Molded by the glaciers and meltwater torrents of the Pleistocene, the broad Mississippi River watershed stretches from the Rockies to the Appalachians. Over the past 2 million years, its major rivers and their numerous tributaries have carried vast amounts of sand and silt from the mountains, plains and Central Lowlands to the Gulf of Mexico, producing a massive delta of braided streams, coastal wetlands, tidal flats and sandbars. Home to a diverse assembly of wildlife, from fish to mollusks to waders and sea birds, this rich ecosystem has also attracted humans, first drawn by the abundant food supply and later by the access to America's interior.
After damming the major rivers and attempting to inhabit the Mississippi floodplain, protected by a network of canals and levees, we have altered the delta ecosystem and have placed ourselves at the mercy of nature's relentlous cycle of inland flooding and tropical storms. Deprived of nutrients and silt by the dams and levees, the Mississippi Delta has been shrinking for decades, offering less protection to other coastal habitats; in addition, sea level is rising in response to global warming and the Gulf of Mexico will gradually flood the remaining delta wetlands.
Today, seven years after Katrina wreaked havoc on the city of New Orleans, Isaac spins offshore, soon to arrive with its storm surge and torrential rains. Whether the expensive new levee system will protect the city remains to be seen but, once more, the folly of living on natural floodplains and wetlands has become apparent. Even before the storm damage is known, the costs of protection and evacuation are beginning to take a toll and, in the spirit of American politics, Governor Jindal is chiding President Obama for not doing enough. In what is otherwise a spectacular natural ecosystem, humans ensure that the Delta Blues will prevail.
