Ascutney Mill Dam
Encyclopedia
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 hydropower
and later, 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 seasonal water flow and provide hydropower for nearby sawmill
s and gristmills, which previously could not operate during periods of low water flow in Mill Brook. The dam allowed water to be stored in the impound
during the winter for release during lower flow seasons.
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.
The Ascutney Mill Dam Company was formed in 1833 to build the dam; it was the owner and was responsible for the dam's maintenance and operation. Despite problems during the financial panic of 1837
, the company 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 dam site.
Construction of the dam was performed 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
in the U.S. 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 (12.2 m) 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.
"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 500000 cubic feet (14,158.4 m³) 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.
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 m) 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.
, 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.
Arch-gravity dam
An arch-gravity dam, curved-gravity dam or arched dam is a dam with the characteristics of both an arch dam and a gravity dam. It is a dam that curves upstream in a narrowing curve that directs most of the water against the canyon rock walls, providing the force to compress the dam...
which is one of the oldest and among the earliest storage dams in the United States. It is made of cut granite
Granite
Granite is a common and widely occurring type of intrusive, felsic, igneous rock. Granite usually has a medium- to coarse-grained texture. Occasionally some individual crystals are larger than the groundmass, in which case the texture is known as porphyritic. A granitic rock with a porphyritic...
and is located in Windsor, Vermont
Windsor, Vermont
Windsor is a town in Windsor County, Vermont, United States. The population was 3,756 at the 2000 census.-History:One of the New Hampshire grants, Windsor was chartered as a town on July 6, 1761 by Colonial Governor Benning Wentworth. It was first settled in August 1764 by Captain Steele Smith and...
in Windsor County near the Connecticut River
Connecticut River
The Connecticut River is the largest and longest river in New England, and also an American Heritage River. It flows roughly south, starting from the Fourth Connecticut Lake in New Hampshire. After flowing through the remaining Connecticut Lakes and Lake Francis, it defines the border between the...
where it functioned as a source of hydropower
Hydropower
Hydropower, hydraulic power, hydrokinetic power or water power is power that is derived from the force or energy of falling water, which may be harnessed for useful purposes. Since ancient times, hydropower has been used for irrigation and the operation of various mechanical devices, such as...
and later, hydroelectric power. It is on the ASCE
American Society of Civil Engineers
The American Society of Civil Engineers is a professional body founded in 1852 to represent members of the civil engineering profession worldwide. It is the oldest national engineering society in the United States. ASCE's vision is to have engineers positioned as global leaders who strive toward...
list of historic civil engineering landmarks and is listed on the National Register of Historic Places
National Register of Historic Places
The National Register of Historic Places is the United States government's official list of districts, sites, buildings, structures, and objects deemed worthy of preservation...
.
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 seasonal water flow and provide hydropower for nearby sawmill
Sawmill
A sawmill is a facility where logs are cut into boards.-Sawmill process:A sawmill's basic operation is much like those of hundreds of years ago; a log enters on one end and dimensional lumber exits on the other end....
s and gristmills, which previously could not operate during periods of low water flow in Mill Brook. The dam allowed water to be stored in the impound
Reservoir
A reservoir , artificial lake or dam is used to store water.Reservoirs may be created in river valleys by the construction of a dam or may be built by excavation in the ground or by conventional construction techniques such as brickwork or cast concrete.The term reservoir may also be used to...
during the winter for release during lower flow seasons.
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.
History and Planning
As early as 1767 several sawmills and gristmills were operating along the banks of Mill Brook in Windsor, however, during periods of low water flow the mills stood idle. Like many early towns their location was often selected on the availability of such a resource. Water-powered mills to save human labor have been used since ancient times, but like all renewable energy resources, their power is not always available when needed. Sawmills were important facilities which cut logs into boards for construction, as were gristmills, which ground grain into flour. In post-colonial Vermont, these mills were essential for building and food supply needs of the growing cities.The Ascutney Mill Dam Company was formed in 1833 to build the dam; it was the owner and was responsible for the dam's maintenance and operation. Despite problems during the financial panic of 1837
Panic of 1837
The Panic of 1837 was a financial crisis or market correction in the United States built on a speculative fever. The end of the Second Bank of the United States had produced a period of runaway inflation, but on May 10, 1837 in New York City, every bank began to accept payment only in specie ,...
, the company 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 dam site.
Construction of the dam was performed 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
Masonry dam
Masonry dams are dams made out of masonry; mainly stone and brick. They are either the gravity or the arch type.The largest masonry dam of the world is Nagarjunasagar Dam in India....
in the U.S. 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 (12.2 m) 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 1834. 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 1834, 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
PMF
PMF may stand for:* Paramilitary forces of India, a paramilitary organization under the Indian Ministry of Internal Affairs* Presidential Management Fellows Program, a US government fellowship...
. 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 500000 cubic feet (14,158.4 m³) 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
United States Geological Survey
The United States Geological Survey is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, and the natural hazards that threaten it. The organization has four major science disciplines, concerning biology,...
(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 m) 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 (2.3 km) ESE |
| Cornish City, NH | 2.4 miles (3.9 km) ESE |
| Squag City, NH | 3.1 miles (5 km) NNE |
| Balloch, NH | 3.1 miles (5 km) S |
| Cornish Center, NH | 3.9 miles (6.3 km) E |
| Brownsville, VT | 3.9 miles (6.3 km) W |
| Hartland, VT | 4.3 miles (6.9 km) N |
| Plainfield, NH | 4.5 miles (7.2 km) NNE |
| South Cornish, NH | 4.7 miles (7.6 km) 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 bluegillBluegill
The Bluegill is a species of freshwater fish sometimes referred to as bream, brim, or copper nose. It is a member of the sunfish family Centrarchidae of the order Perciformes.-Range and distribution:...
, brook trout
Brook trout
The brook trout, Salvelinus fontinalis, is a species of fish in the salmon family of order Salmoniformes. In many parts of its range, it is known as the speckled trout or squaretail. A potamodromous population in Lake Superior are known as coaster trout or, simply, as coasters...
and rock bass
Rock bass
The rock bass , also known as the rock perch, goggle-eye, or red eye is a species of freshwater fish in the sunfish family of order Perciformes. They are similar in appearance to smallmouth bass but are usually quite a bit smaller...
. There are areas for both fly fishing
Fly fishing
Fly fishing is an angling method in which an artificial 'fly' is used to catch fish. The fly is cast using a fly rod, reel, and specialized weighted line. Casting a nearly weightless fly or 'lure' requires casting techniques significantly different from other forms of casting...
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
- Jackson, Donald C. Great American Bridges and Dams, John Wiley & Sons, New York (USA) , ISBN 0471143855, 1984; pp. 106-107.