Background
The feasibility of irrigating the barren Imperial Valley with water from the Colorado River was recognized as early as the 1850s. It wasn't until 1901 that the California Development Company started diverting water to the Imperial Valley through a canal, called the Alamo, which had its heading in the United States but ran most of its course through Mexico.

In 1905, a winter flood caused the Colorado River to jump its banks and flow freely into the Imperial Valley creating the Salton Sea. The sea is still used as a drainage basin for irrigation and storm runoff in the Imperial, Coachella and Mexicali valleys.

The Imperial Irrigation District was formed in 1911 to acquire properties of the bankrupt California Development Company. By 1922, the district had also acquired the 13 mutual water companies that had developed and operated the distribution canals.Since

1942, the Imperial Valley has received its water through the All-American Canal, which runs its entire length in the United States. The 82-mile-long All-American Canal carries water from the Imperial Dam on the Colorado River west to agriculture and cities in the Imperial Valley.

Colorado River
The Colorado River is the lifeline of the Imperial Valley. Its course runs a 1,400-mile distance and its watershed covers 157 million acres of land. The river produces approximately 14 million acre-feet of water per year. One acre-foot is equal to 325,900 gallons - enough to sustain the water needs of a family of five for one year.

The river makes it possible to irrigate nearly 500,000 acres in the Imperial Valley, in addition to farmland in the Palo Verde and Coachella valleys in California and the Yuma Project in Arizona. Water from the river is also diverted to the Metropolitan Water District for use in Southern California urban areas and to other agriculture and urban interests along its course.

A naturally salty river, the Colorado carries salinity from saline springs and agriculture return flows along its way. Salinity is responsible for millions of dollars in damages to agriculture, municipal and industrial users in the lower basin states.

The Colorado is also an extremely silty river. Six desilting basins remove silt from the water at the Imperial Dam before it is diverted into the All-American Canal.

Soils
In the Imperial Valley, irrigated farmlands flourish on layers of soil deposited over centuries by the Colorado River. The soils are formed in two principle landscapes. One landscape is the lower Colorado River flood plain and the dry lake basin of old Lake Cahuilla. The other landscape is the nearly level to gently sloping plain of the Imperial East and West mesas, which lie above the beachline of the old lake.

There is no "top soil" in the usual sense. The valley is a large bowl filled with a conglomerate of elements transported by Colorado River flood waters. The soils are up to a full mile or more deep. Beneath the soil surface is a maze of passages of aquifers and aquicludes of clay barriers and sand lenses. In general, there is no gravel and sand water-bearing stratum. Stratum of any one type of soil does not extend over a large area, but occurs more as a lens or pocket.

Imperial Valley soil is naturally salty. As river floods left alluvial soils, they also left salt. Saline soils are often recognized by a white crust on the surface.

Water
The Colorado River is highly saline and carries about one ton of salt per acre-foot of water applied to fields, posing problems for growers. Imperial Valley farmers battle salinity by leaching salts through the root zone into subsurface tile drainage systems. This saline water is then carried through the district's drainage canals into the Salton Sea. Adequate drainage in the Imperial Valley makes the difference between barren land and highly productive soil. To date, there are 230 miles of main canals, 1,438 miles of canals and laterals of which 1,109 miles are concrete lined or pipelined, and 1,406 miles of drainage ditches in the Imperial Valley.

Weather
Imperial Valley enjoys a year-round climate characterized by a temperate fall, winter and spring and a harsh summer. Humidity often combines with the Imperial Valley's normal high temperatures to produce a moist, tropical atmosphere that frequently seems hotter than the thermometer suggests. The highest temperature on record, 121 degrees, was recorded on July 29, 1995. The lowest temperature ever recorded was 16 degrees on January 22, 1937.

The sun shines, on the average, more in the Imperial Valley than anywhere else in the United States. Even in December and January, the sun shines an average of more than eight hours a day.

The 88-year average rainfall for the Imperial Valley is 2.88 inches. June is the driest month of the year. Since 1914, there has been measurable rainfall three times during that month - 0.04 of an inch on June 2, 1948 and 0.01 of an inch on June 18, 1988, and June 7, 1997. The period from November through March is considered the "rainy" season. On the average there are 16 hours of rainfall during that period, a little more than three hours a month.

Cool winter nights occasionally produce overnight and morning frosts. The only recorded snowfall of consequence occurred in 1932. Up to four inches of snow was reported in the southeast portion of the Imperial Valley on December 13 of that year.

Allowing for year-round crops, the moderate desert climate is a factor in making the Imperial Valley's farmland among the most productive in the world.

Crops
The availability of Colorado River water and a considerate climate make the Imperial Valley one of the most productive agricultural regions in the world. The Imperial Valley has an agriculturally-based economy, producing over $1 billion in crops annually. Roughly one out of every three jobs is directly related to agriculture.

There are 1,061,637 total acres within district boundaries. Annually, 417,931 acres are used for field crops, 81,569 for vegetable crops and 22,347 for permanent crops.