The Crystal Ball is Cloudy
A standing item of the General Manager’s Report for River District board memos, the hydrology update sets the stage for board discussion and decisions each quarter. On Tuesday, October 17, Dave “DK” Kanzer, Director of Science and Interstate Matters, and Don Meyer, Senior Water Resources Engineer, provided updated context for both inter- and intra-state considerations.
“High degree of uncertainty,” Kanzer began. “I just want to repeat that. High degree of uncertainty.”
After a surprisingly wet 2023 Water Year (ending September 30), and with relatively good water supplies across the Colorado River District, Kanzer explained that attention now turns to planning for the significant uncertainties of Water Year 2024.
While conditions remain good with average soil moisture conditions and healthy carryover storage projected for most local reservoirs, the early weeks in October were quite a bit drier than average, and much of the state, especially in the southwest corner, has returned to drought conditions.
Long-term water supply forecasters are encouraged by the projected return of a strong El Niño in 2024, due to significant warming of sea surface temperatures in the eastern Pacific. This generally comes with increased precipitation in the southwestern United States. To date, however, forecast models show only equal chances of wet/average/dry conditions through January. Chances increase after that, however, but only slightly for above average moisture in late winter/early spring.
“The crystal ball is very cloudy,” Kanzer emphasized during his report to directors. “Signals for El Niño are very strong, although this pattern does not often favor the northern part of the basin. Early water year forecasts 98% of average unregulated inflow into Lake Powell. This will determine a Lake Powell release of 7.48 MAF”
Kanzer went on to say that the Lower Basin is moving from a Tier 2a shortage condition to a Tier 1 shortage condition in 2024 – an improvement for Lower Basin states based on the 24-month study provided by the Bureau of Reclamation in August. He also noted that due to healthy levels of precipitation in the Lower Basin, Water Year 2023 recorded the lowest releases from Lake Mead in the modern era.
Don Meyer then zoomed in on West Slope storage and river conditions. “Western Colorado looks forward to some healthy carry-over storage.” He also discussed several major projects which may impact streamflow along the Colorado River mainstem this year.
“They [Northern Water] are nearing completion on the Windy Gap bypass channel,” said Meyer. “And it has put together nearly a mile of stream that didn’t exist previously. Along with that, the work being done on the Gross Reservoir expansion has allowed more water to be bypassed, while the storage there was reduced to allow for construction.”
General Manager Andy Mueller closed the hydrology and water supply conversation by emphasizing that despite the abundance of moisture this year, long-term predictions need to recognize that we are still operating within an ongoing drought.
“In the ten years prior to 2023, we were averaging a 12.5 million acre-foot river,” said Mueller. “And in the five years prior to 2023, we were averaging a 11.5 million acre-foot river. There are reasonable predictions that climate change could drive us down to 9.5 million acre-foot river.”
Acknowledging the first step in addressing these difficult conditions, he concluded, is to “fix the leak” of Lower Basin overuse.