Sewer inventory results are in: it’s not all good news

 

On Monday night, Prein&Newhof engineers Mark Prein and Steve Oosting attended Rockford’s City Council meeting to present additional findings from their evaluation of the City’s stormwater and wastewater systems. This work is compliments of the $843,470 Stormwater Asset Management and Wastewater grant program that the Michigan Department of Environmental Quality (MDEQ) awarded Rockford to determine the condition of our system.

Prein&Newhof partnered with the City of Rockford to apply for the MDEQ grant. When Rockford received notice about three years ago that it was selected as a recipient of this sizable grant, the City hired Prein&Newhof to accomplish this significant work within the MDEQ’s three-year timeline. Prein&Newhof got busy inventorying our stormwater and wastewater assets, using surveying, smoke-testing, and specialized cameras. By knowing the condition of our underground assets, Rockford will be able to prioritize where and how best to make improvements to them.

“Rockford has a lot of underground assets,” said Project Engineer Steve Oosting. “You have 93 miles of drinking water, sanitary sewer, and stormwater piping. For perspective, the drive from Rockford to Cadillac is 85 miles!”

“Most of your sanitary sewer system is in pretty good shape,” said Mark Prein, “but the older parts of the system have some problems to address. About one-third of your sanitary sewer pipes were installed in or before the 1960s. About seven percent (approximately 2 miles) of these pipes are about 100 years old; they date from the 1920s or before.”

Oosting used the chart above to share the age of our sanitary sewer system and said, “Many of the problems we found were with the old clay pipes.” He explained that clay pipe is brittle and any force on it can cause it to crack; varying soil conditions and tree roots are both frequent culprits. Also the joints of the clay pipes have deteriorated and weakened over the years. “It’s common for groundwater to seep into the sanitary sewer pipes, which is an unnecessary load that you are paying to treat at the PARCC Side Clean Water Plant,” Oosting said.

Oosting shared two “Risk of Failure Maps” that Prein&Newhof created. One identifies the condition of Rockford’s sanitary sewers pipes and the other the condition of our storm sewer pipes. The document of most concern is the “Sanitary Sewer Risk of Failure Map”. This map provides the condition ratings for all of our sanitary sewer pipes throughout the City and also identifies the location of our five Lift Stations. The map legend uses a five-point rating scale of ‘Good’ to ‘Failing’ and an associated color key.

Almost 65% of Rockford’s sanitary sewer system is currently in ‘Good’ condition. According to Prein, “We are most concerned about the 2.8% that received the ‘Failing’ rating and the 8.4% that received the ‘Poor’ rating,” he said. “When you locate these sewer pipes on the map, you can see that a lot of them are in your downtown area and along the Rogue River, both of which we want to protect and preserve.” What could happen with a sewer pipe failure? There could be sinkholes in our streets, sewer backups in our homes and businesses, and overflows into the Rogue River. Some investment in repairs and replacements will be needed to reduce these risks and to renew the life of our aging system.

In addition to minimizing our risk of system failure, Oosting said that Prein&Newhof has figured out how to save the City of Rockford money in the routine operation of our system. “We are excited to share that we believe we may be able to help you eliminate the need for one of your five Lift Stations,” said Oosting.

Why does this matter? Our wastewater flows by gravity through our sanitary sewers and then is pumped by lift stations to the treatment plant. Lift Stations cost money to operate and also to maintain. Oosting said, “Some of your Lift Stations currently require a lot of maintenance. We think we found a way to eliminate one of your Lift Stations by building a new sewer line that would allow the wastewater to flow by gravity, resulting in significant ongoing savings.” This is an example of asset management in action. According to Oosting, “The goal of this asset management program is to use the data to find the best alternatives to achieve the lowest life cycle cost, not the lowest immediate cost.” He explained that this requires taking a long range view of our system.

“I know it’s not all good news,” said Mark Prein, “but by having access to all of this information Rockford has the power to provide a stable infrastructure at the lowest long–term cost. The City is proactive and this gives you a game-changing tool to reduce costly, emergency repairs by prioritizing planned replacements.”

Prein&Newhof will continue working with the City to prioritize repairs and to develop a financial plan based on all of the new information. The City Council has scheduled a work session with Prein&Newhof in March to continue the planning work.

The City also recently hired Prein&Newhof to help inventory and evaluate our drinking water system.