AUBURN — A $1 million bond issue would pay for treatments to cut down on algae in Lake Auburn and replace some city water mains, Water District Superintendent John Storer told city councilors on Monday.
Storer made the case for the borrowing package at the council’s Monday workshop meeting. A water rate increase, approved last year that went into effect in January, will cover the debt payments on the bond issue.
“We know that $1 million is a lot of money by any stretch,” Storer said. “But we have to get the lake back in shape if it is going to be any kind of supply for us in the future.”
Storer said the $1 million bond would pay for Auburn’s share of a $2 million treatment plan. The Lewiston Water Department would be expected to pay the remaining $1 million.
Water quality officials discovered more than 200 dead trout along the shore or floating close to the shore in mid-September 2012. They blamed the kill on high phosphorous levels in the lake.
Phosphorous in the water encourages algae to grow, using up available oxygen in the water and suffocating the fish in the lake. The effect is especially notable in the cooler water at the bottom of the lake, where trout like to be in the hot summers.
Storer said water officials have studied the lake and the surrounding shoreline and are unsure exactly where the phosphorous came from. They stepped up testing at the lake last summer, looking for dissolved oxygen and visibility in the water. The blue-green algae has not returned, but the lake was plagued by a cucumber-smelling algae called Synura last summer.
Storer said the current plan is to treat the lake’s water with aluminum sulfate — also known as alum. It binds with the phosphorous and makes it sink to the bottom of the lake.
“The intent is to add these chemicals, under the guidance of the Maine drinking water program,” Storer said. “It’ll strip some of the phosphorous from the water column and serve to create kind of a binding effect on the bottom. That will prevent the phosphorous from becoming part of the algae’s food cycle in the future. It really creates an inert bottom shell that the algae can’t tap into.”
The City Charter requires City Council approval for any bond issue, and Storer said he expects to bring the matter back for a vote at the March 3 meeting.
But Mayor Jonathan LaBonte said it may be time to investigate other treatment options or water sources.
“If there are alternative water supplies that could serve Auburn, or Auburn and Lewiston, we ought to start having those conversations,” LaBonte said. “We’ve made a long-term commitment to growth around the southern end of Lake Auburn. If this council or the community feels that creating a resort or other high-end development around the lake should be part of our effort to grow our tax base, we ought to be able to have that on the table.”
LaBonte said the water district should seriously investigate building a filtration plant to treat the Twin Cities’ drinking water. It might allow the water district and the Lake Auburn Watershed Protection Commission to ease building restrictions around the lake.
Storer said that his best guess estimates say a filtration system would cost the cities about $30 million and would not ease building restrictions.
“When you talk about filtration, you need to start from a pretty good source to start with,” Storer said. “We’d still need to control the raw water quality of Lake Auburn. We would not want to let it decay, where we have phosphorous and algae blooms or sediment.”