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2001_12-12_Newtown-Bee_Historic Hydroelectric Dam Now Has A Protected Future

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Historic Hydroelectric Dam Now Has A Protected Future


The Stevenson Dam Hydroelectric Plant on the southern end of Lake Zoar received National Register of Historic Places designation earlier this year. With that designation, it automatically received state historic designation.

The historic designation covers the concrete dam, the powerhouse at the western end of the dam, and the bridge that carries traffic on Route 34 over the dam. The plant is owned and operated by a subsidiary of Northeast Utilities, Northeast Generation Service.

According to David Poirier of the Connecticut Historical Commission, the dam's nomination was a mitigating measure in the state's consideration of the replacement of the current bridge over the dam. The state Department of Transportation (DOT) conducted documentation of the power plant as part of its plans to build a new $40 million bridge across the Housatonic River just upstream of the Stevenson Dam by early 2006.

This documentation was submitted to the Connecticut Historical Commission's Historic Preservation Office, which submitted the hydroelectric plant for historic designation.

The dam was built between 1917 and 1919 in response to electrical power needs for an area that was developing at a rapid rate, according to Robert Gates, state manager of Connecticut Hydro in New Milford. Today the plant continues to operate, helping to keep the power grid at proper voltage, he said.

He said the company plans to submit the five other power plants it owns on the Housatonic to the Historic Preservation Office for historic designation.

Mr Gates said that as a result of the plant's historic designation, any modifications of the structure would have to be presented to the Historical Commission for its opinion. "We would document what was there, and comply with standards as to replacements."

Mr Gates said that once the new bridge is constructed he would like to see access restricted to the current road over the dam. "It's my belief that an attractive nuisance is being created." He noted, however, that some observation area of Stevenson Dam would have to be considered in the future.

Acting on an 1893 charter that granted it a franchise to build the dam, the Housatonic Power Company hired Crisfield Construction of Philadelphia to construct the project.

In 1918, with pumps diverting the waters of the Housatonic River, rail cars, men, oxen, and horses were used to transport materials between the railcars and the dam site. The 10-mile-long Lake Zoar was created in 1919 by flooding when the dam was completed. It had 27 miles of shoreline for new homes and vacation cottages and bungalows and 1,000 acres of surface area for recreational use, including private beaches and summer camps and boating.

One beach offered an excursion boat, Miss Riverside. In a 1925 Bee article, the "new" summer colony of Shady Rest on Lake Zoar was described as an enchanting vacation spot.

The construction of the dam necessitated the removal of several permanent homes, 17 summer cottages and bungalows, the new, cable suspension Zoar Bridge, Stevenson Union Church, the cemetery, blacksmith shop, and school building. The church and some 300 graves were relocated to a hilltop.

Buildings that remained were converted into camp buildings for workers living at the site, and new structures, including a hospital, were built for a small temporary "city" to care for the workers. There was even a tennis court to occupy workers during the long evenings.

Construction of the dam took two years and cost approximately $4 million. Roads were rerouted, and motorists could now cross the Housatonic via a new highway over the dam. The dam spans about 1,200 feet, is 81 feet wide at the base and tapers to 15 feet wide at the top; 155,000 cubic yards of concrete were used to build it. A lab was built to test samples of concrete daily.

The timetable for construction of the new bridge to replace the bridge over the dam was recently pushed back about one year so engineers could develop detailed plans on how best to construct it with minimal disturbance to riverbed sediments that contain toxic PCBs, mercury, and lead. Concerned citizens have urged the state not to unnecessarily disturb riverbed sediments to avoid dispersing the toxic chemicals downstream.

Traffic would continue on the current bridge over the dam while the new bridge is being constructed. After the new bridge is completed, the bridge on the dam would be closed to traffic.

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