The Long Road to Lower Flow

Sanitary district tackles 20-year project to cut unwanted flow

The Long Road to Lower Flow

Cody Barb (right) and Ronald Miller of the Stoney Creek Sanitary District feed a Reline America pipe liner into a manhole where Mike Barick guides it into an 8-inch sewer line. 

Ten years ago, Stoney Creek Sanitary District embarked on a course to sharply reduce the inflow and infiltration of groundwater into its sewer collections system. Everyone believed it wouldn’t be a quick fix. Everyone was right.

“When we bought the equipment and started relining our sewer system, we knew this would probably be a 15- to 20-year project,” says Stad Hirsh, the district’s maintenance and construction supervisor. A decade later, the I&I problem has been reduced by half. However, because the numbers involved are large, the remaining half represents a lot of water — 1.5 mgd. In March, a relatively benign month for invasive water, 0.67 mgd was recorded.

The district’s I&I problem dates from the original infrastructure put in place in the 1960s. The district is located near the northern end of the Shenandoah Valley in northwestern Virginia, about two hours from Washington, D.C. The area’s relative proximity to the D.C. metropolitan area led to the opening in 1965 of an outdoor attraction — Bryce Resort. The recreation property attracts tourists year-round. In warmer months, they walk its 18-hole PGA Championship golf course. When the snow comes, they ski, tube and snowboard 25 acres of slopes that drop some 500 feet in elevation.

The sewer and water system built for the resort in the 1960s was folded into Shenandoah County’s Stoney Creek district 20 years later, one of two sanitary districts in the county that began as private systems. Though the district replaced the resort’s original waterlines, many of the original sewer lines continue to carry wastewater — and I&I — to the district’s sewer treatment plant.

While the legacy sewer lines from the resort are not notably old as infrastructure goes, the private system was poorly constructed, Hirsh says, which has aggravated the problem. Furthermore, some cracking is occurring in the old pipes and invasive mountain timber roots are breaching sewer line joints.

The result is lots of water making its way into the system. Operators at the treatment plant monitor the flow and let Hirsh know when the I&I volume mounts, as it did much of last year. Actually, 2018 was a bit of an I&I trial for the district. “It was extra bad with all the rain we had. We average 30 to 33 inches of rainfall a year. Last year we were 100% above our average with 67 inches.”

Lining program

The district’s response to the chronic I&I problem was to launch a program to insert liners in the oldest sections of its 300,000 feet of sewer line. The task is 10 years along now and still far from complete. Calling on its own five-person construction crew, the district is, month after month, systematically inserting UV cured-in-place liners in underground lines.

“All the old pipe is still in the ground,” Hirsh says of the trenchless solution. “We don’t dig up and replace very much.” Most of the sewer pipe is 8-inch-diameter stock, though across the system the pipe ranges from 6 to 18 inches.

Stoney Creek’s relining project is methodical — that’s the only word for it. Almost plodding. “We try to do as much relining each week as we possibly can,” Hirsh says. “On average we’ll line 300 feet a week, weather permitting. We try to do at least 5,000 to 6,000 feet a year. If we can get 10,000 feet, that’s great.” So far, Hirsh has not identified pipe problems outside the core area in the old resort lines, so the effort to increase the overall integrity of the system is gaining ground.

The rehab work would drag out even further than is scheduled were the district located in a more hostile climate. While snow regularly flies in the Allegheny Mountains section of the Eastern Continental Divide, winter generally is not a deterrent to the relining effort. Consequently, Hirsh says, his construction crew is able to work pretty much year-round.

For relining materials, Stoney Creek relies upon a firm conveniently headquartered not far away in Saltville. Reline America has the North American rights to a lining material called Alphaliner (formerly Blue-Tek). It is a plastic material reinforced with glass fiber and cured in place with ultraviolet light. The liner is created using a patented technology that lets it adapt to any conventional pipe shape, including elliptical and square. Resins are specially formulated to withstand the particular chemical makeup of the fluid being transported through a pipe. The company also manufactures the specialized equipment employed to insert the liners.

Inserting Alphaliner is not the only repair option Stoney Creek exercises as it works to make its collections system whole. When an isolated failure in a pipe is found, point repair work is undertaken by the construction crew, usually through the winter and into early spring months when weather can be iffy for other projects. Stoney Creek officials settled several years ago on Romac Industries stainless steel couplings and clamps as the preferred choice for sealing off failed pipe joints or fixing a random puncture in the wall of a pipe. The Romac products have been around for 50 years.

Maintenance responsibilities go beyond patching and relining sewer pipes. As part of the I&I upgrade, the district is on the verge of switching to a new generation of flowmeters. The new equipment — make and model have not yet been selected — will replace ultrasonic flowmeters used as submeters and deployed in sewer main flumes.

Fresh view

Stoney Creek was slow to adopt CCTV inspection technology, not only due to the expense, but because moving camera trucks into position for some inspections seemed impossible with the ruggedness of the district’s terrain. This is a water and sewer system, after all, that drops 800 feet in elevation, some of it rather precipitously.

The reservations about cameras disappeared in 2011 when a robotic camera deployed by RedZone Robotics successfully navigated 30% slopes and 2-inch interior bumps in sewer lines. After a trial run, the district contracted with RedZone to assess the condition of 250,000 feet of pipe. Besides showing areas endangered by roots and debris, the survey gave the district up-to-the-minute data on the overall condition of the pipes.

Today, the district’s construction crew does its own camera work using a RIDGID KD350 SeeSnake unit with a high-resolution monitor. After a camera is run through a targeted section of sewer line to determine its condition, the crew concentrates on removing any discovered rocks, roots or other debris. A truck-mounted US Jetting 4018 jetter is transported to the insertion point and a 4,000 psi stream is unleashed into the interior of the pipe. “We leave the pipe pretty well spotless, particularly before we’re going to reline it,” Hirsh says. Then the relining work begins. 

Fighting corrosion

The district’s 1,400 manholes are a separate maintenance concern. Ninety percent of connections from the district’s residential customers empty into manholes. “That is not as common in towns or cities,” Hirsh says. “In this mountain terrain, though, our manholes are not set very far apart, so we can pick up lines from three or four houses and drain them directly into a manhole.”

Hydrogen sulfide has done a number on many of the manhole walls. Hirsh says 50% of the vertical structures are in need of repair. This upgrade work is mostly subbed out to a Washington metro-area firm, Pleasants Construction. The firm’s technicians apply an epoxy coating to the wall of each manhole to seal and stabilize it and return it to service an hour after being coated. “If the manhole is too deteriorated for the coating, the crew returns another day and does point repairs with fast-drying cement before applying the epoxy.”

The company started rehabbing manholes again in April, doing five per week.

Resources

Hirsh is a relative newcomer to Stoney Creek district affairs, signing on 2 1/2 years ago. He is not a newcomer to the area, however, having grown up in the valley and been a licensed plumber for 20 years, sometimes working on Bryce Resort lines. His crew comprises local people, too, several of whom have worked for the district for more than 20 years.

“The senior supervisor has been here 24 years. He has built his crew, and they know what they are doing,” Hirsh says. “I say to the guys all the time, ‘I don’t have to tell you what to do. You know what to do, especially the construction crew.’”

He says the tenure and experience of the district employees is a great asset. “We have the desire to self-perform. We have learned over the years what to look for and where to concentrate our efforts. Having people stay here in the district for years and wanting to do the job is a very valuable resource.”


Gearing up for terrain

When your water and sewer system traverses rugged, mountainous terrain and the rolling equipment in your equipment yard has to do the same, you gear up accordingly.

Stoney Creek Sanitary District is located some 1,200 feet above sea level in the picturesque Shenandoah Valley of northwest Virginia. Picturesqueness comes with some challenges, however. Systematically maintaining lines and manholes is tough enough. Undertaking a years-long pipe relining project is something else.

“Most companies that reline are used to working on flat ground in towns and cities,” says Stad Hirsh, maintenance and construction supervisor at Stoney Creek. “When they first tried the relining here, getting to the work sites was the biggest obstacle to overcome.”

The obvious solution was to acquire a fleet of equipment suitable for the terrain. Consequently, the 1-ton maintenance and construction crew trucks are four-wheel drive, as is the box truck carrying the district’s camera inspection and monitoring equipment. The district’s relining equipment is transported in a military surplus so-called deuce and a half — that is, a 10-wheel-drive, 2 1/2-ton model dating from World War II.

Of the district’s four military surplus trucks in its fleet, one of them is dedicated to toting around a 5-ton boom crane. Other tools parked in the equipment yard include three backhoes (Case, John Deere and Caterpillar, by brand) and two Cat compact track loaders.

And the relining work rolls along.



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