Bays On US Gulf Coast Vulnerable To Flooding

Bays On US Gulf Coast Vulnerable To Flooding

ScienceDaily (Oct. 14, 2008) — The most comprehensive geological review ever undertaken of the upper US Gulf Coast suggests that a combination of rising seas and dammed rivers could flood large swaths of wetlands this century in one or more bays from Alabama to Texas.

The findings, which will be presented at next week's annual meeting of the Geological Society of America in Houston, stem from bayfloor sediment samples, radiocarbon tests and seismic surveys compiled over 30 years.

"In terms of sea-level increases and river sediments flowing into the bays, we're rapidly approaching a time when bays will face conditions they last saw in the Holocene, from about 9,600 until 7,000 years ago," said lead researcher John Anderson, the W. Maurice Ewing Professor in Oceanography and professor of Earth science at Rice University. "That period was marked by dramatic and rapid flooding events in each of these bays -- events that saw some bays increase their size by as much as one-third over a period of 100 or 200 years."

Anderson is presenting the findings at next week's annual meeting of the Geological Society of America (GSA) at Houston's George R. Brown Convention Center. Anderson said the magnitude of flooding seen in bays during the Holocene -- the geological epoch that began 10,000 years ago -- would be noticeable and apparent, even on a year-to-year timescale.

"If you lived at the head of Galveston Bay, near Anahuac (Texas), you could see the bayhead move northward by as much as the length of a football field each year," Anderson said.

Anderson and colleagues, including Antonio Rodriguez of the University of North Carolina at Chappell Hill, compiled their research in a new 146-page monograph published by the GSA, "Response of Upper Gulf Coast Estuaries to Holocene Climate Change and Sea-Level Rise."

Their findings stemmed from an analysis of 30 years of data from hundreds of bayfloor sediment samples, radiocarbon tests and seismic surveys from Galveston, Matagorda and Corpus Christi bays in Texas, Mobile Bay in Alabama, Calcasieu Bay in Louisiana and Sabine Lake on the Texas-Louisiana border.

"There is no question that sea levels are rising in this region at a rate today that approaches what we saw in the Holocene," Anderson said.

He said the Holocene was also marked by alternating wet and dry periods upstream, particularly in central and western Texas. There was significantly less sediment flowing into the bays during the dry periods, and the researchers found that the most dramatic flooding events occurred when less sediment was flowing into the bays at the same time that sea levels were rising faster than four millimeters per year.

Anderson said that's a particularly troubling finding because several recent studies have confirmed that the rate of sea-level rise along the Gulf Coast has doubled in the past century to a current rate of about three millimeters per year. At the same time, the installation of dams upstream has slashed the amount of sediment flowing into every southern U.S. bay.

"Our research paints a pretty clear picture of what happened in these bays the last time they encountered the circumstances that we expect to see during the coming century," Anderson said. "Our hope is that policymakers will take note of the potential danger and take steps to help alleviate it."

For example, Anderson said it doesn't make environmental sense to keep a navigation channel open between the lower Trinity River and upper Galveston Bay because the channel diverts the sediment that is flowing into the bay, preventing it from replenishing the upper bay wetlands near Anahuac.

"Now that we're aware of the dangers, there are clearly things we can do to try and avoid them," he said.

WEATHER NOTE

NOAA: Ninth Warmest September for Global Temperatures

October 15, 2008

The combined global land and ocean surface average temperature for September 2008 tied with September 2001 as the ninth warmest since records began in 1880, according to an analysis by NOAA’s National Climatic Data Center in Asheville, N.C.

Temperature Highlights

• The combined global land and ocean surface temperature for September was 59.79 F — this is 0.79 degree F above the 20th century mean of 59.0 degrees F.

• Separately, the global land surface temperature was 54.50 F — this is 0.90 degree F above the 20th century mean of 53.6 degrees F, tying September 2004 as 11th warmest on record.

• The global ocean surface temperature of 61.86 F tied September 2001 as seventh warmest on record and was 0.76 degree F above the 20th century mean of 61.1 degrees F.

Global Highlights for September

• Arctic sea ice coverage during September was at its second lowest extent since satellite records began in 1979, according to the National Snow and Ice Data Center. Average ice extent during September was 1.80 million square miles, which is 34 percent below the 1979-2000 average and is part of an 11.7 percent decline in extent per decade over the past 30 years. The record lowest extent, set in 2007 was 1.65 million square miles.

• In early September, Hurricane Gustav impacted the Caribbean. Flooding associated with Hurricane Hanna claimed more than 500 lives in Haiti. In the middle of the month, Hurricane Ike claimed about 145 lives, many in Haiti. Near the end of September, Hurricane Kyle brought torrential rain and flooding to Puerto Rico and Hispaniola before heading north. It made landfall in Nova Scotia, Canada as a Category 1 hurricane.

• In the Pacific, Typhoon Sinlaku brought flooding to the Philippines before striking Taiwan and Japan. Parts of Taiwan received more than 40 inches of rain. Then, Typhoon Hagupit hit the Philippines and Taiwan before making landfall in southeastern China with winds of 121 mph. Other typhoons included: Super Typhoon Jangmi, which made landfall in Taiwan, with 130 mph winds. Jangmi was the most intense tropical cyclone and first Category 5 storm in any basin during 2008.

• Heavy rain across southern Chile spawned flooding and mudslides that claimed four lives and damaged more than 10,000 homes. Severe storms in the United Kingdom brought widespread flooding that forced the evacuation of thousands of residents and claimed six lives. Heavy downpours across northern Iraq and Iran destroyed several hydroelectric facilities and claimed 16 lives. And more than 200 fatalities were associated with flooding from monsoonal rains across Malaysia, Thailand, and India.

• With just 0.47 inch of rain, Melbourne, Australia had its driest September since records began in 1855, according to the Australian Bureau of Meteorology. The states of South Australia and Victoria had their eighth driest September on record.

• Fast-moving wild fires raged across parts of southern Africa during the first week in September. The fires claimed 89 lives in Mozambique, Swaziland, and South Africa, and killed hundreds of livestock.

NOAA understands and predicts changes in the Earth's environment, from the depths of the ocean to the surface of the sun, and conserves and manages our coastal and marine resources.

MARITIME NOTE

Round-the-world yachting adventure under way

Mon, Oct 13, 2008

Thunder and lightning marked Saturday's start of the prestigious Volvo round-the-world race, writes Lorna SigginsMarine Correspondent,in Alicante, Spain

GUNS AND thunder, fireworks and lightning marked the start of 10th Volvo Ocean Race in the southeast Spanish harbour of Alicante at the weekend.

Smoking out of the bay, the convoy of eight boats, with Irish sailors on three, was reefed for a fresh 25-knot northeasterly wind. It was enough to sweep the fleet down the Mediterranean, transforming Alicante's imposing Carthaginian citadel, Castillo de Santa Barbara, into a tiny speck in their wake.

Irish-Chinese entry Green Dragonappeared to be the only vessel with a full headsail as the gun was fired by King Juan Carlos.

An hour before, the vessel's two bowmen, Wexfordman Justin Slattery and British sailor Freddie Shanks, had been hoisted some 23m (75ft) up the mast to check a halyard block.

There was momentary silence and some anxious glances on board one of the Irish spectator boats as the Volvo 70 moved out of sheltered water to the starting line, marked by Spanish warship Principe de Asturias.

Inis Oirr musicians Micheál Ó hAlmhain and his two sons struck up a few chords, while Lets Do It Globalchairman Enda Ó Coineen tried to persuade Mayor of Galway Cllr Pádraig Conneely to dance the "Walls of Alicante".

There had been a strained waves, lumps in throats, as Green Dragonand its fellow Irish competitor, Team Delta Lloyd, left the pontoons several hours before.

Green Dragonskipper Ian Walker made light of the heavy moment, joking about his swimming practice with seven-year-old daughter Zoe and four-year-old Emilia.

Green Dragoncrew members Justin Slattery and Damian Foxall had spent their last half-hour on shore, strolling up to the Irish base holding their toddlers, Molly and Oisín. Manned by Tourism Ireland, the base was enlivened by the stilt-walking, U2 imitating antics of street theatre troupe Arcana.

No Government Minister had travelled out for the start, but former minister and sailor Bobby Molloy was present with Galway Harbour Board members, along with a Galway city council delegation, and several Dublin sailors, including yachtsman Michael O'Leary.

Most of the Volvo race entries sail under flags of convenience secured by multinational companies like Ericsson, Telefonica and Puma.

Thus, the Irish base, shared with the Dutch and Russians, had been one of few to provide some national hospitality over the previous days, thanks to the Good Food Ireland network.

For race start morning, however, the Irish base was invaded by an army of 90 Dutch Team Delta Lloydstaff - some of whom were a little surprised to learn that their €5 million sponsorship deal was really "Irish". What's more, Kilrush skipper Ger O'Rourke had adopted a village banking NGO, the Foundation for International Community Assistance, as his boat "charity".

Downstairs, supporters of Team Russia were collecting signatures to save the Orca whale after which their boat Kosatkais named. Even here, there is Irish infiltration. Team Russia's sail designer and trimmer is Kinsale yachtsman Jeremy Elliott.

Out at the bumpy start, spectators endured their own small endurance test as the boats completed a two-mile course, rounding a windward mark and leaving for the first "gate" between the Valencian coast and the island of Tabarca, 11 miles southeast.

By this stage, thunder and lightning had arrived, and a large yellow object had been flung from the Green Dragondeck.

A buoy? A bale? No, just Tom Roche of National Toll Roads, wearing a bright yellow drysuit.

Roche is one of a syndicate of Irish businessmen, including Denis O'Brien, who had promised €100,000 each to finance the Green Dragonbid.

Mr Roche's receipt comprised a 90-minute "race start" experience, followed by a high-speed ducking - there being no time to stop - and his retrieval from the ocean by Green Dragonshore manager Johnny Smullen.

Roche left behind 11 crew who will spend nine months and 37,000 nautical miles living in two metres of space, equivalent to life in a carbon fibre "phone box".

Heading for north Africa, the fleet hopes to picks up the trade wind, navigate the doldrums, and catch a glimpse of Capetown's Table Mountain, marking the first stopover in South Africa, in early November.

The Volvo Ocean Race berths in Galway from May 23rd next year. Further details on websites www.greendragonracing.com and www.volvooceanrace.org

RS