Prescott pipeline work under fire<br>Chino Valley officials allege compaction problems
Chino Valley and Prescott officials are still trying to resolve problems Chino Valley alleges to exist with the main water supply pipeline to Prescott residents.
In the fourth and most recent set of soils compaction testing, Chino Valley officials were surprised to find pockets of air where they expected to find dirt supporting Prescott’s 36-inch water pipeline through the town.
Five of seven tests near Road 4 South showed voids, or air pockets, under the 400-pound-per-square-inch (psi) pipeline.
"I anticipated compaction at less than 95 percent, but never imagined there would be pockets of air under the pipe," said Stu Spaulding, Chino Valley Public Works director.
"I’ve never seen anything like this in 22 years of performing compaction testing," said Brian Carpenter, of Copeland Geotechnical Consultants, the firm that conducted three of the four series of tests around the high-pressure water pipeline.
Chino Valley officials have been concerned about the integrity of the pipeline since late last year when local residents and council members noticed considerable settling of the ground around some areas of the pipeline.
Substandard compaction around the pipeline could cause pipe welds to crack or leak, and continued settling of the trench as time passes could cause the pipeline to break and flood nearby homes and roadways, according to Spaulding.
If Prescott does have to shut down the 36-inch pipeline for repairs, its residents will continue to receive water from one of its wells in Chino Valley through 12- and 18-inch pipelines.
Contractor Johansen Construction Inc. completed the 13.1-mile concrete steel cylinder pipeline in July 2000.
Spaulding first contacted Prescott officials about trench failure in November 2000, after heavy rains several weeks earlier.
Prescott hired Copeland to conduct the first compaction tests during construction of the three-mile pipeline within Chino Valley limits, and the firm’s initial testing showed that the dirt supporting the pipeline was compacted to 95-percent specifications throughout the town.
Brad Huza, a professional engineer and the city’s environmental services director, certified the project’s completion to specifications.
Huza was unavailable to comment on Chino Valley’s allegations, and City Manager Larry Asaro, through Prescott’s Communications Director J.J. McCormack, declined to comment about the pipeline issue.
Chino Valley Vice Mayor Russ St. Pierre said portions of the pipeline trench on Road 4 South had settled about four feet by November, starting the town’s concerns.
"The chip sealing from the road was falling into the trench," he said. "I’d say that’s a good indication that the compaction isn’t there."
In mid-November, Chino Valley hired Engineering and Testing Consultants Inc., a Prescott company, to conduct random tests for compaction along the pipeline, and none indicated compaction at 95 percent.
So Spaulding asked the Arizona Department of Environmental Quality (ADEQ) to work with Chino Valley and Prescott to ensure the integrity of the pipeline.
Copeland performed the third series of compaction tests in April, and ADEQ, Prescott and Chino Valley officials monitored procedures. But, Spaulding said, Prescott limited testing to a four-foot depth on top of the pipe and conducted no tests in the Road 4 South area,
Even so, more than 85 percent of the random compaction tests failed, Spaulding said.
"Our understanding in Chino Valley was that if this compaction testing failed, we would do more extensive testing," Spaulding said. But the town’s questions continued without answers.
Chino Valley kept pushing for resolution and, on June 5, Huza made a presentation to the Prescott City Council, answering what he said were rumors and allegations from Chino Valley.
Huza said Copeland did more than 600 tests on the work Johansen did with only five tests, or 0.8 percent failing to show the required compaction.
However, Huza also noted that when Prescott started compiling the information, they could not locate any test results for the 3,000-foot section in Chino Valley starting at Highway 89.
"We’ve asked the lab to recheck, and they cannot provide the tests," Huza told Prescott City Council members during the June 5 meeting.
Huza said the project involved a number of standards. Both Chino Valley and Prescott, and other local governments, have adopted the Yavapai Area Governments, or YAG, standards, which require a 95-percent compaction.
However, the Arizona Department of Environmental Quality, which oversees water and sewer installations, uses Maricopa Area Government, or MAG, standards, in its tests. Those standards are less stringent, requiring only 85-percent compaction.
"From staff’s perspective, MAG should be considered as the minimum standard," Huza said during the meeting.
Chino Valley Town Manager Carl Tenney attended that meeting, and asked Prescott officials who authorized the more relaxed standards if that’s what actually occurred.
Tenney said Chino Valley officials started getting the MAG/YAG standards runaround only after the third set of tests in April – Copeland’s second testing – showed inadequate soil compaction around the pipeline around the Road 1 East area, between Road 3 South and Road 4 South.
"When they (Copeland) did the initial testing, according to the reports issued by the City of Prescott, 100 percent of the tests passed. When they did the second testing, 85 percent failed," Tenney said.
Tenney told the council the work on the water lines might not be Town of Chino Valley property, but since they run under Chino Valley roads and near Chino Valley homes, the town has the right to get answers about standards.
"This is where our people drive," he said to the Prescott council. "They will continue to drive on these roads."
Council members agreed that the meeting was not the proper forum to air and resolve the disagreement. But the council made it clear to both Huza and Tenney to do what it takes to get the situation resolved quickly and bring back a recommendation for resolution post-haste.
Chino Valley again chose the Copeland firm to perform two days of field testing last week. That’s when inspectors found air pockets against the large water pipeline.
Laboratory results from the testing will be available in two to three weeks, Spaulding said.
Spaulding wants answers to several questions:
• Why did Huza certify that the trench was compacted when it obviously is not?
• Will the City of Prescott try to change the 95-percent compaction standard?
• Will the contractor fix the trench at his expense?
• What will it cost?
• Will ADEQ inspect the nine miles of water pipeline that are in Yavapai County for 95-percent compaction?
• Are there other construction problems as yet undiscovered?