The Center for Land Use Interpretation Newsletter

Through the Grapevine Exhibit

CLUI photo
CLUI photo
Streams of transit through the Grapevine. CLUI photo

CALIFORNIA’S RIDGE ROUTE WAS THE subject of an exhibit at the Center’s Los Angeles space in the latter half of 2010. The exhibit, Through the Grapevine: Streams of Transit in Southern California’s Great Pass featured digital display panels describing different aspects of this landscape of transition. Also on view was a landscan of the region, a continuous shot of the landscape between the edge of Los Angeles’ sprawl and the beginning of the rural valley at the base of the Grapevine, shot by the CLUI and Ron Chapple of Aerial Filmworks from a helicopter with a gyrostabilized high definition camera.

The Grapevine, the mountainous passage that separates the population of Southern California from the rest of the state, is an extended zone of transition from one epic region to another. Located at the collision of the San Gabriel and Tehachapi Mountain ranges, the pass is the high altitude reach between Los Angeles and the abrupt agricultural flat of the San Joaquin Valley.

At the southern end of the road, the truck stop town of Castaic crossfades into sub-suburbanism, and is the northern margin of the populated Southland. At the northern end of the road is the true Grapevine, the 6.5 mile-long interstate highway grade from Fort Tejon to the bottom of Grapevine Canyon. Between those ends is an undulating erosional landscape that contains the channels of connective tissue binding the state, flowing through it like a braided stream.

Three successive roadways, representing three periods of modern transportation, snake through the ridge: the old Ridge Route from 1915, the Alternate Ridge Route of the 1930s (Highway 99), and today’s Interstate 5. Around these structures flow lines of water, petroleum, gas, and electricity that fuel the southern Megalopolis.

Swede’s Cut, on the 1915 ridge route, high in the mountains.
CLUI photo
Swede’s Cut, on the 1915 ridge route, high in the mountains. CLUI photo

The 1915 Ridge Route
The first Ridge Route opened in 1915, connecting Los Angeles and the Central Valley for the first time. Prior to its opening, traffic between the two had to divert either to the Coast Highway (now the 101), or eastward via today’s routes 58 and 14, through Mojave and Lancaster. The new (in 1915) direct route north/south followed the ridge line as much as possible, to stay above the washouts and landslides that occur with great frequency in the steep valleys below.

It took 12 hours to travel this route from Los Angeles to Bakersfield, and the speed limit was set at 15 mph, due to precipitous drops and nearly 700 curves, totaling around 100 full circles, to travel a distance of 43 miles. Much of the original Ridge Route remains in the hills, a ghost road high in the mountains, east of the Interstate, still, barely, physically passable. A ten-mile stretch is now gated by the Forest Service, barring legal passage.

The new asphalt next to the exposed old roadbed on the extinct portion of the Ridge Alternate/Highway 99, heading through Piru Canyon, towards the Pyramid Dam.
CLUI photo
The new asphalt next to the exposed old roadbed on the extinct portion of the Ridge Alternate/Highway 99, heading through Piru Canyon, towards the Pyramid Dam. CLUI photo

The Alternate Ridge Route
The road known first as the Ridge Alternate opened in 1933, after three years of construction. Though it was only ten miles shorter than the old Ridge Route, it was significantly straighter, wider, and faster. Its southern end, from Castaic to Gorman, took a whole new right of way, leaving the most mountainous section of the old Ridge Route a high and dry relic, to the east.

At the north end, from Gorman to Grapevine, its path followed some of the original Ridge Route alignment, the same area now dominated by Interstate 5. In 1936, the road through the Grapevine Canyon grade, the steepest and most dangerous part, was widened to a three lane road, with a passing “suicide lane” in the middle. After WWII the road was widened again, into a four lane highway, two up and two down, with a concrete divider in the middle.

By 1952 the Ridge Alternate was known as Federal Highway 99, and was among the most heavily used long-distance highways in the world. When the Interstate System was introduced, it became State Route 99, and awaited its eventual demise through the late 1960s, as Interstate 5 was being constructed.

Most of the alignment for Route 99, from Castaic to Grapevine, was absorbed by the new Interstate 5, which opened in 1970. One significant exception lies to the west of I-5 now, where a four-lane ghost highway plunges into Piru Canyon, and under Pyramid Lake.

Highway 99, now buried under Pyramid Lake and Pyramid dam.
CLUI photo
Highway 99, now buried under Pyramid Lake and Pyramid dam. CLUI photo
 Interstate 5, at the crest of the pass, 4,144 feet.
CLUI photo
Interstate 5, at the crest of the pass, 4,144 feet. CLUI photo

Interstate 5
The modern “Ridge Route” through the mountains dividing Central and Southern California is Interstate 5. This highway is the transportation artery for the whole of the West Coast, from the Mexican border to the Canadian border, through San Diego, LA, Sacramento, Portland and Seattle, a distance of 1,381 miles from end to end. It is part of 46,800 miles of Federal Interstate Highways, uniting the nation in a continuous high speed network of level asphalt.

Construction on the section of the highway between Castaic and Grapevine started in 1963, and was finished in 1970. The alignment of Highway 99 was used for most of one side of the new divided highway, with the exception of the part along Piru Creek, which was soon to be submerged by a portion of the California Aqueduct system.

The California Aqueduct approaching the pumps that lift it over the ridge.
CLUI photo
The California Aqueduct approaching the pumps that lift it over the ridge. CLUI photo

The Highway of Water
Conveyance through the Grapevine is by more than just road. Water comes over the ridge via the State Water Project’s aqueduct and tunnel system. Of the three long-range aqueduct systems feeding water to the cities of Southern California
the Colorado River Aqueduct, the Owens Valley’s Los Angeles Aqueduct, and the state’s California Aqueductthe state’s system, which comes through the Ridge Route area, is by far the largest, and longest.

Like the Interstate, the State Water Project was constructed primarily in the 1960s and early 1970s. The main long distance channel, the California Aqueduct, travels through the Central Valley from the Sacramento Delta, and enters into a series of pump stations at the base of the mountains. After a lift of around 2,500 feet, the water splits into two aqueducts, one heading southeast through the Antelope Valley to the Inland Empire, and the other southwest through the Ridge Route to Castaic Lake, where it enters the water distribution network of Los Angeles.

The State Water Project interacts with the surface transportation systems passing through the Ridge in a number of ways, affecting the alignment, destination, and existence of roadways. The channels and pipelines of the aqueduct add to the infrastructures of flow through this mountainous terrain.

Gas and petroleum pipelines riding over the ridge.
CLUI photo
Gas and petroleum pipelines riding over the ridge. CLUI photo

The Highway of Energy
The traversing of the Ridge Route opened up the vast resources of the Central Valley, Northern California, and beyond to the growing population of the Southland. Other conduits of conveyance established early on include pipelines and electric lines that meander under and over the ground, bringing energy to the cities to the south. In fact, it was the engineers plotting pipelines and power lines that made the first roads along the ridge that later were developed into the public road.

As early as 1906, before the Los Angeles Department of Water and Power tapped into the resources of the Owens Valley, Henry Huntington was stringing wires over the Tehachapi from hydroelectric plants on the Kern River, northeast of Bakersfield.

Petroleum from the rich fields of western Kern County, some of the most productive in the nation, started to flow through Grapevine pipelines in 1913, and continue to flow today. And gas, compressed to liquid form, connects through the Grapevine to the nation-wide network that extends northward to Canada. The southland is plugged into the continent through the corridors of the Ridge Route. 


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