Persistent Drought Conditions in the West Require New Water Policies and Compacts
In 2015 the atmospheric patterns created a warm dry ridge of high pressure over the western contiguous United States which caused the national drought footprint. Drought statistics, based on the Palmer Drought Index in 2015, appear to be recurring during the Summer of 2021. Only this time, other natural disasters such as wildfires have accompanied drought conditions. The confluence of these natural environmental phenomena will require the formulation of new policies and the implementation of tactical actions for the current years and for years to come.
As we reflect on 2015, all but three months (April, May, and July) had 29 percent or more of the country experiencing very warm temperature anomalies at the 90th percentile. Only February had 20 percent or more of the country experiencing very cold temperatures anomalies.
The drought in the West was characterized by low reservoir levels and poor mountain snowpack during the 2014-2015 snow season. Arizona, California Nevada, New Mexico, and Oregon had experienced six of the previous eight years having below-average levels of precipitation. Drought conditions persist in similar geographical regions in 2021 as they did in 2015.
Over six days during the middle of June 2021, a dome of hot air languished over the western United States, causing temperatures to rise to unprecedented levels. From June 15-20, all-time maximum temperature records were set at locations in seven different states (CA, AZ, NM, UT, CO, WY, MT). "In Phoenix, Arizona, the high temperature was over 115 degrees for a record-setting six consecutive days, topping out at 118 degrees on June 17."
Central Arizona Project
The Central Arizona Project (CAP) is a 336-mile system that brings Colorado River water to central and southern Arizona and is the state’s single largest renewable water supply. The CAP serves 80% of the state’s population. It provides a way for 1.5 million acre-feet of Arizona’s Colorado River allotment to be delivered to the most populous areas of the state and reduces the use of groundwater for farming and other activities.
Under the new drought agreement, Arizona’s supply was cut by 192,000 acre-feet each year in 2020 and 2021, representing about 11% of the Central Arizona Project’s total supply.
The Arizona Department of Water Resources said that the shortage will bring cuts that will fall largely on agricultural water users in central Arizona. This will be the largest mandatory Colorado River reduction in history. The program will, at least in the beginning, mitigate some immediate impacts to communities and is designed to keep the river system sustainable until the next phase of the longer-term plan is developed. Depending on conditions, we should expect to see continuous evolving changes to water management because the severity of future drought conditions cannot accurately be predicted.
The first-tier shortage will likely continue into 2023. During the life of the agreement through 2026, the Arizona Department of Water Resources does not expect any reduction in supply to municipal customers.
But, Pinal County farmers who now receive water from the CAP Canal expect to see their deliveries reduced by more than half next year, and then slashed to zero in 2023. A reduction of this magnitude will require farmers to develop alternative replacement sources, otherwise farm production will be severely impaired
The drought has dramatically worsened over the past year, not only in the headwaters of the Colorado River but also across other southwestern states. A year ago, about 4% of the West was in severe drought. Now, about 58% of the West has been classified as being in a severe, extreme, or exceptional drought.
The Colorado River Compact is a 1922 agreement among seven U.S. states in the basin of the Colorado River. The compact governs allocation of water rights to the river's water among the parties of the interstate compact and has operated under numerous compacts, federal laws, court decisions, and decrees. Contract changes since inception, are a trend that will likely continue.
Salt River and CAP Water Storage
Salt River Project (SRP) and Central Arizona Project (CAP) have agreed to hire HDR to conduct a preliminary engineering feasibility study for an interconnection project that could allow water stored in SRP reservoirs to be pumped into the CAP canal and delivered to customers. HDR specializes in engineering, architecture, environmental, and construction services and is most well-known for tastefully designed high-performance buildings and smart infrastructure. The feasibility study should provide information about whether this type of project would be possible from an engineering standpoint and will help the publicly elected CAP board make decisions about this in the future. Additional studies on operations and water quality will be necessary.
The Salt River Project announced that the 2021 runoff season ranks as the second driest in the 109 years of record keeping. The Salt and Verde watersheds produced just 104,000 acre-feet of runoff this year — most of which gets stored in Roosevelt Lake and a chain of much smaller reservoirs on the Salt and Verde rivers
Preservation of water has always been a priority of the Southwestern states. The recent conditions have prompted the need for even more aggressive management to stave off the risks of drastic allocation changes that could impair economic growth in agricultural and metropolitan communities. Litigation and lawsuits will serve as the canary in the coal mine to assess the intensity of any potential fight among parties intensely impaired by drought conditions.