You don't need to be a ranger, or an outlaw marijuana farmer, to experience the natural beauty of the forested ridges that overlook Crystal Springs Reservoir.
Nearly a decade after it was opened to the public, a 10-mile trail above the man-made lakes in unincorporated San Mateo County remains one of the best-kept -- and most dazzling -- secrets on the Peninsula. Now, plans are afoot to expand trail access in the area.
The Fifield-Cahill Ridge Trail opened in 2003, allowing visitors to explore the wooded heart of the Peninsula Watershed. The rugged territory surrounding Crystal Springs and other reservoirs is part of the Hetch Hetchy Regional Water System, operated by the San Francisco Public Utilities Commission. The path is open for free docent-led excursions, mostly on the weekend.
The trail, an unpaved service road, begins off state Highway 92 at Skyline Quarry, which yielded rock and gravel for construction projects until it closed in the 1960s. It winds up Cahill Ridge through planted Monterey cypress and native mixed woodland -- predominantly live oak, bay laurel and madrone -- before entering a primeval thicket of Douglas fir.
As the trail continues north to Fifield Ridge, the terrain shifts dramatically. Forest gives way to coastal scrub and sweeping views -- when the northerly ridge isn't blanketed in fog -- of Pacifica, northern San Mateo County and beyond, and the East Bay.
"It's the largest concentration of rare, threatened and endangered species in the Bay Area," said John Fournet, community liaison and ridge trail coordinator for the watershed.
Most of the watershed remains off-limits to the public to protect its reservoirs, a key component of the Hetch Hetchy system that provides water to 2.6 million customers in the Bay Area. The Upper and Lower Crystal Springs and San Andreas reservoirs hold Sierra Nevada snowmelt and local rainfall. Pilarcitos Reservoir, tucked to the west of Fifield and Cahill ridges, collects water for the Coastside.
"It's really a water factory," Fournet said of the watershed. "There's some risks you don't want to take if you're managing the property for growing water in perpetuity."
But the size and remoteness of the property prove irresistible to illicit marijuana growers, whose garbage and fertilizer make for an environmental hazard. The San Mateo County Narcotics Task Force has seized 48,529 outdoor plants worth an estimated $170 million countywide in the past five years, a majority of it on the watershed.
More trails on the way
Besides Fifield-Cahill, there are two other public trail systems on the property. The Crystal Springs Regional Trail -- which includes the San Andreas, Sawyer Camp and Crystal Springs trail segments -- runs along the eastern edge of the Crystal Springs and San Andreas reservoirs, and Sneath Lane Trail takes hikers up to Sweeney Ridge, part of the Golden Gate National Recreation Area.
Watershed managers are exploring several trail extensions, two of which are in the early stages of planning. One would connect the Sneath Lane and San Andreas trails, creating a loop on the northern end of the watershed. The other would run from the intersection of Highway 92 and Skyline Boulevard south along Skyline to the federally managed Phleger Estate. Both trails are several years or more from being built and must first pass environmental review.
San Mateo County is also planning a trail extension along the Crystal Springs trail between the Lower Crystal Springs Dam and Highway 92.
The Bay Area Ridge Trail Council helped the watershed secure a $185,000 planning grant from the California Coastal Conservancy for the Skyline project, known as the Southern Skyline Boulevard Ridge Trail Extension. The segment would run 5 miles through coastal scrub and stands of Douglas fir in the north and redwoods in the south.
The nonprofit council aims to create an interconnected trail system, more than 550 miles in length, along the ridgelines surrounding the bay. The Skyline extension, said Bern Smith, the council's regional trail director, would represent an important link in the Peninsula segment.
"It's going to be a very nice, pleasant experience out there," said Smith. "This trail will be a crown jewel in the Peninsula's trail network."
Contact Aaron Kinney at 650-348-4357. Follow him at Twitter.com/kinneytimes.
Free docent-led hikes along the Fifield-Cahill Ridge Trail are typically available Saturday and Sunday and must be reserved in advance.
Visit www.sfwater.org and place your cursor over the "Community" drop-down menu. Put your cursor over "Explore" on the menu that appears to the right and click on "Fifield-Cahill Ridge Trail."
The trail is open to hiking, biking and horse riding. Individual hikes may be canceled due to low participation.