Lately, drivers along Las Positas may have noticed what looks like a construction project across the road from Elings Park. What they are seeing is the City of Santa Barbara’s creek restoration in the Arroyo Burro Open Space. Its goals include replacing the invasive plants that have colonized the area with native species, stabilizing the creek bank, and recreating the natural floodplains on the sides of the creek that have disappeared over the years.
Why did the creek need to be restored?
Over the years, the habitat of the lower Arroyo Burro Creek had stopped thriving as well as it used to due to manmade modifications and the takeover of nonnative plants. The area was thick with highly invasive Arundo donax, a bamboo-like reed that can contribute to erosion and flooding, and cape ivy, a vine that can cover and block the sunlight of native vegetation. At one point, pipe-and-wire revetment (a wire-mesh cage that holds the soil forming the bank) had been installed to help protect eroding banks, and lost its use when the soil behind it eroded anyways due to the lack of native plants that reduce erosion. Before the City’s acquisition of the project in 2016, a developer had been using heavy equipment near the creek in preparation for a planned condominium project, and people had been dumping landscaping waste such as concrete into the creekbed. All of these issues combined to produce a habitat that was less than ideal. It is the City’s hope that once the restoration is complete and the native plants grow in, the area can become a thriving riparian ecosystem as it once was, and support animals such as dusky-footed woodrats, birds, and even the endangered steelhead trout. In addition to supporting riparian wildlife, the newly restored area will likely improve water quality before it flows to the ocean.
How is the restoration being carried out?
The first step in the process was the removal of invasive arundo. In most areas, this was done by cutting the stalks very close to the base and painting an herbicide onto the stumps. While it is not typically recommended to use herbicides near a creek, arundo is extremely difficult to remove otherwise, and steps were taken to keep the chemical out of the surrounding environment. Some arundo will likely soon grow back, but with yearly maintenance it will eventually be eradicated.After an extensive planning process to determine how to best restore the habitat, crews began grading the creek area in July 2018. Since the creek had downcut, meaning that erosion and manmade modifications had caused the flow to be much lower than the top of the bank, it was necessary to alter the topography of the creek in order to recreate the natural floodplains that were once present there. These low, flat areas of vegetation adjacent to the creekbed help prevent erosion, remove pollutants from the water before it reaches the ocean, and provide habitat for wildlife. Temporary erosion control methods were put in place, such as biodegradable netting and an erosion control grass that does not grow back in the next season. Finally, the City began installing native plants. These include oak, sycamore, walnut, lemonade berry, black cottonwood, white alder, and other species endemic to the Arroyo Burro watershed. This is the project’s current stage, and will be finished mid-December.
Visiting the Arroyo Burro Open Space
Currently, visitors to the Arroyo Burro Open Space will find an area that looks more like a construction zone than a creek while the planting gets finished. However, the park is still open to the public, and not all of it is affected by the ongoing restoration. In addition to exploring other areas of the Arroyo Burro Open Space, such as the eucalyptus grove next to Campanil Hill or the native oak woodland upland from the creek, visitors are welcome to observe how the newly restored habitat develops over time into a healthy riparian ecosystem. In mid-December when the planting is complete, the fencing will be removed and the restored area will be more accessible.
For more information, see the page for this project on the City’s website: https://www.santabarbaraca.gov/gov/depts/parksrec/creeks/restore/lowerab.asp