Beneath the streets of Columbia, there are pipelines that will cost the city millions of dollars in repairs and maintenance. The system is aging, the city’s population is expanding, and flooding has overloaded the drainage system. All of this has caused an onslaught of issues for both sanitary and stormwater sewers. To alleviate those issues, the city introduced an integrated management plan to make fixes and updates in a methodical way.

How it all works

First, it’s important to understand how the sewer system works. Kori Thompson, engineering supervisor of Sewer and Stormwater Utilities, explains that the two systems are separated, thankfully, and end up in two different locations. Sanitary sewers are connected to residents’ homes via indoor plumbing and link up with the wastewater sewer underground to be transported to a treatment plant. The stormwater sewers, on the other hand, are connected to the city’s sewer drains. Those pipes hook up with the stormwater sewer and flow into various bodies of water in the area. 

Changing things up

Creating an integrated management plan (IMP) is a tall task for a community to undertake, so in 2011, the Environmental Protection Agency created a framework for what an IMP should look like. The guidelines give municipalities the flexibility to make infrastructure improvements that are necessary and cost-effective. In 2016, Columbia introduced its management plan for sanitary and stormwater sewers. It acts as a road map for the city to follow. The plan also provides a look at the next 20 years and attempts to lay out potential projects that will help address sewage issues while simultaneously saving the city money. Essentially, it attempts to fix problems before they occur. 

The Flat Branch Relief Sewer Project 3 impacts traffic between Elm and Cherry Street

Work on the Flat Branch sewer project closed Sixth Street in 2017. Some of the biggest issues caused by aging infrastructure are sewage overflows into the environment and backups into buildings.

Regulatory red tape

But it’s not as simple as just following the city’s plan. Federal and state regulations dictate what changes must be made first, regardless of urgency. However, because the city has an IMP, it can be flexible with its own 20-year timeline, rather than operating based solely on those mandates.

The city is also required to adhere to the provisions laid out by the Clean Water Act. That means that Columbia must not dump pollutants into the water, and the water has to maintain a certain quality level.

Why it matters

One of the key factors in determining the success of the plan is whether it can reduce the cost of these projects. Although the exact cost can’t be calculated now, the 2016 IMP report estimates that if these problems are addressed in the next 20 years, the total cost could be in the ballpark of $100 million, which would be $75 million less than if left unattended and addressed only when catastrophic. 

Ideally, the city will undertake future projects when needed over the 20-year span, saving the city money, and therefore saving citizens tax dollars. Thompson explains that the timeline allows the city to budget its funds, meaning any rate increases should be small and incremental.

Although some issues like wet weather overflows and sewer system maintenance might still need to be addressed, the IMP helps ensure that Columbia isn’t forced to handle them at the same time. Some projects outlined in the IMP are underway including one that rehabilitates aging biosolid facilities.  


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