By Karen Gleason
The 830 Times
Efforts to eradicate invasive carrizo cane from the banks of San Felipe Creek will now be spearheaded by the Devils River Conservancy, city council members have learned.
Romey Swanson, Devils River Conservancy executive director, briefed city council members on the change in organizations leading the cane removal efforts during the council’s regular meeting Aug. 11.
Council members during their most recent regular meeting on Aug. 11 about ongoing efforts to
eradicate Arundo donax – also known as carrizo cane – from the banks of the San Felipe Creek
in south Del Rio. Swanson told the council the Devils River Conservancy is taking over
eradication efforts from the Texas Parks & Wildlife Department. (Photo by Karen Gleason)
The “cane” is a species of giant grass — scientific name Arundo donax — native to areas around the Mediterranean. It was brought to the southwestern United States in the early 1800s to stabilize the banks of irrigation ditches.
Swanson told the council, “I’m here to present on the San Felipe Creek Arundo Control and Restoration Project. This is not a brand-new project. This is a project that’s being reinvigorated this year, and I’m aware that we have some new council members, so let’s let this serve as a little bit of a primer.”
Swanson said the purpose of the presentation was to create awareness, continue the conversation and notify the public that work on the project will begin again soon.
“We will begin executing this project in the next couple of weeks,” Swanson said.
Swanson began by introducing the Devils River Conservancy, whose mission he said is “to treasure, preserve and protect the Devils River and the broader landscape around the Devils River that supports it.”
“For those that don’t know, the Devils River is a river that dumps into the north side of Lake Amistad. It’s generally considered the most pristine stream in all of Texas,” Swanson said. “The entire wet flowing portion of the Devils River is in Val Verde County. It is a special gem, not just to your community but more broadly to the state of Texas and the southwest United States.”
Historically, Swanson said, the Devils River Conservancy has been “kind of inward-facing, serving primarily the Devils River,” but the organization is now working “to be a better partner to the communities around the Devils River, including Del Rio.”
“One way that we can do that is to serve and use some of the expertise that (we have) and apply it to other stream systems like the San Felipe Creek,” he added.
Swanson said the Devils River Conservancy has previously partnered with local organizations, including the San Felipe Creek Coalition and Casa De La Cultura, on volunteer-powered cleanup events along San Felipe Creek.
Swanson said removal of carrizo cane from the banks of the creek is a major step in creating “riparian health.”
“You want healthy creek sides and healthy streams because they provide so many important services, ecological services and infrastructure services,” Swanson said.
A healthy riparian zone provides wildlife habitat and vegetation that helps prevent soil erosion and downstream contamination or siltation. Swanson said it can also mitigate the effects of flooding and support different types of native vegetation, including trees that provide shade for residents and visitors using the creek for recreation.
“It’s really important to understand that the San Felipe Creek is a civic asset. It’s not just a stream,” Swanson said. “It provides plenty of recreational opportunities to both citizens and tourists.”
Swanson showed council members a photo of an eroded creek bank on one side of the city’s Lt. Thomas Romanelli Memorial Park as an example of an unhealthy riparian area.
“When a (creek side) is not healthy, in addition to not being attractive, it is also not functioning in all those great ways that I just described,” Swanson said. “There’s not an abundance of native plants holding the creek side together, and it is starting to erode away, and all that soil is falling into your stream and it is flowing downstream.”
Swanson said when creek banks are clogged with Arundo donax, they provide only about one-tenth of the erosion control, habitat and water storage provided by native vegetation. The cane also creates a monoculture rather than the variety of vegetation typically found along southwestern creeks and streams.
Another concern is water use.
Swanson said Arundo donax can consume as much as 17.3 liters of water per square meter per day, about three times more than native vegetation.
“It’s an immense water user, and we are in a dry and arid landscape where water is very important,” Swanson said.
The scope of the eradication effort is largely along San Felipe Creek within the city of Del Rio and will involve both city property and private landowners.
“We’re about five years into a 10-year Arundo donax control project, so some of this work precedes me, and there has been a lag over the last couple of years, so the project hasn’t been active for a couple of years,” Swanson said.
Swanson said the Texas Parks & Wildlife Department approached the Devils River Conservancy about stepping in to restart the project in partnership with the city of Del Rio, Laughlin Air Force Base and the Compatible Lands Foundation.
The conservancy has also recruited Julie Lewey, who was instrumental in leading the eradication project when the Nueces River Authority spearheaded the efforts.
Swanson said the primary method of killing the Arundo will be an herbicide called Habitat, with the active ingredient Imazapyr. The treatment is consistent with previous management plans and will cover the same footprint as previous years, although organizers hope to expand the effort through additional cooperation from private landowners.
“We have about four years left on this 10-year project,” Swanson said.
He said the treatment is aquatic-safe when administered according to the Environmental Protection Agency label and that contractors specifically trained for the work will apply it.
After the Arundo donax stalks die, the dead stalks will be removed to prevent them from being swept away during floods and accumulating downstream.
The work will not end with removal of the cane.
Swanson said the conservancy hopes to work with landowners and the city to establish and maintain no-mow zones along sensitive areas immediately adjacent to the creek. With additional investment, organizers hope to plant native vegetation, including native trees, in cleared areas.
“What success means for this project is that it will result in less Arundo growth each year,” Swanson said. “We’re not going to be able to eradicate it in one strong effort. It takes continued and deliberate effort every year after year for that 10-year period.”
The goals include preventing new colonies from forming, increasing native streamside vegetation, stabilizing creek banks and reducing downstream debris problems.
“We want to stabilize the creek banks and see fewer downstream debris problems and provide a creek corridor that is visibly healthier and attractive for recreation, tourists and the community itself,” Swanson said.
Following the presentation, Mayor Al Arreola asked if council members had any questions.
Councilman LeRoy Briones said he only wanted to thank Swanson and the organization for removing Arundo from the golf course grounds.
“We can find our golf balls now,” Briones joked.
The writer can be reached at delriomagnoliafan@gmail.com.
