User:Serock13/Windsor Upper Dam

Windsor Upper Dam
Location	Windsor, Vermont
Construction began	June 1834
Opening date	November 1834
Dam and spillways
Impounds	Mill Brook
Height	40 ft (12 m)
Length	250 ft (76 m)
Width (base)	36 ft (11 m)

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Ascutney Mill Dam, also known as the Windsor Upper Dam and the Mill Pond Dam is a arch-gravity dam which is one of the oldest and among the earliest storage dams in the United States. It is made of cut granite and is located in Windsor, Vermont in Windsor County near the Connecticut River where it functioned as a source of hydroelectric power. It is on the ASCE list of historic civil engineering landmarks and is listed on the National Register of Historic Places.

The Ascutney Mill Dam Company was formed to build the dam. Construction began in June 1834 and was finished in November. The purpose of the dam was to regulate water flow and provide hydroelectric energy to nearby sawmills and gristmills which could not operate during periods of low water flow in the creek. The dam allowed water to be stored in the Mill Brook impound during the winter and to be released during the spring.

Ithamar A. Beard was a prominent New England engineer who surveyed the area and selected the site for the dam. Simeon Cobb and Joseph Mason were the contractors in charge of building the dam.

Background

History and Planning

As early as 1767 there were several operating sawmills and gristmills along the banks of Mill Brook in Windsor, Virginia. Sawmills were facilities where logs were cut into boards and gristmills in which grain is ground into flour. These mills were around since B.C. times and were generally water powered, with a few being wind powered or having other sources. In post-colonial Virginia, these mills were essential for building and food needs of the growing cities. However, during periods of low flow the mills stood idle.

The Ascutney Milldam Company was formed in 1833 to build the dam. The company was the owner of the dam and was responsible for its maintenance and operation. Due to the financial panic of 1837, the company had problems but continued to operate the dam throughout the 19th century. Ithamar A. Beard was the engineer who surveyed the area and made the suggestion for the site.

Construction of the dam was from mid-April 1834 to mid-November 1834. It was built of cut granite and was one of the first [gravity-arch dams] built in the United States. It is also possibly the oldest masonry dam of any significant size. The original dam had a near-vertical downstream face built in an arch form.

Water filled up behind the dam each winter and was allowed to flow over the spillway the following spring. Water and ice falling over the crest and 40 feet to the ledge below caused noise and vibrations throughout the village which concerned citizens. Inspections found that the vibrations caused no damage to the dam, but a stone buttress was built below the dam to stop the vibrations.

Construction

Construction began on April 1934. Simeon Cobb and Joseph Mason were the contractors in charge of building the dam.The first step was to remove a small dam on the site. In June the first granite blocks were placed. The granite was obtained from nearby quarries. The overall construction was fairly simple and finished on November 1934, just seven months after construction began. The finished product was a 12.2 m (40.0 ft) high and 76.25 m (250.2 ft) long dam. The elevation above Mean Sea Level is 115 m (377 ft).

Condition

The National Program for Inspection of Non-Federal Dams performed an inspection of the dam in September 1978. The report was a Phase I inspection report. The author came from the Corps of engineers in Waltham, MA New England division. The abstract of the report writes:

"The dam is considered to be in fair condition. The dam is believed to be safe under normal operating conditions. The test flood is the PMF. It is recommended that the owner engage the services of a qualified consultant to evaluate the stability of the dam. In addition to long term recommendations, there are several remedial measures which should be implemented."

The current policy of the state of Vermont department of environmental conservation requires that only dams that are capable of impounding more than 500,000 cubic feet need to be inspected, which is not the case for the Upper Windsor Dam.

In the twentieth century, a concrete coping was placed on top of the structure to help ensure its stability in times of flood. The dam retains much of its original structural even though it is one of the oldest dams in the United States.

Topographic Information

Topographic Map of Windsor, Vermont

Ascutney

For the United States Geological Survey (USGS), the dam is sourced in the Windsor Windsor quad. The topographic map shows the mountainous terrain of the area. In fact, Windsor County, Vermont is home to a total of 202 mountain summits and peaks. The highest is Gillespie Peak which is at an elevation of 3,343 feet (1,018.95 meters) above sea level. The peak flow in the rivers near uneven terrain could fluctuate vastly between periods of high and low precipitation because much of the rainfall flowing down to a discharge rather than infiltrating into the ground first as it would in flat terrain. This flow could cause a large increase in flow rate and river height in a fairly small amount of time. The fact that the Connecticut River was just a few miles away also played a role in this. Because of all this, the timing of opening and closing the dam to regulate flow and produce hydroelectric power was important.

Nearby Areas

Nearby Cities and Towns	Distance
Windsor, VT	<.1 mile
Cornish Mills, NH	1.4 miles ESE
Cornish City, NH	2.4 miles ESE
Squag City, NH	3.1 miles NNE
Balloch, NH	3.1 miles S
Cornish Center, NH	3.9 miles E
Brownsville, VT	3.9 miles W
Hartland, VT	4.3 miles N
Plainfield, NH	4.5 miles NNE
South Cornish, NH	4.7 miles ESE

Fishing

The Windsor Upper Dam area is a popular fishing spot, just like many of the nearby locations. Fisherman could catch a variety of fish including bluegill, brook trout and rock bass. There are areas for both fly fishing and baitcasting. Either way, the chances for catching a fish are high.

Fishing here is open to the public but a Vermont fishing license is required. The type of license depends on what kind of fishing you are doing.

External Links

• "State of Vermont Department of Environmental Conservation: Inspection of Dams" (PDF).
• "DTIC".
• "Structurae".
• "Hydroelectric Power".
• "Feature Detail Report for: Windsor Upper Dam".
• "Hometownlocator".
• Jackson, Donald C. Great American Bridges and Dams, John Wiley & Sons, New York (USA) , ISBN 0471143855, 1984; pp. 106-107.
• "Windsor Upper Dam USGS Windsor Quad, VT,NH, Topographic Map".
• "Windsor County, Vermont Mountain Peaks & Summits".
• "TerraServer". {{cite web}}: Cite has empty unknown parameter: |3= (help); Text "Vermont" ignored (help); Text "Windsor" ignored (help)
• "Windsor Upper Dam Fishing - Vermont Dam near East Concord".
• "History and Heritage of Civil Engineering".

Category:National Register of Historic Places in Vermont Category:Federal architecture in Vermont Category:Buildings and structures completed in 1834 Category:Historic Civil Engineering Landmarks