Wednesday, September 23, 2009

The Price of Outdated Federal Flood Insurance Policies Is Measured in Wrecked Homes

By EVAN LEHMANN of ClimateWire

Published: September 15, 2009

Hundreds of homes were swept away by waves when Hurricane Ike charged onto Bolivar Peninsula in Texas last year. Eleven survived -- and perhaps not by chance.

Ten of those homes were "fortified" and built several feet above current elevation standards, according to a new analysis (pdf). Researchers see that as evidence: The federal government is underestimating the strength of storm surges as seas rise from worldwide warming, the authors say.

The Federal Emergency Management Agency requires new homes near the beach on Bolivar to be 19 feet above sea level to be eligible for national flood insurance. About 270 houses that were built to that standard -- or below it if they were older -- disappeared when Ike sent engorged seas onto the peninsula last September.

"The flood elevation that FEMA is using is not adequate for these kinds of events," said Tim Reinhold, chief engineer for the Institute of Business and Home Safety and an author of the report. "A difference of 2 to 3 feet makes all the difference of whether a building is there or not."

The report comes as the National Flood Insurance Program is experiencing sharp scrutiny, having dived more than $19 billion into debt following Hurricane Katrina in 2005.

FEMA is replacing outdated paper maps with far more accurate depictions of floodplains using a plane-mounted laser technology called Light Detection and Ranging, or LIDAR. But critics say that's not enough.

The agency currently bases the risk to residents on floods that have historically had a 1 percent chance of occurring each year. The maps seek to show the extent to which water would lap on a hillside, or overspill a riverbank, during that type of storm.

But with increasing rainfall related to climate change, and more concrete development changing the nature of runoff, floods could happen much more often, critics say.

Raise homes or relocate them?

The report by Reinhold, released yesterday, calls on FEMA to encourage homeowners to build their houses higher by offering discounts on flood insurance. He says people should plan for storms that historically have a 0.2 percent probability of occurring annually. Older terminology referred to those events as 500-year floods, but FEMA has stopped using that language because it could give people a false impression of security.

"The evidence is clear that it only takes a few feet of water above the [1 percent annual chance] to wipe out all homes built at or below the minimum NFIP requirements," the report warns. "There essentially is no safety factor for homes in surge-prone areas other than additional height."

The 10 fortified homes surviving Ike were 26 feet above sea level, Reinhold said. Three others at the same elevation were destroyed when the debris of lower homes crashed into them. About 270 other homes were lost; they were raised up to 22 feet above sea level, the uppermost height for which FEMA will give insurance discounts.

One non-fortified house did survive. It is raised 19 feet above sea level.

Others point to the wreckage on Bolivar as a sign that barrier islands and jutting peninsulas should be off-limits to any building, especially at a time when sea levels are predicted to rise by a couple of feet or more this century. The federal government should do more to help homeowners in high risk areas relocate, said John Kostyack of the National Wildlife Federation.

"Those areas are essentially the natural buffers to communities inland," he said of outlying beaches. "The last thing we want to do is destroy those buffers and put more people at risk."

'We're going to fall short'

The report also calls for tougher building codes related to roofs and other parts of a home that can rebut wind-driven water. The Institute for Business and Home Safety is funded by the property insurance industry, which has a financial interest in reducing damage. Some insurers have led efforts to adopt adaptation measures related to climate change.

Codes won't work if there's no money to enforce them, said Michael Armstrong, a senior vice president at the International Code Council, which has endorsed legislation to provide grants to local enforcement offices.

"There simply aren't enough staff on the ground," he said. "And there's an expectation now across the country that we're going to become more energy-efficient, that we're going to become more green, more disaster-resistant. But unless the resources are there for code enforcement, we're going to fall short."

Alexis Dick, the deputy commissioner of wind storm inspections for the Texas Department of Insurance, said the state adopted stronger building codes in 2006. Homes and businesses near the beach are required to have reinforced windows and other openings that can stand up to whipping winds. Her office is reviewing 2009 standardized codes for possible adoption.

"We believe that we have a very strong code," Dick said. "You can always improve them to make the buildings stronger."

The Texas Legislature sought to strengthen the state's troubled public insurance program, which provides windstorm policies to coastal residents. The program is broke, and officials tried to reduce its vast exposure to loss by requiring that new coastal homes first buy national flood insurance before being eligible for state-sponsored wind policies.

But change is occurring slowly, and lawmakers exempted residents from that rule if their homes were damaged by Ike. It was meant to reduce the burden on already struggling Texans.

But Reinhold, the report's author and a Texas resident, is concerned that those homeowners are facing dual threats: Not only are their homes below the federal elevation standard, and more likely to be flooded, but they don't have insurance.

"They're playing Russian roulette," he said.

Copyright 2009 E&E Publishing. All Rights Reserved.

Monday, September 21, 2009

World's river deltas sinking due to human activity, says new study led by CU-Boulder

From: Eureka Alert

24 of world's 33 major deltas sinking, 85 percent have experienced severe flooding recently

IMAGE: 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...

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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.

While the 2007 Intergovernmental Panel on Climate Change report concluded many river deltas are at risk from sea level rise, the new study indicates other human factors are causing deltas to sink significantly. 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.

"We argue that the world's low-lying deltas are increasingly vulnerable to flooding, either from their feeding rivers or from ocean storms," said CU-Boulder Research Associate Albert Kettner, a co-author on the study at CU-Boulder's Institute of Arctic and Alpine Research and member of the CSDMS team. "This study shows there are a host of human-induced factors that already cause deltas to sink much more rapidly than could be explained by sea level alone."

Other study co-authors include CU-Boulder's Irina Overeem, Eric Hutton and Mark Hannon, G. Robert Brakenridge of Dartmouth College, John Day of Louisiana State University, Charles Vorosmarty of City College of New York, Yoshiki Saito of the Geological Survey of Japan, Liviu Giosan of the Woods Hole Oceanographic Institute and Robert Nichols of the University of Southampton in England.

The team used satellite data from NASA's Shuttle Radar Topography Mission, which carried a bevy of radar instruments that swept more than 80 percent of Earth's surface during a 12-day mission of the space shuttle Endeavour in 2000. The researchers compared the SRTM data with historical maps published between 1760 and 1922.

"Every year, about 10 million people are being affected by storm surges," said CU-Boulder's Overeem, also an INSTAAR researcher and CSDMS scientist. "Hurricane Katrina may be the best example that stands out in the United States, but flooding in the Asian deltas of Irrawaddy in Myanmar and the Ganges-Brahmaputra in India and Bangladesh have recently claimed thousands of lives as well."

The researchers predict that similar disasters could potentially occur in the Pearl River delta in China and the Mekong River delta in Vietnam, where thousands of square miles are below sea level and the regions are hit by periodic typhoons.

"Although humans have largely mastered the everyday behaviour of lowland rivers, they seem less able to deal with the fury of storm surges that can temporarily raise sea level by three to 10 meters (10 to 33 feet)," wrote the study authors. "It remains alarming how often deltas flood, whether from land or from sea, and the trend seems to be worsening."

"We are interested in how landscapes and seascapes change over time, and how materials like water, sediments and nutrients are transported from one place to another," said Syvitski a geological sciences professor at CU-Boulder. "The CSDMS effort will give us a better understanding of Earth and allow us to make better predictions about areas at risk to phenomena like deforestation, forest fires, land-use changes and the impacts of climate change."