Tag Archives: water resource operations


2013 Runoff Best in Last Three Years

While the early forecast of an El Nino season never materialized, the 2013 runoff season nevertheless produced just enough snowmelt to refill the reservoirs to near the previous year’s level on the Salt and Verde rivers going into the heaviest-use period of the calendar year.

And, after two of the driest La Nina winters on record, water managers at Salt River Project aren’t complaining with the 444,788 acre-feet of stream flow accumulated in the first five months of 2013, the January-through-May period that amounts to the year’s runoff season.

“We’re thrilled that the runoff we got this year put us back to where we were a year ago,” said Charlie Ester, SRP’s manager of Water Resource Operations. “That may not sound like a lot, compared to years such as 2010 when we filled our reservoirs, but essentially we have regained all of the water that we used the previous year.”

Thanks to another boost from a better-than-average monsoon season, the reservoirs on the Salt and Verde rivers today stand at 55 percent full with 1.28 million acre-feet stored – exactly the same percentage as one year ago following the 23rd and 16th driest runoff seasons among the 115-year-old records kept by SRP.

Theodore Roosevelt Lake, which holds about two-thirds of the combined water stored on the Salt and Verde rivers, today stands at 45 percent full. Current storage on the Salt River system is 54 percent; the two reservoirs on the Verde River are a combined 62 percent of capacity.

This year’s runoff season, while still below the 30-year median runoff of 534,336 acre-feet, was the most productive since 1,418,960 acre-feet of water was accumulated during the 2010 runoff season — the 20th most productive year on record. The snowmelt runoff in 2012 amounted to only about 196,064 acre-feet, which followed the 2011 runoff total of 222,907 acre-feet.

SRP is the largest raw water supplier in the Phoenix metropolitan area, normally delivering about 1 million acre-feet annually.

runoff season

2012 Runoff Season Was 16th Driest

If the 2012 runoff season seemed a lot like the previous year, it’s because it was. In fact, thanks to a rare second consecutive La Niña winter, the January-through-May 2012 period provided very similar runoff season totals.

This year’s snowmelt runoff from the Salt and Verde watershed amounted to only about 193,474 acre-feet, which puts the 2012 runoff season as the 16th driest among 114-year-old records kept by Salt River Project water managers. The runoff from 2011 was 223,916 acre-feet, the 22nd driest on record, and less than half of the 30-year median runoff of 534,336 acre-feet.

Typical of La Niña winters, the storm track is located over the Pacific Northwest with dry, calm conditions over the Southwestern US. The winter of 2012 followed this pattern with the Salt and Verde watershed receiving only 4.75 inches of precipitation between December and March — 62 percent of normal. Even drier was the January-though-March stretch, which was the 11th driest on record.

The good news is that even after back-to-back dry winters, the reservoirs on the Salt and Verde rivers today stand at about 61 percent full with 1.4 million acre-feet stored entering the heaviest-use period of the year. At this time in 2011, the reservoirs were 83 percent full thanks to a 2010 runoff season that was the 20th most productive ever.

Charlie Ester, SRP’s manager of Water Resource Operations, said SRP shareholders can count on full water allocations this year despite the second consecutive dry winter. The likelihood of a normal 2013 runoff season, maybe even one boosted by the hint of the potential for an El Niño condition forming in the Pacific Ocean, would be most appreciated, he said.

“As the final numbers show, 2012 and 2011 were very similar in that runoff was almost non-existent for days at a time,” said Ester. “The only real difference between the two years was that we had more runoff on the Salt than the Verde this year. We received very little runoff from the snowpack this year, simply because most of it came in December and then over a two-day period in later March.”

With all of Arizona — including the Salt and Verde watershed that supplies the greater Phoenix metropolitan area with the majority of its water — in some type of drought condition, Ester said the Salt and Verde reservoirs are still in good shape and are doing exactly what they were designed for: capturing runoff in wet years such as 2010 and storing it for the dry years such as 2011 and 2012.

SRP continues to emphasize the importance of water conservation, Ester said, and he encouraged Valley residents to watch SRP’s Together We Conserve website at www.TogetherWeConserve.com for updates and for easy way to conserve water.

SRP is the largest raw water supplier in the Phoenix metropolitan area, normally delivering more than 1 million acre-feet annually.

For more information on Arizona’s runoff season, visit SRP’s Together We Conserve website at TogetherWeConserve.com.