Underground issues that contribute to why Peers Street floods when it rains have been brought above ground.
“I figured out that it floods on Peers Street,” said Nathaniel Green, a joke that brought laughter from city officials.
Members of the city Streets and Sanitation Committee met and received an update on a storm water study currently being conducted.
Green is an engineer with James C. Hailey & Company. The firm was hired to conduct a city-wide storm water runoff study beginning with Peers Street. The end goal is to determine what can be done to alleviate flooding of low-lying properties within the city, a long-standing issue that residents routinely request board assistance in finding a solution.
“There’s a ditch going along Peers Street and that’s the first invert to a culvert that we have. We found that is an approximate 30-inch corrugated metal pipe. We found that it makes a turn going to a 24-inch corrugated metal pipe, which is a smaller pipe. Then, it makes another turn. This is where things get… I thought it was odd when we went from 30 inch to 24, but it gets even odder. You have 20 inch line, a 30 inch line coming into what is described as a 3-foot by 5-foot box.”
Using McMinnville Water and Sewer Department’s sewer inspection equipment, a camera system that is used inside pipes to locate breaks, roots or anything that would allow for inflow infiltration into the system, Green was allowed a look inside the pipes and container.
“There’s a lot of debris in it,” said Green. “Once you get to Chancery Street, there’s actually a sewer line that crosses through it, because sanitation sewer has to be put on grade (a downward slant). So, that’s an obstruction that you have in it. Then, there are multiple turns. The city was not able with the camera to get to those areas.”
The visual inspection entered a drain at Peers Street going towards Wash N’ Roll Car Wash and then entered a drain at the car wash back towards Peers Street and, according to Green, “went as far as they could go.”
A question was raised if the car washes in that area are using the storm drains or sanitary sewer.
“I’m hoping they are going into the sanitary sewer, but I couldn’t tell you,” said Green.
Alderman Everett Brock replied, “They’ve got soap, so they should be.”
“It’s not going into the sanitary sewer,” said Water and Sewer Department director Ricky Morton.
Public Works Department director Frank Southard added, “Their dumping into the storm drains. I’m pretty sure.”
“That brings up another issue that I’m not going to get into tonight,” said Green.
The inspection did find a partially collapsed pipe, which Green recommended the city repair.
After outlining issues that contribute to flooding on Peers Street, he offered options that the city could consider.
“So, what are your options?”asked Green rhetorically. “One option could be an increase to the size of the lines, which I think has to happen regardless. Then, you can decide what storm flow are we looking at? Are we looking at a two-year, 25-year, a 100-year storm or something in between? Then, you get to thinking about retention. Future development could also be a consideration, because impervious surfaces block rainfall from infiltrating the ground and add to problem.”
Green suggested that the city could also consider purchasing property that would remain undeveloped and used as storm water retention ponds to diminish surface runoff during rainfall events.
Alderman Steve Harvey asked, “So, what’s your recommendation?”
“I’d upsize some pipes,” said Green, who also recommended test excavations, called potholing, to be undertaken. “The biggest thing I’d like to do right now and it will take a little bit of a commitment from the city is potholing and figuring out what some of these line sizes are. That’s the commitment I’d like you guys to make right now – dig down and find them and figure out what size they are. Part of it is collapsed, so I know we need to fix that part.”
Committee members unanimously approved the exploratory test excavations, as recommended.
