Sunday, August 25, 2013

Too much water and not enough - a tale of two Americas


Too much rain in Florida


In the past couple of days Jeff Masters of Wunderground.com has had a couple of blog posts that couldn't be in more stark contrast.  Today he wrote about the risk of a dike failure on Lake Okeechobee in Florida.  He writes:

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. ...
..."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. ...
Read the full article here.

The Colorado River is running out of water


This situation facing the people in the south west of the USA is the opposite.  Not enough water.  Only a few days ago, Jeff Masters wrote:
For the first time in history, the U.S. government has ordered that flow of Colorado River water from the 50-year-old Glen Canyon Dam be slashed, due to a water crisis brought about by the region's historic 14-year drought. On Friday, the Federal Bureau of Reclamation--a division of the Department of Interior that manages water and electric power in the West--announced that it would cut water released from Lake Powell's Glen Canyon Dam by 750,000 acre-feet in 2014. An acre-foot is the amount of water that will cover an acre of land one foot deep; 750,000 acre-feet is enough water to supply at least 750,000 homes for one year. The flow reduction will leave the Colorado River 9% below the 8.23 million acre feet that is supposed to be supplied downstream to Lake Mead for use in California, Nevada, Arizona and Mexico under the Colorado River Compact of 1922 and later agreements. 
"This is the worst 14-year drought period in the last hundred years," said Upper Colorado Regional Director Larry Walkoviak in a Bureau of Reclamation press release. 

Read the full article here.


Climate migration in the USA?


Jeff put up this chart from Schwalm et al in his Glen Canyon Dam article (click chart to enlarge it):


With the south west of the USA facing increasing dryness, where will all the people go?  Or where will all the water come from?

With Miami facing sea level rise sooner rather than later - where will all the people go?


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