Island University Researchers Study the Impacts of Harvey’s Freshwater Floods

CORPUS CHRISTI, Texas — A team of Texas A&M University-Corpus Christi researchers were awarded emergency response funding by the National Science Foundation to examine the impacts of Hurricane Harvey’s massive floods on Coastal Bend lagoons.

HRI Endowed Chair for Ecosystems and Modeling Dr. Paul Montagna was awarded a NSF Rapid Research Response (RAPID) with Co-Principal Investigators TAMUCC Physical and Environmental Sciences Assistant Professor Dr. Xinping Hu and TAMUCC Life Sciences Associate Professor Dr. Michael Wetz for their project, “Capturing the Signature of Hurricane Harvey on Texas Coastal Lagoons.”

The team will conduct widespread sampling across the Matagorda, San Antonio, Corpus Christi and Baffin bay systems to examine whether the storm triggered changes in these important estuarine environments, and the consequences for the coastal environment.

“We’ve been studying the effects of freshwater inflows into our bays for the last 30 years, and this is another piece of the puzzle,” Montagna said. “There’s no way to replicate a huge disturbance like this in an experiment, so this could be a significant opportunity to look at the immediate short-term impacts of an event like this, and how recovery progresses.”

Hurricane Harvey made landfall Friday, August 25 near Rockport as a Category 4 hurricane with winds up to 130 mph, the strongest hurricane to hit the middle Texas Coast since 1961’s Hurricane Carla. Beyond the immediate impacts of hurricane force winds and surge, coastal flooding occurred as the storm lingered along the coast for four more days, dumping as much as 50 inches of rain near Houston, one of the largest floods to ever hit the Texas coast.

Severe rain flooding can cause inflows of freshwater into coastal zones to increase dramatically, upsetting the balance in these brackish environments and possibly triggering enormous algal blooms that consume oxygen and turn the bays hypoxic. It could even convert these lagoons temporarily into freshwater environments, impacting many estuarine and marine animals.

“These animals are adapted to live in a certain level of salinity, and when the salinity drops they can become stressed to the point of death,” Montagna said. “The organisms that are more mobile like fish can move to deeper waters where its saltier, but things like oysters and benthic species that live in the mud will die.”

Flooding wasn’t dispersed evenly across the coast and was worse in the northernmost portions of the study area, including Matagorda and San Antonio bays, Montagna said. Studying freshwater inflows into multiple systems will allow researchers to look at a gradient of impacts, from large to small.

Hu will look at how the storm transferred carbon in the environment, changing the chemistry of the ecosystem. Coastal habitats can host reservoirs of carbon in salt marshes, mangroves, seagrass beds and other habitats known as “blue carbon” beneath the living plants, he said. These habitats may have been disturbed by the storm’s force, exposing large amounts of that organic material to open estuarine water. There they will undergo decomposition by microbes, which will respire carbon dioxide into atmosphere like a giant breathing animal.

“The objective is to look at how the large-scale storm and its induced flood move carbon around the different reservoirs — including the land, water, sediment, and the atmosphere,” Hu said.

The National Science Foundation’s RAPID grants aim to make immediate research dollars available to urgent projects aimed at understanding the immediate impacts of natural disasters like Harvey and help the United States better prepare for, respond to, recover from and mitigate for future catastrophic events. That’s important, as extreme events, such as hurricanes, are only expected to increase in frequency and intensity in the future, Wetz said.

“Traditional grant funding cycles can take up to a year to attain funding. Programs like RAPID allow us to respond immediately large-scale events like Harvey so that we can collect the time-sensitive data that will allow us to better understand these events should they occur again in the future,” Wetz said.