Rural Community Turns to HDPE

The independent spirit and can-do attitude of our American heritage is alive and well in rural southeastern Idaho, where board members of the Fairview Water District rejected the opinion of state regulators and embraced new HDPE technology.

This five-member volunteer board comprised of dairy farmers and residents was personally responsible for maintaining a 24-mile water distribution system. In one short discussion they recognized the long-term benefits of HDPE and they now have a system that is on the leading edge of water distribution technology.

The Fairview Water District is located on the outskirts of Preston, Idaho, a small, picturesque farming community nestled in the dairy-rich Cache Valley just north of the Utah border. The area recently gained notoriety as the setting for the cult hit movie Napoleon Dynamite.

The water district was formed during the 1930s for the sole purpose of providing a reliable source of clean water for local dairy operations that required water for animals and for cleaning and sterilizing equipment for milk collection and storage. This dated water system of cast iron pipes was installed in part by the Citizens? Conservation Corps during the Great Depression and completed by locally interred German prisoners of war during World War II. The system transported clear, cool water from two generous Wasatch Mountain springs to a 100,000-gallon concrete storage tank eight miles down the canyon, then through another 16 miles of 6- and 8-inch cast iron and wood stave pipe to service about 30 dairy farms and 60 homes in the valley.

Fifteen years ago, the water district began limiting growth to only three new connections per year. But even this relatively limited growth added 14 additional miles of pipeline and maximized an already undersized system ? and there was still a long list of customers wanting to connect to the system.

As the original cast iron system exceeded its useful life, a steady decline in the amount of water reaching the storage tank and the lack of water pressure throughout the system was evidence that the leak rate was steadily increasing and the undersized system needed to be replaced. Fred Ostler, working for Sunrise Engineering at the time, was assigned to design improvements to the system. ?We weren?t sure of the exact amount of water loss because the system was completely unmetered,? Ostler said. Interim measures such as a supplementary standpipe tank and altitude valves had been previously built to provide pressure to the system perimeter and to avoid pipeline replacement, but they offered little relief and ultimately could not correct the continuously corroding pipelines or the long extensions of undersized water mains. The board realized that the rapidly failing cast iron pipes placed the entire district at risk of having no potable water source. ?Dairy farming is the bread and butter for the whole community,? said Ostler. ?Cows don?t quit producing milk for pipeline breaks and without water the dairies would be out of business.?

When the water district board members realized that there were no more band-aids for their failing water system, they took action to design and obtain funding for a water system improvements project. These are commonsense people who were already knowledgeable about pipes, irrigation systems and line pressure, but they needed help with their extensive culinary water distribution system and dealing with state regulators and funding agencies. Sunrise Engineering was selected as a consultant to study and model the system, make recommendations, obtain regulatory approvals and guide the district through the funding process.

The Sunrise staff had specialized experience in water distribution systems and had designed many similar projects using PVC C900 in every case. As the design progressed, everyone assumed that ductile iron or PVC would be the material of choice. However, having developed a keen sense of value and sensitivity to tight budgets from working many years in municipal public works, Ostler chose to introduce HDPE to member members, fully believing that they would politely thank him for presenting alternatives, but would ultimately lean toward ductile iron or C900 PVC pipe. Ostler said, ?HDPE made more sense to me, but with that kind of historic loyalty to the area?s pipe producer, I thought it would be a long shot. I didn?t think it would be well received.?

Much to his surprise, the board members quickly recognized the value of HDPE and how its installation methods, durability and relatively low maintenance costs fit their needs. Ostler said, ?From the moment they saw it, they immediately grasped the benefits and fully embraced the HDPE concept.?

There are many reasons why the use of HDPE pipe has been increasing during the past decade.? ?The use of HDPE pipe for water systems goes back to the late 1950s,? said Tony Radoszewski, executive director of the Plastics Pipe Institute (PPI). ?It has a very long life because it is naturally resistant to rust and tuberculation so water continues to move smoothly even decades after installation, and heat fusing sections together makes for a leak-free system.?

According to the PPI, a recent study confirms the 50-plus year life expectancy of pipe made from polyethylene when used in typical municipal potable water systems. ?We expect that the data, when finalized later this year, will show high-performance PE pipe to have a projected service life up to 100 years or more in many municipal water systems,? Radoszewski stated.

HDPE became the basis of the design; however, when the design was submitted for state approval, the local state regulators discouraged the water district from using HDPE as it was a newer product and the state felt the rural water district members lacked the specialized equipment and the ability to maintain an HDPE system.? The board, however, was not afraid of a new challenge and liked the idea of jointless, flexible, corrosion-resistant pipe that could be installed in long lengths at one time. Despite the state?s counsel the water district board felt confident about its decision and proceeded with HDPE.

Routine post-installation maintenance was also a factor. Board member Brian Jensen said, ?By necessity, we (the five board members) fix all our own leaks and do all our own maintenance. We can?t afford to hire a maintenance crew when things go wrong.? The board members themselves became trained fusion technicians during a one-day training program at a nearby HDPE fittings manufacturer and supplier in Fairfield, Idaho. With only a few hours of training they were capable and confident in tapping and repairing their new HDPE water pipes.

As the project entered the final design stage, one of the biggest concerns was the numerous surface irrigation canals that traverse the area, some as much as 40 feet wide and 12 feet deep. The traditional method of crossing a canal is either jack-and-bore underneath it, or wait for it to go dry in the fall then dig through it and try to reseal it with bentonite clay. In Southeastern Idaho where winters can be harsh, waiting for the canals to go dry in October would mean that snow was near and the window for construction could be short. In addition, the jack-and-bore method would be expensive due to the number of canal crossings involved, and high groundwater levels from surface irrigation would require substantial dewatering. ?The traditional methods of waiting for a canal to go dry or dealing with groundwater were both painful options,? Ostler said.

Ostler, always trying to approach issues with common sense and endeavoring to determine the most beneficial and cost-effective solution to a problem thought, ?Why not use HDPE and horizontal drilling and have the option to install anytime during the construction season?? It turned out to be the ideal solution.
Another unexpected benefit became apparent during the bidding process. Contractors presented lower bids ? being eager to perform horizontal drilling and appreciating the longer runs and the time-saving backfill and compaction methods of HDPE. This enabled the small, rural district, which initially faced a funding shortage, to complete the project as designed and within budget.

Edstrom Construction of Rexburg, Idaho, installed 16 miles of new 8- to 16-inch HDPE pipe and more than 400 service lines and water meters during the high irrigation season. Shane Webster, Edstrom?s superintendent, was enthusiastic about working with HDPE. He particularly liked the ability to make HDPE welds above ground, which virtually eliminates the risk of contamination because the joints are already sealed when the pipe is lowered into the trench.

The farmers are thrilled with the amount of water that is now available. ?So are their wives,? according to Debbie Gregory, board secretary. ?Prior to installation of the new system, some of the ladies were doing their laundry late at night due to lack of water pressure during daylight hours.?

Board members have already performed several new connections with their automated fusion equipment. ?The pipe has performed to our highest expectations. We?re looking forward to replacing another eight miles of pipe this year,? Jensen said.

Cynthia L. Felt has 13 years of experience in public works with the City of Blackfoot, Idaho. She recently completed a bachelor?s in English at Idaho State University and is working toward a master?s in public administration.

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