Program Overview

In 1982, the Department began a program that came to be known as CIMIS (for California Irrigation Management Information System) to assist the agricultural community improve the efficiency of its irrigation operations.

CIMIS is a network of weather stations throughout the State that collect weather data and relay those data to a central computer in Sacramento. The data are then entered into an equation that is used to calculate the daily or hourly reference evapotranspiration for tall fescue grass for each station. Evapotranspiration is the amount of water lost from the soil surface (evaporation) plus the amount of water used by plants (transpiration). The rate of this reference evapotranspiration can be multiplied with the appropriate crop coefficient to provide an estimate of the amount of water that the crop used during that day. Thus, the grower can irrigate with only the amount of water needed to replenish the water used by the crop.

Although the CIMIS program was originally intended for use in agriculture, the program is now being incorporated into landscape irrigation management activities for the urban community. It has therefore become a major part of the conservation effort in Southern California, which has both large urban centers and important agricultural areas. Here one can see how the CIMIS program has evolved from an agricultural tool used only by growers to an instrument used by urban dwellers to manage the quantities of water applied to large expanses of turfgrass and landscape.

On November 6, 1982, the first CIMIS station in the Southern District was installed in Imperial County. There are now 48 active stations in the District, of which about half are in large urban areas.

Southern District's Activities

The Southern District is responsible for overseeing the CIMIS program in the District. Its staff is committed to work with local agencies in providing assistance in their efforts to use water efficiently.

Recent installations of new stations include:

• Stations 183 and 189 have been installed on the shoreline of Owens Lake in Inyo County. The data will assist the Los Angeles Department of Water and Power with its Owens Lake Project.

• Station 197 is in operation near the City of Palmdale in Los Angeles County. The data will help farmers and landscape managers in the Antelope Valley with their irrigation management operations.

Other developments:

• Station 101 near the community of Piru in Ventura County was destroyed by flood waters of the Santa Clara River earlier this year. The United Water Conservation District has not said if it will replace the station.

• A new station will soon be in operation near the City of Santa Paula in Ventura County.

• Once telecommunications issues are resolved, the station near the community of Lake Arrowhead in the San Bernardino Mountains of San Bernardino County will be in operation.

The District also works with local water agencies and other organizations in conducting irrigation management workshops. At these workshops, the CIMIS network of stations is explained to local growers, and they are shown how the data from the stations can assist them in developng or refining irrigation schedules for their crops.

For further information, contact:

David Inouye
E-mail: davidi@water.ca.gov
Phone: 818 500-1645 x246

or

Sergio Fierro
E-mail: sergiof@water.ca.gov
Phone: 818 500-1645 x247

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The URL is http://wwwdpla.water.ca.gov/sd/
Last modified: August 2, 2005
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