But the culprit is man-made. ABC News reports:
As the Mississippi River continues to rise and the threat of flooding moves south with the current many critics of the Army Corps of Engineers are blaming man rather than Mother Nature for the high water.
“This is largely a man-made disaster — to point it only to rainfall is naive,” said H.J. Bosworth Jr., civil engineer and director of research for Levees.org. “Yes, there was lots of rainfall, but there was also lots of development. Every time you build a parking lot or a Walmart you add to the burden of the drainage system and all that drainage goes into the Mississippi River.”
Bosworth says many parts of the water system including the levees were built prior to the creation of the fully developed urban areas and that this transition from soil to cement created major problems.
“If the rainfall increased in a forest the forest is going to suck up 90 percent of that rainfall. But if it happens in a urban area the pavement and roofs aren’t going to suck up anything,” Bosworth told ABC News.
The affect is multiplied on the mighty Mississippi because rivers in 31 states drain into it or its tributaries.
“The rivers need some room and we are getting that message explained very clearly to us year after year. It’s time we smelled the coffee,” said Robert Criss, professor of earth and planetary sciences at Washington University in St. Louis. “There is a lot of evidence that floods are not only getting deeper and more severe, but also more frequent.”
Criss attributes the rise in devastating floods to the continued constriction of the waterways and increased building in vulnerable areas. He says that as levees continue to be built higher it creates water that has enough power to tear through a landscape like a tsunami if the levee is breached, destroying everything in its path.
“What we need instead is a more thoughtful system where we have gates within levees and when we require flood water storage these gates are opened,” said Criss. “This will save levees, save farms and rejuvenate soil.”
Criss says that when water is released at a massive rate like in Cairo, Ill., when the Corps blasted the levees to flood farm land and save homes, it is a destructive process and the land is often not salvageable.
Both Criss and Bosworth agree that part of the problem is inaccurate assessments by the Corps.
“There are plenty of people living in designated 100-year flood plain areas and by government standards that’s more like 10-year flood estimates,” said Criss. “Every year is a 10-year flood now or worse. … In terms of the Army Corps of Engineers’ flood statistics I was able to show that there’s not one chance in a thousand that their statistics are correct.”
Bosworth quipped that a 100-year flood is more like a “once a mortgage” flood.
The rest here.