Should the enormous Centennial Watershed State Forest be more accessible to residents?

Connecticut's 15,300-acre Centennial Watershed State Forest centered in Fairfield County is mammoth by the region's standards and continues to rank, more than 10 years after its $90 million purchase, as the state's most expansive and costly public land deal ever.

A patchwork of hundreds of often hard-to-find and mostly small parcels sprawling across 28 municipalities, its establishment helped preserve what the Nature Conservancy's Connecticut chapter calls "a natural cloister," consisting of "pristine waters and woodlands, " and "a remarkable remnant of coastal forest that once stretched along the eastern seaboard from Virginia to Central Maine."

But it's public land that is nearly all off-limits to the public because of worries about drinking-water safety. A soon-to-be adopted 10-year management plan for the forest contemplates no further public access, nor public input. This in spite of a mandate for access contained in legislation that created the forest and despite the national example set by New York City's expansive public access to the 150,000 acres it holds as watershed.

"The more people you get on the property, the more problems you have," says Jerry Milne, who is the state's leading man on a three-person panel that manages the forest. Other members represent Aquarion Water Co., which sold the land to the state, as well as the Nature Conservancy, which provided $10 million toward the purchase price a decade ago.

State law enabling the acquisition from Aquarion explicitly requires that the property be preserved for protection of natural resources "while allowing for recreation consistent with such protection."

Yet Steve Patton, who represents the Nature Conservancy on the state forest management committee, concurs with Milne that public access is "a slippery slope."

"Protecting the health of the forest and water supply is really what this project is about," says Patton, who also manages the 1,750-acre Devils Den Preserve in Weston for the Nature Conservancy and who explains that his group, a national organization, "generally doesn't provide a lot of public access" to its properties.

Shutting out the public is in sharp contrast to an approach taken by the New York City's Department of Conservation, a public water utility. About 72 percent of that agency's roughly 150,000 acres of watershed land in the Catskills and also in the heavily populated Westchester and Putnam counties is open to hiking, fishing and hunting. That city property doesn't include more than 30,000 acres of its reservoir surfaces open to non-motorized fishing boats.

The New York City agency, which touts itself as "the safest and most cost-effective water utility in the nation," has more than doubled the watershed acreage it owns that is available for recreation since 2003. Its current strategic plan calls for further expanding public access, adding 7,500 acres in 2012 alone.

"We're aware of what they're doing, but we just don't want to go there," says Connecticut's Milne, who believes that New York City's watershed managers, despite their actual long-term policy, would prefer diminished public access.

Patton of the Connecticut Nature Conservancy says New York's lightly populated Catskills may not be comparable with Fairfield County, because of lesser population in upstate New York. "I think there tends to be less pressure" resulting from public access in the Catskills, Patton says.

Yet virtually all of New York City's water is pumped through the Kensico Reservoir, which is open to public fishing and lies just a dozen miles from the Bronx.

Although safe drinking water is clearly of critical importance, in fact there is little actual science on which to base decisions regarding appropriate access to watersheds. Rather, "it's probably more intuition and evidence of how it's worked elsewhere," Milne says.

Joseph T. Bushey, professor of environmental engineering at the University of Connecticut, who studies the impact of development on water quality, can't point to any examples of harm caused to drinking water by hiking and fishing, although he believes they may exist.

Decisions regarding public access are based mainly on a "subjective judgment that depends on what level of risk you're willing to accept," says Bushey, who is unfamiliar with conditions at Centennial State Forest and offers no opinion regarding access to state forest lands.

As for the safety of its drinking water, Aquarion, which supplies water to about 500,000 in Fairfield County, is ranked 21st among the nation's 100 largest water utilities by the Environmental Working Group, aWashington, D.C.-based non-profit that analyzes federal data. New York City is ranked 41st.

These ratings, however, don't measure watershed protection, but rather are merely a measure of pollutants discovered in the respective systems. Moreover, New York City chemically treats its water, but under a federal exemption based on the quality of its watershed, doesn't use filtration. Aquarion both filters and treats its supplies.

Despite the closed-off nature of most of the Centennial State Forest, Jeff Yates, president of Trout Unlimited's Mianus Chapter, sees its very existence as a great governmental success.

But Yates, author of the self-published volume Fly Fishing Fairfield County: Secrets of Suburban Streams, notes ruefully that its rivers aren't open to fishing.

"We've been trying to change that," says Yates, who believes access to the properties could be modestly expanded while protecting the safety of drinking water.