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| A Providence engineering firm will sample sediment behind the White Rock Dam in Westerly to see if it is contaminated. A decision would then be made regarding its removal. (Chuck Horbert photos) |
By DAVID SMITH/ecoRI News contributor
WESTERLY — Work has begun on a plan to remove the White Rock
Dam. A contract was awarded Sept. 25 to the Providence-based engineering firm
Fuss & O’Neill to first study and then draft plans for the removal of the
circa 1940 concrete structure.
It would be the third dam on the Pawcatuck River earmarked
either for removal or modification. The effort is designed to improve fish
passage on the 20-plus-mile waterway that stretches from Worden’s Pond in South
Kingstown to Little Narragansett Bay. About 15 miles upstream, the Kenyon Dam and
Lower Shannock Falls Dam have been removed, while a fish ladder was built at
historic Horseshoe Falls.
A total of $1.9 million in federal Hurricane Sandy funds is
available for the White Rock project, according to Scott Comings, director of
land and freshwater in the Rhode Island office of The Nature Conservancy.
A decision on how to proceed on the project will be made when
the test results of soil taken from behind the dam are analyzed. If the soil is
contaminated, that could add to the cost and/or change the approach.
The owner of White Rock Dam is Griswold Textile Print, 84 White
Rock Road, just downstream of the structure. President Paul Bergendahl said he
was “curious to see what the results” will be regarding engineering tests
before he offers an opinion on the dam’s removal.
His company, which makes high-end decorative fabrics and employs
18 people, doesn’t currently use the dam. The dam was built to hold back water
to feed the granite-stoned sluiceway adjacent to it. The water flow was once
used to power the historic mill. While Griswold Textile Print formed in 1937,
the building it occupies is much older.
The existing concrete dam replaced a wooden structure that was
built in either the late 1700s or 1800s, according to Comings. Bergendahl had
said that he believed that the old dam was washed out by the 1938 Hurricane.
While the dam has a 7.5-foot-high gate and let’s some water by,
most of the flow goes down the sluiceway, which is about 150 yards long and now
discharges back into the river.
One option is to block the end of the sluiceway if the dam is
removed to let the river follow its original course.
The Nature Conservancy is under a deadline to use the Sandy
funds on this project. Comings said the work must be completed by 2016. The
state will only allow work in the river during the summer, so if the work isn’t
completed in 2015, the next cycle would be in summer 2016.
“Fuss & O’Neill have the knowledge to get the project done
in the time frame we have,” Comings said. The engineering firm worked on the
three other dam projects on the Pawcatuck River.
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| This granite-walled sluiceway is next to the White Rock Dam and is a favorite with recreational boaters as a means of bypassing the dam. It’s possible it would be closed off if the dam were removed. |
Comings said his agency doesn’t have the permission of the dam’s
owners to remove the 112-foot-wide concrete structure. The company owns the dam
and an island below it that is flanked on one side by the granite-wall
sluiceway and the river. He added that the project is now in the first phase
and decisions will be made as information comes in. He didn’t know when the
tests on the soil behind the dam would be complete.
Comings said the project’s goal is for better river
connectivity. Fish are sometimes unable to swim up the sluiceway, he said. It
is a barrier most of the year.
The Bradford Dam has a fish ladder that was improved several
years ago. The entrance to the ladder was changed to enable fish to find it
easier. But Comings said that “there are some things we could improve in
Bradford.”
It’s because the dam in Bradford has a fish ladder, that the
White Rock Dam was given priority. The only other dam on the river that hasn’t
been the focus of a study is the Potter Hill Dam, which is between White Rock
and Bradford. It has a fish ladder.