Polyurethane For Infrastructure Repair
CLARKSVILLE — The town of Clarksville has entered into a contract for sanitary sewer work in the Stansifer Avenue area which is expected to alleviate some inflow and infiltration issues in the area.
The town council voted unanimously Monday in favor of a $37,200 contract with Heritage Engineering, LLC to survey and design new sanitary sewer lines along Stansifer, and Howard and Park avenues in south Clarksville.
“The reason that we need to do it is that we’ve had a lot of problems with inflow and infiltration in the area and we’ve tried to identify where it’s coming from,” Brittany Montgomery, utilities and capital project coordinator for Clarksville, said. “We have found a couple of storm sewers that are connected into the sanitary sewer and we believe there may be more.”
Sanitary sewers are the ones that carry waste from residential and public facilities’ toilets, sinks or other drains. Storm sewers contain runoff from rain and other drainage outside.
Montgomery said part of the issue comes from infrastructure improvements in this part of town in the 1940s and 1950s.
“The new sanitary sewers were laid and they were separated from the storm sewer; it used to just all go to the river,” she said. “What we’ve found is there are places where there isn’t complete separation. Some of the storm sewers were turned into sanitary sewers but they still get runoff as if they were storm sewers.”
One such area they have identified is on Park Avenue between Howard and Arlington avenues where there is a flood control flap-gate connected into the storm sewer, she said.
“That’s the one we have positively identified,” she said. “Through dye testing, we identified the possibility of some catch basins at Stansifer and Park, but we won’t be able to fully confirm that until we get it opened up to see exactly what’s connected.”
Montgomery said the goal is to start construction by late fall, work through the winter and be ready for paving in spring.
As another way to help reduce the inflow and infiltration in town, the council approved a $76,107 contract with Groundworks Solutions to repair and secure around 20 manholes.
A report from Stantec, the company that mapped the town’s sanitary sewer system throughout 2014, showed that there were 474 manholes that needed to be further reviewed. According to Montgomery’s staff report, utilities staff reviewed and categorized ones that needed to be cleaned only, ones that were OK and ones that needed bigger repairs.
New concrete liners will be installed in nine of them, and 11 will get polyurethane injections in certain areas to stop the infiltration of water. Three manholes will have both a new liner and the polyurethane.
Montgomery said the town has worked with Groundworks Solutions before; last summer the company did repairs around sewer access points connected with pump station 33, which is on the east side of I-65. She said those repairs have saved an estimated million gallons of flow a month.
“We contacted the same company to have the same technology because we knew it worked,” she said. “We saw it work.”
The nine spots that will get new liners, Montgomery said, will be a proactive solution to keep serious issues from happening.
“It will provide the structural stability and help prevent the possibility of collapse, because some of these manholes are in very bad shape,” she said. “So this will prevent the need to go back and do a complete replacement.
“It will prolong the life on these, which gives us another 20 years.”
The polyurethane fills are scheduled for later this month and the concrete liners for the end of September.