PHOENIX (3TV/CBS 5) -- A megadrought is defined as a period of years where our rainfall totals are consistently below average.
"This current megadrought began in the mid-1990s. So if you do the calculations, 25 years now," said Dr. Kevin Murphy, researcher of Hydro-climatology at Arizona State University.
Megadroughts can run 10 to 30 years. Dr. Kevin Murphy from ASU looked at tree ring records and found our current one.
"This has been the most severe megadrought over 1,000 years; that’s what we found by looking at the records," said Dr. Murphy.
A drought like this can put a significant stress on our water supply.
"The Salt River Project was formed in 1903. It was a direct result of the severe drought that occurred between 1898 and 1905," said Charlie Ester, Water Manager for SRP. That project has kept the water supply flowing into the Valley ever since.
"In this desert climate, with all the drought years that we've had, our supply has been reliable and resilient, and we are always looking towards the future," said Ester.
The Salt and Verde rivers rely on mother nature to keep them replenished, with 75 percent of the water coming from our winter storms. Currently, our reservoirs are at 90 percent capacity.
Dr. Murphy says we should not be too concerned about our megadrought based on what's happened in the past.
"Go back a little bit to 1973, that was a very wet year. That's when we were coming out of the 1950s megadrought. So coming out of a megadrought, you'd be surprised to the upside of a very wet year, resulting in some flooding," said Dr. Murphy.
The real question is, with climate change and a warmer atmosphere, is the next wet period going to be excessively wet and far wetter than we've seen before.
"That's a question we really don't know the answer to," said Ester.
Hoping the megadrought ends in the next five years, we'll get that answer. If it does bring dramatic flooding, SRP will be ready.
“We always have a plan in place. We can deal with both spectrums, conserving for a drought and preparing for a flood,” said Ester.