In the woods of Orange County, N.Y.,
the Cuddebackville Dam crosses a tributary of the Delaware River named the Neversink.
The Nature Conservancy calls it “one of the most pristine rivers in the
northeast.” But the dam, which has sat unused for half a century, breaks
up the river for its local inhabitants: a variety of species of fish, insects
and freshwater mussels, including the endangered dwarf wedgemussel.
Workers attempt to put in a temporary inflatable dam in preparation for removing
the Cuddebackville Dam, located on the Neversink River in upstate New York.
Courtesy of The Nature Conservancy.
Although the mussels are healthy, they are not found upstream; fish species
also cannot cross the dam to spawn upstream. “You have [the mussels] locked
in a really small area,” says the Nature Conservancy’s Emily Whitted,
and their population, though healthy, is declining. And so, in partnership with
the Army Corps of Engineers and local constituents, the environmental organization
is leading a project to remove the dam.
Whitted says that this is the first time that a dam in New York State is being
brought down for environmental reasons. It’s probably not going to be the
last: Across the country, removing dams, whether for safety concerns or for
restoring river habitat, is on the rise, with some surprising partnerships and
results.
The National Inventory of Dams lists close to 77,000 dams across the United
States, all of which are taller than 6 feet or hold at least 50 acre-feet of
water (one acre-foot is the volume of water covering one acre to a depth of
one foot). Maintained by the Army Corps of Engineers, with assistance from the
Association of State Dam Safety Officials, the Federal Emergency Management
Agency, and other state and federal agencies, the database lists dams mostly
for safety reasons; if one breached or were deteriorating, lives and property
downstream could be in danger.
The list does not count the many small dams erected on streams and rivulets
over the past century or more. Farmers may have raised small berms to make impoundments
for agricultural purposes, but more likely, industrial mills or other users
that are long gone erected small dams. These structures may not be life-threatening,
but they still could affect the environment downstream if they were to breach
unexpectedly, and they certainly create a barrier to local wildlife, disrupting
what was once the natural flow of a stream or river.
Elizabeth Brink of the International Rivers Network, based in Berkeley, Calif.,
estimates that 40 to 60 dams are removed across the nation every year, mostly
small ones that fall under the radar of the federal database. Brink says that
there is “definitely a trend” toward removing smaller dams, and that
environmental organizations also have their eyes on the removal of much larger
dams.
An important partner for many of these projects is the Army Corps of Engineers.
Since the mid-1980s, Lonnie Mettler, an Army Corps engineer, has watched the
culture of the institution subtly shift from building to maintaining dams. He
says that merely suggesting removing a dam, once unheard of, was not as surprising
in the organization by the mid-1990s.
Now the Army Corps generally acts as a consultant to a private or government
partner that finances and shepherds a dam removal project to its completion.
Doug Putnam, an Army Corps engineer who works on several dam projects in the
Northwest, says that the main consideration for removing dams is a rule concerned
entirely with aquatic ecosystem restoration, but the Army Corps also assesses
technical feasibility, among other criteria.
For dams that produce electricity, for example, “a lot of projects have
come up for relicensing, and a lot of them have filled with silt and aren’t
working,” Putnam says. “The big trick there is how do you take it
out without creating a problem?” Releasing silt downstream that contains
contaminants, or that might change the river morphology in unexpected or unwanted
ways, may be worse than keeping a dam in place.
“Often these dams were built for industrial purposes,” before controls
were in place on many industrial contaminants that were released, says John
Catena, a wildlife biologist who heads the Northeast Restoration Center of the
National Oceanic and Atmospheric Administration (NOAA). But, Catena says, “there
are ways to deal with that,” including dredging before removal.
Local residents may also raise aesthetic concerns, Catena says; surprisingly,
some people may not want a dam removed because “they’re used to seeing
a lake.” But other concerns may start to take precedence, from environmental
concerns on the part of individuals or organizations to the federal perspective
of getting fish to their spawning grounds.
On
the lower Snake River in Washington, for example, which feeds into the Columbia
River and is a major highway for spawning salmon, the Army Corps recently completed
an assessment of four federally owned hydropower dams. At the behest of the
NOAA National Marine Fisheries Service, which tracks the status of endangered
and threatened species’ environments, the Army Corps looked at several
scenarios for the dams, from leaving them alone to their complete removal —
all with the welfare of Chinook, steelhead and other salmon in mind.
A fish ladder at the Ice Harbor Dam on the lower Snake River, pictured here,
helps salmon make their way upstream. Removing this and other Snake River dams
remains too costly because of the economic and social impacts, but the removal
of smaller dams is on the rise. Courtesy of the Army Corps of Engineers.
They found that removing the dams would lead to the loss of electricity generation
amounting to $271 million a year over 100 years. The Army Corps also determined
that the loss of agricultural water sources would have too high an impact on
the local communities that relied on the river, affecting low-wage farmworkers
and Native Americans. The final report recommended not breaching the dam, but
instead improving the fish ladders (structures that allow fish to jump up the
dams in steps) or continuing to ferry fish upstream in what are basically aquariums
on wheels.
The decision created an uproar in local communities. Several groups, including
Native American tribes that have treaty rights to Columbia River salmon, argued
that fish ladders and trucking fish upstream are not effective methods for protecting
endangered fish — certainly not as effective for spawning as a natural
river environment. But Mettler, who managed the assessment, points out that
even if the four federal dams were removed, there are several privately owned
dams on the river that would continue to block fish from spawning upstream.
However, he says, the federal dams’ status will be reviewed every three
years or so, and their removal “is not off the table.”
In some ways, dam removal has never been more on the table. Catena says that
when he joined NOAA’s restoration program just over a decade ago, “dam
removals were not even a subject for discussion.” Then, after one of the
first dam removals in the Northeast, the Edwards Dam in Maine about five years
ago, interest escalated. “The trend is a tremendous increase in proposals
coming in for dam removals and much more public interest in it,” he says.
Now, NOAA is funding 54 such projects, totaling over $2.2 million, and Catena
says that the program will probably double its dam removal projects in the next
year.
In the meantime, the starting date for removal of the Cuddebackville Dam on
New York’s Neversink River has been delayed a year. “It’s really
complicated,” says the Nature Conservancy’s Whitted. “Usually
you think that you stick a stick of dynamite in, and boom, you’re done,”
she says.
But the two-part dam has tons of silt built up on one side, Whitted says, and
the northeast half of the dam feeds a nearby canal that is important to the
local community. Plus, when the dam is removed, the streambed must be allowed
to dry out for regrading, boulders must be placed strategically for proper riverflow,
and fish and mussels must be rescued from an area suddenly without water. So
the Nature Conservancy, under consultation with the Army Corps, has decided
to carve a fish ladder into the northeast side of Cuddebackville Dam, and bring
down only the dam’s southwest portion.
“You have to deal with the whole system, and really, a lot of this hasn’t
been done before,” Whitted says. “There’s an art to this.”
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