The Colorado River Basin has faced a challenging year in terms of hydrology. The mountain snow season, which started dry, experienced a strong middle period but came to an abrupt halt in April. This pattern resulted in a less-than-expected runoff to swell Lake Powell’s reservoir storage, according to government hydrologists. The U.S. Bureau of Reclamation reports that this will likely lead to a holding pattern for drought responses over the next two years.

Impact on Lake Powell and Lake Mead

Water levels in Lake Powell and Lake Mead, the two primary reservoirs in the Colorado River system, are not expected to rise significantly as they did after the strong snowpack accumulation during the 2022-2023 winter. However, they are also unlikely to fall to levels that would necessitate new water austerity measures in the Southwest.

The snow-water equivalent, which describes the amount of water that would result from melting snow, showed a significant drop. From an April 1 reading of 113% of the median, it fell to just 89% by May 1. Reclamation predicts that the water flowing toward Lake Powell through the end of the runoff season in July will be 81% of the average, totaling 7.9 million acre-feet. With a planned release of 7.48 million acre-feet towards Lake Mead, Powell's storage capacity is expected to remain relatively stable, moving from 34% to a predicted 37% full by the year's end.

Variability Across the Basin

Most areas of the seven-state watershed experienced below-average precipitation and snow in April, with the exceptions being the Colorado headwaters and Arizona’s Verde River. This variability has led to different outcomes across the region. The Colorado Basin River Forecast Center noted that much of the watershed experienced only 50% to 70% of normal April precipitation.

Drought Restrictions and Agricultural Impact

The Colorado River is a crucial water source for over 40 million people in cities and on farms across seven states, including Arizona. While drought restrictions have not significantly affected urban water users, they have impacted agricultural operations, particularly in Pinal County, Arizona. These restrictions have curtailed water flow to some farmers, highlighting the ongoing challenges in managing water resources in the region.

Negotiating Long-Term Guidelines

Despite the current year's less-than-ideal hydrological conditions, the stability of water supplies is expected to continue for the next couple of years, thanks to emergency water conservation measures. These measures, adopted in the Southwest, aim to keep supplies stable. Officials announced in March that a negotiated plan would keep 3 million acre-feet of water in storage through 2026.

Looking beyond this period, states, tribes, and federal officials are negotiating longer-term guidelines to ensure water savings. These guidelines will be critical unless a significant wet streak refills the reservoirs to capacity, a situation not seen this century. The U.S. Interior Department is set to propose its chosen guidelines by the end of the year.

Positive Outlook for Salt River Project

In contrast to the overall mixed outlook for the Colorado River Basin, the Salt River Project (SRP) in Arizona has a strong water supply outlook for the second year in a row. The SRP’s Salt and Verde watershed reservoirs entered May at 93% of capacity, providing a robust water supply for the Phoenix metropolitan area.

The Colorado River Basin's hydrological conditions this year illustrate the complexities and challenges of managing water resources in an arid region. While the immediate future does not hold severe austerity measures, the situation underscores the importance of continued negotiation and implementation of long-term water conservation strategies. Ensuring the stability and sustainability of water supplies remains a priority for the millions of people and agricultural operations that depend on the Colorado River.