Res faces uncertain future
by R.J. Grubb in The Arlington Advocate, Thursday, November 30, 2000

Like a story in progress, the Arlington Reservoir ebbs and flows - uncertain of its future.

Yet, faced with a state recommendation to fix the dam, the town is currently weighing questions, which may potentially alter the structure and recreation of the Res.

Concerned about dam safety, the state Department of Environmental Management recommended that the town cut down all the trees and bushes along the Reservoir's earthen dam.

The roots of the trees, it is argued, undermine the integrity of the dam structure. Proof of the dam's potential for disaster occurred in June when equipment failure flooded nearby Colonial Village.

Despite deforestation, other significant questions loom. For example, the high cost of maintaining and repairing the Res threatens its function as a public swimming facility and a wildlife habitat.

Faced with these projections, Gene Benson, member of the Vision 2020 Environment Task Force Group Reservoir Committee, said that the news is alarming on two levels.

"There will be significant changes to what the Res will look like in the near future," he said. "People are concerned about the report from DEM. They don't want to get rid of the trees and they don't what to get rid of the beach."

As a favorite summer swimming hole, locals frequently flock to the Res. As such, issues abound concerning impacts upon recreation, swimming, birding, walking, and playground use.

To bolster concern for the Res, the Reservoir Committee netted 1,400 responses from residents who replied to a survey inquiring about Res usage last year. Seventy-eight percent responded that they wished to maintain the Res for swimming. A full report of the survey results will be inserted in the town census mailing next month.

A 65-acre body of water, the Res is located on the Arlington/Lexington line between Massachusetts Avenue and Lowell Street. It was created in 1871 by the damming of Monroe Brook. The dam, an earthen embankment roughly 600 yards long and as much as 14 feet high, was originally built to supply drinking water for the town. But in 1899, Arlington joined the state's metropolitan water district and began receiving its water supply from sources outside the town.

The swimming area at the northern edge of the Res is separated from the main Res by a rock fill berm. The berm in its current condition does not hydraulically separate the beach area from the Res.

According to engineering consultants Weston & Sampson's September 2000 report, it was recommended to keep the Res at its lowest water level height of 153 feet and also to remove trees from along the dam to maintain the structure of the dam.

Yet, if the town keeps the elevation at 153 feet, either the beach area needs to be hydraulically isolated from the Res or a substitute for the beach area needs to be constructed, said the report.

Lowering the water elevation in the Res will also lower the water elevation in the beach area and might result in losing the use of the beach.

Currently the peak water level at the Res is at 159 feet, while the low is 153 feet.

On Monday, the Reservoir Committee hoped to hear a proposed "time line" or "management plan" from Director of Public Works Richard Bento at its monthly meeting. However, Bento, who is working on an analysis, has not finished his research.

"There's a half dozen solutions and I'm not really there yet," said Bento. "When enough facts are known and I have enough quantitative information, it will be in front of each board that has jurisdiction and that has an interest in the project. But I'm not far enough along yet."

The town is moving closer to making a decision regarding deforestation.

"The facts have not come out that will impact our strategy," said Bento. "We're getting closer to making a decision to the extent of how the dam is being deforested."

Ultimately, Bento said his "goal is to minimize the requirement for tree removal on the dam structure."

Regarding recreation, Bento also noted that his "target is not to lose a swimming season."

Discussions, however, are still pending about the specifics - and costs - of the plans which will include design, permitting costs, landscaping, and possible beach isolation.

Regarding monies, Bento acknowledged that he has no cost estimates regarding the studies. According to Bento, the town needs a plan that accurately locates the Res' topographical features. Such features would include an underwater survey which shows the upstream side of the dam, signs of seepage, sub-surface exploration, and a measure of soil stability.

"We need to take all the information and come up with a plan to fix the dam," he said.

Still the thicket of permitting will conceivably halt the process.

"The tricky part is getting permission from the Conservation Commissions here and in Lexington to investigate and fix the dam," he said.

Still, the town is not under the gun as the state has not mandated an enforcement order.

"[That's] good because it gives us options and time to find out what is best for the town," said Benson. "It's going to need a lot of citizen participation."

The next Reservoir Committee meeting is Wednesday, Dec. 20 at 7:30 p.m. in the second floor conference room.

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