The city of Ames, Iowa, is moving steadily toward a DIY approach in sewer line cleaning and inspection. As in: Do it yourself.

 

Several years ago, Ames began doing more of its sewer inspection in-house. Now the community is on the verge of bringing line cleaning inside, too. The reason? More flexibility, better customer service and lower cost, says Dale Weber, utility maintenance supervisor for the Department of Public Works.

 

“We put a lot of priority on service to our customers,” Weber says. “By assigning our employees to do the work, and getting them the tools and support they need, we believed we could do a better job with service and really get more work done.”

 

So far it’s working out with inspection: The department has already moved up to its second generation of TV equipment. But the real proof may be in the coming year, when the city buys its first combination truck and begins assigning its own crews to clean the system.

 

College town

Ames has a population of about 51,000, and students at Iowa State University account for about half of that. The city is responsible for 211 miles of sanitary sewers from 8 to 66 inches, as well as nearly 4,000 manholes.

 

The city bought a used inspection camera in the 1990s, before Weber joined the department. It wasn’t very dependable, and the city bought its first new camera 10 years ago. Since then, public works has steadily ramped up its inspection and cleaning routines.

 

“We’re getting more aggressive with the televised inspection, going from where we were just looking at blockages or backups and trying to determine the cause,” says Weber. By expanding routine inspection, the city hopes to catch problems sooner.

 

Inspection needs run the gamut: detecting the source of backups when they occur, checking pipes in new developments, and assessing the condition of sanitary and storm sewers in advance of street construction, so that if an area will be torn up for new pavement, deteriorated sewers can be repaired or replaced at the same time.

 

“Some of that is being contracted out,” says Weber. “But we are shifting to doing more of the inspecting in-house.”

 

New camera

By 2008, the city was ready to upgrade. The older camera was no longer supported by its manufacturer, and it needed repairs that led to downtime.

 

Ames chose the Pathfinder PE3300 camera from Aries Industries Inc. for 6- to 24-inch pipes. It has 360-degree viewing rotation, zoom and a backup camera. “It just seemed user-friendly and lightweight,” Weber notes.

 

The camera travels on a steerable TR3300 tractor with wheels for maneuvering around objects in the line. Zoom capability allows the camera to collect information 70 feet or even farther away.

 

The city kept the 2000 Ford step van inspection unit it had used with the previous camera. Aries retrofitted the van for the new camera and crawler and installed a new cable reel.

 

Other upgrades are coming. City workers still log inspections with a pencil-and-paper system, but they plan to move to a software package purchased through Aries in the new fiscal year. The ultimate goal is to link the records that software creates with the city’s ESRI GIS mapping system, which has been in place for about a decade.

 

“We want to get it to the point where we have video and inspection point data all linked together, so that our engineering department also has access to it,” Weber says. “The more history we can put at everyone’s fingertips, the better.” Once the software is in place, Weber hopes to meet the city’s goal of inspecting 10 percent or more of its lines a year.

 

Multiple issues

As in any system, Ames’ sewer problems run the gamut. The causes of backups, blockages and leaks include tree roots, grease clogs, problems from taps and utility crossbores. City inspectors are finding that what at first appears to be a tree root piercing a line might in fact be a gas line or an electrical conduit.

 

“It seems that with horizontal direction boring, we keep finding more and more stuff that has been bored through the sanitary system and is creating problems,” Weber says.

 

Inflow and infiltration (I&I) is a concern, and leaking manholes are one culprit. “The ones that seem to cause the most problems are the ones that are out of the way, along the two streams here that cut through town,” Weber says. “We’re trying to target the manholes in the floodplain first. We’re trying everything from replacing manhole castings to raising buried manholes so they’re accessible, so we can do maintenance and inspection on them.”

 

So far, an intensive inspection project has covered through about half the manholes. Workers use a standard checklist, noting the type of casting, whether the manhole lid has holes, and whether the structure is brick or concrete. They also identify any defects where pipes enter the manholes.

 

“We suspect a lot of these are being flooded during heavy rains,” Weber says. “In the floodplain, we’re trying to change to bolt-down manhole lids and castings, so we don’t have a hazard. The biggest fears are of flooding that lifts manhole covers as water fills the sewer lines, and the risk of injury or worse to workers or members of the public.”

 

Cleaning routines

Over the years, the city has taken various approaches to structuring its cleaning routine. Ames used to use certain major roads and streams as dividing lines in choosing where to clean. Now it divides the work by focusing on each of 16 drainage basins, so that all lines that drain into a larger trunk line get cleaned at once.

 

The current cleaning routine calls for covering 20 percent of the system each year, so that the entire system is covered in five years. But Weber hopes to shorten that cycle once the city acquires its combination truck.

City officials believe that moving the cleaning in-house will save money and improve service. Today, the city has only a jetter that can flush debris down lines. “We have no way of physically removing it,” Weber says. “With contract cleaning, we’ve been spending almost $100,000 a year. And we’ve got a city employee with that contractor most all of the time.”

 

To simply assign a two-person crew to the city’s own truck wouldn’t cost much more in labor, he says. “By the time we go through a five-year contract, we could pay for the truck and the maintenance on it.”

Better yet, doing the work in-house should enable the city to be more nimble. That’s especially important when it comes to cleaning lines near the streams, one of the city’s higher priorities. “You’ve got two times a year when you can get in there — when the ground is frozen, or when it’s extremely dry in the summer,” Weber says.

 

But coordinating with contractors and ensuring their availability at those times can be challenging. By assigning its own crews, the city can respond immediately. “Probably 75 percent of what we do is responding to the latest emergency,” says Weber. “So what you have planned, versus how things actually unfold, can be drastically different.”

 

Weber hopes the do-it-yourself approach will serve the city well — through lower costs, faster response, more predictable scheduling and better service to city residents.