Years of I&I Remediation Are Paying Off for This Iowa City

I&I work is never done, but the plan is coming together for Indianola, Iowa.

Years of I&I Remediation Are Paying Off for This Iowa City

Wastewater operators Tye Herrick (left) and Norman Hart work on clearing out a blocked line in Indianola, Iowa.

Water leaking out of a water pipe is bad enough. Rainwater leaking into a sewer collections system is a headache of another sort because it strains wastewater treatment facilities. Then there’s the matter of wastewater leaking out into neighboring soils, introducing pollutants into groundwater. Indianola, Iowa, has experienced all of the above but is well on its way to restoring the integrity of its sewer lines.

The Warren County seat in south-central Iowa had an awakening in 2009 when the state’s Department of Natural Resources issued a mandate to the city of 16,000 people to remove all groundwater from its sewer collections system. Total elimination of inflow and infiltration is pretty much an impossible task given the ability of water to get around gaskets, seals and other sealants, but the DNR wasn’t looking for perfection.

It ultimately settled for less, lifting the mandate in 2014 on the strength of progress made and the community’s pledge to keep reducing I&I. City Manager Ryan Waller and wastewater department Superintendent Rick Graves have been overseeing the effort to live up to the terms of the consent order since their arrival in 2016 and 2015, respectively.

“My understanding is that the data point for I&I was fairly high in 2009, leading the DNR to issue its order,” Graves says. The city’s Water Pollution Control employees subsequently worked their way through the system, first inspecting and sealing manholes against water infiltration. Then they methodically inspected the network of pipes — one quadrant of the city at a time — searching out leak-points in pipe that averages 35 to 40 years old.

Inspection results

The inspection turned up lots of lateral line problems, but also significant infusions of groundwater in sewer mains. In 2017, Indianola’s city council approved a regimen of pipe inspections on private properties with penalties for failure to correct discovered problems. Property transactions required inspection of sewer laterals and hookups.

Typical violations called out by inspectors included the connection of roof gutters and sump pumps to the sanitary sewer system, cracking of laterals by tree roots or aging, and uncapped cleanout pipes. The inspections on private properties became voluntary in 2018. In the interim, some of the oldest properties were inspected and corrected. The community’s newer housing stock generally harbored fewer improper hookups and aging laterals.

“We still have some issues with laterals,” says Graves. However, City Hall is counting on property buyers volunteering for inspections to protect their investment. “We’re going to move ahead and get our sewer mains buttoned up and go from there.”

“When Rick and I got here, not much was being done,” Waller says. “So, we had conversations with our community partners at local real estate offices and they had a hand in crafting the inspection ordinance. That was a good thing. The question was how we could work with residents and Realtors in selling our community. The collaborative effort was in the best interests of the property owners and of the department.”

Working with the various components of the community is a key guideline for Waller. He refers to the Four C’s — communication, collaboration, community engagement and customer service — in talking about that work.

“The state’s mandate was kind of a heavy hand, and the first smoke-testing to find leaks had a negative connotation in the community,” he says, looking back. “We have a great team and hosted a community meeting to share with residents what we were doing, showing them that collapsed lines cost them money and that the inspections were doing them a service. We didn’t want to come down heavy handed, too.”

The interaction had the residual effect of building long-term public trust in the administration and the wastewater department. That makes sewer rate increases more palatable for residents. In fact, Indianola recently raised its rates for the first time in seven years, upping them to a base rate of $18 for the first thousand gallons and $9.85 per thousand gallons after that. Some of the money will help fund the city’s new wastewater treatment plant.

“Nobody likes rate adjustments,” Waller says. “But we’ve not heard many complaints. We’ve had a lot of conversations the last several years. The community understands we can’t get out of meeting state regulations.”

I&I work ongoing

The I&I issues remaining to be addressed are not negligible. Graves estimates that as much as a million gallons of rainwater still infiltrate the city’s sewer system on a rainy day. “Here’s an example of that. We had about an inch of rain on Nov. 10 of last year and our flows jumped up 700,000 gallons a day for two days and then went right back to normal. An extra 1.4 million gallons of flow. I call it a spike event.”

To reduce that big number to something more incidental, Indianola is budgeting $250,000 a year for inflow and infiltration corrective work. In 2020, that funded lining of 2,300 feet of pipe in 10 sewer main sections and 50 laterals. In addition, 10 manholes were repaired. This fiscal year, an equivalent amount of sewer main was completed by December and the lateral work continues.

That level of investment in the system will continue for the foreseeable future along with $30,000 a year for replacement of lift station pumps. The type of projects varies from year to year. For example, the current contract calls for additional manhole makeovers, less than a thousand feet of sanitary sewer lining and about 350 feet of storm sewer repair. 

Private partners

The heaviest part of the city’s ongoing and planned infrastructure work will be bid out. Waller, who has worked in the industry for 20 years, says contracting out some services ensures that vital infrastructure is in the best shape possible. 

“We do projects in-house when we have the equipment to do it. Our team does a great job televising and cleaning lines and replacing manholes. Sometimes, though, we bid out those jobs, too. Smoke services is one of the services we typically partner with the private sector to get done.”

The excess work is prioritized and competitively bid, even spot repairs. In the last round of bids, a trio of Iowa companies won contracts. Municipal Pipe and Tool lined the mains. Central Iowa Televising worked on laterals. Dependable Maintenance Systems overhauled manholes.

Sewer lines mostly are 8-inch clay, with some PVC mixed in, according to Graves, with larger sections of pipe ranging up to 30 inches. To keep an eye on the buried infrastructure, the department calls on its 3-year-old CUES push-camera system and an even newer Envirosight Rovver X sewer inspection crawler.

The department has budgeted the purchase of a Bobcat Toolcat in 2022. Among other uses, the compact loader will carry the Envirosight system to less accessible sewer mains along with a Honda generator to power the camera system. To clean the lines, the city has a Vactor 2100 jetter rig.

Graves came to Indianola after a dozen years of serving as superintendent for two other Iowa sewer systems and is licensed for a variety of wastewater treatment and distribution tasks. “He’s the expert,” Waller says. As such, Graves is well qualified to oversee cross-training of his crew. Cleaning pipe. Repairing pumps. Running the cameras.

“We do 50,000 feet a year of camera work,” the superintendent says. “Everyone works at it in rotating shifts, with four operators working in the collections system and another person in the lab.”

The result is a sewer system that, despite ongoing I&I repair work, is in “a pretty good place,” he says. “The last three or four years have helped considerably.”

Waller concurs. “I was just talking to staff about that. Anything related to municipal work and infrastructure — the work is never done. You say, for example, we have all the streets paved, so the end is in sight, but that’s not possible. Yes, we have more I&I work to do and the storm sewers need a little more TLC, but they’re not in bad shape. We’re sitting pretty nice. We’re good.” 



Discussion

Comments on this site are submitted by users and are not endorsed by nor do they reflect the views or opinions of COLE Publishing, Inc. Comments are moderated before being posted.