Standing apart from nearby peaks, Viejas Mountain can be seen from many parts of metropolitan San Diego as a dusky, obtusely triangular feature along the eastern horizon. A faint, partially overgrown trail Fed by countless ravines and rivulets on the slopes of the Cuyamaca Mountains, the Sweetwater River eventually becomes a watercourse worthy of the name "river" -- at least in the rain or snow season. Below Green Valley Falls, the sweet, bubbling liquid slides placidly down a pleasant little gorge lined by alders, willows, and live oaks. The Merigan Fire Road -- a wide, oak-shaded path for hikers, horses, and mountain bikers -- clings to the high bank of the river for a mile, offering the self-propelled traveler vistas of ice-cold, sparkling water tumbling over a gravelly canyon floor.
At about 3500 feet in elevation, the fire road was actually an excellent cross-country ski route for a brief period last month, when snow blanketed East County down to as low as 1700 feet. The snow's surely gone now, but muddy ground remains. Wait at least two weeks if you want drier, warmer weather, and the onset of botanical spring. By April, the chaparral-covered hills above the path will have turned emerald green, speckled with the lavendar blossoms of ceanothus (wild lilac). At least a dozen species of showy wildflowers should soon pop up along the trailside, including Indian paintbrush, which sports clusters of bright, red petals.
The Merigan Fire Road starts at a small parking lot next to a ranger residence on Viejas Boulevard, 0.6 mile east of the main crossroads in Descanso, or 1.1 miles west of Highway 79. You cross an open meadow, climb onto a chaparral-covered slope, and descend a little to enter a strip of live-oak woodland high on the river bank. Don't miss a spur trail on the left, leading to a silted-in diversion dam that has become an artificial waterfall.
At 1.9 miles in, the fire road (denoted by double-dashed lines on the map) turns east toward Highway 79, while other trails continue north toward Green Valley Falls and Green Valley Campground. Hikers and equestrians may continue on the trails, but mountain bikers must stay on the fire road and not use the narrow trails.