Bridge collapse recalls earlier desert flood disasters

In the eons prior to the turn of the 20th century, the Whitewater and San Gorgonio rivers and their tributaries sent flood and storm waters rushing into the Coachella Valley, spreading tremendous volumes of water harmlessly across the desert floor.

These floodwaters flowed unimpeded as they made their way through washes and shallow depressions south toward the Salton Sink — a geographic trough roughly 234 feet below sea level.

Excessive rainfall wasn’t a problem until people began settling in the desert and developing its arid, sandy lands. The new residents faced the Herculean task of taming these wild waters that threatened to wipe out their homes and farmlands.

The July 19 collapse of the Tex Wash bridge on Interstate 10 near Desert Center is among many disastrous reminders over the past century of how susceptible the desert and its residents are to the ravages of floodwaters.

The natural starting point to illustrate desert flooding in modern history is the Salton Sea, created more than 100 years ago. Heavy rainfall in the Colorado River basin in 1905 caused the river to swell and eventually breach a man-made dike in the Imperial Valley.

It took nearly two years to control the river’s flow into the Salton Basin and stop the flooding. The result of the sudden influx of water and the lack of natural drainage from the basin resulted in the formation of California’s largest lake.

Prior to 1915, the people of the valley — although few in number but with investments in ranches and new developments in the area of Indio, Coachella and Thermal — realized a regional effort was needed to divert floodwaters into controllable channels and away from their homes.

By this time, two small agencies — Indio Levee District and Coachella Stormwater District — existed, but were inadequate to protect the growing desert communities.

In 1915, the Coachella Valley Stormwater District was organized and an initial board of three men was elected. Meeting Aug. 7, 1915, at the Thermal Cantaloupe Growers Union packinghouse in Thermal were J.H. Northrup, a west Indio area rancher and developer; J.W. Newman, of Thermal, manager of the growers union; and Charles McDonald, a Coachella merchant.

The new district had just begun plotting its diversion strategy when Mother Nature unleashed a series of torrential downpours on the unprotected desert floor.

On Jan. 17, 1916, record rainfall inundated the area. More than nine inches fell in two storms — the greatest concentration of rainfall in any one month recorded at the time. The mountain slopes had been saturated by December storms. The snow pack was heavy in the Santa Rosa, San Jacinto and San Bernardino mountains. The storm dropped 4.28 inches at Beaumont and 4.40 inches at Cabazon.

The storm moved west to east and, by noon, floodwaters reached Palm Springs. As it bore down on the valley, it picked up water from tributary canyons, flooding desert towns, farms and roads.

Another severe storm devastated the valley on July 26, 1936, The Desert Sun reported then.

“Exceedingly heavy rains did much damage to the Indio-Palm Springs highway, now under construction. A subdivision near La Quinta Hotel was badly washed out. Near Indian Wells, a dozen families were driven from their homes when a cloudburst struck on the mountain slopes.”

The raging Whitewater River in March 1938 flooded downtown Palm Springs, preventing visitors from leaving the city for almost a week. There were a number of fatalities throughout Riverside County and damages approached a staggering $2 million. To put that cost in perspective, the average cost of a five-room house in 1938 was $3,000.

Nearly all county bridges across the Santa Ana River were swept away, including the Pedley (Van Buren) Bridge, Riverside, and the Norco Bridge.

The bridge across Owl Wash, on U.S. Highways 60, 70 and 99 — between Banning and Cabazon — was washed out on March 3. This was a principal thoroughfare from Los Angeles to the desert at the time.

In September 1938, the Palm Springs City Council requested that the state highway department quickly replace the bridge and eliminate the “hazardous (sharp and difficult) detour in the interest of protecting the lives of Palm Springs visitors and residents.”

Six months after the flood, no work had been done to either repair or replace the bridge and city leaders were getting worried since tourist season would pick up soon.

A year later, “El Cordonazo,” or “The Lash of St. Francis” struck Southern California and caused the greatest September rainfall ever. The tropical storm lost hurricane status shortly before moving onshore at San Pedro. Seven inches of rain drenched Indio in just three hours.

Another storm dropped 6.45 inches of rain on Indio in six hours on Sept. 24, 1939.

The devastating floods of 1938 and 1939 made it “painfully clear” the county did not have adequate flood protection. For some reason — most likely preoccupation with World War II — county supervisors didn’t take action to create a flood control district until 1944.

Progress made

San Bernardino County, with the creation of its flood control district in 1939, provided a blueprint that served as a guide for its neighboring county.

On July 7, 1945, a bill approved by the California Legislature and signed into law by Gov. Earl Warren established the Riverside County Flood Control and Water Conservation District.

In the ensuing years, numerous levees and other water diversions were designed and built, including the Tachevah Dam in 1964, to control floodwaters originating from the steep, mountainous watershed above Palm Springs.

Built by the Corps of Engineers for $1.2 million, the dam was partially funded by the district and the state.

It was a challenge for the county to keep pace with unpredictable desert weather. A quick, unexpected downpour could cause flash flooding in a matter of minutes. All desert communities were at risk.

The floods of 1965 demonstrated the need for major flood control improvements throughout the district. Cottonwood Creek overflowed at I-10 east of the Highway 111 junction and all traffic was stopped for several hours. The lack of all-weather bridges and flooding of major roads resulted in the cities of Desert Hot Springs and Palm Springs being isolated for a period of time. Access to other communities in the Coachella Valley was severely impaired. Several lives were lost as a result of people trying to drive across streams. Cars were swept away, some with passengers trapped inside.

Highway 111 in Palm Springs was cut in two places disrupting traffic for several days. Indian Avenue was destroyed by floodwaters from the Whitewater River. The closing of Indian Avenue for 30 days added to the isolation of Palm Springs.

The January and February 1969 floods in Riverside County caused extensive damage when the Whitewater flood control channel broke through and over control levees to “an untold number of residences,” The Desert Sun reported on Jan. 27, 1969. “The Dream Homes area, along the eastern side of the Palm Springs Airport, was hardest hit when sections of the dike on the southern side gave way. The Crossley Tract, adjacent to the Municipal Golf Course (now Tahquitz Creek Golf Resort) also was hard hit.”

Estimate of damage to the Whitewater River Flood Control Channel, extending through Palm Springs and nearly 50 miles to the Salton Sea, was $2.5 million.

A bridge at Highway 111 south of Thermal was wrecked and it was estimated it would take about six months to construct a bypass roadway around the flood-damaged structure.

“In the meantime, traffic over the important approach road to the Salton Sea is being routed over a lower crossing of the storm channel,” The Desert Sun reported on March 25, 1969. “The Highway 111 bridge was constructed in 1938 after the disastrous floods of that year. It withstood the onslaughts of the Jan. 24 and Feb. 5, (1969) floods but caved in during the Feb. 24-25 flooding. Southern Pacific bridge which adjoins the road span was downed in the January flood.”

Another major tropical storm