Presidio of San Francisco (September 21, 2011)
-- As the height of dry season arrives in San Francisco, the work to restore and expand the wetlands at Dragonfly Creek begins again this week in the Presidio. This effort provides an exciting opportunity to improve the parkland for both wildlife and visitors.
This is just one of a number of restoration projects in the Presidio and across the Bay Area intended to bring long buried or obscured waterways back to the surface, a process described as “daylighting,” which consists of excavating fill, removing buried culverts, and contouring the soil to create more natural, above-ground stream channels.
The many environmental and community benefits of these revitalization projects are currently visible in the Presidio, where Dragonfly Creek is one of several waterways that will be daylighted over the next couple of years.
“We have a unique opportunity in the Presidio to restore this creek to a more natural state,” says Mark Frey, an ecologist with the Presidio Trust. “Dragonfly Creek supports a remarkable diversity of native plants and animals.”
Revitalization of the creek, located in the historic Fort Scott district near the Presidio Native Plant Nursery, began several years ago with removal of eucalyptus trees and other non-native plants in favor of native wetland species. Now, as part of the environmental mitigation efforts associated with construction of the Presidio Parkway, the Trust is working with Caltrans to restore and expand the creek’s wetlands. Excavation and removal of Army-era fill will widen the floodplain, allowing the creek water to flow more freely and increase new wetland habitat. As a result, a small thicket of willows that grows along the creek and is teeming with birds will expand to four times its current size.
“We are pleased to have this opportunity to restore Dragonfly Creek,” says Craig Middleton, Executive Director of the Presidio Trust. “We thank Caltrans for its commitment to restoring the scenic beauty and natural character of this area as part of the Presidio Parkway project.”
The Presidio’s first daylighting project began six years ago in the area known as Thompson’s Reach, in the lower Tennessee Hollow watershed near Crissy Field. As part of that habitat restoration effort, the Trust removed some 77,000 tons of debris from the former Army landfill site, and a 400-foot section of creek was taken out of an underground pipe and brought to the surface. That winter volunteers planted 35,000 native plants of 100 different species in the area. The abundance of wildlife that has moved in— including birds, salamanders, spiders and rare butterflies—gives testament to the site’s success. A video highlighting the transformation at Thompson's Reach can be seen at http://youtu.be/gPLmzJKtyRk
Daylighting's history stretches back nearly four decades, but with public interest growing and community planners becoming more aware of the benefits, such projects have gained a new popularity in recent years. In addition to the efforts in the Presidio, three other projects are in the works in San Francisco and another in downtown Berkeley. Projects are also being planned or undertaken in cities as diverse as Reno, Nevada; Seattle; Portland, Oregon; Providence, Rhode Island and Zurich, Switzerland.
In addition to the work at Dragonfly Creek, the Trust is planning its most extensive and dramatic daylighting project at Quartermaster Reach, between Thompson’s Reach and the Crissy Field marsh, where the creek lies buried beneath a decaying parking lot. The plan re-unites this disjointed piece of habitat with the surrounding wetlands, transforming the lot into a large natural wetland full of native plants and animals. The creek will be unearthed and eucalyptus trees and other invasive species removed, creating a contiguous stretch of above ground stream flowing from Thompson’s Reach into Crissy Field marsh. Work is expected to begin as early as 2013.
Additional daylighting projects in the Tennessee Hollow watershed are set to begin in the next several years.
The Presidio Trust was established by the United States Congress in 1996 to administer the Presidio of San Francisco, an urban national park site located at the base of the Golden Gate Bridge. The areas overseen by the Trust include expansive open space and spectacular views, a 300-acre historic forest, and rare and endangered plants and wildlife. The park is home to 13 distinctive plant communities featuring 280 native plant species, 16 of which are rare or endangered. Thousands of hours of volunteer work have restored many acres of natural resource habitat. The Presidio Native Plant Nursery grows 60,000 plants each year to make this restoration possible. 21st-Century “green” practices are employed in all building and landscape rehabilitation efforts.