The Battle to Draw Down Lake Okeechobee - Jeff Masters

[malaise]

http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=2499
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After the wettest July ever recorded in Florida, the Army Corps of Engineers is battling to draw down the level of Lake Okeechobee before the September peak of the rainy season. The huge lake represents an important source of fresh water to South Florida, but also poses a grave danger. The 25 - 30'-tall, 143-mile long Herbert Hoover Dike surrounding the lake was built in the 1930s out of gravel, rock, limestone, sand, and shell using old engineering methods. The dike is tall enough that it cannot be overtopped by a storm surge from anything but an extreme hurricane, but the dike is vulnerable to leaking and failure when heavy rains bring high water levels to the lake. The Army Corps of Engineers is scrambling to complete a $300 million upgrade to the dike to reduce the chances of such a failure. However, those repairs are not scheduled to be completed until 2018, and the Corps is warning that the Lake Okeechobee dike is in danger of failure this year should heavy rains from a tropical storm or hurricane raise the lake level and put high stresses on the old dike. A 2011 risk assessment estimated the dike's probable failure rate at every fourteen years. A 2008 Army Corp of Engineers study said this about the vulnerable dike:

"There is limited potential for a dike failure with lake levels as low as 18.5 feet. The likelihood of a failure increases at higher lake levels. At a lake level of 21 feet--a 1-in-100 year flood event--a dike failure would be likely at one or more locations. In the event of a dike failure, waters from Lake Okeechobee would pass through the breach--uncontrollably--and flood adjacent land. Flooding would be severe and warning time would be limited. And with 40,000 people living in the communities protected by the Herbert Hoover Dike, the potential for human suffering and loss of life is significant. Our engineering studies indicate the southern and eastern portions of the dike system are more likely to fail than the northern and western portions of the dike. In general, we would expect a warning time of 24 to 48 hours prior to a dike failure that releases water from the lake; however, under some conditions the warning time might be longer, and under others, a dike failure could occur with no warning."

The city most at risk from a dike failure may be Belle Glade (population 18,000) on the southeast shore. Belle Glade is at 16' elevation. If Lake Okeechobee is at 20' above mean sea level when the dike fails, this implies that at least three feet of water could flood Belle Glade. If a wide section of the dike breaks and there is a Cat 3+ hurricane driving a massive storm surge at the time, then the flood could be much higher. During the 1928 hurricane, which had 130 mph winds while over the lake, the water from the storm surge reached seven feet above ground level in Belle Glade.

[HooptieWagon]

1. The article is an accurate summary.

The dike is essentially an earthen berm. There are locks to permit boat traffic, and flood control gates at critical locations. All of this dates back to the Great Depression, and is in rather poor condition.
The 1928 flood is infamous in state history. Many thousands died. A failure of the dike would result in a repeat.

[malaise]

2. These days I only ask one question

Will this affect any 1%ers?
If not they don't give a flying fugg.

Jeff Masters is one of the good guys on the planet.