Space-age technology helps growers manage water

It's no secret that water drives California agriculture.

For a variety of reasons – a growing urban population, more water allocations for endangered species, climate change, a smaller snowpack in the Sierra – the state's water supply is expected to shrink in coming years, forcing growers to use it even more efficiently. Faculty members from CSU Monterey Bay have teamed with engineers and scientists from NASA and other partners to help growers do just that. They are using remote sensing and modeling tools to estimate irrigation needs at the Constellation Vineyards (formerly the Mondavi vineyards) in the Napa Valley and at multiple sites throughout the San Joaquin Valley. After full-scale pilot project this year, the system will be ready for use with a range of crops in other areas of the state. The key is images taken by satellites circling the earth, passing over California regularly. The condition of crops revealed in the imagery can assist farmers in determining when and how much to irrigate.

"Certainly many growers in California are highly efficient with water use already," said Forrest Melton, a senior research scientist at CSU Monterey Bay, who is working with NASA Ames on the irrigation project.

"By providing information on current crop conditions, we hope to support farmers in continuing to get the most value out of the water available."

Melton said that many farmers currently receive updates from the California Irrigation Management Information System (CIMIS), operated by the state Department of Water Resources. CIMIS provides weather information and valuable daily estimates of baseline or "reference" evaporation and transpiration, which can be used to determine when and how much water crops need.

But translating the information from CIMIS for use in schedulinig irrigation can require additional calculations and the use of look-up tables, according to Melton, which don't fully account for year-to-year variations in growing conditions. NASA's satellites will be able to provide this information, along with forecasts of precipitation and soil moisture calculated from models running on CSUMB, NASA and National Oceanic and Atmospheric Administration (NOAA) computers.

Growers can access that information on their laptops or cell phones. Tapping into information from the NASA satellites and computer models – which will take into account irrigation information, weather data, crop types and soil conditions – will give growers strategic guidance regarding water use. Dr. Lars Pierce of CSUMB says the primary contribution of the researchers has been to bring together several sources of information and technologies that growers use to estimate their water needs, automating the process of mapping those needs. That makes it easier to interpret and use the information.

Partners in the project include CSUMB, NASA's Ames Research Center in Mountain View, the Jet Propulsion Laboratory in Pasadena, NASA's Marshall Space Flight Center in Huntsville, Ala., the U.S. Department of Agriculture, the Western Growers Association, and the California Department of Water Resources.

Listen to a National Public Radio story about the project.