IMPERIAL VALLEY, a large section of country in the middle of Imperial County, Cal. The county is 84 miles long from east to west and 54 miles from north to south and has an area of 4,536 square miles or about 2,600,000 acres. Its southern boundary is the inter national line between Mexico and the United States; its eastern line is the Colorado River; on the north is Riverside County, while on the west the San Jacinto or Coast Range of moun tains separates it from San Diego County. The territory is below sea-level and some 300 feet below the level of the Colorado River to the east. In the northeastern part of the county is the Salton Sink or Sea, which has a water surface area of 247 square miles. The Imperial Valley section of this county is about 400,000 acres in extent, nearly one-sixth of the entire county area. It extends from the boundary line on the south 40 miles northward and has a width of about 30 miles. The climate of the section is one of great heat and dryness. Sum mer temperature is sometimes as high as 112° or 116°, but there is a very low humidity. The winter is mild, the temperature rarely falling below the freezing point. Precipitation is small and variable. The average annual rainfall at Imperial City for a period of five years was 4.45 inches.
The territory was part of what for genera tions had been known as the great Colorado Desert, an arid land with temperature rising as high as 125° to 140°, a barren waste where neither man nor beast could live. The silt which had been deposited by the river had made a good soil, although scientists were slow to recognize this. But when the subject of the irrigation of Western lands in the United States assumed prominence after about 1890, it was realized that this desert valley was a rich field for reclamation. Plans for irrigation were con sidered before 1900 and were tentatively entered upon at once. Within six years from the be ginning of irrigation there were 125,000 acres of productive farm land in the valley, 40,000 acres of alfalfa and 85,000 acres of' grain and other crops, 20,000 head of beef cattle, 4,000 milch cows and much other stock. The annual production of commodities for shipment reached the value of $2,000,000. The range of products is wide. The land is too valuable for grazing or grain crops but an extensive system of farming fruits and vegetables is the best paying. Cantaloupes, asparagus, alfalfa, grapes, oranges, onions, honey, hogs, poultry and dairy products are the main dependence of the farmers. Dates are also being cultivated. Cotton culture has been introduced and a great success has been attained in the growth of the valuable long staple cotton.
Imperial was the first town established, located near the centre of the valley. The county-seat is El Centro. Brawley, termed the
°Garden City,* is the distributing and shipping point for 80,000 acres of rich farming country. Holtville on the banks of the Alamo River, Calexico, on the southern border of the county, and Heber, situated half way between Calexico and El Centro: these three complete the sex tette of the valley towns, all which, except Heber, were incorporated towns of the sixth class in 1909.
The water that irrigates Imperial Valley is taken from the Colorado River at a point four miles north of the international boundary line near Yuma, Ariz. The headings there provide for the admission of water sufficient for more than two and a quarter million acres of land. The canal carries the water to the former chan nel of the Alamo River leading northward toward the Salton Sea and the first 60 miles, over a semi-circular course, are in Mexico. Just before leaving Mexican territory and entering Imperial Valley the canal divides into four main branches and these main canals are in turn divided and subdivided again and again until the net work of waterways covers the entire valley, there being in all over 1,000 canal miles.
In 1905 the floods of the Colorado River breaking through a canal cut which had been made on Mexican soil, just south of the bound ary line, widened and' deepened until the entire flow of the river was turned west down the steep slope of the hills into the valley and the Salton Sink, threatening the destruction of farms and other property.
The situation was serious and President Roosevelt took cognizance of it by action and by a subsequent message to Congress that raised what up to that time had been a matter of merely local interest and importance into a question of national concern. To aid in the efforts to close the break, the Southern Pacific Railroad, whose tracks were imperiled and whose traffic was seriously impeded, took charge of the situation. The break was closed in November 1906. A month later there was an other runaway of the river and the water broke through the newly constructed levees, again forcing itself into the basin of the Salton Sink.
In this emergency President Roosevelt with out waiting for congressional action arranged with the Southern Pacific Railroad to go on with the work of repairing the break and re storing the river to its proper channel in order to save the valley and the Laguna Dam which was then in process of construction by the government. This work was successfully done and in 1911 Congress reimbursed the railroad company for the expenses which it had in curred. This relief accomplished, measures were at once instituted for the permanent pro tection of the valley from the annual floods of the Colorado River and for the meeting of its irrigation needs.