Heavy Winter Snowpack Prompting Releases From Salt River Project Reservoirs

Heavy Winter Snowpack Prompting Releases From Salt River Project Reservoirs

March 9, 2023
SRP Measuring Snowpack at Sampling Site. Photo Courtesy of Salt River Project

Even before the parade of February snowstorms began marching through Arizona’s high country, meteorologists and hydrologists were beginning to see the handwriting on the canyon walls: 

The Southwest’s moisture-laden winter was going to force the Salt River Project to begin “spilling” water from its reservoir system in order to create storage space for the Spring runoff season.

SRP recently began a low-level release of water from its Verde River system. Initial releases began flowing over Granite Reef Dam – located about four miles below the confluence of the Salt and Verde rivers - at a rate of approximately 500 cubic feet per second (CFS), which increased to 1,000 CFS last weekend.  

The releases, which originate out of Bartlett Dam, are expected to continue through March.

“SRP monitors the watershed and reservoir system year-round to ensure a reliable supply for the Valley,” said Charlie Ester, Manager of SRP Water Management. “This winter has proven to be a productive year for the watershed, which is good news as SRP is able to store the water for future years.”

Because of the productive storms experienced this winter and the subsequent runoff, the SRP reservoirs on the Verde River are nearing full capacity. 

SNOTEL Map Showing Arizona Snow Water Equivalent as a % of Normal

SRP officials report that while the releases are expected to be maintained at a low level, the water will eventually be visible flowing through the normally dry Salt River. The flows are expected to close McKellips Road in the East Valley until later in the Spring.

This is the first water release since 2019. Water releases in winters with abundant precipitation and runoff are an essential tool to safely manage SRP’s water supply to the Valley and to ensure dam and public safety.

Strategically releasing water into the Valley of the Sun is a major part of SRP’s mission.

Throughout the year, SRP releases water from the dams on the Salt and Verde rivers into a series of canals to meet the water needs of the Valley. In particularly wet winters when the reservoirs are nearing capacity, some releases outside of the canal system are required to make room for additional expected runoff.

Map Showing SRP Watersheds and Service Area

Unlike the Colorado River System, which is facing severe shortages due to the drought and a structural deficit where annual demand exceeds annual runoff, the Salt and Verde reservoir systems are nearly in balance where annual demand is close to the annual supply. However, in wet years runoff can exceed the available capacity of the reservoir system.

Though identified as “excess capacity,” the water SRP is releasing is not lost water. It will flow downstream in the Salt River and recharge the aquifer, which helps Valley cities and water providers.

The 2022-2023 winter snowpack in Arizona, especially along the Verde River system, has been substantial.

Recent SRP surveys have determined that snowpack on the 13,000-square-mile watershed that replenishes the Verde River reservoirs is the second deepest it’s been in 30 years. SRP officials regularly check the snow levels in Arizona’s high country during the winter to develop seasonal runoff forecasts and provide valuable data for planning. 

SRP reports that it is working on increasing the storage capacity for the Verde River reservoir system over the next decade. A group of 23 partners - including tribal, agricultural, and municipal organizations - has committed to support the Bureau of Reclamation feasibility study of options to modify Bartlett Dam to improve management of water resources provided by the Verde River.

SRP provides water to about half of the Valley’s residents, delivering more than 244 billion gallons of water (750,000 acre-feet) each year, and manages a 13,000-square-mile watershed that includes an extensive system of reservoirs, wells, canals and irrigation laterals.