An active monsoon season drove record amounts of runoff throughout the Salt River Project's watershed in Arizona, but California and most of the West remain in drought conditions despite some recent rain.
Roughly 250,000 acre-feet of water inflow was recorded into the Salt and Verde rivers' reservoirs managed by SRP, the public utility said in a Sept. 15 news release.
"This productive summer comes after a very dry winter, which brought in only about 103,000 acre feet of water—the second driest on record," SRP said. The monsoon season was the wettest on record, in terms of rainfall, for July through August since the 1950s, and was 0.02 inches short of the record for the period.
"We know we have great climate variability in the Southwest," Charlie Ester, manager of SRP watershed management, said in the release. "The past two seasons demonstrate that by producing the second driest winter season ever followed by the second wettest summer season ever."
SRP said its hydrologists "are happier with a productive winter as the watershed relies on winter rain and snow for the majority of the system's water supply." But the runoff from the past winter was the second-driest in records stretching back 109 years.
Although SRP's system is in roughly the same geographic region, it is not connected to the Colorado River system and will not be affected by the 2022 Tier 1 shortage conditions.
"Even though we've seen an increase in inflow into our system due to the monsoon rains, we were still at the highest demand of the year," Ester said. "While we are receiving inflow, we have also been releasing water primarily from the Salt reservoirs (including Roosevelt) to meet water demand within SRP's service territory."
Water is stored in seven lakes in the SRP system and delivered through a series of canals to Salt River Valley cities. It is treated and provided to roughly 2 million people living in the valley. The system provides nearly half of the valley's water supply. Its water portfolio includes surface and groundwater as well as water stored underground. SRP also operates C.C. Cragin Dam, which collects East Clear Creek runoff that can be pumped into the East Verde River.
Salt River Project storage was at 74 percent of capacity as of Sept. 16, with roughly 1.48 million acre-feet of water stored in the system, according to SRP's daily report.
Elsewhere in the West, some rainfall across Northern California and interior portions of the Pacific Northwest was welcome; however, most of the region "had no change in the drought depiction." There were some slight improvements in drought levels and level degradation in the Northwest, "mostly due to assessment of earlier precipitation events, water-supply reports, and vegetation health," the U.S. Drought Monitor said. In most cases, any benefits were "largely offset by above-normal temperatures."
The Drought Monitor noted that record-setting rainfall occurred Sept. 10 throughout the West. This includes Ephrata, Wash., which recorded 0.63 inch; 0.61 inch in Redmond, Ore.; and 0.26 inch in Red Bluff, Calif.
The latest assessments of regional topsoil moisture by the U.S. Department of Agriculture find that the percentage of topsoil rated short to very short of moisture in Washington state remains at 100 percent as of Sept. 12, while Montana is at 96 percent; California, 85 percent; Oregon, 83 percent; Wyoming, 79 percent; and Idaho, 73 percent.
Roughly half of the rangeland and pastures in the region were rated as in very poor to poor condition in eight of the 11 Western states. Conditions were the worst in Washington, Montana and Oregon, according to USDA.
Low water storage levels at major reservoirs continue to be closely monitored. Lake Powell remains at 31 percent of capacity, according to the U.S. Bureau of Reclamation's Sept. 13 report.
The full Lower Colorado River system is at 39 percent of capacity, with 23,383 thousand acre-feet of water.
Of the reservoirs that BuRec operates in the Western U.S., six had the lowest observed storage levels in the past 30 years of data collection as of either Sept. 13 or 14, including Lake Mead-Hoover Dam; Lake Powell-Glen Canyon Dam; Shasta Lake-Shasta Dam; and Blue Mesa Dam and Reservoir in Colorado. New to the list are Franklin Roosevelt Lake-Grand Coulee Dam in Washington state and Guernsey Dam and Reservoir in Wyoming.
The Guernsey impoundment reports having no water in storage. Reclamation did not respond by press time to requests for more information, including how water levels were affecting operations at the 6.4 MW Guernsey Power Plant.
Lake Oroville is at an elevation of 628.95 feet as of Sept. 16, with 789,348 acre-feet of water in storage, which is 22 percent of capacity and 35 percent of average.
Reservoirs in California had 60 percent of their average normal amounts by the end of August. The Drought Monitor said the 154 reservoirs held 13.8 million acre-feet of water. Elsewhere in the West, preliminary reports summing up August conditions showed statewide reservoir holdings were less than one-half of the end-of-August average in Nevada, New Mexico and Oregon.
The Drought Monitor also summarized the state of wildfire conditions. Many fires are active across Northern California and the Northwest. Nationwide, for 2021 through mid-September, wildfires have burned more than 5.6 million acres.
"Even as Western wildfire activity has slightly waned in recent days, broad reductions in air quality have continued in parts of the region," the Drought Monitor said. "Four of California's active wildfires—the Dixie (more than 960,000 acres), Caldor (219,000 acres), Monument Fires (215,000 acres), along with the River Complex (187,000 acres)—were among the twenty largest blazes in state history."
The Dixie Fire "has made several impressive runs while threatening to become the largest wildfire in California history," the agency said. "That blaze has also destroyed more than 1,300 structures."
The Drought Monitor noted that the Caldor Fire, located south of Grizzly Flats, "has destroyed more than 1,000 structures—only the seventeenth wildfire in state history to do so."
Roughly 59.2 million people in the Western U.S. now live in drought conditions, according to the Drought Monitor.