“We are lucky we live on a planet that keeps a diary
of its own evolution,” observes Christopher Paola, professor of geology and geophysics, whose research specializes in the study of the Earth’s strata. “One form of that record is found in sediments and sedimentary
rocks. It is possible to extract from them information
about how the Earth behaved in the past and how river systems work in natural settings.”
Paola is director and co-founder of the National Center for Earth-surface Dynamics (NCED), a research center funded by the National Science Foundation (NSF) and headquartered at the University’s St. Anthony
Falls Laboratory (SAFL), as well as a founding fellow of the University’s Institute on the Environment. Currently,
his primary research revolves around restoring river deltas, with their dynamic interaction of sedimentation,
flow rates, and aquatic organisms. In particular,
he has used the Indoor StreamLab at SAFL to model how stream channels are formed in deltas and how plant life affects the kind of flooding that deposits
sediment at the mouth of river systems.
Christopher Paola, professor of geology and geophysics, specializes in the study of the Earth’s strata. His primary research revolves around restoring river deltas, with their dynamic interaction of sedimentation, flow rates, and aquatic organisms.
SAFL’s new Outdoor StreamLab will facilitate this ongoing research by making it possible to study the interaction of plants and stream morphology on a larger scale. “The Outdoor StreamLab will enable us to do experiments with a larger variety of plants, more realistic ecosystems, and a more realistic ratio between the size of plants and the size of streams,” he explains.
His work could not be more timely. Since 2002, he has been part of a nationwide research team that is working on restoring the Mississippi River Delta. Its dramatic decline played a major role in the flooding of New Orleans following Hurricane Katrina and is one of the causes of the growing dead zone in the Gulf of Mexico.
“Altogether, the Delta has lost about one-third of its historic surface area,” Paola said. “The primary cause has been damming upstream which has deprived
the Delta of its sediment supply.
Above is sedimentary “peel” taken from an experiment conducted in the Experimental Earthscapes
Basin. By taking vertical slices of the geomorphology modeled, then transferring them onto sheets of polymer, strata sections like these can be more closely examined.
Although Paola makes it clear there is no way to restore the Mississippi River Delta to its “natural” state—the same is true of any ecosystem altered by human agency—it is possible to restore some of the river’s natural functions, and at this stage, absolutely
critical if we are not to lose one of the richest ecosystems in the world.
“The choice is between a living Mississippi Delta versus a dead or dying Mississippi Delta,” he said. “If you fly over the Delta today, you’ll see large tracts of dead trees and brown grasslands. It is too diked and dammed—we have made the river far too efficient in carrying sediment to the Gulf.”
Restoring the Delta would take decades, rather than years, and requires summoning the collective political will to take the initial steps necessary to bring it back to life. “The first step is to make the decision to carry out the restoration,” he said. “That will involve removing or circumventing some of the dike systems that currently channelize the lower Mississippi and prevent sediment from settling on the Delta.”
“Our aim is to create a more compact but vital Delta that can sustain itself, provide recreation and support for the fishing industry, and that can take the brunt of Gulf storms and protect cities and towns in the region,” he said.
“If we can achieve that, you would see a dramatic turnaround of the Delta—green versus brown.”
