Essential Paddling Guide: Rio Grande River Grapples With High Salinity, Bacteria Loads

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Careful monitoring of the Rio Grande, here flowing through Santa Elena Canyon, is needed to keep it healthy./Rebecca Latson

Born in southwestern Colorado’s San Juan Mountains, the Rio Grande pulls in the currents from the Pecos and Chonchos rivers, and that of lesser tributaries, as it builds its international reputation. And while a nearly 200-mile stretch of the river carries a “wild and scenic” designation, stresses and strains have exacted a toll on it.

Running as it does through the desert Southwest, the Rio Grande often runs low; it’s estimated that only about 20 percent of its natural input reaches the Gulf of Mexico. But the river also is stressed by high salinity and bacteria, including fecal coliform and E. Coli, in places.

Big Bend National Park and the Rio Grande Wild and Scenic River claim 245 miles of this renowned river. And while many of those miles wend their way through rugged and remote canyon country, sections of the river nevertheless are on the state of Texas’ list of impaired water bodies. The primary concern is high total dissolved solids (high salinity), but bacteria can be a problem in the very upper reach.

National Park Service officials note that “the quality of water in the Rio Grande through the Big Bend region is highly variable.” Monthly testing over the years has demonstrated that bacteria levels rise after rainstorms, a phenomenon thought to be tied to animal wastes and other pollutants washed down tributaries and into the main river. While bacteria levels fall during low river flows, that’s when high salinity levels return, notes the Park Service.

That said, water quality in the river as it flows through the national park and its adjacent state park is not an obstacle for paddlers. But vigilance must be ongoing to see water quality issues don’t become a problem for them.

“The Rio Grande is constantly trying to supply water to a human population that demands more and more,” says Suzanne Dixon, who heads the National Parks Conservation Association’s Texas regional office. “Rainfall is uncertain, groundwater resources are threatened, and recreational boating here in Big Bend is dependent on both. But despite the ever-increasing demands and threats to this river, the river still flows year-round and offers itself up once again, this time to people who love to paddle on rivers.”

Recent Park Service studies point to “outstanding recreational values” along the Wild and Scenic River stretch of the Rio Grande, values which add to our knowledge about this river stretch administered by Big Bend National Park. Recent research publications about the river continue to publish and expand our knowledge of this river.

Yet no matter how unique and precious we view this river, it needs more of our attention and understanding to be able to absorb the demands made upon it. You can help improve the Rio Grande’s health by volunteering at the annual river cleanup day held in Big Bend National Park and in the Big Bend Ranch State park. And if you live in the region, conserve water resources.

Volunteer opportunities also exist within the park to work with visitors and scientists seeking to learn about and restore the Rio Grande and manage/assist park visitors to enjoy this resource.