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NEWS
August 1, 2013 | By Tony Barboza
Hydroelectric dams may be known as a relatively clean and low-cost energy source, but a new study says that the sediment trapped behind them makes them hot spots for greenhouse gas emissions. A team of European scientists found that methane, which is produced by organic matter in the sediment that collects behind the impoundments, bubbles up through the water and contributes more of the greenhouse gases driving climate change than previously thought. The scientists studied six small dams on the River Saar in Germany and found “hot spot emission zones” of methane, a potent greenhouse gas that is many times more effective at trapping heat than carbon dioxide.
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SCIENCE
March 8, 2014 | By Karen Kaplan
Scientists have made a surprising discovery in the waters off the coast of Iraq: a coral reef made up of more than half a dozen species of the marine animals. A team of divers from the Freiberg University of Mining and Technology in Germany and the Marine Science Center at the University of Basrah in Iraq captured video footage of the murky waters where the Shatt al-Arab river flows into the northwestern portion of the Persian Gulf. (You can watch the video above.) The river carries sediment -- and frequently oil -- into that portion of the gulf, which is often churned up by strong winds and currents.
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SCIENCE
October 19, 2012 | By Jon Bardin
At the bottom of a lake near Japan's Wakasa Bay, more than 50,000 years of history has been pulled out of the ground in the form of sediment and leaves. The information contained in those samples will allow scientists to determine the age of organic materials and fossils with new clarity by improving carbon dating, according to a study published Thursday in the journal Science. Carbon dating works by detecting the relative amounts of two varieties of carbon: carbon-14, or C-14, and carbon-12, or C-12.
OPINION
January 17, 2014 | By Christle Balvin
California's coastal mountains have a compulsion to get to the sea. They are constantly sending sand and sediment downstream to the beaches. Or at least they're trying to. But today, a system of 14 dams along the foothills of the San Gabriels prevents much of the sand from reaching the shore. The result is a slowly eroding coastline, a network of ugly concrete storm channels where streams once flowed, and an ever-increasing accumulation of earth behind the dams. Southern California rivers are notoriously unpredictable.
OPINION
January 17, 2014 | By Christle Balvin
California's coastal mountains have a compulsion to get to the sea. They are constantly sending sand and sediment downstream to the beaches. Or at least they're trying to. But today, a system of 14 dams along the foothills of the San Gabriels prevents much of the sand from reaching the shore. The result is a slowly eroding coastline, a network of ugly concrete storm channels where streams once flowed, and an ever-increasing accumulation of earth behind the dams. Southern California rivers are notoriously unpredictable.
CALIFORNIA | LOCAL
February 16, 1996 | MARY MOORE, SPECIAL TO THE TIMES
Los Angeles County and the Army Corps of Engineers announced Thursday that together they will fund a dredging project in Marina del Rey to clear a silt-choked waterway that leads from the marina to the ocean. At a cost of $1.25 million, about 360,000 tons of sediment that has built up in the marina's entrance channel is to be scooped out, much of it silt carried down the coast or from Ballona Creek to the channel during storms. The dredged material will end up on nearby Dockweiler Beach.
CALIFORNIA | LOCAL
June 13, 1995 | DOUG SMITH, TIMES STAFF WRITER
To his doubters, Bill Blomgren came across as a hopeless neophyte and dreamer, a small-time excavation man who said he could move a mountain and pay the government for the privilege of doing it. No ordinary mountain, this one covered 1,500 acres in the northeast San Fernando Valley and was as flat as the Mojave Desert.
NEWS
March 26, 1997 | MARLA CONE, TIMES ENVIRONMENTAL WRITER
Off Southern California's shore, purity is an illusion that lies only a few feet deep. The trouble's not with the water; it's with what lies beneath it. From Santa Catalina Island to New York Harbor, the mud and silt that line the bottom of rivers, bays and lakes contain chemicals deemed potent enough to kill aquatic animals and endanger the health of people who consume marine life.
CALIFORNIA | LOCAL
January 14, 2011 | By Louis Sahagun, Los Angeles Times
Several weeks of debate over the fate of a grove of oaks and sycamores in the Arcadia highlands have left a community at odds, even after nearly 200 trees were bulldozed by Los Angeles County work crews. At least 179 coastal oaks and about 70 sycamores were uprooted and ground into wood chips on an 11-acre site just below Santa Anita Dam to make way for 500,000 cubic yards of sediment to be dredged from behind the structure. Three of four tree-sitters arrested after a 12-hour standoff Wednesday with Los Angeles County sheriff's deputies were released on their own recognizance Thursday after being charged with misdemeanor counts of trespassing and obstructing a police officer.
NATIONAL
May 20, 2011 | By Tina Susman, Los Angeles Times
Earl Billiot guides his boat down a quiet bayou and explains how it used to be, when the water that runs as wide as a two-lane highway was so narrow you could reach out and touch the land. Branches heavy with Spanish moss draped over the bayou, and forests covered marshes that are bare now except for the skeletons of dead cypress trees. Eighty miles away, tourists and locals gather atop a levee in New Orleans to gape at the magnificent Mississippi River, swollen by floods and higher than most have ever seen it. They relax in the afternoon sun with plastic cups of daiquiris and beer, certain that the structure they sit on will keep the water back.
SCIENCE
October 28, 2013 | By Bettina Boxall
The destructive environmental legacy of Gold Rush mining in the Sierra Nevada could last for thousands of years in the form of ongoing erosion of mercury-laced sediments, according to new research. Mercury, a toxic heavy metal, was used in copious amounts in California's hydraulic gold mining operations in the mid- and late 1800s. Miners blasted gold-bearing sediment out of vast, ancient gravel beds with water cannons. They then added liquid mercury to the slurry, allowing the gold-mercury amalgam to sink to the bottom of troughs.
CALIFORNIA | LOCAL
October 26, 2013 | By Abby Sewell
Los Angeles County flood control officials presented several options for removing built-up debris and mud from a basin above Devil's Gate Dam in northern Pasadena in a draft environmental impact report released Thursday. The basin became choked by mud and debris after the 2009 Station fire and storms that followed. Flood control officials have warned for years that the buildup compromises the dam's ability to contain debris and floodwater in another major storm. Officials say locations downstream from the dam along the Arroyo Seco that could be in danger of flooding include the Rose Bowl, 110 Freeway, neighborhoods in Pasadena and South Pasadena, and the northeastern Los Angeles communities of Highland Park, Hermon, Montecito Heights, Mount Washington and Cypress Park.
NEWS
August 1, 2013 | By Tony Barboza
Hydroelectric dams may be known as a relatively clean and low-cost energy source, but a new study says that the sediment trapped behind them makes them hot spots for greenhouse gas emissions. A team of European scientists found that methane, which is produced by organic matter in the sediment that collects behind the impoundments, bubbles up through the water and contributes more of the greenhouse gases driving climate change than previously thought. The scientists studied six small dams on the River Saar in Germany and found “hot spot emission zones” of methane, a potent greenhouse gas that is many times more effective at trapping heat than carbon dioxide.
SCIENCE
October 19, 2012 | By Jon Bardin
At the bottom of a lake near Japan's Wakasa Bay, more than 50,000 years of history has been pulled out of the ground in the form of sediment and leaves. The information contained in those samples will allow scientists to determine the age of organic materials and fossils with new clarity by improving carbon dating, according to a study published Thursday in the journal Science. Carbon dating works by detecting the relative amounts of two varieties of carbon: carbon-14, or C-14, and carbon-12, or C-12.
CALIFORNIA | LOCAL
November 16, 2011 | By Mike Reicher, Los Angeles Times
Work crews have finished scooping tons of chemical-laden sediment from the historic Rhine Channel in Newport Harbor, completing a $4-million project ahead of time. The channel, once a bustling home to fishing fleets and cannery operations, has long been contaminated by mercury, pesticides and other toxic chemicals. The city's contractor, Dutra Dredging, beat the year-end deadline to dredge the channel and haul the contaminated sediment to Long Beach, where it will be used as fill dirt for a construction project.
CALIFORNIA | LOCAL
July 17, 2011 | By Joe Piasecki, Los Angeles Times
The removal of 25,000 cubic yards of sediment from the basin behind Devil's Gate Dam in Pasadena has been put on hold until August in order to prevent the destruction of a habitat for toads. Work was set to begin last week, but Pasadena officials decided to postpone the job pending further environmental review after Hahamongna Watershed Park users complained that Johnson Field, where the dirt was to be temporarily stored, was home to a large number of toads that would be smothered underneath the piles of dirt.
SCIENCE
October 28, 2013 | By Bettina Boxall
The destructive environmental legacy of Gold Rush mining in the Sierra Nevada could last for thousands of years in the form of ongoing erosion of mercury-laced sediments, according to new research. Mercury, a toxic heavy metal, was used in copious amounts in California's hydraulic gold mining operations in the mid- and late 1800s. Miners blasted gold-bearing sediment out of vast, ancient gravel beds with water cannons. They then added liquid mercury to the slurry, allowing the gold-mercury amalgam to sink to the bottom of troughs.
CALIFORNIA | LOCAL
April 3, 1996
Weather permitting, work will end Friday on a dredging project in Marina del Rey to remove sediment that is blocking part of the entrance channel to the marina. Next week, when the dredging is completed, workers will remove a discharge pipeline installed along Dockweiler State Beach as part of the project, said Deputy Fred Pausch of the Los Angeles County Sheriff's Department. The 235,000 cubic yards of sediment dredged out of the entrance channel is being deposited on the beach.
NATIONAL
May 20, 2011 | By Tina Susman, Los Angeles Times
Earl Billiot guides his boat down a quiet bayou and explains how it used to be, when the water that runs as wide as a two-lane highway was so narrow you could reach out and touch the land. Branches heavy with Spanish moss draped over the bayou, and forests covered marshes that are bare now except for the skeletons of dead cypress trees. Eighty miles away, tourists and locals gather atop a levee in New Orleans to gape at the magnificent Mississippi River, swollen by floods and higher than most have ever seen it. They relax in the afternoon sun with plastic cups of daiquiris and beer, certain that the structure they sit on will keep the water back.
OPINION
May 11, 2011
Water won't wait Re "Messing with Devil's Gate," Editorial, May 6 I lived in La Crescenta during the great flood of 1938. I remember listening to radio reports that Devil's Gate Dam was in imminent danger of collapsing. Fortunately it didn't, and the Arroyo Seco and the communities below were saved from a deluge of mud and water. The fact that the dam's basin has been allowed to fill with sediment over the years is a sign of ignorance and mismanagement. The L.A. County Board of Supervisors should make clearing out the basin a top priority.
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