Weed Control Near Sawyer Camp Trail--First of Several Projects Now Complete

San Francisco Public Utilities Commission crews recently launched a series of short projects to control invasive weeds on parts of its Peninsula Watershed land near the Sawyer Camp Trail for approximately a one-mile stretch slightly north of Mile Marker 1. The first project, which started Monday, February 18, is now complete. The trail remained open throughout the work period.  

The weed control is being done to preserve and enhance the native grasslands that were seeded in late 2016 as part of a continuing long-term habitat restoration program in various areas throughout the watershed.  The 2016 seeding followed the removal of acacia trees and other large, invasive vegetation that had displaced the watershed’s historic native habitats near the trail and at other watershed sites.

Subsequent intermittent short periods of weeding and other vegetation control measures will occur in the Sawyer Camp Trail area in the course of the next couple of years or more. Trail users will be notified in advance.

The approximately 36-square-mile Peninsula Watershed is home to a diversity of long-time coastal habitats, ranging from conifer and oak forests to chaparral, grasslands, and marsh. In all, they harbor an abundance of native plant and animal life, including a high concentration of rare, threatened or endangered species. The watershed is also a State Fish and Game Refuge. 

The First Crystal Springs Bridge

The Lower Crystal Springs Dam across San Mateo Creek went up in 1888, and the first bridge on top of it opened soon after.

The narrow wood-planked crossing easily accommodated the horse-drawn vehicles of the time, and members of the Association of Civil Engineers soon turned out in force to inspect and celebrate.      

The new dam secured an additional welcome supply of more fresh, clean Peninsula water for thirsty San Francisco to the north. And the inventive gravity-arch structure itself, built of staggered interlocking concrete blocks, has lasted without fail ever since. It survived unimpaired the next two major earthquakes of 1906 and 1989.

Lower Crystal Springs Dam stands 149 feet tall on a 176-foot-wide base. The SFPUC recently upgraded it to ensure safe discharge of reservoir water during high rain periods. The more

contemporary bridge of the 1920s was removed just beforehand, with plans to construct a more seismically stable one in its place. 

The new 21^st-century bridge opened this past January 11.  

Today Upper and Lower Crystal Springs operate as one reservoir and have a combined capacity of 22.5 billion gallons of water. The stored stream runoff, rainfall and surplus Sierra Nevada waters are continually drawn on as an essential local supplement to the Hetch Hetchy drinking water we serve throughout the Peninsula and San Francisco. 

Life on the Watershed: When Birds of Different Feather Flock Together--Look for Winter Activity along the Ridge Trail

February is still a good time to catch winter’s unique activity in the woods, where a single quiet tree can suddenly become a hub of fluttering, chirping commotion. 

This  is the season when songbirds of various sizes and colors band together in flight and feeding. They'll descend in mass on one or a couple of trees to feast on insects from leaves or the bark.  Each species has its own way of foraging (depending on bill size, shape, and other features), so that many of them are after different specific foods and coexist with less competition.

And there’s strength in the numbers, since flocking in a large group makes it harder for hawks and other predators to target a specific bird.  

Good places to catch a winter feeding frenzy are stands of our native coastal live oaks, especially in the mornings.

You can get well into the Peninsula Watershed woodlands by signing up for one of our Fifield-Cahill Ridge Trail hikes. There’s something scheduled for almost every weekend through March and into April. Events range from easy 5-mile round trips to brisker hikes across the 13-mile length of the trail.  For more information, and to reserve your space on line, please visit sfwater.org/ridgetrail.    

The 36-square-mile Peninsula Watershed has been protected since the late 1800s to safeguard the

quality of our local drinking water resources. A key side-effect is that the place remains an oasis of historic native habitats that support a diversity of plant and animal life, including 165 bird species, 50 different mammals, and 30 reptile or amphibian species. The SFPUC continually works to enhance the indigenous wetlands, grasslands, forests and other ecosystems by removing the non-native trees, shrubs and weeds that spring up, and replacing them with seeds or saplings from the original species.