First published study of 2009 Atlanta floods may hold clues to recent urban flooding in other U.S. cities-warnings, too

September is normally a hot, dry month around Atlanta, Ga. The first hints of autumn usually don’t arrive until the end of the month, if then. So it was a surprise last fall when record rainfall turned much of the metro area and north Georgia into a lake, plunging such attractions as Six Flags Over Georgia underwater and in places exceeding flood levels expected only once every 500 years.
Now, in what is likely the first scholarly published study of the floods, a team of climatologists, meteorologists, geologists and hydrologists, led by the University of Georgia, has shown that a convergence of record-setting events, perhaps unprecedented in the area’s history, combined to cause tens of millions of dollars in damages and at least 10 deaths.

And while the future of such floods is unclear, as are possible ties to global warming, conditions may be ripe for a reoccurrence, said Marshall Shepherd, lead author of the study just published in the online edition of the Bulletin of the American Meteorological Society.

“More frequent or intense flooding events, coupled with expanding impervious surfaces like roads and parking lots, will affect the ecosystem and the very fabric of societal infrastructure,” said Shepherd. “We are thus going to need revolutionary designs, management and policies if we are going to mitigate the impact of future events.”

Other authors of the paper are Thomas Mote, John Dowd and Mike Roden, who with Shepherd are in the UGA Franklin College of Arts and Sciences; Pamela Knox of the Office of the State Climatologist; Steven McCutcheon of the U.S. Environmental Protection Agency; and Steven Nelson of the National Weather Service in Peachtree City, Ga.

Recent studies have noted that regions of the southeastern U.S. face an increasing vulnerability to climatic extremes because of population growth and the addition of impervious surfaces. The floods this year in Oklahoma City (June) and Nashville (May) point out how serious the issue has become, and even in a sparsely populated area of Arkansas, authorities reported at least 19 dead in a flash flood in June.

But even the knowledge of an increased threat couldn’t have prepared metro Atlanta leaders for what befell them last September.

“Just as an example, the U.S. Geological Survey measured the largest flow ever recorded on Sweetwater Creek near Austell, which has a streamflow record dating back to August 1904,” said Shepherd. “And a climatological assessment by the National Weather Service showed that September 2009 was fifth wettest in Atlanta’s history.”

While newscasters and commentators have turned the phrase “perfect storm” into one of the most-used clichés of the age, no two words describe better what led to the Atlanta flooding, the new research shows.

First, of course, was the massive and unrelenting rainfall, caused by an odd combination of events. Prior to the record rainfall in north Georgia, a low-pressure system stalled over parts of a three-state area called “ArkLaTex,” pulling moisture from the Gulf of Mexico. Many days of rainfall nearly saturated the soil and filled many streams, rivers and reservoirs over the Southeast. Remnants of two tropical storms in the Pacific and Atlantic (and evaporation from the Gulf of Mexico) generated some of the wettest air observed over the Southeast. Inherent instability in the atmosphere and the mountains northwest and north of Atlanta produced “training” or repeated heavy rainfall.

The spark that set the floods metaphorically afire, though, may have been all the concrete and paving of the metro area itself. The water, unable to soak into the ground, overfilled sewers and drainage and flooded roads, schools, neighborhoods, Interstate-20 and Six Flags Over Georgia, all designed to rarely be submerged.

Satellite data, multi-sensor Doppler radar estimates, traditional National Weather Service gauges and a relatively new community volunteer network, defined the multifaceted causes of flooding during the event.

“Though the meteorological set-up was unique, the role of Atlanta’s impervious surfaces and rapid continued growth should not be missed,” said Shepherd “This increase in roofs, roads and parking is known to alter runoff intensity and, in the future, make flooding potentially just as bad and in many cases worse.”

Another possibility is that large cities may initiate or alter storms through so-called heat-island, convergence and pollution effects. How (or if) this played a part in the Atlanta floods will be the subject of future research by Shepherd, who plans to recreate the event using computer simulations, though without Atlanta included.

“The September 2009 flooding that definitively ended the drought in Georgia is consistent with the Intergovernmental Panel on Climate Change projections that the frequency and severity of extreme hydroclimate events such as droughts and floods will likely increase,” the authors say in their study—bad news for areas such as Atlanta, Nashville and Oklahoma City, which have had enough already.

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Prepare for Rising Water

Precautions taken at the first sign of rising water can help save lives and help minimize damage during a flood. Typically, your standard homeowners insurance policy will not cover flood damage, though federal flood insurance is available through most insurance agencies, if your community participates in the National Flood Insurance Program. If you have flood insurance, your agent will advise you how to file a claim.

Whether you have flood insurance or not, Allstate recommends you take the following steps as soon as a flood watch is issued, or news of rising water hits, which may prevent thousands of dollars in unnecessary damage.

-- Keep informed by listening to a battery-operated radio. That way, you
can track the storm or follow the progress of rising water and make a
better decision about any further action that you should take,
including the possibility of evacuating your home.

-- Fill bathtubs, sinks and containers with clean water so you will have
a ready supply in case the community's water supply becomes
contaminated.

-- Move outdoor possessions indoors, such as patio furniture, chairs and
bicycles.

-- Elevate valuable furnishings and possessions from basements or first
floors to upper floors or move them away to higher ground if you have
time.

-- If advised by local authorities, shut off all utilities including gas,
electricity and water.

-- Prepare to evacuate by gathering your emergency supplies. Don't forget
flashlights and extra batteries, essential medicines, cash, credit
cards, food, water and a battery-operated radio with extra batteries.
If you have pets, make sure they have an adequate supply of food and
water, in a safe place, on an upper floor, or prepare to take the pets
and such provisions with you. Do not leave pets chained or fenced
outside.

-- Once rising waters reach your home, school or business, your first
priority is occupant safety. If you're advised to leave, do so
immediately and follow the evacuation instructions given. Travel to
higher ground by whatever means is available and stay there. The
sooner you leave the better your chances of avoiding flooded,
congested roads.

-- Do not attempt to drive through flooded roads. Turn around and go
another way. If your car stalls, leave it immediately and walk to
higher ground. More people drown in their cars than anywhere else
during floods.

-- If avoidable, do not attempt to walk through floodwater. Drowning is
the top cause of death during floods, in many cases because people
underestimate the power of even a small amount of water. A mere six
inches of quickly flowing water can knock you down. In areas covered
by standing water, use a long pole or stick to make sure the ground is
firm. Be especially cautious with children.


Information on the National Flood Insurance Program can be found at http://www.fema.gov/business/nfip/.

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Soggy September floods north Georgia

Heavy rains caused record flooding in north Georgia in mid-September, while other parts of the state experienced and normal to below-normal rainfall.

A large, slow-moving low-pressure system brought extremely humid air into Georgia mid-month. It triggered days of intense rainfall, producing what was estimated to be a 500-year flood around Atlanta, according to the U.S. Geological Survey.

The highest rain totals estimated by National Weather Service radars were 15 inches to 20 inches in Douglas County and other areas east and west of downtown Atlanta.

Twenty-one counties were declared eligible for federal disaster funds. Preliminary damage estimates were $500 million to $1 billion. Thousands of homes were affected, and 500 were destroyed or significantly damaged.

The flood is considered the worst since 1919, when flood waters almost destroyed West Point in western Georgia.

Parts of four interstates were closed. I-20 remained closed for more than 24 hours as flood waters rose 3 feet over the pavement and inundated Six Flags Over Georgia.

Following the rain, Lake Lanier rose 1.5 feet in 24 hours. Lake Allatoona rose almost 9 feet during the week after. More than 130 dams and many bridges now require stability inspections.

Four water-treatment plants in Atlanta were damaged and dumped raw sewage into the Chattahoochee River. A pipe in a levee near Macon broke and discharged millions of gallons of raw sewage into the Ocmulgee River at the end of the month. Citizens were urged to stay out of the flood water. Some communities issued advisories to boil water.

Ten people were killed, most while driving onto roads covered by moving water. Seven deaths were in Douglas County, where the heaviest rainfall occurred. Additional deaths occurred in Carroll, Chattooga and Gwinnett counties.

The highest monthly total from National Weather Service reporting stations was 10.68 inches in Macon (7.42 inches above normal). The lowest was in Alma at 1.59 inches (1.75 below normal). Atlanta received 8.94 inches (4.85 inches above normal), Athens 9.86 inches (6.33 inches above normal), Columbus 5.30 inches (2.23 inches above normal), Augusta 3.63 inches (.15 inch above normal), Savannah 2.43 inches (2.65 inches below normal) and Brunswick 4.57 inches (1.67 inches below normal).

Forty-eight Community Collaborative Rain, Hail and Snow Network observers reported 15 inches or more total rainfall for the month. The highest single monthly total was 22.86 inches near Kennesaw in Cobb County. However, two observers in Douglas County reported overflowing rain gauges. An observer in Lilburn in Gwinnett County reported 21.79 inches.

The highest daily rainfall reported by a CoCoRaHS observer exceeded 11 inches in a few hours near Douglasville on Sept. 21, when the rain gauge overflowed. The Carrollton observer nearest the area of maximum rainfall reported 10.64 inches in 24 hours ending that morning.

The Georgia Automated Environmental Monitoring site at Dallas in Paulding County reported 16.15 inches for the month, including 5.61 inches on the Sept. 20 and 4.54 inches on Sept. 21.

Numerous daily and monthly rainfall records occurred at National Weather Service cooperative observing stations around the state. Dallas and Carrollton broke 30-year records of heaviest daily rainfall. Atlanta broke a daily maximum rainfall of 3.52 inches on Sept. 19, and Macon broke daily records with 2.32 inches on Sept. 17.

No tornadoes were reported. Scattered reports of strong winds or small hail where reported four days resulting in toppled trees or scattered power outages.

The heavy rains in north Georgia caused extensive damage to nurseries, vineyards and hay fields. Many counties reported rot in cotton and insect infestations. Fieldwork came to a stop in many areas. In other areas, the rain was beneficial to crops and harvesting proceeded at a good pace.

Temperatures across the state were near normal in September except in Augusta where the average temperature was 75.6 degrees (1.6 degrees above normal).

By Pam Knox
University of Georgia

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Officials Provide Information for Employees Victimized by Flood

Defense Department officials have issued information to assist federal employees and agencies affected by the recent flooding throughout the Midwest and Mississippi River Valley, military officials said.

"Our Defense Department employees are a valued resource and an essential part of our total forces," said Marilee Fitzgerald, principal director of the Office of the Deputy Undersecretary of Defense for Civilian Personnel Policy. "The department is committed to doing all that we can do to assist our civilian work force during this difficult and challenging time."

Information on flexibilities currently available -- such as family support, telework and emergency hiring -- are on the department's Civilian Personnel Management Service Web site at www.cpms.osd.mil/disasters/. The site also includes a link to an Office of Personnel Management handbook on pay and leave benefits for federal employees affected by severe weather or other emergencies.

The handbook contains information on salary advances to employees ordered to evacuate for safety reasons, excused absence with pay, travel and subsistence payments, and various pay contingencies, officials said.

Families can call the department's emergency employee toll-free phone number, 888-363-4872, to ask questions regarding their employment and to update their employing components of their conditions. Employees also can provide the information by e-mail to disasterresponse@cpms.osd.mil, officials said.

The Defense Department will update and post information regularly to the Civilian Personnel Management Services site to keep its agencies and employees informed, Fitzgerald said.

By Army Staff Sgt. Michael J. Carden
American Forces Press Service

Midwestern Guardsmen Respond to Rising Flood Waters

Thousands of National Guard troops in the Midwest have moved into high gear reinforcing levees, conducting security patrols, and delivering food, water and relief supplies as record-breaking floods surged through the heartland.

Nearly 4,000 Iowa National Guard troops are deployed across the state as flood levels break records in almost every river community on the Cedar, Iowa, Des Moines, Raccoon and Mississippi river basins, reported Army Lt. Col. Greg Hapgood, Iowa National Guard public affairs officer.

With 17 civilian fatalities and 106 injuries reported, 25,000 people evacuated from their homes, and flood waters still rising, the Guardsmen are reinforcing threatened levees, filling and delivering sandbags, and providing aerial reconnaissance of the region, Hapgood said.

The Army and Air Guardsmen also are transporting packaged meals, drinking water, cots and other relief supplies, conducting security patrols in support of local law enforcement officials, and providing high-water vehicles to utility crews evaluating homes for unsafe conditions.

"We're ... trying to prevent people from going where they shouldn't for their own safety," said Army Sgt. Jason Boesen, a 2nd Brigade Combat Team, 34th Infantry, Brigade Special Troops Battalion, soldier mobilized to support flood--relief operations. "We assist by roving patrols with vehicles."

In Cedar Rapids, one of the hardest-hit cities, the troops used a CH-47 Chinook helicopter to sling-load seven 800-pound water pumps to a repair facility so wells could be returned to full capacity, Hapgood said.

Meanwhile, nearly 100 members of the Iowa Guard's 334th Brigade Support Battalion and 1st Battalion, 133rd Infantry, built a 3-foot levee from about 12,000 sandbags to protect a power substation in Ottumwa from being overrun by rising waters.

About 800 Iowa Guardsmen conducting annual training in South Dakota were recalled to the state to support the flood relief, Hapgood said.

Air Force Col. Brian Miller, commander of the Air National Guard's Sioux City-based 185th Air Refueling Wing, predicted that the Army and Air Guard will be "here for the long haul" supporting the mission.

"We're going to be here as long as it takes," he said.

Hapgood noted that many of the Guardsmen involved in the effort have served combat tours in Iraq or Afghanistan and now have stepped up to assist their own communities.

"This shows in a very tangible way the incredible amount of flexibility built into our skill sets that we can conduct combat missions and also help people here in the United States," Hapgood said. "It's demonstrative of the broad capabilities we have in the National Guard."

Army Sgt. Sean Rohret, a Company C, 133rd Infantry, soldier who has deployed as part of the Sinai Peninsula peacekeeping mission and served a tour of duty in Iraq, said it feels good to be pitching in to help rescue his home state.

"It's pretty gratifying to actually be able to get out here and help the community," he said. "I've seen a lot of people out sandbagging, a lot of people coming up to us, asking us where they can go to help. It's been a pretty wonderful experience getting to see everybody come together."

"It's a pleasure giving something back to the community," agreed Army Sgt. 1st Class Chino Halpin, from 334th BSB. "It's good service."

Meanwhile, more than 500 Illinois National Guard soldiers and airmen are working alongside local citizens to build up levees along the Mississippi River in the western part of the state. Another 400 have been called to duty and are expected to be on site by tomorrow to provide sandbagging, communications and transportation support, state National Guard officials reported.

Army Sgt. Jon Stonewall, a member of the Illinois Army Guard's 233rd Military Police Company, is among those supporting the effort. Stonewall joined the Army after the Sept. 11, 2001, terror attacks, and deployed with his unit to Iraq in 2003, and also was called to duty in December 2006 when a severe winter storm hit Illinois.

"Being here is typical of the Guard," he said. "Part of our mission is here at home, helping the residents in an emergency."

Support from Stonewall and his fellow Guardsmen will be critical in the days ahead. River levels in the Quincy area of Illinois' Adams County are expected to crest tomorrow at 31.9 feet – almost 15 feet over flood stage, county officials reported.

To the south, hundreds of Missouri National Guardsmen are fighting to hold back the surge of water flowing downriver from Iowa and bracing for more to come.

"To be successful in this mission, we will deploy every necessary resource available," said Army Lt. Col. William McKinney, who commands a task force set up to oversee seven units supporting the effort. "Missouri's Guardsmen are an asset for our people to utilize when they face an emergency requiring additional assistance."

The Guardsmen are monitoring levees, working security and filling sandbags along the Mississippi River, state National Guard officials reported.

The Missouri Army Guard's 548th Transportation Company left annual training in South Dakota early to deliver 20 pallets of packaged meals to flood-ravaged Iowa earlier this week. The pallets, which were donated by the South Dakota National Guard, amount to 11,520 meals.

The mission was personal for the Missourians, who had spent much of the past week in South Dakota training alongside Iowa Guardsmen, who also left training early to respond to the severe flooding back home. "This is what we do," said Army Sgt. 1st Class Christine Chane. "Iowa needed the [meals], and we could help. They knew we had the assets to make the delivery."

Army Spc. John Crawford, whose 1438th Engineer Company just finished its annual training exercise, said he's happy to be able to provide flood relief support. "It is a great thing the Guard is doing up here," he said.

Meanwhile, almost 200 Wisconsin Army and Air Guardsmen are on duty as major flooding continues across the southern part of that state.

The Wisconsin Guardsmen are helping with flood control along flooded highways, filling and grading washed-out roads, securing traffic-control points, and providing aviation support for aerial damage-assessment missions, National Guard Bureau officials reported.

By Donna Miles, American Forces Press Service; Army Pvt. Cassandra Monroe and Sgt. Chad D. Nelson from the Iowa Army National Guard's 135th Mobile Public Affairs Detachment, Air Force 1st Lt. Peter Shinn from the Iowa Air Guard's 185th Refueling Wing, 2nd Lt. Stacey Rieger from the Illinois National Guard, and Robert Seyller from the Missouri National Guard contributed to this article.