting point.
Significant advancements are being made for both the external and internal inspection and condition assessment of pressure pipeline infrastructure. These technological advancements parallel the need for utilities to create reliable condition scores as part of their on-going asset management program. The combination of good inspection technologies, smart asset management strategies, and useful planning tools will help utilities plan, improve, and maintain their vast and complex network of buried pressure pipe infrastructure while reducing emergency repairs and unplanned capital improvements. By doing so, they will gain better skills in maintaining their role of trusted stewardship to their 24/7/365 customers.
“The Clean Water and Drinking Water Infrastructure Gap Analysis”, 2007, EPA Office of Water (4606M) EPA-816-R-02-020
“Drinking Water infrastructure Needs Survey and Assessment – Sixth Report to Congress”, Office of Water (4606M) EPA 816-K-17-002 March 2018
“Improving Water Utility Capital Efficiency”, 2009, Water Research Foundation and EPA (page 10)
“Report Card for America’s Infrastructure”, American Society of Civil Engineers, 2021, Washington, D.C.
“Condition Assessment of Water Mains” Manual of Water Supply Practices, M77, American Water Works Association, 2019
“Potable Water Pipeline Defect Condition Rating” The Water Research Foundation, WRF ISBN; 978-1-60573-388-3, WRF Project No. 4498, 2018
Mark G. Wade, P.E., is with BlueWater Solutions Group Inc and is a member of the NASSCO Pressure Pipe Committee.