SRP opens spill gates of Roosevelt Dam for extended annual test
May 13, 2023, 7:15 AM
(Photo courtesy Salt River Project.)
PHOENIX — Salt River Project conducted an annual spill gate test of Roosevelt Dam Wednesday, extending the time to more than 3 hours.
This annual test confirms operational readiness in the event of flooding and provides information on the dam’s ability to handle inflows from flood events.
After a wet and productive winter, Roosevelt Lake had the highest water levels in its history. Water had risen to its dedicated “flood control space” which is designed to slow down large floods. This was the third time this has happened since 1996 and after the dam had been raised by 77 feet.
During the test, all four spill gates were open for the first 50 minutes and then the two spill gates on the right side closed. The other two gates remained open for about 2.5 hours minutes, and in total, the test released about 2,000 acre-feet of water or about 650 million gallons of water downstream into Apache Lake.
This is compared to a typical release which consists of both gates being open for about 10 minutes and a release of about 5 acre-feet of water.
“This functional test, which is performed annually, is a sure-fire way to ensure the readiness of our water release capability,” Ivan Insua, SRP’s Director of Hydro Generation said.
“We will also be leveraging this season’s generous runoff by releasing some water in our Flood Control Space, which is above and beyond our normal conservation elevation, to perform an extended spill gate operation. This gives us very useful information on the gate and spillway performance.”
This past winter, snowpack on the 13,000-square-mile watershed that replenishes SRP’s reservoirs was the deepest it’s been in 30 years. More than 700,000 acre-feet of water or about 228 billion gallons have been released into the normally dry Salt River since March to ensure the reservoirs can handle all inflows from this winter’s snowmelt. Currently, the SRP reservoir system is at full capacity.
“Our dams and reservoirs are doing exactly their intent: to store as much water as possible in times of wet and serve our communities for times of dry,” Insua said.