PHOENIX — Some states are using a technique called cloud seeding to produce more snow and rain. So, how about drought-stricken Arizona? It's not being done here yet, but it's something local agencies are researching.
The Salt River Project distributes water to about half of the Valley, getting its supply from the Verde and Salt Rivers. It recently entered into a partnership with the White Mountain Apache Tribe to research the feasibility of cloud seeding, a complicated technique discovered in the 1940s.
"Cloud drops can exist in a liquid state even below freezing - that type of water is called super-cooled liquid water. If you can inject extra ice nuclei in there, then you can promote the growth of snowflakes and increase the amount of snow that falls in winter storms," says Hydrologist James Walter, Salt River Project.
Hydrologist James Walter says SRP is focusing its nearly year and a half study on the White Mountains. He believes it could be the most favorable area for cloud seeding in Arizona and can bring big benefits to the state.
"A healthier forest, fewer catastrophic wildfires in the region, more ecological diversity, improved repairing areas," says Walter.
At the same time, the Central Arizona Project has been helping fund research on cloud seeding in other states for years. Those states also utilize the Colorado River for its water supply. In 2006, CAP entered into a multi-year pilot study of the Wind River Mountain Range, with the Wyoming Water Development Office.
"One of the most difficult parts of cloud seeding and cloud seeding research is to differentiate or distinguish when precipitation falls. How much of it fell naturally and how much of it fell due to cloud seeding?," says Nolie Templeton, PhD., Central Arizona Project.
The study yielded promising results, showing a 5 to 15% increase in precipitation. That has led to the current funding agreement between CAP and a few other lower basin agencies.
"Our partners in Colorado, Wyoming, and Utah, they are in the Upper Colorado River Basin where 90-percent of the Colorado River streamflow comes from. So, for us to be able to increase their snowpack, helps the Colorado River flow and that's what we care about," says Templeton.
CAP then distributes that water to around 6 million people in Maricopa, Pima and Pinal counties. It's also currently in its first-ever Tier 1 shortage: "resulting in a substantial cut to Arizona's share of the Colorado River." In this unprecedented time, we're told, anything helps.
"If there is anything we can do to augment the precipitation and the snowfall in the Colorado River Basin, we want to pursue that opportunity," says Templeton.