AUBURN – An updated analysis of proposed revisions to ordinances in the Lake Auburn watershed predicts the changes could reduce the amount of phosphorus entering the lake, but says that to achieve its overall goals, cities in the upper watershed must make similar changes.
In a news release Tuesday, city officials said the analysis shows Auburn is on the “right track” with its proposed changes.
City consultant FB Environmental of Portland has updated its previous modeling based on proposals to change the septic tank standard in the watershed, as well as move to a minimum lot size of three. acres from a minimum of one acre. The proposal to reduce the permitted density came in response to concerns that the updated septic tank ordinance would allow more residential development.
The new septic rules would allow landowners to use alternative soils in the design of septic systems – something that has not been allowed in the watershed, but has also restricted development. FB Environmental’s initial report recommended an update to a more efficient septic design, but acknowledged that the change would make more land available for development.
In May, the city council tabled a vote on the septic modifications, instead sending it back to the planning board to consider a zone change for larger lots and continue with updated modeling.
Following the new analysis, city staff recommended that officials implement both changes at the same time. The Planning Board held a workshop on updated modeling on Tuesday, which indicates the city’s proposed moves would reduce the total annual phosphorus load to 937 kilograms per year. The report gives an overall goal of reaching 900kg per year, which it says will likely depend on upper watershed towns like Minot, Turner and Buckfield to implement similar changes.
A memo from planning staff said: ‘This proposed zoning change is not a solution on its own, but would work with future proposals to limit phosphorus inputs to Lake Auburn. Increased phosphorus can lead to lower water quality, necessitating a filtration plant that would cost millions of dollars and increase water bills in the city.
The phosphorus load in 2018 was 1,114 kg, which was reduced to 842 kg in 2020 following an application of aluminum sulphate. The report says the 937kg level poses a “low risk” of triggering a breach of the waiver, but the 900kg level would pose “no” risk.
The city’s efforts to pursue the new septic ordinance, as well as the rezoning of land along the edge of the Lake Auburn watershed, have prompted an outcry from residents concerned about the development that could have a impact on the lake. This led to a petition effort, as well as “Protect Lake Auburn” lawn signs and a lawsuit from nearby Lewiston.
Tuesday’s press release said Auburn “has received confirmation that it is on the right track with proposed ordinance changes” and that the city can move forward toward its goal of “modernizing ordinances.” protection of lakes by limiting density and incorporating best practices in phosphorus control and underground sewage disposal in the Lake Auburn watershed.
Mayor Jason Levesque said Wednesday the city listened to residents’ concerns and “took a smart approach and then vetted it.”
“I am happy to see that all the work we are doing is on the right track and will make the lake healthier,” he said, adding that the city must now “force” its neighboring towns to adopt similar controls. phosphorus. “We did the hard work and the controversial work. We are not trying to damage the lake, we are trying to improve the lake.
Responses to the press release on the city’s Facebook page on Tuesday reflected the divisive nature of the ordinance changes. One person said the new analysis “does not change anything” to the “original recommendation not to develop the watershed further”.
The original report found “no net environmental, economic, or social benefits supporting the expansion of development in the Lake Auburn watershed.” However, among its recommendations was changing the watershed boundary along Gracelawn Road and updating the Septic Tanks Ordinance.
A “building analysis” showing the projected number of buildings that may be allowed in the future under the changes estimates 85 in Auburn and nearly 700 combined in cities in the upper watershed.
According to the report, the analysis used existing or proposed ordinances, existing natural features, and “other development constraints to estimate the number and location of possible new buildings under the simulated zoning.”
John Blais, deputy director of planning and permits, told the Planning Board on Tuesday that the city would need to implement septic design and reduce density “at the same time for it to be effective.”
“These two things have to happen together for water quality, in our view,” he said.
Asked about the possibility of modeling lower phosphorus levels than they are now, he said work was underway to identify sources of high phosphorus.
Levesque said the city will likely finalize the changes this fall.
Photo: Androscoggin Water Quality Monitoring