Mangroves help protect coastal areas against sea level rise

Blue & Green Tomorrow: Mangrove forests could play a crucial role in protecting coastal areas from sea level rise caused by climate change, according to new research involving the University of Southampton. A joint study between researchers at the University of Southampton along with colleagues from the Universities of Auckland and Waikato in New Zealand used leading-edge mathematical simulations to study how mangrove forests respond to elevated sea levels.

Taking New Zealand mangrove data as the basis of a new modelling system, the team were able to predict what will happen to different types of estuaries and river deltas when sea levels rise. They found areas without mangroves are likely to widen from erosion and more water will encroach inwards, whereas mangrove regions prevent this effect – which is likely due to soil building up around their mesh-like roots and acting to reduce energy from waves and tidal currents.

Coastal estuaries and recesses in coastlines that form bays receive the run-off from erosion on steep catchments, which give them the tendency to fill in over time. As they infill, the movement of the tidal currents over the shallow areas create networks of sandbanks and channels. The sand banks grow upward to keep pace with water-level changes, while the channels get deeper to efficiently drain the excess water out to sea.

The researchers’ latest work shows that mangroves can facilitate this process, by adding leaf and root structures into the accumulating sediment, which increase the elevation while enhancing the trapping of new sediment arriving from the catchment.

Dr Barend van Maanen from the University of Southampton explains: “As a mangrove forest begins to develop, the creation of a network of channels is relatively fast. Tidal currents, sediment transport and mangroves significantly modify the estuarine environment, creating a dense channel network. Within the mangrove forest, these channels become shallower through organic matter from the trees, reduced sediment resuspensions (caused by the mangroves) and sediment trapping (also caused by the mangroves) and the sea bed begins to rise, with bed elevation increasing a few millimetres per year until the area is no longer inundated by the tide.”...

Mangroves in Zanzibar, shot by Fanny Schertzer, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license

NOAA report highlights climate change threats to nation’s estuaries

NOAA: The nation’s 28 National Estuarine Research Reserves (NERR) are experiencing the negative effects of human and climate-related stressors according to a new NOAA research report from the National Ocean Service.

The national study, Climate Sensitivity of the National Estuarine Research Reserve System, points to three East Coast reserves, Sapelo Island NERR in Georgia, ACE Basin NERR in South Carolina and Waquoit Bay NERR in Massachusetts, and  the Tijuana River NERR on the California-Mexico border, as the most sensitive to climate change.

“The National Estuarine Research Reserves are uniquely positioned across the U.S. to assess ongoing climate change in our nation’s estuaries which is the degree to which the natural resources and the local communities who depend on them are affected by changing climate conditions,” said Dwight Trueblood, Ph.D. a co-author and NOAA program manager for the study. “This information is important to helping coastal managers and local community leaders make informed decisions about the best ways for coastal communities to adapt to climate change.”

Estuaries are places where rivers meet the sea, providing nursery habitat for fish and shellfish while buffering many coastal communities from the impacts of coastal storms and sea level rise. The climate exposure of each reserve provides first alarm indicators about the effects of climate change on the coastal ecosystems. Ongoing research at each of the reserves provides real-time data about how climate change impacts these important natural resources.

Almost 40 percent of all Americans, or about 123 million people, live in the counties directly along the shoreline and depend on these resources for food, jobs, storm protection, and recreation. Approximately 50 percent, or $6.6 trillion, of the nation’s gross domestic product comes from coastal watershed counties which support more than 51 million jobs. Researchers determined the extent of relative climate sensitivity in the reserves by looking at five factors: social, biophysical, and ecological sensitivity, and exposure to temperature change and sea level rise....

Researchers advocate a simple, affordable and accurate technology to identify threats from sea-level rise

AlphaGalileo via the National University of Singapore: Potential for method to be used within a network of wetland monitoring programmes in Southeast Asia and globally for assessing shoreline security and stability

A team of researchers led by Associate Professor Edward L. Webb of the National University of Singapore (NUS) is calling for the global adoption of a method to identify areas that are vulnerable to sea-level rise. The method, which utilises a simple, low-cost tool, is financially and technically accessible to every country with coastal wet­lands. The team seeks to establish a network to coordinate the standardisation and management of the data, as well as to provide a platform for collaboration.

...Recognising that some wetlands may be able to keep up with sea-level rise, the research team argues that scientists must quantitatively evaluate which wetlands may persist in the future, and which may be most threatened by sea-level rise.

Although the science behind the tracking of sea-level is well-advanced, a large gap exists in the measurement of the biophysical processes underlying the vertical movement of coastal wetlands, so it remains unknown which coastal wetlands will be most vulnerable to future sea-level rise. Collection of relevant data across global wetlands is critical to informing not only local policies, but to generating more realistic regional-level predictions to inform costal management and policy.

In a bid to address this gap, the research team, comprising members from NUS and the United States Geological Survey, argues for the widespread adoption of a standardised, simple and inexpensive method to measure the vertical movement of coastal wetland surface and its constituent processes that determine whether a wetland can keep pace with sea-level rise. The method utilises a rod surface elevation table (RSET), in which a benchmark rod is drilled vertically through the soil down to the base of the mudflat. A portable horizontal arm is attached at a fixed point to measure the distance to the substrate surface. The RSET is thus a permanent reference point to measure the rate and direction of the mudflat’s surface movement. ...

Nei Lingding Island, view from Hong Kong, shot by Minghong, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license

Marsh plants actively engineer their landscape

EurekAlert via Duke University: Marsh plants, far from being passive wallflowers, are "secret gardeners" that actively engineer their landscape to increase their species' odds of survival, says a team of scientists from Duke University and the University of Padova in Italy.

Scientists have long believed that the distribution of plants within a marsh is a passive adaption in which species grow at different elevations because that's where conditions like soil aeration and salinity best meet their needs. But this team found intertidal marsh plants in Italy's famed Venetian lagoon were able to subtly tune, or adjust, their elevations by producing different amounts of organic soil, and trapping and accumulating different amounts of inorganic sediments as part of a complex interplay with the environment.

"Our study identifies the visible signature of a two-way feedback occurring between the vegetation and the landscape," said Marco Marani, professor of ecohydrology at Duke's Nicholas School of the Environment and Pratt School of Engineering. "Each species builds up the elevation of its substrate to within a favorable range for its survival, much the way corals in the animal kingdom do." The finding may help scientists better predict marsh ecosystems' resilience to climatic changes such as sea level rise. "Obviously, this is not a conscious choice on the part of the plants," Marani said. "It's a natural mechanism -- how marshes work. We just didn't understand it in such detail until now."

...The team used numerical modeling to visualize the dynamic interactions of marsh ecosystems over time, and tested the models against detailed topographical surveys of elevations and distributions of plant species in the Venetian lagoon.

"We've been studying this same marsh for 15 years and, as in similar studies around the world, we were using GPS technology with an accuracy of plus or minus one centimeter in elevation," Marani explained. For the new study, they used a more precise surveying instrument, an electronic theodolite, which measure elevations accurately to within less than one millimeter. "It allowed us to observe differences so subtle that they went unnoticed before," he said....

A digital map of one portion of the Venetian marsh shows the distribution of several species of marsh plants. Courtesy of Marco Marani, Duke University

Chesapeake Bay shows signs of recovery, but pollution persists

Ian Simpson in Reuters: The Chesapeake Bay, North America's biggest estuary, is still ailing but making some progress as it struggles to recover from over-fishing and pollution, a partnership overseeing its revival said on Thursday.

The number of juvenile crabs is the highest in two decades, rockfish are stable and last year's "dead zone," the part of the bay without enough oxygen to support life, seems to be the smallest since 1985, the Chesapeake Bay Program said in its 2011-12 "Bay Barometer."

On the down side, water clarity was very poor and only a third of the bay met standards for dissolved oxygen, a measure of water's health. The oyster population also was at less than 1 percent of historic levels. "While we clearly have a lot of work to do, the bay is resilient and we have reason for hope," Nick DiPasquale, director of the federal and state program, said in a statement.

The Chesapeake Bay, home to more than 3,600 species of plants and animals, has been fouled by decades of over-fishing and pollution. Pollutants include sediment, manure, trash and chemicals that flow into it from its 64,000-square-mile (166,000-square-km) watershed across six states.

The Chesapeake Bay Program was formed in 1983 to restore the estuary, where salt water from the ocean mixes with fresh water. It includes Maryland, Pennsylvania, Virginia, the District of Columbia, the Environmental Protection Agency and citizens groups.

The group said that most of the bay's feeder freshwater streams were in poor or very poor condition. Water murkiness and algae levels in 2011 were the worst since 2009. But the big Susquehanna Flats grass bed survived Tropical Storm Lee in 2011. In another sign of health, grasses in the middle of the Chesapeake showed "dramatic increases," the program said....

A creek beside Cedar Lane, Bethesda, Maryland, making its way to the Chesapeake, shot by Andrew Bossi, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 2.5 Generic license

Salt marshes may cool climate by trapping carbon

Futurity.org: As the planet warms up, salt marshes could play a role in capturing and removing carbon dioxide from the atmosphere, perhaps slowing the rate of climate change, a study suggests.

Carbon dioxide acts as an atmospheric blanket, trapping the Earth’s heat. Over time, an abundance of carbon dioxide can change the global climate, according to generally accepted scientific theory. A warmer climate melts polar ice, causing sea levels to rise. A large portion of the carbon dioxide in the atmosphere is produced by human activities, primarily the burning of fossil fuels to energize a rapidly growing world human population.

 “We predict that marshes will absorb some of that carbon dioxide, and if other coastal ecosystems—such as seagrasses and mangroves—respond similarly, there might be a little less warming,” says the study’s lead author, Matt Kirwan, a research assistant professor of environmental sciences at the University of Virginia.

Made up primarily of grasses, salt marshes are important coastal ecosystems, helping to protect shorelines from storms and providing habitat for a diverse range of wildlife, from birds to mammals, shell- and fin-fishes, and mollusks. They also build up coastal elevations by trapping sediment during floods, and produce new soil from roots and decaying organic matter.

“One of the cool things about salt marshes is that they are perhaps the best example of an ecosystem that actually depends on carbon accumulation to survive climate change: The accumulation of roots in the soil builds their elevation, keeping the plants above the water,” Kirwan says.

Salt marshes store enormous quantities of carbon, essential to plant productivity, by, in essence, breathing in the atmospheric carbon and then using it to grow, flourish, and increase the height of the soil. Even as the grasses die, the carbon remains trapped in the sediment. The researchers’ model predicts that under faster sea-level rise rates, salt marshes could bury up to four times as much carbon as they do now....

A salt marsh near Hayward Shoreline Interpretive Center building, adjacent to highway 92, Hayward, California, shot by Mercurywoodrose, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license

Virginia's dying marshes and climate change denial

Daniel Nasaw in BBC News Magazine: Dying wetland trees along Virginia's coastline are evidence that rising sea levels threaten nature and humans, scientists say - and show the limits of political action amid climate change scepticism. In the salt marshes along the banks of the York River in the US state of Virginia, pine and cedar trees and bushes of holly and wax myrtle occupy small islands, known as hummocks.

But as the salty estuary waters have risen in recent years, they have drowned the trees on the hummocks' lower edges. If - when - the sea level rises further, it will inundate and drown the remaining trees and shrubs, and eventually sink the entire marsh. That threatens the entire surrounding ecosystem, because fish, oysters and crabs depend on the marsh grass for food.

"These are just the early warning signs of what's coming," says avian ecologist Bryan Watts, stepping carefully among the fallen pines. The sea level in the Chesapeake Bay area and in south-eastern Virginia is predicted to rise by as much as 5.2ft (1.6m) by the end of the century.

Ancient geologic forces are causing the land literally to sink, while the amount of water in the oceans is increasing because of global warming, scientists say. As a result, the low-lying coastal areas - and the towns in it - are at tremendous risk of flooding.

...But in Virginia's state capital Richmond, as in Washington, many politicians remain sceptical about the extent to which humans are responsible for global warming. They fear measures needed to curb climate change would hurt the economy, threaten private property, and harm commercial and industrial interests....

This is a map of the York River Watershed and includes the Mattaponi and Pamunkey rivers. Karl Musser, created it based on USGS data. Wikimedia Commons, under the Creative Commons Attribution-Share Alike 2.5 Generic license

New report questions hard-edged 'living shorelines' in estuaries

Science Codex: The increasing use of large breakwaters and other hard structures to reduce erosion in "living shorelines" along coastal estuaries may be no better for the environment than the ecologically harmful bulkheads they were designed to replace, according to a report this week by scientists at Duke and Western Carolina universities.

Originally, living shorelines were designed to use natural methods such as replanted native marsh grasses and oyster reefs to stabilize and protect eroding shorelines.

Many environmental groups and government agencies have advocated this approach in recent years as an eco-friendly alternative to wooden bulkheads and other forms of shoreline armoring in low wave-energy environments such as estuaries and sounds.

But this new report reveals that since 2000 the use of large-scale hardened structures such as rock walls or offshore breakwaters has increased dramatically at a growing number of sites classified and funded as living shorelines. The researchers surveyed sites from Maryland to Texas -- including the Chesapeake Bay, North Carolina's Pamlico Sound and the South Carolina Low Country -- and found dozens of miles of living shorelines armored with hard stabilization, constructed at a cost of tens of millions of dollars.

"The intent is often to deflect waves and provide extra protection until new grasses or oyster reefs can take hold. But once installed, the barriers are rarely removed," said Orrin Pilkey, James B. Duke Professor Emeritus of Geology at Duke's Nicholas School of the Environment.

"Many projects now contain massive rock structures, with little habitat gain," he said. "These kinds of living shorelines are probably no more ecologically responsible than bulkheads."

"We're concerned the use of massive hard-engineered structures in some of these so-called living shorelines will cause long-term environmental degradation, provide a false sense of accomplishment and shift the focus away from trying to maintain the most natural estuarine shoreline feasible," said Robert S. Young, professor of geology and director of the Program for the Study of Developed Shorelines at Western Carolina....

Old sea defence on Dee estuary Wall of stones placed upright in a line - now overwhelmed by erosion, shot by Peter Aikman, Wikimedia Commons via Geograph UK, under the Creative Commons Attribution-Share Alike 2.0 Generic license

Three-quarters of the Severn Estuary's mudflats could be lost to sea level rises

Graham Henry in Wales Online: Sea level rises of between 30-40cm in the Severn Estuary over the next 60 years could cause more than three-quarters of the estuary’s intertidal area to be lost, a new report has warned. In stark findings, The State of the Severn Estuary report warns that the impact of climate change could cause 77% of the zone – the area that is above water at low tide and underwater at high tide – to disappear over the next 100 years.

The rapid loss of intertidal areas could have knock-on implications for wildlife that feed on the mudflats and sandflats of the intertidal zone, such as wading birds and waterfowl, with the report warning that intertidal mudflats were of “major conservation importance”. It is coupled with a warning of repeated flooding in areas along the Estuary in the future if no action is taken, and current sea defences were not maintained.

Environment Agency Wales has previously warned that without flood defence improvements, rising seas could cause damaging floods to towns along the Severn Estuary by 2060, including Cardiff, Penarth and Newport.


Plans identified Lavernock Point in the Vale of Glamorgan ... at particular risk, while there are risk points identified all along the estuary to Gloucestershire, which includes around 250,000 homes.

The report – produced by the Severn Estuary Partnership and Cardiff University in collaboration with Environment Agency Wales – also predicts that 38% of vital saltmarshes could be lost in the next century as they become “squeezed” against flood defences....

Mouth of the Severn Lavernock Point is an atmospheric spot where wind, tide and Glamorgan meet. The view towards Somerset is that of a drowned land whose one-time hills now protrude above the surface of these waters as islands or project out into them as promontories. Shot by Alan Bowring, Wikimedia Commons via Geograph UK, under the Creative Commons Attribution-Share Alike 2.0 Generic license

Sluice proposed to curb flooding in Ho Chi Minh City

Vietnam News: Scientists have proposed the construction of a sluice to regulate tidal flow in and out of the Soai Rap estuary in HCM City, in an effort to reduce salination and flooding in the city as well as Dong Nai and Long An provinces.

Prof Nguyen Tat Dac of HCM City University of Industry, who has conducted research on the proposal, said HCM City's topography had 65 per cent of low land, and as a result, the city could easily be hit by tidal flooding, especially now with climate change. Prof Dac also added that work to prevent salination and flooding was direly needed. However, any construction must ensure good irrigation towards the sea, smooth waterway traffic and low environmental impact.

The proposed sluice should be built to work well with 12 other small sluices that have either already been built or will be built on several estuaries in Long An Province. Dac recommended building an 1km wide sluice on the three-km Soai Rap estuary.

The estuary, which is part of the Sai Gon – Dong Nai river system, lies on the border between the city Can Gio mangrove forest and Long An and Tien Giang provinces. Tidal flow and salination through the estuary, and the nearby Long Tau estuary, could affect the city as well as Dong Nai and Long An provinces....

Bleak future for Bay area tidal marshes?

Terra Daily via SPX: A new study, led by PRBO Conservation Science (PRBO), projects a bleak future for San Francisco Bay's tidal marshes under high-end sea-level rise scenarios that are increasingly likely. PRBO and colleagues found that in the worst case scenario 93% of San Francisco Bay's tidal marsh could be lost in the next 50-100 years [with 5.4 feet or 1.65 meters of sea-level rise, low sediment availability and no significant restoration].

PRBO's study indicates, however, that not all marshes will be lost and that society's actions today, including restoration currently underway, can keep more marshes intact as sea levels rise.

This first-of-its-kind study assesses how sea-level rise, suspended sediment availability, salinity and other factors might impact San Francisco Bay's tidal marshes. The study, which considered multiple scenarios to project possible future outcomes, was authored by researchers from PRBO as well as ESA PWA, University of San Francisco, UC Berkeley, and San Francisco State University.

Tidal marshes are vital to migratory birds, commercial fisheries, other wildlife and people. Marshes act like giant sponges, protecting highways, businesses, homes and other structures by reducing flood impacts in large storm events and as sea levels rise. Tidal marshes also filter out pollutants and sequester carbon.

"Tidal marshes are incredibly resilient to changes in sea level, depending on how fast seas rise and how much sediment is available. Unfortunately, marshes cannot keep up with the high-end sea-level rise predictions on their own. They will need our help." said Diana Stralberg, the study lead author of PRBO and the University of Alberta...

Shortly after dawn at Charleston Slough, Palo Alto Baylands, California, shot by Ingrid Taylar, Wikimedia Commons via Flickr, under the Creative Commons Attribution 2.0 Generic license

San Joaquin River delta's biggest enemy hard to pinpoint

Alex Breitler in Recordnet.com (Stockton, California): There are more than 40 potential causes for the [San Joaquin River] Delta's decline, scientists said Friday, but ranking them in order is just too difficult "We're not in a position now - we may be in a position later - to say it's these three stressors that are causing 90 percent of the problem, or one stressor causing 45 percent of the problem," said Richard Norgaard, chair of the Delta Independent Science Board, a panel of 10 experts established by California's sweeping water reform in 2009.

"At the present state of knowledge, we just think there's a lot of interacting stressors," Norgaard told the Delta Stewardship Council on Friday. Scientists say many causes may be contributing to the decline of the Delta:

Global causes: Climate change (sea level rise, changes in water flows, higher temperatures and changes in ocean conditions); earthquakes; population growth; state economy.

Historic causes: Habitat loss; mercury from the Gold Rush accumulating in fish; toxic selenium runoff from farms; sinking Delta islands; artificial levees that may break, causing flooding; upstream dams that cut off breeding areas for salmon; agricultural subsidies; development, zoning and building codes; invasive species.

Current causes: Water withdrawals upstream of the Delta, in the Delta and outside of the Delta; fish sucked into export pumps; nutrients from farm runoff and city wastewater treatment plants; pesticides; metals that enter the water from farms, cities and industry; channel dredging; illegal harvest of threatened species; hatcheries that alter the genetic makeup of fish.

Anticipated causes: Landscape changes; urban expansion; land use along streams feeding the Delta; people's lifestyle decisions on where and how they live….

The San Francisco Bay Area, home to the San Joaquin River Delta, via NASA

Could oysters clean up Chesapeake Bay?

Science Daily: Chronic water quality problems caused by agricultural and urban runoff, municipal wastewater, and atmospheric deposition from the burning of fossil fuels leads to oxygen depletion, loss of biodiversity, and harmful algal blooms. This nutrient pollution is prevalent in many coastal marine and estuarine ecosystems worldwide. Chesapeake Bay is the largest estuary in North America and although many efforts have been taken to improve its water quality, nutrient pollution still keeps it at unacceptable levels.

In a study funded by the U.S. Environmental Protection Administration and administered by the National Fish and Wildlife Foundation, biologists at Virginia Commonwealth University measured the nutrient removal capacity of the Eastern oyster, Crassostrea virginica.

Researchers found that an additional 2.5 cm of growth allowed a farmed oyster to remove 2.2 times the nutrients of a regular oyster. In fact, a large scale oyster farm harvesting 1 million of these 76 mm oysters can remove 132 kg of nitrogen, 19 kg of phosphorus, and 3,823 kg of carbon. The full study is available in the January/February 2011 issue of the Journal of Environmental Quality.

Oysters were a novel yet obvious choice to enhance the ecosystem's water quality. They process nutrients while feeding on phytoplankton and then store the nutrients in their shells and tissue through a process known as bioassimilation. Although Chesapeake Bay is a natural habitat for the Eastern oyster, 99% of the native population has been lost. This prompted researchers to explore the use of commercial oyster farms.

…According to Colleen Higgins of Virginia Commonwealth University, "Based on these results, it would take eight large-scale oyster farms harvesting one million (of these) 76 mm oysters per year to remove one ton of nitrogen from the Bay, providing managers with the ability to determine the practical implication of such an ecosystem service."…

Virginia oysters, shot by Dheillyx, Wikimedia Commons, under the Creative CommonsAttribution-Share Alike 3.0 Unported license

How will sea level rise affect local communities?

Dan Wiessner in Scarsdale Patch: Larchmont is practically underwater. Not the upscale Sound Shore community; this Larchmont is a middle-class neighborhood in Norfolk, VA that's surrounded by the Chesapeake Bay and the mouths of several rivers.

Much of the area is under constant threat of inundation, as the surrounding waters have risen by 14.5 inches since 1930—the highest relative increase in sea level of anywhere on the East Coast. A recent New York Times article called Larchmont "the front line" in the battle against rising waters and detailed the tribulations of local residents and the multi-million dollar projects that may or may not produce a solution.

But how far off is this headache for Westchester's Larchmont and other communities along the Sound and the Hudson River? What does it mean for residents? The potential consequences could affect local utilities, regional commuters, waterfront businesses and local property owners.

"It could happen next summer," said Kristin Marcell, a member of the State Department of Environmental Conservation's (DEC) Hudson River Estuary program, referring specifically to a once-in-a-generation storm that, coupled with rising waters, could wreak havoc on waterfront developments, including homes, roads, train tracks and recreation areas.

…New York Harbor has seen a 15-inch increase since 1860 and a 6-inch rise since 1960, according to the DEC, and the story is the same for the Long Island Sound, where consequences could be grave for the low-lying communities that make up the Sound's 600 miles of coastline.

A new report from the DEC's Sea Level Rise Task Force says the increase in the lower Hudson Valley could be as much as five inches in the next decade and 23 inches by 2100; but, in the case of a scenario called rapid ice melt, in which polar ice caps recede at an alarming rate, area waters could rise by as much as five feet by century's end….

New York harbor, downstream from one of the Larchmonts

Climate change puts Delaware estuary resources at risk

Leah Hoenen in Cape Gazette.com (Delaware): Key Delaware estuary resources, including drinking water and shellfish, are threatened by sea-level rise and must be protected, a new study finds. Increased salinity moving up the estuary could have a devastating effect on drinking water.

The Partnership for the Delaware Estuary, along with dozens of partners, examined drinking water, tidal wetlands and shellfish, specifically oysters and freshwater mussels. All three are key resources for the estuary; all three are vulnerable to effects of climate change, including warmer temperatures, higher sea levels and saltier water. The partnership released a report, “Climate Change and the Delaware Estuary,” Wednesday, July 21, detailing how those three resources might be affected by climate change and how people can adapt to help protect resources.
Prime Hook marsh dying »

The report says current mitigation efforts, such as reducing car emissions, will produce results in 20 to 30 years. But, the group warns, “no amount of mitigation will prevent the changes we will see between now and then.” One of the most serious concerns is the potential increase in salinity, which would affect all three resources highlighted in the report.

…The group’s report states 15.2 million people drink water from the Delaware River Basin. Keeping the drinking-water resource safe could become expensive if the water has to be treated to remove salt, according to the report. The Philadelphia Water Department’s Paula Conolly contributed to the report, which said drinking water infrastructure could be damaged or inundated by flooding, sea-level rise and storm surge.

Treatment plants and other water infrastructure are placed close to water resources, right in the path of flooding and storm surge, the report says. Scientists also worry that heavier precipitation and continued development could lead to more runoff, which delivers pollution to waterways and will degrade source-water quality….

Delaware Bay map by Matthew Trump and uploaded by Decumanus at en.wikipedia, Wikimedia Commons, under the Creative Commons Attribution ShareAlike 3.0 License

Sea-level rise threatens Prime Hook Refuge

Ron Macarthur in the Cape Gazette (Delaware): Prime Hook National Wildlife Refuge, one of the most unique ecosystems on the East Coast, faces an uncertain future. Damage from a series of storms and sea-level rise threaten to change the delicate natural balance forever in the refuge and nearby Primehook Beach. This is the third in a series which explores the problems facing the refuge and analyzes possible solutions aimed at stemming the inevitable tide.

In a recent visit to Prime Hook National Wildlife Refuge, Tom Alvarez was shocked to see how much beach and marsh have been lost. The U.S. Fish and Wildlife Service staffer from Massachusetts had not been to the area for more than 30 years. “In their lifetime people living there will see a progressive change. I saw it immediately. You expect changes, but you don’t expect the landscape to change so dramatically,” he said.

Gradual change could accelerate if current predictions of sea-level rise come to fruition. Some scientists predict that in as little as 75 to 90 years, large sections of the refuge – which today serves as a critical stopover point for an estimated 1 million migrating birds each year – could be under water.

If Delaware Bay water rises one-eighth inch per year, by 2100, sea-level rise would essentially wipe out more than half of the marshland, according to a model developed by the U.S. Fish and Wildlife Service, known as the Sea Level Affecting Marshes Model (SLAMM). Alvarez said the threat to Prime Hook and Bombay Hook refuges have placed them among his agency’s top five areas of concern nationally for sea-level rise and climate-change implications.

Today, the refuge is 15 percent open water, 47 percent marshland, and the remaining 38 percent is uplands and forested wetlands. A rise of 1.6 feet would leave the refuge about 65 percent open water and 21 percent marshland, leaving only about 14 percent as uplands and forested wetlands….

Snow geese at the Prime Hook National Wildlife Refuge, from the refuge's website

Global warming won't affect all deltas

Richard Lovett in Nature News: Whether river deltas become swamped by rising sea levels will depend on a multitude of factors, including the type of soil and the tectonic action of any nearby plates, say researchers. "In coastal systems we have to think about combined impacts," said oceanographer Richard Feely of the Pacific Marine Environmental Laboratory in Seattle, Washington, at this year's meeting of the Coastal and Estuarine Research Federation in Portland, Oregon on 3 November. Every system is different, he says.

In the Mississippi Delta, for example, not only is the sea level rising, but the soils are subsiding, causing the land to submerge more rapidly than the river can deliver new sediment. "It's quite clear that if we try to focus on conserving the outer areas, it's going to be almost impossible" to save the delta, says Carles Ibáñez Martí, director of the Institute for Food and Agricultural Research and Technology's Aquatic Ecosystems unit in Sant Carles de la Ràpita in Spain.

…A very different combination of factors threatens California's Sacramento–San Joaquin Delta, east of San Francisco. There, the region's natural wetlands were long ago drained and dyked to create intensively farmed islands. Unfortunately, the soils consist mostly of peat, which has slowly oxidized — releasing carbon dioxide — or blown away so the islands are now as much as 8 metres below sea level.

…One delta that seems set to survive is the Danube Delta in the Black Sea. Because it is in a region of tectonic uplift creating central Europe's Carpathian Mountains, says Liviu Giosan, a sedimentologist at the Woods Hole Oceanographic Institution in Massachusetts, the sea level has remained stable for several thousand years. Furthermore, he says, even though upstream dams have cut down its supply, the delta seems to be receiving enough sediment to remain stable.

Somewhere in the middle of the Danube delta, shot by T. Lessiak, Wikimedia Commons

Chesapeake Bay gets clean water funding; $1.5b more for stormwater proposed

Environment News Service: To pay for better clean water accountability and regulatory enforcement in the Chesapeake Bay watershed, Congress has authorized new funding to reduce pollution in local rivers and streams flowing into the bay. Legislation passed by the House and Senate contains a record $50 million for the U.S. Environmental Protection Agency's Bay cleanup efforts, with $19 million in new funding for regulatory enforcement and accountability.

"Congress has clearly recognized that the Obama Administration's commitment to reduce pollution from all sources will place additional demands on both the EPA and the states," said Chesapeake Bay Foundation President William Baker. "With this funding, significantly higher than the administration requested, EPA will be accountable to ensure that pollution reductions promised are actually delivered," he said.

Language in the Interior and Environment appropriations bill says the funding must "support additional regulatory and accountability programs to control urban, suburban and agricultural runoff in the watershed."

"Maryland's communities want to do the right thing by the environment, but they can't do it on their own. That's why I've worked so hard to put money in the federal checkbook that creates jobs, builds communities, and takes care of our environment," said Senator Barbara Mikulski, a Maryland Democrat who sits on the Senate Interior, Environment and Related Agencies Appropriations Subcommittee. "I will always fight for the bay and the lives and livelihoods that depend on it."

"For too long, the federal-state partnership to restore the bay has issued ambitious goals, but yielded too little action to actually improve the bay," said Congressman Jim Moran, a Virginia Democrat who sits on the Interior Subcommittee and played a key role in the funding increase….

Sligo Creek in Silver Spring, Maryland, which flows into the Anacostia River, to the Potomac, and into Chesapeake Bay. Shot by Moreau1, Wikimedia Commons

World's river deltas sinking due to human activity, says new study

EurekAlert: A new study led by the University of Colorado at Boulder indicates most of the world's low-lying river deltas are sinking from human activity, making them increasingly vulnerable to flooding from rivers and ocean storms and putting tens of millions of people at risk.

…The researchers concluded the sinking of deltas from Asia and India to the Americas is exacerbated by the upstream trapping of sediments by reservoirs and dams, man-made channels and levees that whisk sediment into the oceans beyond coastal floodplains, and the accelerated compacting of floodplain sediment caused by the extraction of groundwater and natural gas.

The study concluded that 24 out of the world's 33 major deltas are sinking and that 85 percent experienced severe flooding in recent years, resulting in the temporary submergence of roughly 100,000 square miles of land. About 500 million people in the world live on river deltas.

Published in the Sept. 20 issue of Nature Geoscience, the study was led by CU-Boulder Professor James Syvitski, who is directing a $4.2 million effort funded by the National Science Foundation to model large-scale global processes on Earth like erosion and flooding. Known as the Community Surface Dynamic Modeling System, or CSDMS, the effort involves hundreds of scientists from dozens of federal labs and universities around the nation.

The Nature Geoscience authors predict that global delta flooding could increase by 50 percent under current projections of about 18 inches in sea level rise by the end of the century as forecast by the 2007 Intergovernmental Panel on Climate Change report. The flooding will increase even more if the capture of sediments upstream from deltas by reservoirs and other water diversion projects persists and prevents the growth and buffering of the deltas, according to the study….

Deltas around the world are sinking, according to a new study led by CU-Boulder. This image of the Pearl River Delta in China taken was by NASA's space shuttle Endeavour, with the areas below sea level shown in purple. Credit: Image courtesy NASA, CSDMS, University of Colorado.

Obama administration releases Chesapeake Bay restoration plans

Environment News Service: The federal government is getting serious about solving the stubborn problem of cleaning up the polluted Chesapeake Bay and restoring the nation's largest estuary to health. In 2008, after 20 years of restoration efforts, Chesapeake Bay water quality was rated "very poor," with only 21 percent of the established goals met.

Proposing a mix of carrots and sticks, federal agencies today complied with President Barack Obama's May 12 Executive Order on the Chesapeake Bay by issuing seven draft reports on ways to reduce polluted runoff by increasing government accountability and public involvement.

"Communities in the Chesapeake Bay watershed expect and deserve rivers and streams that are healthy and thriving," U.S. EPA Administrator Lisa Jackson told reporters on a teleconference call today. "The poor health of the Chesapeake remains one of our nation's more significant environmental problems."
Chesapeake Bay, the Severn River and Annapolis, Maryland (Photo by Gary Hymes)

…The recommendations in the reports were shaped by consultations with the six states in the Chesapeake Bay watershed and the District of Columbia, as well as suggestions from stakeholders and the public. "We will use federal leadership, and federal muscle when necessary, to get states to realize the time of working without accountability is over. We must have accountability," Jackson said….

Stereoscopic view of oyster sloops on Chesapeake Bay, around 1896