New research finds that every U.S Gulf Coast bay in Texas and Louisiana is vulnerable to significant flooding and expansion within the coming century due to a combination of rising seas and reduced silt flowing from dammed up rivers.
"Looking back over the past
New research finds that every U.S Gulf Coast bay in Texas and Louisiana is vulnerable to significant flooding and expansion within the coming century due to a combination of rising seas and reduced silt flowing from dammed up rivers.
"Looking back over the past 10,000 years, we find the evolution of each of these bays is punctuated by rapid flooding events that result in landward shifts in bay environments of tens of kilometers and increases in bay area up to 30 percent within a century or two," said John Anderson, the W. Maurice Ewing Chair in Oceanography and professor of earth science at Rice University in Houston. "These flooding events can be triggered by either a rapid increase in sea level or a rapid decrease in the amount of silt flowing into the bay, and there's ample evidence to suggest that both of those will occur in each of these bays during the coming century."
Anderson will present his findings today at the Geological Society of America's 118th annual meeting at the Pennsylvania Convention Center in Philadelphia.
Anderson's results are based on his research group's analysis of dozens of sediment core samples drilled during the past decade from Galveston, Corpus Christi and Matagorda bays, all in Texas; Calcasieu Lake in Louisiana; and Sabine Lake, which straddles the Texas-Louisiana border.
"Over the past 10,000 years, there are an average of a half-dozen of these flooding events in each bay," Anderson said. "They don't correlate with any global increase in sea level, and they happen at different times in different bays, so we're confident that the driving factor in these events is a decrease in the amount of river-borne sediment flowing into the bay."
In the past century, multiple dams were constructed on each of the rivers flowing into each of these bays. Anderson said there is ample evidence that the dams have reduced the amount of sediments flowing from the rivers into the bays.
In addition, there is a growing body of evidence that sea level will increase more rapidly in the 21st Century tha