The refurbishment is part of a larger project to upgrade Highland Park, which is shared between western Queens and Brooklyn.
The reservoir was built in 1856 on a natural basin and remained in regular service until 1959. It was used sporadically as a back-up water supply for the two boroughs until 1989, but its basins have become overgrown with vegetation over the intervening years. Today, the reservoir consists of three basins, pump houses and a caretaker's cottage, but the majority of the park is undeveloped.
There is no water in the reservoir's basins, which contain marshes, birds, vegetation and forest land.
But preservationists said they were upset that the reservoir's third basin would be breached in all three of the plans.
"This is going to affect the species in the basin," said Christina Wilkinson, a member of the Juniper Park Civic Association. "There are perfectly good recreational opportunities at Highland Park by refurbishing fields that are already there and not destroying natural space."
Park Slope bird watcher and preservationist Rob Jett said that endangered species of plants have been identified in the reservoir's third basin, which is the largest of the three basins.
"I'm very leery of what [Parks officials] say they are going to do," he said. "I think the least intrusive plan is leaving it as a nature preserve. But, if they breach the third basin, they won't do much to preserve the forest that is inside of it."
But a spokesman for the Parks Department said the agency would take recommendations from city environmental groups and neighborhood resident associations into account.
"We're looking at the different options and presenting them to community groups for feedback," he said.
He said the department would conduct meetings in the near future with community boards from the two boroughs.
Parks officials said design plans for the park would probably be completed in 2008 and that a ground breaking could be held in 2009. The plan will need approval from Community Board 5, Borough President Helen Marshall and Councilman Dennis Gallagher (R-Middle Village), as well as elected officials and community boards in Brooklyn.