Two of six sewer zones in the city now have modeling completed, according to Steve Casey, an engineer with Civil & Environmental Consultants, who has been hired by the city to analyze the system and recommend improvements.
Casey said the modeling allows engineers and city staff to more closely monitor sewer activity and identify areas that could benefit from improvement projects.
“Dating back to the mid-2000s, we worked with the city to get the sewer maps more up to date. Previously, they had been late-1970s [to] early-1980’ drawings, and so, we digitized those over a several-year-phase project,” Casey said. “Fast-forward several years: We worked with the city to come up with the idea of actually modeling the whole sewer system in an effort to better understand what you have and also to help plan for future improvement instead of just trying to do things and see how they work.”
In addition to the model, the city has also installed pressure gauges throughout the city to monitor water pressure more accurately.
The city’s model to date has helped identify issues on the north side of Belle Meade, the section of the city that has the most problems, Casey said. Public works officials said that area of the city gets the most calls for service.
Public works employees also said while most residents likely are not affected, high water pressure in some areas is causing equipment to wear out more quickly.
“The residents don’t notice it, but what we notice is the lifespan of the [pumps]: Where you should be getting eight years, we’re getting four,” Public Works Director Larry Smith said. “The pressures are so high, and these pumps are ready to pump a certain amount ... Eventually, it’s going to wear out faster.”
Smith said growth in the city since the early '80s has added a greater burden on the system.
“You’ve got larger houses with more bathrooms, with more plumbing. Some of these houses have three washing machines,” Smith said. “You’re adding more flow. It’s not what it was in 1955 or 1957 or even in 1983 when the system was installed.”
Should the city move forward with an improvement project on the north side of the city, which could include adding new pipelines parallel to existing pipes to relieve pressure,planning could begin as early as this summer, with construction taking place in 2021, Casey said. Costs for proposed improvements had not yet been determined, according to the city.