River
dam removal and in-channel restoration enhances fisheries
I wrote this piece for my
Recorder Newspapers column last year.
51 dams were deconstructed in 2013
through a nationwide movement to return rivers to free, flourishing flows. Here
in the Highlands, The Musconetcong River Partnership won the 2012 Presidential Coastal
America Award for removal of Musconetcong River dams. The Partnership is a team
of agencies, organizations, and individuals, including New Jersey Trout
Unlimited, the Musconetcong Watershed Association, American Rivers,
NJDEP-Division of Fish & Wildlife, US Fish & Wildlife Service, and many
others, all honored by the Office of the President of the United States.
While the Musconetcong is getting the
most attention through a process ancillary to dam removal—in-channel
restoration—continuing this year, efforts in New Jersey to improve rivers aren’t
limited to the Highlands. Somerset County’s Raritan River has had three dams
removed, and soon the Millstone River will flow freely from the dam at Carnegie
Lake in Princeton to the Raritan. Trout are a concern in the Highlands, but
these three rivers share shad and herring in common as a migratory possibility.
In fact, shad and herring have been videoed at the Raritan in recent years. Remaining
are two Raritan dams: the 1995 Island Farm Weir constructed with fish ladder
and video devices just below the Millstone confluence, and the Headgates Dam,
located a short way below the South and North Branch Raritan Confluence by Old
York Road in the northernmost reach of Duke Island Park. The Millstone River
awaits the removal of Blackwell’s Mills Dam well upstream of the town of Millstone
possibly this summer. The Weston Causeway Dam at Manville will go sometime soon.
Both Millstone River dams are low head varieties, but do obstruct the migration
of fish.
Two of the remaining dams on the
Musconetcong River are anything but low head. The Hughesville Dam—expected to
be deconstructed in 2015—is 10 feet high, the Warren Glen Dam an enormous 35 ½ feet
tall. The latter will be an extremely difficult project, but Trout Unlimited
Musconetcong Coordinator, Brian Cowden, is confident that The Musconetcong
River Restoration Partnership will pull it off.
“We’re talking about multiple
millions of dollars, and where will that money come from?” Cowden said. More
daunting than money, perhaps, is dealing with the sedimentary results of (?) years
of the river gorge being dammed—too many tons of mud to guess the number.
“Removing the concrete is easy. How do we get that sediment out of there, and
where do we put it?”
I’m sure ways will be found, since
the political will behind the project is powerful.
“Everyone in the partnership wants
that dam gone, including the owners,” Cowden said. “That’s gonna clean up the
Musky Gorge for trout fishing. It’s also going to be good for kayakers and
canoers. That habitat is phenomenal, and significantly more water will be flowing
through than the Ken Lockwood Gorge. Over time, sediment has settled over those
beautiful boulders at the river’s bottom behind that dam, and this will renew
the gorge as it naturally was.”
At present, more than four miles of
the Musconetcong between Finesville and the Delaware River have been opened and
flow without obstruction. Six dams have been taken out, considering that the
Partnership’s Riegelsville project involved two solid wood coffer dams and a
hand built stone dam. Gruendyke Mill Dam, Seber Dam, and the Finesville Dam are
also gone. Removal of the Bloomsbury Dam is under consideration, but Saxton
Falls—way upstream above Hackettstown in Stephen’s State Park—is not a concern.
“That dam is part of the State Park
System. We’re not even targeting that. Our focus is downstream,” Cowden said.
When Bloomsbury Dam goes, shad will
have a long, free flowing revitalized river to travel and spawn well upstream.
Wild trout will respond with a healthier population to increased oxygen, lower
water temperatures, and better insect hatches. And river ecology is also
improved by in-channel restoration.
Trout Unlimited has been overseeing
restoration efforts on the Musconetcong. This year, 1/3rd mile of the Point Mountain Trout Conservation
Area, a full mile of the Wattle’s Tract, 1/3rd mile at Asbury, and a
section at Beatty Farm, as well as a half mile of tributary West Portal Brook,
will be shaped into environmentally sound configurations. Channels are narrowed
where they become too shallow and wide, because increased run-off from impervious
surfaces like parking lots homogenize the river bed. Pools are dug, boulders
added, and point bars shaped, all to keep the river flowing strong,
transporting sediment, and producing more trout in these enhanced habitats.
While the river is spring fed, trout
generally reproduce in protected feeder streams, which tend to carry more
spring water by volume. Nevertheless, the long term effect of restored habitat
is likely to increase trout numbers, because offspring will find fit places to
mature.
