The City of Boulder is working with an engineering firm to remedy a potential source of contamination of one of the wells used for drinking water.
The source of potential contamination is surface water from an irrigation ditch that was moved too close to Well several years ago, according to Director of Public Works Dennis Wortman.
The possible contaminants are micro-particulates, which are not bacteria or viruses, and those have the potential to leach into the groundwater, said Council member Michael “Bear” Taylor when the issue was discussed at the Oct. 19 City Council meeting.
Micro-particulates are small particles, such as dirt, clays, sediments or algae, said Senior Construction Engineer Alan Erickson with Morrison-Maierle, who is assisting the city with this issue.
The city has published a notice concerning the issue and can be found on page 2 of this newspaper.
City Council President Drew Dawson described the notice, and the fix being initiated by the city, as “an abundance of caution.”
The city received notice on Aug. 19 from the Montana Department of Environmental Quality that Well 3 was under the direct influence of surface water that could result in contamination. The city has since reduced the use of Well 3 and has begun using Well 1 as the primary source of water.
The irrigation ditch that was moved by the state is located between Jefferson High School and the former Montana Development Center. Well 3 is located east of the high school.
The city is working with the state to get the ditch moved back at least 100 feet away from the well to meet state requirements, said Erickson.
In Montana, wells are evaluated on a point system, and Well 3 reached the threshold that triggered action by DEQ. Areas that received points include the distance of the ditch, the well intake construction, the static water level and the well seal. However, the water continues to test negative for fecal coliform, said Wortman, adding that the well was built before this point system was enacted.
Meanwhile, the city has increased water sampling from Well 3, as well as having increased the amount of chlorine and disinfection, and sample results are available at City Hall, said Erickson.
The weekly samples are looking for e-coli and fecal coliform and so far, all test results have been negative, said Erickson.
Before the city can take Well 3 offline, it needs to install a disinfection system on its backup well, number 2, the same system being used in Wells 1 and 3, and have that approved, said Erickson.
Removing Well 3 from service will eliminate the risk of introducing untreated surface water contaminants to the water distribution system, according to Erickson.
Using the back up well will give the city time to look at permanent solutions while remaining compliant with DEQ regulations, according to Erickson.
The city has 18 months to find a permanent fix, according to Erickson.
To get the process started, the city has applied for a Community Development Block Grant for $37,500, with a $12,500 match from the city for a total of $50,000.
Morrison-Maierle has provided a timeline for the project, which includes the distribution of informational mailers to water users and two public review and comments periods, currently scheduled for April and May of 2021.
The project also includes the completion of a preliminary engineering report that will assess the options available to the city, such as disinfection and filtering, reconstructing existing wells, drilling a new well, expanding current water treatment to existing wells or other improvements to meet state requirements.
