Surrounded by the Gulf of Mexico, the Laguna Madre, the Rio Grande, resacas and oxbow lakes, Jude Benavides picked a good place to study water.
The Navy veteran and University of Notre Dame and Rice University graduate is an associate professor of Hydrology and Environmental Sciences at the University of Texas Rio Grande Valley’s School of Earth, Environm ental and Marine Sciences in Brownsville, which also happens to be his hometown.
In addition to teaching, part of Benavides’ research involves a partnership with the Texas Water Resources Institute to study watershed and watershed quality issues, research that’s funded through the Texas Commission on Environmental Quality and U.S. Environmental Protection Agency.
Among the watersheds he studies are the two main watersheds in deep South Texas: the Arroyo Colorado and the Lower Laguna Madre/Brownsville Ship Channel. Water samples are sent to a state-certified private lab for testing for bacteria, salinity, clarity, acidity, temperature, dissolved oxygen and other indicators, with the results entered into a database maintained by the state.
The database covers all over Texas, serving as a resource for researchers and members of the public, and giving a general idea of whether a given body of water meets state and federal guidelines for water quality. The ultimate goal of Benavides’ work is to improve water quality.
“The data we’re collecting is helping refine and decide whether these bodies are in violation,” he said.
Benavides is conducting a “watershed characterization study” of the Lower Laguna watershed, the least studied of the county’s two main watersheds because it lacks a primary drainage feature such as the Arroyo Colorado in the case of that watershed.
Instead, water gets to the Lower Laguna and the ship channel via a series of drainage ditches and resacas, a more complicated set up. Everything that flows into the ship channel winds up in the Lower Laguna and eventually the Gulf, Benavides said. A common misconception is that water runs into the Rio Grande here, which it doesn’t since the river’s ancient natural levees prevent runoff into the river, he said.
The Lower Laguna watershed encompasses all of Brownsville, Rancho Viejo, Olmito, part of Los Fresnos, South Padre Island, Laguna Vista, Laguna Heights, Los Indios, Laguna Atascosa Wildlife Refuge and all the bays inside it. The Lower Laguna watershed is bordered on the north by the Arroyo Colorado watershed, which includes Harlingen and portions of Willacy and Hidalgo counties.
Then there are the resacas, five major examples in the Lower Rio Grande Valley that together constitute 200 linear miles — 150 of them wet, Benavides said. The Lower Valley also has between 300 and400 oxbow lakes, he said. Another misconception is that all resacas are oxbow lakes, or curved bodies of water left behind when a river, the Rio Grande in this case, cuts out a bend, Benavides said. In fact, the five major resacas — Town Resaca, Resaca de las Palmas, Resaca del Rancho Viejo, Resaca de Los Fresnos and Resaca de los Cuates, which separates the Lower Laguna and Arroyo Colorado watersheds — are actually ancient distributaries of the Rio Grande.
All have narrow watersheds except Town Resaca, which plays a vital role for Brownsville in that it drains all of downtown, Benavides said. That’s just one reason resacas are important and should be treated as such, though that’s not always the case, he said.
“People have the wrong impression that resacas are simply drainage ditches,” Benavides said. “That’s a very dangerous, slippery slope. It leads to thinking that doesn’t value the resacas, thus people don’t take care of them. I think we as community need to continue to lead the way in raising awareness and appreciation for these water bodies.”