Arizona Storms Fill Verde Reservoirs, Prompt Major Releases

The storms that drenched Arizona over Halloween weekend brought flooding, evacuations and damage, but also delivered welcome water to the Valley’s reservoirs, said Salt River Project senior hydrologist Jacob Richardson. He said recurring rain over recent months has been beneficial for supplies in a drought-prone region.

SRP manages reservoirs on the Verde and Salt river systems. The smaller Verde system, including Horseshoe and Bartlett reservoirs, filled during the storms, requiring releases. The Salt system also received substantial water, but its larger storage capacity meant releases from Roosevelt Lake and other reservoirs were not needed.

Bartlett Dam releases peaked at about 60,000 cubic feet per second before falling to roughly 33,000, Richardson said. He expected flows to keep declining as upstream waters receded, while the Salt River could continue flowing for days or weeks. Releases of this scale from Bartlett are uncommon; Richardson said the last comparable event he knew of was in 1993.

Some released water may seep through riverbeds into aquifers, but Richardson said most travels downstream. The Salt joins the Gila River west of the Valley, and SRP cannot reclaim the water once it passes Granite Reef. Downstream water-rights holders may access it.