The San Diego County Water Authority (SDCWA)—a major wholesale water provider in Southern California—started conducting routine condition assessments of its large-diameter pipeline in the early 1990s. While the agency lacked a formal asset management program, it managed critical assets through programs focused on elements such as pipeline and valves. Like many programs of the era, upgrades often were based on the age of the assets rather than a detailed analysis—an approach that failed to account for specific conditions. The result was that some equipment was replaced when it had years of life left and some facilities failed before they were deemed old enough for replacement.
By 2009, it was clear that a more sophisticated approach was needed, and SDCWA established an Integrated Asset Management Plan to better manage more than 69,000 discrete assets scattered over hundreds of square miles. But the agency did not go out and buy an expensive customized software package for the work. In an era of holding the line on expenses, SDCWA staff developed software at virtually no cost beyond labor. Over three years, a handful of engineers and software experts researched, developed, tested and deployed a system that has significantly increased the agency’s ability to forecast and respond to asset fatigue before major problems develop. While many companies offer customized and more sophisticated systems, SDCWA’s low-cost approach is an example for agencies that want to establish a program but cannot afford to pay top dollar.
Today, SDCWA’s Asset Management Program is helping to maximize the value of more than $5 billion in assets, such as pipeline and facilities over their life span, using readily available technology that helps staff prioritize projects and provides rationale for decision-makers faced with budget choices. The program enhances and maintains the condition of assets over decades at the lowest possible cost, allowing SDCWA to continue providing its 24 member agencies with a safe and reliable water supply for more than 3.1 million people across the region. The program has resulted in the deferral of $210 million in pipeline and facility projects because detailed condition reports showed they still had years of life left and other projects were a higher priority. In addition, several pipeline and facility failures have been prevented thanks to this program, saving an estimated $4 to $6 million in damage and repair costs.
The Asset Management Program adheres to the industry’s best practices, employing an asset registry, condition assessments, and ongoing efforts to determine both the remaining life of assets and the liabilities created by their potential failure. Condition assessments include visual inspections, thermal analyses, internal inspections, steel thickness measurements (for pipe), prestressed pipe wire-break data (from remote field eddy current data and real-time acoustic fiber-optic data) and real-time cathodic protection data.
The online asset registry (or inventory of assets) was the most time-consuming element of the program to design—and the most significant. It incorporates data on asset design characteristics, locations, conditions, performance indicators and estimates of remaining asset life spans. The registry also can integrate with enterprise software such as SDCWA’s GIS and computerized maintenance management system.
Facilitating data collection in the field for a variety of crews also was important. Therefore, SDCWA developed a customized program that uses step-through screens, push-button boxes and pull-down menus similar to programs widely used by the general public. SDCWA’s version allows field crews to quickly enter and store data using a touch-screen laptop that includes a data validation function to minimize the chance for erroneous values. These features ensure efficient, repeatable and logical data entry from remote spots where many SDCWA assets are located. To date, the agency has used the program to collect data about the condition, backup capabilities and consequences of failure for all 6,000-plus facility assets.
Risk Assessment & Mapping
SDCWA’s assets are classified into three main groups:
Pipeline. More than 300 miles of large-diameter pipeline transports water around the San Diego area. It ranges in diameter from 20 to 108 in., and is constructed of a variety of materials such as steel and prestressed concrete cylinder pipe. This category also includes 1,400 related structures used for operating, draining and filling pipeline.
Facilities. SDCWA relies on more than 120 facilities to meter, pump, treat and control the flow of water. In addition, two facilities generate electricity.
Equipment. Construction equipment, SCADA system hardware, software and specialty tools required to operate and maintain the water delivery system belong to this class. (Repair and replacement of items in this category are addressed by other programs at this time.)
SDCWA’s asset management team systematically issues condition ratings every three to five years for facilities and every two to 10 years for pipeline. Asset managers generate recommendations for construction, operation, repair and replacement based on two main factors: the amount of time an asset is expected to last before it fails, and the risks created by its failure.
Probability-of-failure ratings account for the assets’ conditions and include factors such as age, visual condition, non-destructive testing condition, monitoring reports, wire breaks, design features, construction practices, modes of operation, maintenance history and environmental factors. Consequence-of-failure ratings account for loss of asset functionality, likely water supply interruptions, potential damage to property, risks to other assets such as buried utility lines, and whether backup systems are in place.
The individual factors are weighted based on their relative significance to generate scores that range from one to 100. In most cases, assets with more than 50 points in either category are considered medium to high risk.
Assessments are done for both individual assets and components of assets, such as valves, meters and pipe that make up a service-connection facility. Asset-by-asset results are presented in a common format so they can be plotted on a matrix (see Figure 1), which provides a visual cue about which upgrades should be made first.
The red quadrant contains assets with scores of 50 or more in both categories, clearly identifying the top priorities for more evaluation. Assets in the yellow and green quadrants remain on the watch list. The asset management team routinely assesses lower-priority items, however, to determine whether it is cost-effective to combine repairs and/or replacements with “red” projects. For instance, when repairing a pipeline in the red quadrant, it may be cost-effective to rehabilitate “yellow” facilities connected to that pipeline.
SDCWA also maps assets, combining 3-D figures and color coding with Google Earth. The result is an interactive map (see Figure 2) that allows asset managers, agency executives and board members to see the physical locations where problems have developed. This visual interpretation is particularly important for grouping repair/replacement projects in the same geographic area and for identifying spots in poor condition. It also provides an important sense of place for people unfamiliar with the details of the water delivery system. For instance, seeing a community park next to a red pipeline underscores the consequences of failure during the decision-making process.
Prioritizing Repair Projects
Asset repair and replacement projects are defined and prioritized for presentation to an Asset Management Committee. The committee comprises managers from various groups and departments within SDCWA. It reviews projects before each budget cycle. It also considers available resources, economic factors, customer rate and delivery impacts, timing, and other issues.
During the current two-year budget cycle, the Asset Management Program identified 16 major projects in the red and yellow categories. Several of them are large-diameter pipeline only 50 years old. The advanced data collected by the Asset Management Program indicate that sections of pipelines will not last their designed service life of 100 years. Rather than waiting for failures, abandoning or replacing the pipelines now, SDCWA plans to rehabilitate them by inserting steel liners. This extends pipeline life spans without major disruptions to nearby residents—for instance, by closing traffic lanes to reach buried pipe—and reduces costs. Without this approach, SDCWA would be left to respond to interruptions and failures, reducing its reliability.
Comprehensive condition assessments leading up to the current budget cycle also identified several high-risk assets that had not been identified earlier. One service connection facility appeared to be in average condition until the assessment team found heavy corrosion under a pipe where crews typically do not look during service calls. If that facility were to fail, it would pose a flood risk to a busy intersection and a large high school. To complicate matters, a failure at the site could not be easily isolated and an unplanned outage could have widespread effects. The combined probability and consequences of failure identified this as a high-risk asset. The Asset Management Committee reviewed this project, and the design for its rehabilitation is in the current budget cycle.
As a result of ongoing assessments, SDCWA has rehabilitated seven red facilities since 2009. Rehab work typically includes patching corroded pipes, replacing worn meters and control valves, painting, and replacing equipment that has reached the end of its service life.
Money for launching the Asset Management Program came from established projects and programs without increasing the operating budget or the size of the Capital Improvement Program; however, this presented some challenges. Industry conferences and publications are full of information about the topic, but it often is so technical that any advances seem out of reach without high-end consultants and contractors. SDCWA took a different approach by meeting with several agencies to learn about their asset management strategies and completing the asset management training program offered by the U.S. Environmental Protection Agency.
With that information, SDCWA structured its program to leverage existing data and in-house expertise. The plan was to start simple and slowly add components. SDCWA is gaining momentum and plans to expand its program by gathering information on valve use, failure modes and root causes of failure. It also is developing better decay tables based on specific types of assets. Finally, program managers are going to look further into how potential failures may impact SDCWA’s mission of providing a safe and reliable water supply for the San Diego area.
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