The Golden State: Where & How to Live, Secure, Visit, Enjoy and Thrive in California

Sprinkler Irrigation

Definition Of Irrigation

Irrigation is the application of water to the land in lieu of rain fall. In some areas there is not sufficient rain fall to grow any crop, and in other areas, while there is adequate annual rain fall, the distribution is such that there is little or no rain fall during the period of crop maturity. Even in areas where there is enough rain fall, with proper seasonal distribution as a rule, every few years something happens to upset nature, and a crop is lost. It is therefore necessary to apply supplemental water in practically all areas, either during the entire growing season or during periods of limited rain fall.

Application Of Irrigation WATER

There are two general methods by which water is applied to the soil: surface irrigation and overhead irrigation.

Flood irrigation, border irrigation, corrugations and furrow irrigation are referred to as surface irrigation. The flood and border methods are the only ones that afford a uniform coverage of the applied water and since their use is limited to fairly level land they cannot be generally utilized. (The slope must not exceed 1 and 1/2% slope in the direction of irrigation and ½ of 1% cross slope.) These methods also require large quantities of water for each application, not less than 1 cfs or 450 gpm. On steeper slopes corrugations and furrows may be used, the length of runs varying with the slopes. When this method is used the distribution of water is not uniform and there is considerable water loss. As much as 50% of the water is lost on slopes of 5% and over. The greatest hazard of all types of surface irrigation is soil erosion which is slowly but surely taking the nation's top soil. All types of surface irrigation require extensive land leveling before water can be applied to the land, which not only increases the cost of the irrigation system but takes the fertile top soil from the high areas which require years of fertilizing to rebuild.

Sprinkler irrigation, when properly engineered and installed can be applied to all slopes with no water loss through run off and a minimum of soil erosion. Excessive leveling jobs are not required. Land level enough to permit normal farming is level enough for the installation of a sprinkler system.