Historic US 99 Guide

Imperial Valley

Whitewater River bridge near Palm Springs This bridge also carried US 60 and US 70 and was in operation from 1925 to 1952 when it was replaced by the freeway. Mt San Jacinto is in the background.

The Imperial Valley and the Salton Sea

The Imperial Valley is rich with history. It gets its name from promoters from around the turn of the century, who used the word "imperial" to give the valley an exotic feel for potential farmers. At the time, the valley was little more than a blistering section of the Colorado Desert, but the promoters knew that it could bloom if water could be brought to it. The reason for this is that the Colorado River dumped sediment on the valley floor over millions of years.

At one time, the valley was part of the Gulf of California and the Colorado drained into it at a point roughly a little south of the confluence with the Gila River. When the river started carving the Grand Canyon several million years ago, it carried the sediment away to its delta. Over time sediment accumulated which effectively created a dam that separated the Imperial Valley from the rest of the gulf. The water eventually evaporated, leaving a barren desert. However, the Colorado River being a fickle entity would shift course and alternately drain in the ocean or in the valley. When it drained in the valley it created a lake called Lake Cahuilla, which at times filled the whole valley. Today it is possible to see the ancient shoreline of this lake.

Contrary to popular belief, the existing Salton Sea is not a remnant of Lake Cahuilla, but the result of a man made disaster that occurred during 1905-06. A sand dike which was part of a diversion for an irrigation canal collapsed and as a result, the Colorado River went along a new course carving out what is now called the New River. This flooding lasted for over a year, until, by a heroic effort, the Southern Pacific Railroad was able to seal the rupture. In the aftermath of this disaster several farms and a lot of railroad as well as a salt works factory were left submerged. The Salton Sea would have evaporated long ago except that runoff from farms and from neighboring Palm Springs and Indio to the north constantly replenish the evaporated water. This has made the Salton Sea a foul smelling cesspool since all the toxic chemicals and other undesirable substances remain while the water evaporates.

US 99 began its northward trek at the International Border near Calexico in Imperial County and goes through the fertile farm land of the Imperial Valley. The current border crossing was put in during the 1970s and is located to the west of the original terminus which was at Heffernan Ave. US 99 followed that north to 3rd St, then cut over to Imperial Ave, which is current SR-111. From the intersection of 3rd and Imperial Ave, US 99 went north along SR-111 through the town of Calexico. Just to the north of the border, the road goes below sea level where it remains until Indio.

The bridge over the All-American Canal was built in 1938 and stands today. The All-American Canal gets its name from the fact that it does not cross the border; it stays entirely within the United States. This is very significant since it was a tremendous engineering feat to keep this canal within the United States and that problems with international water rights are avoided by not having it go through Mexico as had previous canals. The four lane expressway just to the north was not a part of US 99, as it had been built in 1965; previously the road was a standard two lane highway. In fact, about 1/2 mile north of the All American Canal, there is an old US 99 bridge that is now a part of the western frontage road which crosses an irrigation ditch.

SR-111 intersects SR-86 about five miles north of the International Border. From this point to Indio, US 99 was replaced by SR-86 in 1964. This intersection also marked the southern terminus of SR-111 until it replaced US 99, also in 1964. US 99 continues west on SR-86, a two lane road, through the town of Heber where there remains evidence of concrete under the asphalt lanes. Heber was named after a turn of the century promoter of the Imperial Valley. Outside of Heber, the road make a fairly sharp turn, changing direction to the north. This curve shows the signs of a 1930s era US highway with an embanked and (at the time) gentle turn. The junction with I-8 is six miles beyond SR-111. This section of I-8 was completed in 1967 and bypassed El Centro and old US 80, which was located to the north. After another 1 1/2 miles, SR-86 intersects County S80, old US 80. From this point, US 99 and US 80 were co-signed for about a mile and split just beyond the point where the road angles to the west. This four lane section is very well preserved with the original concrete and old style center diving curb still in use. Many old buildings and even street lights remain making this section look like it did back when it was US 99. At the intersection with Imperial Ave (SR-86, north) go right and continue straight. While the current SR-86 expressway was built in 1981, it still contains the original alignment of US 99 which ran under the southbound lanes.

US 99 entered the town of Brawley along the present alignment of SR-86. Soon after the left turn on to Main Street (now SR-78), SR-86 again becomes an expressway. The old alignment of US 99 has been covered up by this expressway. However, the expressway follows almost the exact alignment of US 99. The old road was reworked between 1979 and 1981 in preparation for the conversion to expressway status. This expressway is sorely needed, as SR-86, like US 99 before it, is the major farm to market route out of the Imperial Valley. Almost 50 per cent of the traffic along SR-86 is made of trucks, or weekend recreational vehicles which is considerably more than other highways. This makes a two lane road a hazard and many accidents and fatalities have occurred as a result. This problem has existed since the 1930s, and as an acknowledgment, this section was submitted for Interstate Highway status in 1947. Unfortunately, the submission was turned down; consequently the widening of this highway was delayed for many years. Caltrans estimates this expressway will be completed by 2000.

The drive north of the Salton Sea is fairly uneventful, mostly due to the fact that the scenery does not vary much and that all traces of the old road, even bridges, have been eliminated in favor of the expressway. However, it is along this stretch that traces of the old shoreline are visible on the mountains to the left. The expressway currently ends at the north end of the Salton Sea, right before the intersection with SR-195. The completed expressway will continue north, parallel to the alignment of SR-195 and join up with the SR-111 expressway. This is good news for the old road, as SR-86 gets interesting between this point and Indio.

Continuing to the north, SR-86 follows the exact route of US 99. In a couple of places, remnants of the old concrete road are visible to the right as frontage roads for fields. After a few miles of driving through date palms, SR-86 intersects Dillon Rd. While this looks like a rather unassuming interchange, it was, until 1964 the intersection of US 60/70 with US 99. The three routes are co-routed from this point until Los Angeles, save for US 60 splitting from the other two between Beaumont and Los Angeles. While this interchange has been modified, it still shows how the original configuration worked. Dillon Rd. comes in at an angle, heading toward the northwest and actually merged with present SR-86. It is still important today as it is the primary connection to I-10 south of Indio. The next segment of of this tour covers the city of Indio and continues through the Coachella Valley and San Gorgonio pass to the intersection with US 60 in Beaumont.

Top of Page

North: Indio and the Coachella Valley

Go to the Historic California US Highways Main Page