The city’s sewer separation is finally complete. Sophisticated equipment has allowed the wastewater department to literally see and identify problems in any pipes or parts of the system. The system, itself, is being expanded to provide additional storage capability to reduce the number of times that heavy rain and/or flooding causes overflows into the Yellow River.
Work is currently being performed to “take the bottleneck out” of a portion of the sewer system, Davidson said recently. Working with Commonwealth Engineer-ing in a process called modeling, the city found large diameter sewers in the area of the Conservation Clubhouse on Magnetic Parkway. But smaller lines were feeding into it. Working on those lines on East Jefferson Street along the Yellow River, as well as at the wastewater plant out on Oakhill Avenue, and in the area of 6th Street, problems are being resolved.
Davidson said the East Jefferson Street work included a lot of earth moving because the sewer line actually runs north-south under the river all the way to the old city parking lot on the south side of the former Cook Brothers Furniture Store on South Michigan Street. The Yellow River snakes its way from East Jefferson in some major curves to eventually cross South Michigan Street. That portion of the sewer line was increased in size, Davidson points out, to reduce overflows into the river at a couple of points.
One of the goals is to “get the park area in the downtown restored so the public can use it,” Davidson explained. The park, which has been prone to flooding as the Yellow River overflowed its banks, is to be linked with a future phase of the city’s Greenways Trails, a part of the park department’s program. Plans call for the downtown park’s usage to include being a pleasant place for workers to go for an outdoors lunch, the site of future festivals, and more.
“It’s not going to be an eyesore,” Davidson said of the new sewer system at the park area. “The public won’t even see it. I think it’s going to be a good example of how we can blend the critical needs of the population with the everyday quality of life experiences we all want.”
All of the pipes are air-tested, and manholes – much larger than an actual man – are “gasketed” so that no water or debris can compromise the new system, Davidson said. The work is to provide what’s called a “10-year, one-hour storm event.” The public is more familiar with the “100-year storm event” terminology, Davidson understands. The new terminology meals that the system is designed to prevent overflows of up to a 1.33-inch rainfall lasting over a one-hour period of time, he explained.
The goal, once the construction is completed, is to “reduce overflows down to four or less a year,” he said. “And, of course, that’s all driven by weather.”
At the wastewater plant, capability to provide extra storage of wastewater should also help reduce overflows. There, a system of four rows of 5-foot diameter pipes averaging 200 feet in length and 10-foot manholes is being added. And there will be room for more should conditions – or future IDEM mandates – warrant. The result is an additional 140,000 gallons of storage, which will directly benefit the Cleveland Street area, for example.
In 2007, there were only four overflows of the Yellow River, Davidson reported. Those amounted to about 1.8 million total gallons, and “most were stormwater runoff,” he said. EPA guidelines helped him calculate that about 20 percent of the total was estimated as sewage.
Cost for phase two of the plan, including professional and construction fees, is about $2.1 million, Davidson said.
So, what happens after all the construction is completed? The beginning of a two-year period of system monitoring and data collection to see what’s working and what’s not, Davidson explained.
Monitoring also will be done so that professional cleaning and maintenance can continue. “That never ends,” Davidson said, adding that it accounts for a large portion of his department’s annual budget. Monitoring includes accounting for industrial waste discharged by area businesses.
“Industry here has been, on the whole, very cooperative,” Davidson said of monitoring required by IDEM. “They all realize we need to continue to meet our mandates.”
For the next two years the wastewater and sewage department professionals will analyze data to see how effective their plan has become in establishing a system of checks and balances to reduce discharges directly into the Yellow River. Davidson hopes the city is on the right path, and he may have good reason to believe.
A program to “tag” manholes and other common areas of direct discharge to the Yellow River has people paying attention. Workers placed small, round, blue metal markers on the outlets.
“I think it’s been very effective,” Davidson said. “A lot of people have told me they never knew it went straight to the river from there. And, something as small as that probably gets more attention, especially with the kids downtown. They see it, and that’s where education begins. They go home and ask their parents.”
Efforts by the Plymouth community – from the wastewater and sewer department to businesses, homeowners, and children – are helping not only to make the Yellow River cleaner and improve the numbers and variety of fish and adjacent wildlife and plants, but also are part of a bigger plan to clean our country’s national waters. And the community is doing it at a cost of $2.10 per thousand gallons of water it treats.