Posted on March 11, 2024
SACRAMENTO, California – Before leadership in the U.S. Army Corps of Engineers gives the go-ahead on any of the Sacramento District’s multimillion-dollar projects, they ensure that the district has taken proper steps to minimize the environmental impact of operations.
“Environmental mitigation is a requirement of both federal and California law,” said Dave Fluetsch, senior environmental manager for the USACE Sacramento District. “California is home to more than 250 endangered or threatened species, so these must often be relocated before construction starts.”
Case in point—the Tenmile Slough Levee in Stockton, California (USACE calls it TS-30L). The district is preparing to begin improvements to this levee later in 2024 starting with vegetation removal as part of the Lower San Joaquin River Project.
Blue elderberry is the sole habitat for the Valley Elderberry Longhorn Beetle, a federal threatened species. The Endangered Species Act (ESA) directs federal agencies to take all available means to avoid harm to threatened species if they are in or near construction areas. Since blue elderberry shrubs can be found dotted along TS30L, USACE is subject to this requirement on the Lower San Joaquin River Project.
That doesn’t mean it’s easy, though. On the levee, isolated stands of elderberry are tangled in mounds of blackberry bushes. As many local homeowners can attest, removing the matted, thorny blackberry bushes can be difficult.
“We planned for this, bringing an excavator, chain saws, and of course, personal protective equipment for the operators,” said Lorena Guerrero, a biologist with the Sacramento District and the lead environmental manager for the elderberry relocation. “The week of February 12-15 was very busy with brush clearing, digging up the shrubs and moving them to a transplant site about two miles down the levee.”
The district takes measures to minimize their impact on the site, including tamping down loose soil after shrubs have been dug up, clearing a minimal amount of space around each elderberry stand, and even cleaning mud off tires and tracks to avoid tracking it onto paved roads.
Elderberry is not only significant because of its threatened status. Its berries are edible once they have been properly cooked, and central California Native American tribes have used elderberries in traditional food and medicine for thousands of years.
The San Joaquin Area Flood Control Agency and the Central Valley Flood Protection Board, the non-federal sponsors of the project, are subject to the California Environmental Quality Act (CEQA) as well as the federal ESA. The elderberry relocation meets the requirements of both state and federal law, enabling all three agencies to move forward on the project.
“Construction activities on the levee are scheduled to start in fall of this year,” said Fluetsch. “This is just the first of many levee improvements set to take place from now until 2037, when the entire project is scheduled for completion.”
On different projects, environmental mitigation can look different. Sometimes USACE purchases credits from mitigation banks, which can be used to construct or restore habitat off-site. Other times, like on the Lower San Joaquin River Project, direct mitigation is required.
“We pride ourselves on being good stewards of the immense natural beauty and resources across our district,” said Guerrero. “Our goal is for our projects to exist in harmony with the natural environment and ultimately help species move out of threatened or protected status, as well as protecting the natural world for future generations of humans to enjoy.”
