AUGUSTA — A proposal to build a 1-million-gallon, roughly 100-foot diameter concrete tank that would hold a combination of stormwater and sewage on Greater Augusta Utility District land next to the city’s East Side Boat Landing on the Kennebec River is the most affordable option, at the most practical available site in the city, and would be done with an eye on its appearance, district officials assured city councilors Thursday.

City officials expressed concern about the visual effect of such a large tank so close to the boat landing, as well as its potential visibility from the Kennebec River and from the downtown area across the river, which has been the focus of extensive redevelopment efforts in recent years.

District Trustees Patrick Paradis and Cecil Munson, both former city councilors, and Superintendent Brian Tarbuck met with councilors Thursday to discuss the proposal, in a meeting requested by City Manager William Bridgeo after he heard about the proposed tank. They said the district would seek to have the tank situated as low as possible on the site, without taking on the major added cost of burying it underground, and would be creative in finding ways to make the tank blend in so it wouldn’t be an eyesore or a visual blemish prominent from the river or the downtown area just beyond it.

Munson said the district has many options that could help improve the proposed tank’s appearance, which he said could include having a brick facade on it, or screening it with trees so it wouldn’t be visible from across the river.

Tarbuck said an artist even could do a painting on the tank.

Munson noted that what he described as an ugly, small district building on the site now would be removed as part of the project.

“Hopefully it could improve the appearance” of what is there now, Munson said of the tank project.

Bridgeo said he assumes the district would be willing to invest a small amount of additional funds into the project to “create something that is attractive, or possibly even a draw for tourists.”

Tarbuck noted the proposal is in its preliminary stages and the district’s own board of trustees hasn’t had an extensive presentation about the proposed tank. He said it still remains to be determined whether the tank would work at the site, and, if so, what its height and diameter would be.

He said it would likely be roughly the same height at the utility district’s garage, which is on Arsenal Street just above the proposed tank site.

The proposal is the district’s latest step in an ongoing, multi-million-dollar effort to install systems to prevent the overflow of sewage into the river during major rainstorms. The goal for adding the new tank to the district’s existing infrastructure would be to catch overflow during heavy rainfall when so much stormwater, combined with sewage, enters into the treatment system that it becomes unable to treat it all.

During such major storms, the tank would collect combined stormwater and untreated sewage that otherwise might overflow into the river. Once the storm subsides and the plant is functioning normally, the fluid would be released from the tank and sent to the treatment plant to be treated.

Tarbuck said using an above-ground tank would save the district, and its ratepayers, millions of dollars. Underground tanks cost around $5 per gallon to build, while an above-ground tank could be built for as little as $1 per gallon, he said.

He said the site is ideal, which could provide additional savings compared to the cost of building elsewhere. The site is low, helping gravity move stormwater and sewage to the site, and a pump station already is there, so a new pump station for the tank wouldn’t need to be built.

Tarbuck also said underground tanks are harder to maintain safely.

“For a lot of different reasons, this option rose to the top,” he said. “So that’s the one we’re considering now.”

Bridgeo said the Planning Board would review the proposal at some point, but the city might be unable to reject the proposal.

Marci Alexander, at-large city councilor, noted the district saving money would save ratepayers money and, because the city is the district’s biggest customer, also save taxpayers money. She said there are creative people in Augusta who could help come up with ways to ensure the tank has an attractive appearance.

“It would keep rates down and thus help keep taxes down,” she said, “and you’re going to look at aesthetics; that’s good.”

In 2012 and 2013, the utilities district in a $15 million project installed two massive, 670-foot-long storage tanks under Mill Park to collect combined sewer overflow on the west side of the river. The district also has another underground storage tank under a portion of the Kennebec River Rail Trail, which cost about $10 million. The proposed new tank would be the last major piece of infrastructure needed to prevent most overflows and be in compliance with state Department of Environmental Protection requirements regarding overflows.

Munson said when he first learned of the project after he became a district trustee, it was estimated a new underground tank would cost about $10 million. He said engineering changes brought the cost down to an estimated $4 million. He said the above-ground option is expected to be much cheaper than any of the other options the district has looked at.

Tarbuck said construction ideally could start in about a year. He said the district has been working on complying with DEP mandates to prevent overflows for more than 30 years, and has a deadline of 2020.

District trustees and city councilors are expected to discuss the proposed tank at an Oct. 25 meeting.

Keith Edwards — 621-5647

[email protected]

Twitter: @kedwardskj