Dry is the New Black

To set the stage for the Board of Directors’ conversations around water management, Director of Science and Interstate Matters Dave “DK” Kanzer, along with Senior Water Resources Engineer Don Meyer, provided an update on local, state, and basin wide hydrological conditions. Read the full report in the General Manager’s update by clicking here.

Monsoons Come Early

According to Kanzer’s report, with the seasonal peak for snowmelt runoff now behind us in the Upper Colorado River Basin, attention is shifting to potential monsoonal flow patterns.

“The good news to date is that there has been better atmospheric moisture streaming into the district and the Upper Colorado River Basin than originally forecasted and many reservoirs across the Colorado River District (and mostly across the state) are at, or near capacity,” said Kanzer.

Although this unexpected moisture has propped up streamflow throughout early summer, overall water availability and long term reservoir storage will not greatly improve. With a weakening El Nino and decreasing sea surface temperatures in the eastern Pacific, the North American Monsoon is expected to be weaker than average going forward, indicating drier conditions as we move into fall.

Kanzer explained that by mid-July, the “water supply season” is nearly over, with 80% of the year’s supply having already been accounted for. Short-term forecasts predict wet and warm conditions may help for a time, but natural streamflow is expected to decline sharply by the end of July.

Basin-wide Outlook

Across the Upper Basin, the total water supply is forecasted to be at around 80% of the 30-year average. This means that overall, net water supplies in Lakes Powell and Mead are projected to remain flat or decline by March 2025. This below average inflow forecast for Lakes Powell and Mead is a significant departure from the big flows of 2023 and over the next 12 months there is little chance of adding any net storage to the system.

“To the positive,” said Kanzer, “Soil moisture conditions are relatively average across most of the Upper Colorado River Basin, this should moderate water demands this summer.”

West Slope Water

Next, Don Meyer presented on reservoir operations and water supply within the Western Slope. Overall, with healthy reservoir storage rolling over from last year and a cool, precipitous June, the outlook is generally positive in the short term.

Of note, in mid-June, multiple water agencies including the Colorado River District, Denver Water, Grand County and the Bureau of Reclamation participated in Coordinated Reservoir Operations. During these operations, water was released from multiple storage buckets in the headwaters region to simulate seasonal hydrology surges in the 15-mile reach of the Colorado River near the town of Palisade. This high flow, mimicking the natural cycles of the river, aids in the spawning efforts of the four listed fish species, aiding in their recovery.

In the Yampa River basin, inflow to Elkhead Reservoir is forecasted to be 95% of average, and the 5,000 acre-foot Recovery Pool will be available for release this water year. Sustained high water flows in the Yampa River as measured at Deerlodge were a bright point in West Slope hydrology.

The Upper Gunnison Basin had one of the best snowpacks and seasonal runoff volumes in the Colorado River District area. The Peak SWE for the Gunnison River basin exceeded the long-term median value, above Blue Mesa reservoir.