New projections for low #ColoradoRiver flows speed need for dramatic conservation

Projected Lake Powell end-of-month elevations from the latest 24-Month Study inflow scenarios.

Projected Lake Mead end-of-month elevations from the latest 24-Month Study inflow scenarios.

From The Colorado Sun (Michael Booth):

A new federal system for projecting Colorado River water flows in the next two years confirms dire news about drought draining the West’s key reservoirs, and increases pressure on Colorado to conserve water immediately to avoid future demands from down-river states, conservation groups say.

The federal Bureau of Reclamation’s new system for projecting vital Colorado River flows in the next two years drops earlier, wetter years out of the historical reference, and gives more weight to two recent decades of drought. The regular October update this week shows water runoff into Lake Powell, the storage basin for four Upper Colorado Basin states, was only 32% of average for the 2021 water year, which runs from October to September.

The new projections for the next two years show that even with federal officials draining portions of Blue Mesa, Flaming Gorge and Navajo reservoirs to get more water to Lake Powell’s hydroelectric generating station, a moderate winter would leave the Colorado River in the same crisis a year from now. And a low-water scenario this coming winter season would drop Lake Powell well below the minimum level required to generate electricity by November 2022.

In addition to federal officials trying to protect hydroelectric generation at Lake Powell, and at Lake Mead as the downstream water bank for the Lower Basin states, water compacts govern how much Colorado River water needs to go downstream for use by agriculture and cities…

“We don’t have any more time to talk about it,” Matt Rice, co-chair of the Water for Colorado Coalition and Director of American Rivers’ Colorado River Basin Programs, said after reviewing the latest Bureau of Reclamation update.

Starting with the October update, the bureau begins the historical average calculations in 1991, instead of the 1981 cutoff used until now. The 1980s were much wetter in the Colorado River Basin, Rice said.

“These projections are worse than they have been in the past, but they’re also more realistic,” Rice said. Many conservation groups find that a positive step despite the bad news, Rice added, because it increases pressure on state water officials, local water conservancy districts, agriculture interests, cities and environmentalists to work faster on solutions.

At the same time, Rice said, the updated numbers should drive home the reality that there is 20% less water available now in the Colorado River than as recently as 2000. “There’s no more flexibility in the system, right? We’re looking over the edge of the cliff.”

Water conservation experts in Colorado have worked for years to avoid their worst-case scenario, which is a “call” or a sudden demand from federal managers to deliver more water for hydropower or to satisfy the compacts with the Lower Basin. Without advance planning, a call would force the state water engineer and local conservancy districts to cut irrigators’ water rights based only on the seniority of their water-use rights.

While state and local officials have been working with nonprofits on conservation plans, there are legal tangles that could require new legislation, and seemingly endless ethical questions about which parts of the state would suffer the most water loss, said Sonja Chavez, director of the Upper Gunnison River Water Conservancy District…

Blue Mesa Reservoir in her region has been nearly drained by drought and by federal officials taking extra from Western reservoirs to solidify Lake Powell’s power pool. Blue Mesa is projected to soon be down to 27% full, Chavez said. Blue Mesa was 33% full in mid-September, according to Bureau of Reclamation records.

State and private officials have cooperated to experiment with “demand-management” programs, where instead of buying agriculture land and its accompanying water rights outright, they buy the right to rent the water for a few years out of a decade. That rented water can be sent downstream in dry years, and in theory the restoration of water in other years should preserve the farm or ranch land while providing income for the farmer.

But renting or buying of water rights on the scale to meet compact demands would require hundreds of millions of dollars, with no current pot of money to pull from, water experts say. Colorado officials have mentioned the possibility of using money from the infrastructure stimulus plan currently under debate by Congress, but it’s uncertain whether the bill will pass, and how much water-related money will be in it if it does…

The largest amounts of water to be conserved are in agriculture, by far, but Front Range residents must be part of the statewide discussion about finding more water for the downstream Colorado River, Rice and Chavez said.

“You’re not going to get as much out of a city compared to what is the amount of irrigation water diverted for agriculture,” Chavez said. “But there’s also agriculture on the Front Range that benefits from our transmountain diversions,” some of which are created and controlled by urban water departments. “That has to be part of the picture.”