Managing a water system with more than 9,000 valves and 26,000 connections is challenging. Without accurate location data and history, it could be overwhelming.
That used to be the case for the City of San José (Calif.) Environmental Services Department, Water Utility Divi-sion. Ongoing water valve rehabilitation across its system was a daunting task.
Until recently, the division had limited tools to keep system maps current or to track changes made to the infrastructure. As a result, maintenance crews spent excessive time trying to locate specific components in the field. That was frustrating, especially in emergencies when an asset had to be pinpointed quickly.
All that is changing. By incorporating GPS technology, GIS mapping and data collection with its scheduled valve maintenance program, the San José Municipal Water System (MuniWater) is creating a solution that will make maintenance more efficient, enable quick location of all assets, support hydraulic modeling and assist future capital expenditure planning.
GIS to the rescue
Over the past 44 years, MuniWater has planned and built facilities to provide more than 100,000 customers with a reliable, safe water supply. Scheduled valve rehabilitation is critical to the agency’s overall distribution system maintenance plan. The MuniWater system contains some 9,000 valves. Until recently, locating each valve was time-consuming, costly, and sometimes impossible.
Previous valve rehabilitation projects did not include a specific locational component. Consequently, a valve could be rehabilitated, then paved over during road maintenance or buried during new construction.
“Although key information associated with a particular valve was stored in a database, when the maintenance crews went back out into the field to try and locate a specific valve, it was sometimes no longer visible,” says Tim Hayes, senior geographic systems specialist for the Environmental Services Department.
“This resulted in crews spending hours trying to locate some valves using as-built drawings, which were sometimes inaccurate, and then excavating the street to determine where the valve was located. The city had used GIS mapping and GPS data logging successfully for other infrastructure mapping projects, so the staff decided to develop a similar program for valve rehabilitation.
Two-in-one method
To get the desired results for the lowest cost, MuniWater decided to combine efforts. As part of its yearly program, San José rehabilitates valves on a specified number of assets on a rotating basis, typically covering the entire system in five years.
Valve rehabilitation consists of opening and closing each isolation valve in the system. Typically, this is done manually or is automated, using a truck-mounted valve exerciser. Working like an automatic wrench, the exerciser opens and closes the valve multiple times to determine proper function.
The automated process typically takes five to 15 minutes per valve, depending on valve size (larger valves take longer). Each valve is opened and closed, and critical data is collected. If the valve is inoperable or does not perform as specified, it is added to a list for replacement or repair.
Under the new combination tasks method, a TM-6 valve exerciser is connected to VITALS (Valve Information Tracking And Logging System), both from E.H. Wachs Co., via a data cable. This allows automatic transfer and recording of valve information. During exercising and rehabilitation, a handheld data collection device records:
• Valve ID (entered manually).
• Number of turns (entered automatically).
• Valve size (entered manually).
• Torque (entered automatically).
• Date (entered automatically).
• Starting and ending time (entered automatically).
Going a step further
This data is useful in itself, but GPS integration makes it more so. Latitude and longitude coordinates provide the efficiency and cost-savings MuniWater was seeking. While valve exercising crews work, they obtain GPS coordinates for each valve, using a GeoXH handheld GPS unit and Zephyr antenna by Trimble Navigation Ltd.
Before exercising a valve, a crew member positions the antenna directly above the valve and spends two to three minutes collecting the location for the asset. The unit provides exacting coordinates, accurate to within one foot. Crews repeat the process of exercising, data collection, and GPS locating for each valve. To date, crews have located and inventoried 3,000 valves within the city’s potable water system and 200 valves within the recycled water system.
“It gets difficult to locate valves sometimes,” says Robert Wilson, Water Utility Division engineering unit manager, Environmental Services Depart-ment. “By collecting GPS coordinates with relatively high accuracy, we’re able to go back after paving or development projects and find them. Usually we’re looking for valves when there’s an emergency, like a water leak, and we need to shut the water off. Having a tool to be able to do that quickly and accurately is very, very helpful.”
Benefits of integration
All data collected in the field is processed later, rather than directly onsite. “Although the exerciser, data logger and GPS units can all work hand-in-hand and merge data out in the field, we choose to process the data a little differently,” says Kent Brown, geographic systems specialist II. “We chose to post-process our GPS data before joining the data, allowing for higher accuracy and greater control.”
Three software programs are involved:
• VITALS data software for capturing data from the VITALS data logger by E.H. Wachs Co.
• TerraSync software from Trimble for the GeoXH GPS unit.
• Pathfinder office software from Trimble for post-processing.
The processed and verified data is incorporated with the department’s extensive GIS system built on ArcGIS 9 by ESRI Inc. and distributed to staff via Web-based GIS using ArcIMS 9 by ESRI, and GeoSmart.net by MoosePoint Technology Inc. By sharing information across the systems, the agency can effectively track all its assets.
“Now we can track assets not only by their physical locations but also by what’s there,” Wilson says. “For example, at a pump station there are all types of equipment. When something fails and is changed out, the replacement unit could be from a different manufacturer or have slightly different characteristics than what was there originally.
“That could mean different parts, different life expectancy, or different maintenance requirements. By having a database that keeps track of those details, we can maintain assets more efficiently, plan for capital replacements and make repairs in a timely manner.”
The data is also used for hydraulic modeling. San José models its system using InfoWater for ArcGIS by MWH Soft Inc. to ensure that available capacity can effectively sustain and protect new development. Now, all information can be incorporated directly and automatically into the hydraulic model, creating accurate updates in less time, at lower cost.
Combined efforts pay off
“We are always looking for ways of combining efforts that can give us better data to make us more efficient later, and yet isn’t costing us a lot extra,” Wilson observes. “That’s the reason we’re doing valve rehabilitation the way we’re doing it.”
By integrating data collection with scheduled maintenance tasks, Muni-Water can keep project costs low. Meanwhile, the agency is on the fast-track toward building an information database that will lower future maintenance costs, improve operations efficiency, and help the city plan effectively for the future.
