Chileno Canyon, Little Mermaids Canyon and Big Mermaids Canyon from the north, and then the much larger Bear Creek, which originates at Islip Saddle near the summit of Mount Islip. Less than a mile (1.6 km) below Bear Creek it is joined by the North Fork before flowing into San Gabriel Reservoir, where it joins with the East Fork. North Fork The North Fork is the shortest and steepest of the three major forks. It begins as a series of streams falling off the crest of the range between Mount Islip and Mount Hawkins, more than above sea level. Cedar Creek flows south from Windy Gap, , to join with Soldier Creek, which continues south past Falling Springs to join with Coldbrook Creek, forming the North Fork. The North Fork continues south for past Valley of the Moon Plantation, forming a braided channel along its relatively wide canyon floor. It flows into the West Fork just below Hoot Owl Flats, a short distance from the larger river's mouth at San Gabriel Reservoir. The North Fork is the most heavily developed fork of the San Gabriel River, with many campgrounds and facilities along its course. The popular Crystal Lake Recreation Area in the upper North Fork includes the only natural lake in the San Gabriel Mountains. The North Fork valley provides the route for Highway 39, which until 1978 provided automobile access from San Gabriel Canyon Road to the Angeles Crest Highway. Since then, the upper part of the road north of Crystal Lake has been closed due to chronic landslides and erosion. As of 2016, there are no plans to reopen the road. San Gabriel Canyon Below the confluence of the East Fork and West Fork, the San Gabriel River flows through the deep San Gabriel Canyon, the only major break in the southern part of the San Gabriel Mountains. Although this stretch of the river was once free-flowing, today is it impounded by major reservoirs for water supply and flood control. San Gabriel Dam, a high rockfill dam, forms the San Gabriel Reservoir. The concrete gravity Morris Dam, just downstream, creates the Morris Reservoir. A small hydroelectric plant in the city of Azusa is supplied with water from a diversion of the San Gabriel River, located directly below San Gabriel Dam. The reservoir water levels fluctuate widely at the upper San Gabriel Reservoir, which serves mainly for flood control