As a result of recent infrastructure failures, particularly the tragic failure of the Interstate-35 bridge in Minnesota, the US Senate passed the National Infrastructure Improvement Act (NIIA), which would create the National Commission on the Infrastructure of the USA. The commission’s broad mandate would be to assess the nation’s infrastructure and its ability to meet current and future demands. Such policy development coincides with ongoing efforts to manage and restore degraded ecosystems. This provocative intersection of aging infrastructure and environmental degradation provide unprecedented and largely unappreciated opportunities for ecosystem restoration.
Convergence of Phenomena
The United States is at an unusual juncture of three growing phenomena. First is the widespread decay of infrastructure. The 20th century saw rapid growth in population, the economy, and infrastructure (see chart). Many structures have been in place for 50 years or more, and increasing portion of national infrastructure is now approaching or exceeding it’s originally intended design life and will require over $1.6 trillion to reach acceptable levels of safety and function (1).
The second phenomenon is the degradation of the environment and loss of associated ecosystem services (2). Substantial ecological degradation can be attributed, at least in party, to infrastructure expansion. Roads increase sediment erosion, fragment habitat, and facilitate the spread of invasive species (3). Dams and levees restrict fish migration and have drastically altered river flow regimes (4). Offshore platforms discharge waste, release atmospheric pollution, and compete with commercial fishing (5).
Third is the burgeoning of ecosystem restoration as both a science and an industry (6). To date, restoration has often been limited in scale, and its effectiveness is frequently unclear (7). Nevertheless, there is growing demand, political will, and funding for restoring degraded ecosystems (7, 8).
Restoration via Decommissioning
Decommissioning can take several forms, including full removal, partial removal of key components, or abandonment. Publicly versus privately owned infrastructure may differ in decommissioning procedures and ability, but all are subject to the National Environmental Policy Act and equivalent state laws, although these laws generally do not facilitate ecological restoration.
On rivers, dam decommissioning is increasingly common, whereas levee decommissioning is rare. Of the 79,000 dams in the United States, 3500 have been rates as unsafe, collectively in need of $30 billion for rehabilitation, repair, or removal (1). Levee inventories are less clear, but estimates exceed 25,000 km (9), many with unknown structural integrity (10). To date, 600 dams have been removed, primarily for safety and economic reasons. Dam removal is followed by rapid recovery of invertebrate, fish, and riparian vegetation communities (11). Levee decommissioning, often abandoning breached levees, reduces economic demands of levee reconstruction while improving floodplain habitat and water quality (12).
Of the 6 million km of roads in the United State, 885,000 km are on public lands maintained by federal land agencies, a portion of which are rarely used (13). The U.S. Forest Service (USFS), with 250,000 km of roads over 50 years old, estimated its maintenance backlog at $10 billion for 26% of system roads (13). The USFS decommissioned 7900 km of roads between 2002 and 2005 and has identified almost 300,000 km for possible decommissioning over the next 40 years (14). Decommissioning decreases economic liabilities but is also an important tool for restoring forest ecosystems (13).
In U.S. federal waters, there are 3900 offshore oil and gas platforms, primarily in the Gulf of Mexico (GOM), about one-third of which are idle (15). Federal policies require that platforms be removed within 1 year of lease expiration, and 2700 platforms have been removed. Removed platforms have been primarily shallow-water platforms and mostly disposed of onshore (15). Costs and environment impacts of removing deep water platforms are substantial.
Full platform removal has drawbacks, including environmental impacts and loss of the potential ecological values of the structure as an artificial reef (16). Research shows that platforms facilitate the expansion of coral populations in the GOM (17) and act as refuges for juvenile fish, increasing fish production off the coast of California (18). Rigs-to-Reefs Programs allow reuse of decommissioned structures as artificial reefs. Through 2004, 190 retired platforms were dedicated for fisheries enhancement, which reduced decommissioning costs and led to $20 million in industry donations to state environmental management trust funds (15).
Department of Defense (DOD) facilities pose an unusual challenge and opportunity. Of the 257 million ha of federal lands in the United State, 10 million ha belong to the DOD (19). Access restrictions have made military bases some of the richest ecological reserves of any of the nation’s public lands (19). Through the Base Realignment and Closure (BRAC) program, 400 military sites were closed or reclassified between 1988 and 2002. To date, management of 21 bases on 445,000 ha has been transferred from the DOD to the U.S. Fish and Wildlife Service to become National Wildlife Refuges (e.g., Jefferson Proving Ground became Big Oaks National Wildlife Refuge).
Perhaps the largest combination of infrastructure management and ecosystem restoration is the Comprehensive Everglades Restoration Project (CERP), an effort to restore the 2.3 million-ha watershed and its ecosystem (8). Hydrology in the Everglades is manipulated through hundreds of control gates, thousands of kilometers of levees, 2900 km of canals, and dozens of pump stations, which largely continue to function well. The CERP is based on infrastructure modification and partial removal to move the ecosystem to a more natural and sustainable configuration through a 40-year, $20 billion project.
Policy Directions and Exit Strategies
Infrastructure policy should do more than fund projects; it should set national priorities and initiatives. The National Commission on Infrastructure would set such strategic priorities and consider infrastructure financing, rehabilitation, and maintenance. Rehabilitation under the NIIA includes considering removal of infrastructure that is deteriorated or no longer useful. When infrastructure has been decommissioned, ecological restoration has been a side benefit. Prioritizing decommissioning sites based on a combination of ecological, economic, and safety concerns can benefit multiple stakeholders, possibly reducing overall decommissioning costs (15).
Infrastructure decommissioning is likely to occur during discrete windows of opportunity. These may be policy-related (e.g., expiration of a dam license), natural (e.g., flooding), or through deliberate legislation (e.g., CERP). However, political will for such expenditures is difficult to maintain, particularly during political transitions (20). A less broadly applied funding mechanism is the use of market-like principles in which infrastructure decommissioning is used to generate credits to offset environmental impacts elsewhere (see figure above).
The greatest lesson from current aging infrastructure is the need for exit strategies, which vary greatly among infrastructure types. Policies for decommissioning dams are surprisingly rare and vague (11), whereas policies for decommissioning offshore platforms are unambiguous (15). Because the costs of decommissioning and cleanup for infrastructure can be substantial, more explicit policies should require provisions for decommissioning as part of infrastructure license or lease terms, perhaps similar to that for offshore facilities, where bonding requirements are specified and based on the estimated cost of full removal.
Any infrastructure policy approach must confront the national conundrum of pressing infrastructure problems and continuing environmental degradation. Specifically, a National Commission on Infrastructure should squarely face decommissioning as a viable option, and the environmental benefits gained through such decommissioning should be assessed as definable benefits and leveraged when possible and practicable.
From Science Magazine, VOL 319, January 18, 2008
Martin W. Doyle,1* Emily H. Stanley,2 David G. Havlick,3 Mark J. Kaiser,4 George Steinbach,5 William L. Graf,6 Gerald E. Galloway,7 J. Adam Riggsbee8
As part of its environmental offsets, PTI has restored a Guilford County stream.
By Taft Wireback
LIBERTY — It’s the southernmost piece of the FedEx project, located 30 miles from the package-sorting hub under construction at Piedmont Triad International Airport.
No cargo planes will ever land there. But plenty of blue herons, meadowlarks and woodpeckers touch down regularly near the unnamed stream on Smithwood Road in southeast Guilford County.
The restored stream on the Causey Farm is what’s known as an “offset,” an environmental project that compensates for damage done by large-scale construction elsewhere in the same river network.
“We’ve met all the success criteria here,” said John Preyer, co-owner of the firm that restored the stream and about 40 acres of adjoining land. “We were able to encompass the entire stream system, so there’s no great risk of development ever affecting its water quality.”
Even the farm’s 100 cows seem content with the outcome, though they can’t drink from or mill about the stream anymore. Instead, they drink from a high tech watering fountain that provides a more reliable supply of cleaner water.
PTI paid roughly $2 million for the site and the work to repair 46 acres of stream and adjoining land, damaged by decades of cattle use.
“It had been absolutely trashed,” said George Howard, Preyer’s partner in Restoration Systems of Raleigh and Greensboro.
Year after year of grazing cattle had turned the banks into bare mud flats with no trees or other significant vegetation. The small stream was contaminated by the upchurned dirt, erosion and animal wastes.
Now, literally thousands of saplings from 17 species of tree grow on either side of the creek, including ash, black gum, hickory, oak and poplar.
Wildlife making use of the once denuded stream include 44 species of birds, plus raccoons, deer, frogs and snakes.
The project’s success is an example of what can happen when the federal government’s “no net loss” policy, developed in the 1990s, is carried out effectively, Howard said.
The policy requires such projects as new roads and airport expansions to limit environmental damage at the building site itself, then make up for unavoidable harm with other efforts to improve water quality.
PTI Director Ted Johnson said that in addition to the Causey Farm, the airport spent more than $6 million on hub-related environmental projects, including those at or near the airport that deal directly with water pollution from the hub.
In addition to Restoration Systems, key players in the Causey Farm project included Thomas Trauger, nephew and heir of the farm’s late owner, former school teacher Eloise Causey Butler.
Trauger and his two co-heirs sold a conservation easement to Preyer’s and Howard’s firm, an agreement that allowed them to fence off the stream so cattle could not disturb it anymore. PTI then paid Restoration Systems for the restoration.
“I like the idea of making sure it will stay as it is, not turning every nook and cranny into a housing development,” Trauger, a lawyer in Washington, said of the 450-acre farm.
Another important player was farmer Bruce Humble, whose family has leased the pasture and stream from its owners for years.
Trauger and his co-heirs wanted to continue that relationship, telling Restoration Systems that Humble had to be satisfied with the redesign or it was a no-go.
Humble and his late father worked with the environmental engineers, although they were skeptical about the concept.
Today, three years after the project’s completion, Bruce Humble says it’s a mixed bag: “They took about 35 acres of pasture, but it’s like a lot of things where there’s a trade-off.”
The positive part of that trade-off is the two wells and the water fountains Restoration Systems provided. The stream dried up during this summer’s drought, but Humble says the wells provided his herd with clean, fresh water.
In addition to digging the wells, technicians working for the Preyer-Howard company spent about four months returning the stream to something like its natural shape.
Farmers had spent generations straightening the stream’s meandering course, turning it into the equivalent of a milelong water trough. Good in some ways for cattle, bad for the stream.
Gushing water eroded the bank after each rain, carrying pollutants into nearby Stinking Quarter Creek, no doubt helping the creek live up — or down — to its name at times.
As a guide for what the reworked Causey Farm stream should look like, environmental designers used a small stretch of it that had not been used for farming.
They planted similar trees, brush and other plants along the newly twisting course. They added rock formations to reinforce the stream’s new direction of flow.
Then they sunk biodegradable netting into the banks to prevent erosion until the vegetation could put down strong root systems to serve the same purpose.
“Eventually, there’s going to be a gorgeous (tree) canopy all through here,” Preyer said recently.
Most of what was added came directly from Mother Nature, but there also is an electronic component to the project. Underground monitoring equipment provides regular read-outs on the health of wetlands next to the stream.
Another essential part of the project involved fencing off most of the reborn stream to keep out the cows.
Workers built several bridgelike fords so Humble’s herd could move easily between pastures on either side of the creek.
Restoration Systems will continue monitoring the site for several more years to ensure steady growth for the required five-year period, which experts say is long enough to ensure long-term viability.
So far, Preyer said, scientific monitoring by electronic gauges and by technicians over the past two years has shown the stream much healthier and the wetlands thriving.
But the newly arrived dragon flies, woodpeckers and deer didn’t need a scientific report to figure that out all by themselves.
Contact Taft Wireback at 373-7100 or email@example.com
Local public figures and residents gathered Friday at Lowell Mill Park to celebrate the county’s recent ownership of the land in a dedication ceremony.
By Jamie Hodges
The park rests within a 17-acre plot, which surrounds the Little River at Lowell Mill Road just outside of Kenly. It used to be owned by Restoration Systems, a Raleigh-based mitigation company. But since it’s been turned over to Johnston County, the park is now officially open to the public.
Kenly Town Council will hold a public hearing on Oct. 8 to get public in-put on whether the town should take over the park. Commissioners have asked the town if it would like to take it over and receive the $140,000 endowment that goes with the park for upkeep.
“This is a great opportunity for the city of Kenly and all of Johnston County,” said George Howard, co-founder of Restoration Systems. “I hope they take advantage of it.”
Along with the land transfer, Restoration Systems has also provided the county with a private endowment of $140,000 to be used for the park’s maintenance.
“Without the endowment, I seriously doubt that we would have been able to take over the park,” said County Manager Rick Hester.
The county has now offered the park, with the endowment included, to the town of Kenly.
Kenly has scheduled a public hearing on Oct. 8 during its monthly town council meeting to further discuss the issue.
“We don’t know if any action will be taken,” said Kenly Town Manager Scott Shelton. “It’s an information gathering meeting. We have to determine the benefits against any negative issues we may have to deal with it.”
The park is located at what used to be Lowell Mill Dam, which was demolished in Dec. of 2005. Work on the park, which is approximately two acres, started last October.
The dam was removed despite strong protest from several Kenly area residents who were concerned that it would negatively affect their fishing.
Adam Riggsbee, an environmental scientist who works for Restoration Systems, said the removal of the dam will have an overall positive effect on the ecosystem of organisms living in Little River.
“Before the dam was removed, it blocked off several spawning sites for the American Shad fish,” said Riggsbee. “And it formed a lake-like effect that made it hard for river dwelling organisms, such as mussels who live at the bottom of the river, to survive. Now that it is no longer there, the river has returned to its natural free flowing state that will benefit the environment.”
Selma resident Doug Tetrick, who lost his son, Paul Tetrick, to a fatal swimming accident near Lowell Mill Dam in 2000, was glad to see the park erase the last physical remnants of a spot that caused his family so much tragedy.
“It’s a great way to turn a negative event into a positive one,” said Tetrick. “I’m glad to see that the dam is gone. It was a dangerous spot. A lot of people died here, including my son. It’s a big relief.”
Tetrick’s daughter, Morgan Tetrick, who lives in Smithfield, said she hopes Friday’s dedication ceremony will put some closure on the tragic event.
“It just looks so much better now,” she said as she glanced across the bank of the river. “It doesn’t even look like the same spot where my little brother died. It looks so nice with the park next to the river. Paul would have loved this scene.”
County Commissioner Tony Braswell also hoped that Friday’s ceremony will allow the community to put the past behind.
“I think this park represents a great opportunity for everyone involved,” said Braswell. “I understand all of the controversy behind it. But it’s time to move forward.”
CARBONTON — A little fish got a big break when science paired with business two years ago to remove an old hydroelectric dam on the Deep River in this rural community near the Lee-Moore county line.
By Nomee Landis
The construction of the dam in 1921 divided a group of minnow-size fish called Cape Fear shiners. The dismantling of the dam has removed the obstacles — a concrete structure and nearly 10 miles of deep, stagnant water behind it — that have kept the populations of the little fish separated for decades.
Now it looks as though the little shiner is returning to an area of the river that had been a dead zone for this species, along with other species that prefer free-flowing river habitats.
That is good news because the little shiner is a federally endangered species. The two populations need to reunite and, in polite scientific terminology, exchange genetic material. In other words, they need to produce a lot of baby Cape Fear shiners in order to move the species further from the possibility of extinction.
A Raleigh-based company called Restoration Systems dismantled the dam with money from the state Environmental Enhancement Program.
The program’s purpose is to protect or restore ecosystems, such as wetlands and streams, to compensate for damage to similar areas during highway construction.
On Thursday, environmental scientists from The Catena Group, an ecological consulting firm under contract with Restoration Systems, waded into the Deep River at the site of the old dam to check for Cape Fear shiners. They are monitoring the fish’s progress in repopulating the river upstream of the old dam site.
Shay Garriock and Tom Dickinson, scientists with the group, each held the wooden handle of a seine and dragged the net through shallow, riffling areas of the river. After walking with the outstretched net for several strides, the two turned it upright to examine their catch.
With each pass, they captured a dozen or more minnow-size fish that all looked remarkably similar to untrained eyes.
Tim Savidge, an environmental supervisor with The Catena Group, named each as he sifted through the catch of silver fish in the center of the net: juvenile largemouth bass, speckled killifish, satinfin shiner, Piedmont darter. I
t took a few minutes of fishing in several spots in the river before the trio found what everyone was looking for: a single Cape Fear shiner.
Adapting to change
The endangered shiners prefer riffling areas of the river, where the water is bubbling and shallow. Last year, Savidge and his group marked the areas of the river upstream of the former dam where they thought riffles would develop. They are going back this year to check those sites for fish.
So far, their research indicates that the fish has been quick to respond to the changes in the river.
And the changes in the river have been dramatic. The Deep has fallen more than 10 feet in many places upstream of the dam site. Plants are growing in large swaths that used to be covered by water. The river has returned to its narrower, more meandering path.
Savidge said workers have noticed young freshwater mussels in the river upstream of the dam. The mussels, like the shiners, prefer swift, shallow waters and do not thrive in the lake-like waters behind dams.
The Deep River is a highly dammed waterway. Many old mill dams, most now defunct, remain on the river between its headwaters near High Point and its confluence with the Haw River below Jordan Lake. Together, the Haw and Deep rivers form the Cape Fear River.
In 2002, a state task force ranked the Carbonton Dam fourth on a list of dams in the state that should be removed for environmental reasons.
Adam Riggsbee is an environmental scientist and a dam removal authority with Restoration Systems. He said the state wanted the dam removed to improve the quality of water in the river, to improve habitat for the fish species there and to restore the riverbanks to their natural state.
The process of removing the old dam began in fall 2005.
The old powerhouse still stands alongside the river just downstream of the N.C. 42 bridge. It will remain. Both it and the adjoining park will be turned over to the Deep River Parks Association this month. Restoration Systems is providing an endowment for development and upkeep of the park.
When state officials said that the dam would be removed, fishermen strongly resisted the idea. Dismantling the dam meant losing a miles-long, deep fishing spot that was accessible to larger boats.
Dickinson, one of the scientists with The Catena Group, said the largemouth bass are still there, and the fishing is still good. He said he and others paddled the river upstream of Carbonton in a canoe last year, casting along the way. With nearly every cast into the deeper pools, Dickinson said, the party hooked a big fish.
A 25-mile stretch of the river and its tributaries will be monitored for five years to ensure that the project achieves the goals established before the dam’s demolition.
Scientists will continue to test the chemistry of the water and the presence of aquatic insects, both of which indicate a stream’s health. They will monitor the progress of the freshwater mussels. And they will continue to look after one special little silver fish.
Staff writer Nomee Landis can be reached at firstname.lastname@example.org or 486-3523.
CARBONTON – Biologists say an endangered minnow is rebounding in central North Carolina, thanks largely to demolition of a dam.
Scientists first identified the Cape Fear Shiner in 1971. It was then known only in small reaches of the Haw and Deep rivers in Randolph, Chatham, Lee, Moore and Harnett counties.
By late 1987, the fish was on the federal Endangered Species List because of dwindling habitat caused by a long history of dams. The dam that was taken down was part of a hydroelectric plant built in 1921. It closed in 2004 and the dam was removed by 2006.
Officials say removal of a dam near Carbonton in southern Chatham County has resulted in one of the biggest ecological success stories in North Carolina.
The yellowish minnow with black stripes and pointed fins has been found in a 10-mile stretch of the Deep River. Biologists believe the fish had not inhabited that area in at least 80 years.
Raleigh-based Restoration Systems, which coordinated demolition of the dam while partnering with the N.C. Ecosystem Enhancement Program, continues to monitor 58 sites along the Deep River to track its restoration.
"The speed at which this recovery has taken place is what stands out," said Adam Riggsbee, an environmental scientist with the company.
Company co-owner George Howard said the project has breathed new life into the once-sluggish river. "Unfortunately, it’s such a lonely part of the world, not many people get to see it," Howard said. "But it really is a wonderful thing to see."
CARBONTON — The Cape Fear Shiner is a yellowish minnow with black stripes, pointed fins and a hard-luck past.
By Taft Wireback
But with the help of an environmental firm that has offices in Greensboro, the fish that seldom exceeds two inches in length is becoming one of North Carolina’s biggest ecological success stories.
Biologists working for Restoration Systems have found the endangered species in a 10-mile stretch of the Deep River it hadn’t inhabited in 85 years or perhaps even longer, thanks to the removal of an old dam near Carbonton in southern Chatham County.
"The speed at which this recovery has taken place is what stands out," said Adam Riggsbee, an environmental scientist with the company, which has headquarters in Raleigh and a branch in Greensboro.
Restoration Systems coordinated demolition of the dam through early 2006 in partnership with the N.C. Ecosystem Enhancement Program. It continues to monitor 58 sites along the Deep River as part of the project, keeping track of what happens to a once-impounded river when restored to its free-flowing state.
The project has breathed life into what had been a sluggish, bloated stretch of river, said company co-owner George Howard.
"Unfortunately, it’s such a lonely part of the world, not many people get to see it," said Howard, a Greensboro native. "But it really is a wonderful thing to see.
"You can think of the tiny yellow-and-black minnow as a sort of miner’s canary that swims, a bellwether for the health and restored vigor of the water that surrounds it.
The tiny minnow was unknown to science until 1971, when it was identified in a very limited range that included small reaches of the Haw and Deep rivers in just five counties — Randolph, Chatham, Lee, Moore and Harnett.
By September 1987, it already had been placed on the federal Endangered Species List because of its dwindling habitat.
The minnows need water of decent quality riffling in shallow depths over gravel, stone and boulder bottoms.
The dam that was demolished was a small, hydroelectric operation built in 1921 and shut down in June 2004. But the site, near the line between Chatham and Lee counties, had hosted a series of dams stretching back into the 19th century.
So biologists couldn’t be sure how long two separate colonies of Cape Fear Shiner had been separated by one dam or another and its 10-mile stretch of backed-up water, too deep and slow for the minnow’s liking.
Meanwhile, on either side of the dam, the isolated populations of Cape Fear Shiner were dwindling. Removing the dam produced results aimed at fixing that problem faster than anyone had been willing to hope, Riggsbee said.
"If you provide the habitat, the theory is that you should get the species back in place," he said. "That’s exactly what has happened here in less than two years. The river responded very quickly and so did this key species."
Last year when aquatic biologist Tim Savidge sampled the numerous testing sites along the newly emancipated stretch of Deep River above the former dam, he found no Cape Fear Shiners.
But he did see a lot of the riffled habitat starting to form, the faster and shallow water over a rocky bottom that is home to the little minnows.
"Then this year, we picked up numerous Cape Fear Shiners at multiple sites throughout that 10-mile section," said Savidge of the Catena Group, an environmental consulting firm that is helping Restoration Systems with its follow-up duties.
State officials are still awaiting the company’s annual report, documenting the endangered shiner’s return. But as a sign of improving water quality and nature revived, it is welcome news, said Tad Boggs of the state’s ecosystem enhancement program.
"Assuming it’s accurate, it represents a win-win situation for what our program is designed to do," said Boggs, whose agency has supervised about 700 such projects statewide since its creation four years ago.
Restoration Systems works on such projects as the dam with state and federal officials to provide "mitigation credits." The credits are bought by public and private agencies to offset environmental damage done by such developments as new dams, roads or neighborhoods in the same region.
Among other things, credits from removing the dam at Carbonton allowed the state Department of Transportation to build or expand a number of roads in this part of the state.
Contact Taft Wireback at 373-7100 or email@example.com
KENLY — Town officials are considering taking over Lowell Mill Park near Interstate 95 from Johnston County.
Herald photo by Michael McLoone
The county has owned the park for a few months, said County Manager Rick Hester. But Johnston is now looking to hand the 17-acre property over to Kenly.
“It would be an asset for someone to have,” Hester said.
The Kenly Town Council will discuss the possible park transfer during a public hearing at 7 p.m. Oct. 8. “I’m intrigued with the possibilities the park offers,” Kenly Town Manager Scott Shelton said. “We’re hoping to get some input from the public.”
But it’s too early to say what Kenly would do with the property if it acquired it, Shelton said.
Ernie Wilkinson, a former Kenly mayor and the current director of Johnston County Animal Services, has been involved with the park for years.
A dam that used to be at the site was removed a few years ago, Wilkinson said. Restoration Systems, the Raleigh-based natural resources conservation company that used to own the land, gave the county a $140,000 endowment for the park’s upkeep.
“There’s no tax money in that thing,” Wilkinson said of the park.
The property is adjacent to a lot that was added to town by satellite annexation.
“I personally think this is an asset to the county,” Kenly Councilman Scott Turik said at last week’s council meeting.
“It would be a shame to let it become an eyesore. If we ever do have growth out there, this could be a centerpiece.”
Wilkinson said he would like to see walking trails on the property, which already features picnic tables and a kayak launching pad.
Taking over the park could be beneficial for Kenly also because the town could use the interest from the endowment for other recreational purposes, Wilkinson suggested.
“It’s a mighty lucrative deal,” he said.
Herald Staff Reporter Sarah Nagem can be reached at 934-2176, Ext. 137, or by e-mail at firstname.lastname@example.org.
Evidence unearthed at more than two dozen sites across North America suggests that an extraterrestrial object exploded in Earth's atmosphere above Canada about 12,900 years ago, just as the climate was warming at the end of the last ice age. The explosion sparked immense wildfires, devastated North America's ecosystems and prehistoric cultures, and triggered a millennium-long cold spell, scientists say.
At sites stretching from California to the Carolinas and as far north as Alberta and Saskatchewan—many of which were home to prehistoric people of the Clovis culture—researchers have long noted an enigmatic layer of carbon-rich sediment that was laid down nearly 13 millennia ago. "Clovis artifacts are never found above this black mat," says Allen West, a geophysicist with Geoscience Consulting in Dewey, Ariz. The layer, typically a few millimeters thick, lies between older, underlying strata that are chock-full of mammoth bones and younger, fossil-free sediments immediately above, he notes.
New analyses of samples taken from 26 of those sites reveal several hallmarks of an extraterrestrial object's impact, West and his colleagues reported at the spring meeting of the American Geophysical Union in Acapulco, Mexico.
Samples from the base of the black mat yield most of the clues to its extraterrestrial origin, says Richard B. Firestone, West's coworker and a nuclear physicist at the Lawrence Berkeley (Calif.) National Laboratory. Some of the particles there are small, magnetic grains of material with higher proportions of iridium than are found in Earth's crust, he notes.
Also in the mat's base are tiny lumps of glasslike carbon that probably formed from molten droplets of the element. These lumps, as well as little spheres of carbon with a different microstructure, contain nanoscale diamonds formed under intense pressure.
A host of unusual geological features, collectively known as Carolina Bays, hints at the cataclysm's location, says team member George A. Howard, a wetland manager at Restoration Systems, an environmental-restoration firm in Raleigh, N.C. Around 1 million of these elliptical, sand-rimmed depressions, measuring between 50 meters and 11 kilometers across, scar the landscape from New Jersey to Florida. In samples taken from 15 of the features, Howard and his colleagues found iridium-rich magnetic grains and carbon spherules with tiny diamond fragments similar to those found at Clovis archaeological sites.
The long axes of the great majority of the Carolina Bays point toward locations near the Great Lakes and in Canada—a hint that the extraterrestrial object disintegrated over those locales, says Howard.
Because scientists "haven't discovered a large, smoking hole" left by the event, the object that blew up in the atmosphere probably was a comet, says West.
Heat from the event would have set off wildfires across the continent, the scientists suggest. The heat and shock from the explosion probably broke up portions of the ice sheet smothering eastern Canada at the time, they add. The flood of fresh water into the North Atlantic that resulted would have interrupted ocean currents that bring warmth to the region, and thick clouds of smoke and soot in the air would have intensified cooling across the Northern Hemisphere.
The inferred date of the event matches the beginning of a 1,200-year-long cold spell that geologists call the Younger Dryas, which in its first few decades saw temperatures in the Northern Hemisphere drop as much as 10°C.
From Science News, Vol. 171, No. 22, June 2, 2007, p. 339.
Device aids study of Little River fish
By Suzette Rodriguez
KENLY — Joshua Raabe might not have snagged the biggest fish out of the Little River. But he could claim bragging rights for building the granddaddy of all fish traps.
A bass headed up or down stream would have to pole vault to clear it. But it’s flexible enough for canoes and boats to drift downstream over it.
The contraption, as locals call it, is a resistance-board weir, designed to safely capture fish coming and going in the waters where the 10-foot-thick concrete dam of Lowell Mill once stood.
Restoration Systems, a Raleigh company that specializes in environmental restoration, bought the dam, then blasted and cleared it away in December 2005 and January of 2006. It plans to give the 17-acre site and a $140,000 endowment to the county for use as a park.
The purpose behind removing the dam was to open up spawning areas to striped bass, herring and shad — species of saltwater fish that spawn in fresh water. With the removal of the dam, the fish can now migrate from the Atlantic Ocean up the Little River all the way to Atkinson Mill.
Raabe, 25, a graduate student, built and installed the weir as part of a study by the N.C. Cooperative Fish and Wildlife Research Unit at N.C. State University. U.S. Fish & Wildlife is funding the study, while Restoration Systems put up the $15,000 to buy the materials.
For his design, Raabe borrowed from a blueprint of a weir used to catch salmon in Alaska. He spent about five weeks drilling, cutting and connecting sections of PVC pipe to make the two cages and floating panels. Pieces of plywood attached to the panels give them lift as the river rises and falls.
On either end, metal pickets block the fish and steer them toward the cages.
Raabe will leave the weir up through May. He’ll take it down, then reinstall it for the March-to-May period of 2008.
Every morning, he wades out to the cages to see what he’s caught.
On Friday, he scooped out of the trap a gizzard shad, a fish more suitable for bait than eating. But in earlier weeks, he had caught an American shad as well as a few suckers, or bottom-feeding fish.
On one particular morning, Raabe got a startle when a curious beaver swam up to his feet as he was working at the weir.
Locals have also dropped by to see what’s going on. On weekends, two or three people come to cast their lines, Raabe said. “But most come, look and leave,” he said.
“All remember the dam,” he added. “And they ask if the shad are running. There’s definitely an interest.”
Dr. Joseph Hightower, a biologist with the U.S. Geological Survey stationed at N.C. State, says he’s disappointed that more American shad aren’t at the Lowell Mill site. He thinks the river’s low flow brought on by the drought is to blame.
Hightower said the fish adjust their migration to river conditions. At the weir, the river is two feet at its deepest point, he said.
“We have no idea how many there are, so we don’t know what to expect,” Hightower said Friday. “We assumed we’d have more.”
Back in the 1800s, the American shad were considered fine eating, he said. Nowadays, they’re becoming popular for sport fishing. He’d like to see the population in the Little River build up as much as the hickory shad in the Roanoke River.
At one time, North Carolina produced more American shad than any other state. But catches plummeted from more than eight million pounds in 1896 to 205,000 pounds in 1995, according to information in a brochure about the project.
Hightower says the shad can rebound quickly, however, with quality habitat. A mature fish can lay as many as 600,000 eggs.
As part of the study, Raabe and an assistant, Dana Sackett of Fayetteville, are sampling the river farther upstream and downstream for the tiny fish eggs that ride with the currents.
Raabe records the length and tags the American shad and suckers before turning them loose. To keep track of the gizzard shads, he notches their tails.
But the one he scooped up Friday wiggled its way free while being measured. If not for Sackett’s quick hands, the fish might have gotten away.
Herald Staff Reporter Suzette Rodriguez can be reached at 934-2176, Ext. 128, or by e-mail at email@example.com
Somerset farm conversion is watershed condition of Wicomico airport project
By Liz Holland
PRINCESS ANNE — Mount Vernon residents will soon see a 50-acre farm converted into a natural area along the Wicomico River as part of wetlands replacement for a construction project miles away at the Salisbury-Ocean City: Wicomico County Regional Airport.
In the next few weeks, workers will begin grading the land and planting native trees on the Bobtown Road property to turn it into a combination of marsh near the river and forested nontidal wetlands closer to the road.
"Technically, we’re not creating wetlands, said Joe Carroll of Restoration Systems LLC, consultant for the project. "We’re restoring what it once was."
Although the land has been used for farming for many years, Carroll said it was once a "fully-functioning ecosystem" that had man-made "improvements" over the years, including leveling of the earth and the addition of drainage ditches for the fields. Carroll said part of his job was to figure out what the land once looked like, and to help restore it.
While a small portion will be turned into a marshy area near the river, most of the property will be a forested area that will only flood during certain times of the year. Native trees and shrubs are already on order from a nursery and should be ready to go in the ground over the next few weeks.
Other species, such as pine, will seed themselves naturally on the property.
"Nature takes care of a lot of it, but we want to give some species a head start," he said.
The project also will include the elimination of phragmites — an invasive reed — along the riverbank. Workers will also fill in the drainage ditches.
Carroll said it’s unlikely the new wetland area will encroach on adjoining properties because there is a 5-foot fall from the road where neighboring houses are located down to the river, so water will drain away from the houses. The work in Somerset County is necessary because airport runway projects are disturbing 40 acres of wetlands along a small creek that feeds into the Wicomico River, and federal environmental regulations require Wicomico County to create new wetlands somewhere else in the same watershed.
Last year, Wicomico officials identified more than 160 possible sites along the Wicomico River in Wicomico County, but they turned out to be either unsuitable or the property owners refused to sell, Carroll said. The Mount Vernon site met all the Maryland Department of the Environment criteria — including 50 contiguous acres of hydric soil — and the owner was willing to sell.
Although Somerset County officials questioned why it was necessary for Wicomico County to bring its wetlands mitigation over the county line, residents in Mount Vernon don’t seem to mind it too much, said County Commissioner Rex Simpkins, who represents that district.
"I’ve only heard one or two negative remarks," he said. Carroll said.
The property — which will eventually serve as part of the important filtration system for the Wicomico Watershed — will be an attractive, natural area when it’s completed. The project also has pleased state and federal environmental officials because poorer quality wetlands near the airport are being replaced.
"The restored area will be better than what is being taken away," he said.