Guilford reservoir

Walkers use the path around the Druid Hill Park Reservoir. (Kim Hairston, Baltimore Sun / October 12, 2012)

Baltimore's scenic reservoirs could be transformed into lakes criss-crossed by rowboats as the city removes them from the water supply to comply with a federal health mandate.

To meet the 2006 federal water safety rule to protect drinking water from contaminants, the city is spending tens of millions of dollars to install underground tanks to replace the reservoirs. The Department of Public Works will fill its small reservoir in Guilford to install tanks there, but other reservoirs will be decommissioned by 2018 and could become places for recreation.

"It is something that can take this neighborhood to the next level," said Baltimore City Councilman Nick Mosby, who represents the West Baltimore communities surrounding Druid Lake. He envisions it, without a perimeter fence, as a focal point for fireworks displays and a place for boaters.

The consequences of the reservoir decomissioning will ripple throughout the city's neighborhoods. The decision to take Druid Lake out of the water system may be a boon to Reservoir Hill. The choice to fill in Guilford's reservoir, community members say, could have the opposite effect if the site is not maintained.

"Our concern is the impact on housing values," said Catherine Boyne, who lives just south of the Guilford reservoir, a 7-acre body of drinking water off East Cold Spring Lane.

The city plans to replace the Guilford reservoir with two underground water storage tanks over a period of up to three years.

Baltimore gets most of its water from the Gunpowder River and the North Branch of the Patapsco River. Water from those sources is held in the Prettyboy, Loch Raven and Liberty reservoirs in Baltimore County before it is pumped through pipelines to three filtration plants in the city. The treated water then is moved to tanks and open-air reservoirs for storage until it is used by consumers.

In 2006, the Environmental Protection Agency instituted a rule requiring all water systems that use open-air reservoirs to hold "finished" water — water ready to drink — to either enclose the reservoirs or add another layer of treatment before the water comes out of faucets.

The rule is intended to reduce the possibility of contamination by biological agents that could enter water supplies by accident or poor oversight.

Two small reservoirs, in Mays Chapel and Pikesville, have been replaced by water storage tanks. A reservoir in Towson and another near Lake Montebello currently are being swapped for tanks. (Lake Montebello itself is a holding reservoir for untreated water.) The cost for those four locations is about $96 million.

The city now is hammering out plans for the Guilford, Druid Lake and Lake Ashburton reservoirs.

At the Guilford site, the city has planned for years to meet the federal mandate by draining and filling the reservoir, largely because 36 million gallons of water contained by an earthen dam there could cause substantial damage if the dam fails.

Under the Department of Public Works' current plan for Guilford, two tanks will be buried where the reservoir is now, creating hills in the center of what would become a field. There would be a pedestrian plaza created at the corner of East Old Cold Spring Lane and Reservoir Lane and a walking path would be constructed around the tanks, similar to the path that now encircles the reservoir.

"It has been 31/2 years of discussion between community members and the Bureau" of Water and Wastewater to reach agreement about the reservoir replacement plan, said Guilford Association President Tom Hobbs. But "there are still anxieties … existing in the community."

The community is preoccupied with what the rolling field is going to look like and how it would be kept up.

"There has been concern about the Bureau of Water's ability to maintain just the grass" at the reservoir as it is now, Hobbs said.

Boyne, too, expects the community will have problems getting Public Works to maintain the property after conversion. Maintaining a reservoir necessary for water service is one thing; maintaining green space around tanks may not be as important, she said.

The $44 million conversion of the Guilford site is not expected to begin for at least a year. Like the other reservoir conversion projects, all of the costs are to be paid with money collected from water bills. The Guilford conversion will be completed by February 2016, according to the city.

Druid Lake, at the southern tip of Druid Hill Park, also has an earthen dam. But the lake's enormity and the fact that the dam is not a major hazard has led Public Works to conclude it does not need to fill in the reservoir.