When looking for ways to conserve water, the desert community of El Paso, Texas, knew it would take more than just getting residents to be more water conscious.
With an evolving program of community outreach, product incentives and rebates for residents, system-wide leak detection, asset tracking, and a dynamic shift in thinking on how to make water system improvements, El Paso Water Utilities has reduced water demand by 40 percent and is able to put its capital improvement resources to the most effective uses.
Give and take
Conservation is vital in a dry city like El Paso. Although the Rio Grande River runs next to this metropolis of 750,000 residents, water from the river and other surface sources is only available seasonally. From March through October, surface water is diverted for the region’s agricultural industry, and the city must rely on groundwater supplied by two aquifers during the remainder of the year.
A significant drop in the surface water supply was forecast in 2004 based on an extended drought, and that prompted the city to act aggressively. “We have developed an evolutionary process here,” says John Balliew, vice president of engineering and operations for El Paso Water Utilities. “We started with educating our customers about water issues, how water can be conserved, and how they could contribute to our conservation measures. We then added product giveaways and rebates, reclaimed water, and rate incentive programs. Both sides have to give and take to make it work.”
Incentive programs for residents were extremely well received, and the utility provided everyday, necessary items that customers could incorporate quickly to start saving water. The first rebate program was for water-saving toilets. It paid $100 for each 3.5-gallon or 6-gallon commode that was replaced by a new 1.6-gallon-per-flush unit.
The second conservation program involved a giveaway of water-saving showerheads. Distribution centers were set up, and the utility gave away more than 200,000 units to residents who asked for them.
Another initiative was to encourage efficient use of evaporative cooling (swamp cooling) systems, common in dry climates. That kind of cooling saves electricity, but it can consume large amounts of water. In El Paso, evaporative coolers could account for up to 30 percent of water demand at the height of summer. To counteract this, the utility educated customers on how to make swamp coolers save water by installing free restrictor clamps that control flow through the units.
“We wanted to accomplish two things with these programs,” Balliew says. “First, reduce the difference between the average pumping and peak pumping — effectively bring the peak down and reduce the gallons per person per day. For our pumping, we had a peak of 195 mgd at the start of the program, and last year it was down to 150 mgd.
“Second, increase conservation per capita. We went from 240 gallons per person per day to 135 gallons, so our investment of giving to receive has paid off.”
Listen and learn
Once community involvement efforts were underway, the utility began a comprehensive leak detection program. For its distribution system, acoustic-based listening devices were used to monitor all key valves in the system. All leaks were then repaired. That worked well for lines of 16 inches or less, but larger pipes required a different approach.
For larger lines, El Paso contracts for non-destructive acoustic inspection and testing utilizing a Sahara Pipeline Inspection System by PPIC (The Pressure Pipe Inspection Company). Inspections are conducted while the main remains in service. A sensor is inserted into a tap 2 inches or larger, and a small parachute uses the water’s flow to draw the sensor through the pipeline. The sensor is tethered to the surface, giving crews real-time results. A tracking device on the surface locates the position of leaks and other pipeline features to within 18 inches.
Detailed reports of the inspection findings give staff members the decision-making tools to plan replacement or rehabilitation.
For repairing water lines, El Paso sometimes uses carbon fiber, externally and internally. In the area’s highly alkaline and corrosive soil, utility officials have found that carbon fibers in an epoxy matrix wrapped around the exterior of a damaged pipe provides the strength to create a sound and lasting repair. The material is also applied to pipe interiors when appropriate and possible. Before application, the pipe must be clean and dry. That means draining the pipe and applying the material by hand, in a manner similar to painting.
The city also looked at its concrete reservoirs as potential sources of water loss. To measure losses, the reservoir valves were closed and the elevation of water in the reservoir was measured over time. “As you start lowering the water level foot-by-foot and measure the amount of water loss, you can pinpoint at what level of the structure significant leakage may be occurring,” Balliew says. “By doing it this way, you can concentrate your rehabilitation and remediation efforts on the specific sections of the structure that are experiencing the heaviest degrees of loss.”
As part of the process, leaking expansion joints were replaced. Where structures had settled, crews excavated and replaced sections with new concrete. If there were no obvious large points for leakage and loss was occurring from surface age or wear, those surfaces were lined. In some cases, lining consisted of large sheets of plastic placed inside the reservoir and seamed together to form a solid barrier. In other cases, crews used a spray-applied layered polyurethane coating.
Track and measure
As it implements water conservation and leak detection initiatives, El Paso tracks its activities with Hansen Asset Management software and ESRI geographic information system. “We keep track of anything related to a pipe’s condition, its inspections, assessments and repairs,” Balliew says. “At any time, we can view any section of the system or a particular length of pipe and analyze it.
“So anything that happened along that pipe in terms of a leak, a repair or a structural defect or something else that was noted by our field crew shows up, along with its geographic relationship. With that information, we’re able to make informed decisions. Do we do some sort of further condition assessment? Do we schedule it for a replacement? Does it need to be replaced now or does it need to be replaced 10 years from now?”
With detailed documentation on hand, El Paso has been able to delay capital improvements and use its budget to the best advantage. In one case, an aging pipeline that was thought to be a candidate for complete replacement proved to have only five defective joints that could be repaired at relatively low cost.
Incidents like this have created a switch in the utility’s paradigm for viewing asset life expectancy. “Our previous paradigm stated simply that a pipe should be replaced after a fixed number of years in service. I think that approach is shared among many utilities and needs to go away and be replaced,” Balliew says. “The new paradigm should be: if you have a pipe that isn’t leaking and is structurally sound, you don’t have to replace it.”
“We have some pipes that are over 100 years old with no problems, and others that are just a few years old and are experiencing abnormal issues. Base your repairs and capital improvements on the system’s actual conditions, and not what ‘should be’ or is typical.”
Expand and grow
Each year, the utility has added a new element to its conservation program. Some have shown more dramatic results than others, but the net result is resounding success. The staff will keep adding new facets based on knowledge gained as the program progresses.
From one community outreach program to an ever-expanding inspection and rehabilitation program, El Paso has shown that by strategically blending different technologies and methods, the common goals of community and utility can be achieved.
