Following a test last summer that showed higher-than-average levels of haloacetic acid, the city of Ringgold has decided to implement a computer modeling system to better monitor the flow of its drinking water.
In late October, the city issued a letter to residents disclosing that the Environmental Protection Division (EPD) had tested a water sample that reflected high levels of "disinfection byproducts above drinking water standards."
According to the letter, the state safe level for haloacetic acid is set at .060mg/l, and the city's June reading exceeded that level with a reading of .063.mg/l.
In December, City Manager Dan Wright discussed the issue with the mayor and City Council, recommending that a modeling system be put in place to help prevent such a reading from occurring in the future.
"In my opinion, the water system that we have needs to have a computer model done on the system," Wright said. "In other words, we need to have someone put meters (on the system) that will measure the flow of the water in various locations around the city, take all of our water data that we have on file through GIS system, and with the topographical information we will be able to tell where weak and low flow areas are within the city."
Wright also stated that the abnormal reading could simply be the result of where the sample was pulled from.
"The EPD tries to find the most isolated, low-flow area in your system and that's what they did...they found the lowest area of our water flow and that's where we had to pull this particular sample," Wright explained. "With that said, the majority of our system of water customers, they aren't even on the same water tank as this particular location. It was totally different water so to speak. During this issue, I started asking questions. It turns out, we were pulling the sample from a vacant lot."
Wright said that the reason for the high testing could be due to the site not having consistent water flow.
"It's actually a mobile home that had burned...it's not like somebody is using water there all the time," Wright said. "There are concerns about the site that we're pulling the sample from because you need to have water flowing, in my opinion, to keep fresh water there. If the house is not even being occupied, then you know and I know there's no water being used."
Since the reading was taken last June, Wright says the city has increased the flushing out of the specified area, and that the city's water treatment plant has transitioned from powder to all liquid chemicals, which will garner "better readings on all aspects of our water."
After pitching the modeling plan to the board during the final City Council meeting of 2017, the board unanimously approved an engineering contract with CTI Engineering on Jan. 8 in the amount of $9,100.
"I think for the amount of money, a modeling of the system would be our absolute, most technical way of trying to address the issue that we were faced with back in October," Wright said.
Due to the EPD sampling taking place quarterly, Wright said there's a likelihood that one test could cause the city's average to report back higher than expected.
"Unfortunately, we will continue to have another letter that we'll have to send out at some point in time because they do it on averages, and it's going to take us a couple of quarters to get that one high reading off of our average because it kicked it up a little bit," Wright said. "I think we need to be prepared that we'll more than likely have to send out another letter."
Wright said Council members and staff have plans to include a cover letter in the future explaining why the abnormal reading came in.
"We want to really emphasize that this is not an emergency," he said. "There was a lot of concern there, and while we certainly take our water seriously, the form EPD gave us plainly stated it was not an emergency, we just need to make everybody aware of it."
Wright added that the area in question has been tested since the high reading, and that levels have returned to normal.
"It went way back down," Wright said.