This drone image shows the last 4 miles (6 kilometers) of Loomis Pass, a constructed channel that branches several times along its path from the Mississippi River. The foreground shows approximately 50 acres (20 hectares) of emergent and shallow-water wetlands that were created and are being maintained by the Loomis Pass restoration channel. (Credit: Gabe Griffen)
The dynamic Bird's Foot Delta
From US Coast Guard surveys, this 1874 map shows the end of the Mississippi River Delta, Plaquemines Parish, Louisiana. (geographicus/public domain)
Sink or save?
The discovery of wetland subsidence, or sinking and compacting over time, led many to the idea that wetlands in the Bird's Foot Delta were unnatural and unsustainable, Nyman said.
"However, there's excellent geologic data from the 1950s showing that there are three layers of these events stacked up like pancakes," he said. Sediment cores taken in the delta contain three peat layers, representing three cycles of deposition, stability and subsidence. "Those peat layers indicate that the wetland building of the late 1800s was a part of the cycle of natural wetland building."
In fact, Nyman said, the Bird's Foot Delta is the "second healthiest part of Louisiana's extensive coastal wetlands in terms of changes in wetland acres since the 1980s."
Nyman thinks that Bird's Foot Delta could still be helped with restoration efforts.
"It just seems with the river currently being able to build wetlands at Bird's Foot, this could be a very efficient use of our dollars," he said. "I suspect that we could tweak the river to get 1, 2, or even 5% more wetlands out of it."
