A view of Route 4 and the public boat launch on Lake Auburn in 2017. Sun Journal photo by Russ Dillingham

AUBURN — The commission responsible for protecting the public drinking water source for the Twin Cities said it is opposed to amendments to the city’s agricultural zone, which it argues could cause “irreparable harm” to Lake Auburn.

The proposed amendments, which are under consideration by the Planning Board, were the result of a controversial process intended to loosen the zone’s historically strict rules, making it easier for people to build homes on land they own, while encouraging small agricultural operations.

The Agriculture and Resource Protection zone accounts for about 40 percent of the city’s land, and the amendments as written would also impact land within the Lake Auburn Watershed Overlay District.

On Thursday, the Lake Auburn Watershed Protection Commission sent a resolution to the Planning Board and City Council stating its opposition to the proposal.

“The commission’s opposition to these particular amendments within the watershed is grounded in the principle that development damages the lake,” a news release from the commission said. “The science available to date not only supports this conclusion, it encourages more restrictions on development within the watershed.”

The commission said its opinion relates solely to the part of the zone in the watershed.

The resolution highlights the friction that has bubbled up over the past year over water quality at the lake, as water officials are monitoring more phosphorus and algae production in the water at the same time Mayor Jason Levesque has called for the district to consider building a filtration plant.

Since 1991, the district has had a waiver of filtration from the federal drinking water program, allowing it to deliver unfiltered water. To keep it, the water quality must continue to meet high purity standards.

Levesque and others have argued that it’s only a matter of time before the district loses the waiver, at which point it will be forced to build a filtration plant.

However, Auburn Water District Superintendent Sid Hazelton has estimated a filtration plant could cost between $35 million and $40 million and would increase local water rates. Hazelton also serves as clerk for the watershed protection commission and issued the news release Thursday.

Lewiston officials so far have mostly stayed on the sidelines of the filtration issue. In Auburn, Levesque plans to go ahead with a proposed committee to study water filtration even after the City Council voted not to support it.

The resolution from the commission argues the standards within the agricultural zone are “a critical component of the commission’s efforts to protect and preserve the water quality at Lake Auburn.” It insists the standards not be amended “in any manner that would relax development standards for land located within the physical boundaries of the Lake Auburn Watershed Overlay District.”

The zoning amendments were drafted in the hope of modernizing Auburn’s agricultural zone, but many who live in the zone still have concerns about how it should be executed.

Since the 1960s, zoning laws have stipulated that in order to build a house in the zone, a property owner must have at least 10 acres and earn 50 percent of household income from agriculture or forestry.

The changes proposed by Levesque’s action group on agriculture would lower the standards to allow anyone with at least 3 acres to build a house, and would also amend the definition of a farmer and dramatically ease the current income standard.

Levesque said Thursday the opinion from the watershed protection commission means that the group “recognizes the fragility of the watershed, which brings it back to my point that we need to take action” regarding a filtration plant.

He said the move also highlights a “push and pull” between agriculture and the watershed, as additional farms could potentially add to stormwater runoff and more nutrients reaching the lake.

“It’s a balance,” he said. “At what point do we say nothing can happen in a huge swath of land in Auburn?”

Levesque added he “values the input” of the commission, and said the Planning Board could consider a modification to the ordinance to not allow the amendments in the watershed.

The amendments to the zone are “not about development,” he said. Rather, they are designed to encourage “small agriculture industries.”

The commission’s news release Thursday continues the group’s argument that the watershed is vulnerable and needs to be protected from more development.

“Proponents might disagree with the commission’s concerns regarding the impact of additional development but, if they are wrong, irreparable harm will occur leading to a loss of this invaluable resource to the two cities,” the release said.

“The negative impact of delaying some development will not outweigh the benefit of preserving the lake’s quality.”

During a recent Great Falls Forum in Lewiston, Holly Ewing, a Lake Auburn researcher and Bates College professor, said as more nutrients enter the lake, further watershed protection will be needed to stave off irreparable damage.

Levesque said the Planning Board is taking up the zoning amendments over several meetings, with input from state experts on agriculture and modern farming techniques. It will then move to the City Council for consideration, likely in June.

arice@sunjournal.com