Hike along the redwood flume that brought water to La Mesa

The newest segment of the Helix Flume Trail between the old El Monte Pump Station on El Monte Road to Lake Jennings opened to the public in February 2017. The opening of this trail was a joint-partnership effort of San Diego County Department of Parks and Recreation, Helix Water District, and the San Diego River Conservancy. The trail follows a portion of the route of the redwood flume that was completed in 1889, bringing water from the Cuyamaca Mountains to a reservoir in La Mesa, a distance of some 40 miles. The El Monte Pump Station was built in 1898 to draw groundwater from the El Monte Valley and transport it up the hill and into the flume to its ultimate destination at the La Mesa reservoir.

Beginning at the historic El Monte Pump Station, the single-track hiking path zig-zags parallel to the old redwood flume route. Several pictorial story boards detail aspects of the flume and its construction. Several pumps were added over time to push the well water from the San Diego Aquifer to the flume on the hillside. The pump station was later retrofitted, and by 1937 it was responsible for all of the water that entered the La Mesa, Lemon Grove, and Spring Valley irrigation district.

This new trail segment — when combined with the other flume trail that is accessible from El Monte County Park — shows a large remnant of the massive flume that cut through eight hillsides. Also visible is a sealed tunnel measuring approximately 300 feet that once supported the conveyance of the full flume water system.

The trail ascends at a somewhat continuous 5 percent grade, taking the observer through different flora as the microclimates of the changing elevation provide optimal conditions for differing life forms. Some of the plants encountered on this hike include coastal prickly pear, elderberry, horehound, laurel sumac, monkey flower, spiny redberry, white sage, sagebrush, and tree tobacco. Intervening private property precludes a connection with the two trails at this point in time. Both trails are part of the San Diego River Trail, which is in the process of being established to allow uninterrupted hiking, biking, and horse riding along 50-plus miles of waterways extending from Ocean Beach to the mountains near Julian.

The last half of the trail has less than 100 feet of elevation gain, finally ending at the top of the hillside with sweeping views of Lake Jennings, El Cajon Mountain, and El Monte Valley. From there it is possible to continue on a trail that winds westward over to Lake Jennings and its campground. In addition, there is a horse trail that extends to the east approximately three-fourths of a mile.

Distance from downtown San Diego: About 30 miles (Lakeside). Allow 40 minutes driving time (Lakeside). Take I-8E and exit at Lake Jennings Park Rd. Go north on Lake Jennings Park Rd. 1.5 miles to El Monte Rd. and turn right (east). Drive 6 miles east to the park entrance. Pay a $3 fee for parking/picnicking in the county park or park for free in the equestrian staging area across El Monte Rd.

Hours open: 9:30 a.m. to sunset (Note: Call first, as the trail hours may start at 7:00 a.m. 619-443-1474. Closed Christmas day.)

Hiking length: Less than 2 miles out and back.

Difficulty: Moderately strenuous with over 400 feet of elevation gain/loss. No facilities. Leashed dogs allowed.