By Col. Joseph R. Geary, Commander, Savannah District, U.S. Army Corps of Engineers
SAVANNAH, Ga. – As a federal resource agency, the Army Corps of Engineers provides certain protections to wetlands, wildlife at Corps’ reservoirs, and in operation of our nation’s rivers and harbors. Not only do we have a legal obligation to do so, we also have a moral responsibility which we take very seriously – and personally.
While protecting the environment and the plants and animals in it, we must also accomplish other duties such as providing clean, renewable energy at our reservoirs; constructing military facilities; and maintaining and improving our nation’s harbors. Sometimes these missions seem to conflict. Therefore, we strive to find ways to bring them into balance.
To fulfil our legal and moral responsibility to the environment, we constantly seek ways to protect the most vulnerable species we encounter while performing our other missions. Harbor maintenance and improvement demonstrates our efforts to protect the environment while keeping commerce moving, a key to a healthy economy. New equipment, techniques, and methods to maintain our harbors strike that balance to protect endangered and threatened species.
FOLLOW THE SCIENCE
We often hear the phrase “we must follow the science” these days. Let me tell you, the Corps of Engineers has “followed the science” for decades (indeed from its very beginning) and continues to do so. We work closely with other federal resource agencies dedicated to protecting the environment – agencies like the Environmental Protection Agency, the Fish and Wildlife Service and NOAA Fisheries.
In our mission of harbor maintenance and improvement, we work hand-in-hand with the EPA and especially with NOAA Fisheries. This latter agency has great interest in protecting marine animals, their habitats and ability to reproduce. This includes critically endangered right whales, endangered shortnose and Atlantic sturgeon, and multiple species of endangered sea turtles. The Corps, in partnership with NOAA Fisheries, uses science to find ways to protect and recover these animals.
Before recommending actions to us, NOAA Fisheries’ team of scientists spent a decade working to understand Corps activities and animal habits and movements that intersect these activities. Their report, the South Atlantic Regional Biological Opinion (SARBO), sought to reduce threats to the North Atlantic right whale, sea turtles, and sturgeon. It balanced the need to keep America’s harbors operating at full capacity in the southeastern United States, Puerto Rico, and the U.S. Virgin Islands. The SARBO shows how this can be done.
SEASONAL CHANGE BENEFITS
The SARBO pointed out the significant technological and operational changes harbor dredges now employ. These changes didn’t exist when the winter-only dredging schedule went into effect. Today, protection of sea turtles has vastly improved. The SARBO points out how hopper dredges today have shields on the dredge head to exclude turtles and to disturb turtles resting on the bottom, prompting them to move. The drag heads (think large vacuum cleaner heads) remain “off” until well embedded into the sediment, thus avoiding pulling turtles into the suction as the head descends to the bottom of the channel.
Dredging contractors use trawlers with specialized nets to precede the dredges, as well. Equipment on the trawlers gently wakes sleeping turtles. And for turtles that can’t quite wake up in time, the nets gently pull them to the surface, where specialists capture them and carefully relocate them away from the dredge.
Dredging during warmer months, according to the SARBO, has another significant advantage. With warmer water, turtles spend less time on the bottom and more time in the water column above the dredge heads. These technological and operational changes described in the SARBO make dredging year-round not only possible but safer for the turtles. Sturgeon also benefit from dredging in warmer months, since they move upstream to spawn in summer.
DOING RIGHT BY THE WHALES
Moving dredging to warmer months also provides more protection for critically endangered North Atlantic right whales which spend the winter in waters off the U.S. Southeast Coast calving and nursing their newborns. These whales swim near the surface, have no dorsal fin to identify their location and blend in with the color of the sea. Constant ship traffic to and from the ocean disposal area vastly increases the danger of striking the mothers or their offspring.
Even with their massive size, these behemoths of the sea remain hard to locate. The Corps provides funding to conduct aerial surveys for whales during the winter months along the Atlantic coast to aid location efforts. We require trained spotters on the dredges as well to watch for them. Changing weather conditions, nighttime dredging operations and their natural camouflage can make this difficult. We have a great record of avoiding right whales, with no confirmed strikes in many years, but constant dredge traffic in winter poses continuing danger to them.
With so few right whales remaining in the world, losing even one breeding female or its calf greatly damages the population. NOAA Fisheries’ science team recommends moving the dredging season to a time after the right whales depart for cooler northern waters to lessen the chance of injury or death.
THE SARBO IS SCIENCE
Scientific findings constantly change as we learn more, observe more, and study more. Rightly applied science leads to positive changes. Changes lead to benefits, whether to wildlife, humans, or commerce. By employing and embracing the changes outlined in the SARBO the Corps of Engineers aids protection of nature while increasing efficiency in commerce from year-round dredging. These changes came through scientific study over a full decade and account for advances in dredging and in knowledge of wildlife.
We seek to follow the science as we fulfill our mission of harbor maintenance. But we never turn our back on our legal and moral obligations of caring for the environment.
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