Interior official concerned by threat of falling water levels to #LakePowell operations — The #GrandJunction Daily Sentinel #ColoradoRiver #COriver #aridification #DCP

From The Grand Junction Daily Sentinel (Dennis Webb):

An Interior Department official speaking Friday at a local forum voiced concern about continuing falling Lake Powell water levels that now pose the possibility of threatening hydroelectric power production at Glen Canyon Dam as early as next year.

Tanya Trujillo, Interior assistant secretary for water and science, addressed the topic during the Colorado River District’s annual water seminar, which was held at Colorado Mesa University and also in a virtual format. Some of the events involved simulcast presentations with the Getches-Wilkinson Center at the Natural Resources, Energy, and the Environment at the University of Colorado Law School, which also was holding its own water conference this week.

Trujillo noted that last week, the Bureau of Reclamation indicated the potential of water levels at Lake Powell falling below the minimum power pool level of 3,490 feet above sea level as early as next July if the current streak of extremely dry hydrology continues into next year.

Beyond next year, Reclamation says there’s a 25-35% chance of Powell falling below that level over the next few years. Trujillo also noted that there is about a 90% chance that Powell’s water level over the next year will fall below the 3,525-foot elevation established to provide a protective buffer above the minimum power pool amount needed to produce electricity.

Trujillo called that prediction “very concerning” and said she’s particularly nervous about concerns related to the operational integrity at the dam due to low water levels.

“The engineers use words like cavitation and that gets my attention,” she said.

Cavitation can occur when oxygen mixes with water as levels drop, posing a threat of damage to power turbines. Lost power production also would result in lost revenue that pays for programs like salinity control and endangered-fish recovery in the Colorado River Basin. Also, if water could be released only through the dam’s bypass tubes and not through the power plant, that could threaten the ability of water to be delivered to downstream states at volumes required by a 1922 [Colorado River Compact].

Under provisions of a 2019 agreement, the Bureau of Reclamation began releasing water from Flaming Gorge, Blue Mesa and Navajo reservoirs with the goal of providing up to 181,000 acre-feet of water to Powell by the end of this year. Trujillo said she’s happy that talks continue among Colorado and other states in the Upper Colorado River Basin regarding additional drought-response measures…

Below-average precipitation last winter was aggravated this year by factors such as warmer temperatures and dry soil conditions that resulted in even worse runoff levels. Gigi Richard, director of the Four Corners Water Center and an instructor at Fort Lewis College, said at Friday’s forum that the region is starting to experience novel forms of drought, such as ones where, due to higher temperatures, drought conditions prevail after a normal amount of seasonal snowpack accumulation.

Thankfully, she said, monsoonal moisture this summer relieved drought conditions in the region somewhat.

A La Niña climatological pattern that is setting up for this winter could result in storms tracking further north, which Richard said might mean less precipitation in Colorado, but she said individual storms still can result in a significant amount of moisture in a given year.

Brad Udall, senior water and climate research scientist/scholar at Colorado State University, said reductions in annual precipitation in the months of March and April are aggravating the increased aridification occurring in the region, setting up a process of further drying out land in the summer when there are higher temperatures and reduced precipitation.

He’s also concerned by what he sees as a general trend of more aggravated declines in average streamflows in more southern river basins in the region during this century when compared to the period of 1906-1999. Flows in the San Juan River at Bluff, Utah, have fallen 30%, and flows of the Dolores River near Cisco, Utah, have fallen 21%.

Flows for the mainstem of the Colorado River are down around 5%, he said…

Trujillo said the federal government will be advocating for water conservation in all sectors, with opportunities ranging from more water reuse/recycling to irrigation efficiency…

Andy Mueller, general manager of the river district, mentioned conservation opportunities ranging from replacing Kentucky bluegrass lawns with native vegetation, to farmers and ranchers potentially being willing to remove irrigation from marginal lands.

He called on various interests not to turn against each other as sometimes happens in societies when a resource gets scarce.