By Barbara Currier Bell Environmental Writer Editor's Note: 'Beaver River' is the first installment in a related series of articles by Barbara Currier Bell. Although Milford is known for its location on Long Island Sound, its abundant freshwater has always been equally as important - if not more so. Our Puritan forebears used the Sound to travel east-west, and to put seafood on their tables, but they used the rivers to go north, to supply water for their crops and domestic needs and, later, to generate power for mills. Five significant watercourses historically flowed through or alongside Milford: The Housatonic on the western boundary; next, Beaver River - now called Beaver Brook; the Wepawaug in Milford Center; then the Indian River, and the Oyster River at the eastern border. In 2013, every child knows the name "Long Island Sound," but how many can name the five rivers? Oddly enough, the river with the most common name, the most local, and the most unique, geologically, is the one that's most invisible: Beaver Brook. This 3.5-mile watercourse originates in North Milford near where Milford Parkway joins the Wilbur Cross: Its narrow watershed lies entirely within Milford. It's fed by the largest artesian springs in Connecticut, possibly New England. Always camouflaged by wetlands, it's now further disguised by development landscaping. No sooner had the Milford Water Company incorporated in 1893 and started acquiring Beaver Brook watershed land for management, about a third of the river was turned into a canal, dammed ponds (Mondo Ponds), and a reservoir; other sections were buried in culverts and conduits. With these makeovers, Beaver "River" is no longer recognizable as a river. Nor can people remember Beaver Brook's productivity. For two decades after 1900, it contributed significantly to Milford's water supply, but runoff rates changed as farms reverted to forest; filters failed and left drainage uncontrolled; the reservoir proved too small, filling up with sediment and algae; and '60s droughts interrupted flow. The most insidious problem was polluted runoff from land development, especially roads, and, most adversely, I-95. In 1977 the South Central Connecticut Regional Water Authority (RWA), the successor owner, abandoned production from the Beaver Brook system. At that point, Beaver Brook's value went from natural resource to real estate. RWA proposed to sell off its 242 acres of watershed land held in 12 different parcels: The city had the right of first refusal on each. Beginning soon after 1982, when an environmental scientist hired by RWA issued her comprehensive report on these properties (a main source for this Hot Air), a parcel-by-parcel campaign began, environmentalists urging acquisition for open space and public access, private developers proposing residential and commercial use. Over all these years, no parcel has been more important to the public than the largest one: 57 acres of mixed uplands and wetlands known as the Beaver Brook Marsh, which the 1982 report considered the most significant in terms of biodiversity and wildlife habitat. Its trails, improved by a boardwalk over a decade ago, have offered Milfordites recreation for generations, but, right now, land use at the Beaver Brook Marsh is up for grabs.