San Francisco Chronicle - (Sunday)
NASA constructs platform to help water managers
DENVER — NASA has created an online platform with information on how much water evaporates into the atmosphere from plants, soils and other surfaces in the U.S. West, data it says could help water managers, farmers and state officials better manage resources in the parched region.
The platform, OpenET, uses satellite imagery from the Landsat program, a decadeslong project of NASA and the U.S. Geological Survey that records human and natural impacts on Earth’s surface.
Specifically, it provides data for 17 Western states — down to the quarter-acre — on how much evapotranspiration has taken place. That’s the process by which moisture in leaves, soil and other surfaces evaporates into the air.
The West has been mired in drought for more than two decades. Scientists say humancaused climate change has intensified conditions. Water levels at key reservoirs on the Colorado River have fallen to historic lows alongside growing demand, prompting the federal government to declare water cuts for some states next year.
A hot summer and years of huge wildfires have also zapped moisture from the ground.
Detailed information on soil moisture could help farmers and water managers better plan during dry conditions and reduce how much water is used for irrigation, scientists said.
“Farmers and water managers have not had consistent, timely data on one of the most important pieces of information
Houseboats float in a depleted Lake Oroville in Butte County in August. NASA’s tool provides data for 17 Western states — down to the quarter acre — on water loss due to evaporation.
for managing water, which is the amount of water that’s consumed by crops and other plants as they grow,” said Robyn Grimm, a water specialist with the Environmental Defense Fund, which helped NASA develop the tool alongside other environmental groups and Google.
“To date, that data has been expensive and fragmented,” said Grimm.
Many large farms in dry areas, such as California’s Central Valley, already have years of experience using advanced data systems to measure evapotranspiration and other water metrics that influence their growing and harvesting seasons and watering schedules. Cannon Michael runs an 11,000-acre farm in Merced County. Michael said he looked at NASA’s new platform, but
didn’t think it would provide any additional benefit for his farm. But Colorado rancher Joe Stanko, who grows hay for cattle, said the platform could help determine which fields need more water to replenish soil. It could also help decide when to harvest hay.