By Dan Simon
While many communities are reassessing the need for small dams and
considering removing old ones, some communities are turning to technology
to permit what they consider the best of both worlds — a now
you see it, now you don't inflatable dam.
The idea is to use inflatable rubber bladders to impound enough water
to permit the use of power boats on such rivers as the Susquehanna
where it flows through the Wyoming Valley region of Pennsylvania.
Two Pennsylvania communities, Wilkes-Barre and Nanticoke have floated
plans for such dams, far enough apart to permit both of them to be
built. The Wilkes-Barre project has the backing of U.S. Representative
Paul Kanjorski.
Engineers would like to install an inflatable dam on the
Susquehanna River at Wilkes-Barre, Penn., to increase summer
recreational opportunities. ©Photo by Dan Simon for GreenWorks.
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" The dam would be inflated until it's about nine feet high,"
said James J. Brozena, Luzerne County engineer. "It will fill
up like an inner tube. Once inflated, water will continue to flow
over the top of it, once it's created a 400-acre lake that's about
four and a half miles long.
"It creates opportunities for boating, fishing and jet-skiing,
maybe sculling too. The river itself isn't that wide, maybe 900 feet
on average. It's also not deep enough for big boats, maybe just eight
or 10 feet."
Wilkes Barre's problem is during dry summers, the river's frequently
too low for even small powerboats he said. In theory, the inflatable
dam would hold back water during the wettest months of early spring
when it shouldn't be missed from downstream flows. Come October or
so, engineers let the air out, and the deflated dam rests on the river
bottom out of the way.
"Typical summer depths range from zero to about five or six feet
deep," Brozena said, "and they're typically closer to zero.
"We're just trying to keep some water in the river."
Neither the Wilkes-Barre, nor the Nanticoke dams would present any
increased risk of flooding.
Inflatable dams use rubber bladders that are inflated by
air to impound water in the spring and deflated when the boating
season ends. ©Photo by Dan Simon for GreenWorks.
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"Automatic sensors monitor the river level," Brozena said.
"As the river rises and falls they adjust the level of the dam
accordingly."
For those thinking this is the stuff of science fiction, such a beast
already exists less than 40 miles away in Shikellamy State Park, near
Sunbury, Penn. This dam is also inflated in the spring and deflated
in the fall providing recreational opportunities for boaters and fishermen.
The Adam T. Bower Dam is the world's largest inflatable dam and when
erect, creates a 3,000-acre impound known as Lake Augusta. The dam
backs up water for six and a half miles up the Susquehanna's north
and west branches. They say the bass fishing at the base of the dam
is pretty good.
The Wilkes-Barre project is the farther along of the two dam proposals.
While there's no specific funding in place for it, the Army Corps
of Engineers does have a flood control project for the river in
place and some money from that effort could go toward the inflatable
dam. Brozena thinks it could be in place by 2005 "if all the
planets align properly."
The Adam T. Bower Dam is the world's largest inflatable
dam and when erect, creates a 3,000-acre impound known as
Lake Augusta. ©Photo by Dan Simon for GreenWorks.
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Not everyone feels the idea is a good one. Members of the Greater
Wyoming Audobon Society fear it could adversely impact area waterfowl,
plus damage the riparian environment the avian community relies
on.
While members of the organization weren't available to interview
for this story, a position paper at their web site put forth their
reservations, including concerns that the Susquehanna River's fishery
might be degraded by the presence of an inflatable dam.
The Wilkes-Barre proposal wouldn't flood nearly as large an area
mainly because the river in that area is heavily levied. There are
however, trees along the bank whose root systems could be affected,
plus some areas along the four and a half mile impoundment where
water that could be affected by a rising water table that would
accompany the rising waters.
Once the dam is inflated, water flow will be back to usual (which
in the summer would be minimal with or without the dam.) The theory
is you're inflating in the spring when the river's up and once the
impoundment is filled, additional water spills over the top of the
dam. There are some small islands in the impoundment area that would
be flooded and the Audobon Society is arguing that this flooding
would kill the trees on the islands.
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