Thursday, November 15, 2018

Trail runs through oasis below sea level

Springs created when action on the San Andreas Fault brought water to the
surface created oases of hundreds of fan palms.
Aerial photo of San Andreas Trail
Day hikers can enjoy a massive desert oasis that hosts some of California's rarest flora and fauna at the Dos Palmas Preserve.

The 0.9-mile San Andreas Trail weaves through an oasis and wetlands that sit atop expansive alkali flats. Much of this lollipop trail is below sea level; in fact, the entire preserve at the base of the Orocopia Mountains is an average -112 feet elevation.

To reach the trailhead, from the Coachella Valley take Calif. Hwy. 111 south of Mecca to along the Salton Sea. Once past North Shore, turn left/northeast onto Parkside Drive. Go right/southeast onto the dirt Power Line Road. Then turn left/east onto the dirt Dos Palmas Road (some maps show this as Sea Breeze Drive). In about 1.5 miles, you'll reach a metal gate. The parking lot is on the right. At the lot, look for the "San Andreas Trail" sign and follow the sand path, bordered with rocks, toward the oasis.

The stem of the trail heads across the flat dotted with scrub and mesquite bush common to the Colorado Desert. It nicely gives the feeling of desolation as the hope of a hazy green oasis grows on the horizon.

The gradually gradually descends. Several times during and since the last ice age, the preserve sat beneath a freshwater lake, most recently about 600-1100 years ago when Native Americans fished the shores of what geologists call Ancient Lake Cahuilla.

At 0.3 miles, the trail crosses a service road and reaches the wetlands portion of the oasis. It is one of at least three oases in the preserve with the larger ones to the east.

Artesian springs and seepage from the nearby Coachella Canal feed the oases. A shift in the San Andreas Fault during the 1800s allowed underground water to reach the surface as springs; during the mid 1800s, only two fan palms grew at the oasis; by 1900, there were 40 palms at the site, and by 1940 several hundred were counted in three distinct locations.

Endangered species
Three rare and endangered species make the oases home.

The Yuma clapper rail will be the easiest to spot. Building its nest in the oases’ cattails, the large footed brown clapper eats crayfish, clams, isopods, fish and various insects. It can be found in isolated spots across the Southwest – the Gila River in Arizona, the Virgin and Muddy rivers from Utah to Las Vegas, and here. It is disappearing in large part because its wetland habitats have been eliminated.

Kneel next to the oases’ warm pools and see if you can spot the desert pupfish, which was far more common in the Pleistocene era when ice covered much of North America and lakes much of the California desert. Less than three inches in length, during the breeding season males turn bright blue with a lemon yellow tail. They exist in remnants of former Salton Sea and Colorado River habitats that are disappearing due to evaporation and by man’s heavy use of the Colorado. Unlike other Ice Age creatures that have gone extinct, the pup fish has hung on thanks to its ability to tolerate extreme environments.

If the air smells a bit like lavender, you’re probably near the rare and endangered orocopia sage plant. A low, rounded shrub that tops out at about three feet high, it usually can be seen in floodplains and along washes. It’s found only in California and then only in the area between the Salton Sea and the Little San Bernardino Mountains.

A common sight at the oases but rarely seen across the rest of the Coachella Valley are damsel and dragonflies, which flit over the ponds and wetlands. The Blue Dasher, Western Pondhawk, and Marl Pennant are the most common.

Much rarer but still worth keeping an eye out for is the Rambur's Forktail, whose colors seem to glow in the desert sun. Also watch for the Red-tailed Pennant; the males with their aptly named tail are quite striking.

Jungle-like environment
The trail soon winds through hundreds of fan palms swaying in the desert. Thick dead leaves surround their trunks, helping protect the tree from the desert heat.

Once the trail reaches the service road, turn left. In 0.1 mile, the road intersects the stem trail you walked in on; turn right onto it and retrace your steps back to the parking lot. As doing so, keep an eye to the sky for various birds. Both osprey and the snowy egret use the oases while the northern harrier and prairie falcon hunt in the surrounding desert.

Because of the desert heat, the trail is best done October through May and then only in the mornings during late spring. Always bring and drink plenty of water, even in the oases. As part of the hike is unshaded, wear sunscreen, sunglasses and a hat.

The preserve is administered by the Bureau of Land Management and sits within the Salt Creek Area of Critical Environmental Concern.

Learn more about national park day hiking trails in my Best Sights to See at America’s National Parks series.