Colorado Drought Contingency Plan - Current Events

The Other Shoe is Falling on the DCP 

In the May 11, 2021 LWS blog, we went over the basic concepts of the Colorado River Drought Contingency Plan (DCP). With the implementation of the DCP, the Lower Basin States initially agreed to leave 340 KAF (thousand acre-feet) of their allocation in Lake Mead if the elevation in the lake is between 1,090 and 1,075 ft MSL (Tier 0). In fact, in the past decade (2011-2020), Lake Mead has fallen into this water level elevation range, or below, in 8 of those 10 years. In 2015 and 2016, Lake Mead actually dropped below 1,075 ft MSL (mean sea level). A graph showing the historic annual high and low water level elevation in Lake Mead is available from the Bureau of Reclamation website. As the historic graph of water levels at Lake Mead shows, the lake levels have been in steady decline since approximately 2000.

Tier 0 restrictions are currently in place and affect Arizona’s and Nevada’s allocation, but not California’s allocation: Due to a 1963 Supreme Court decision in Arizona vs California, California’s allocation will not be reduced unless Lake Mead water levels drop below 1,045 ft MSL. Under Tier 0, Arizona has the largest reduction in allocation (192 KAF), while Nevada’s reduction is (8 KAF). Mexico also has to reduce its allocation by 41 KAF.

However, these Tier 0 restrictions are about to be replaced with a higher Tier 1 restriction. The Tier 1 restrictions are to be implemented on January 1, 2022 based on Reclamation’s most recent future forecast. Under Tier 1 restrictions, Arizona’s allocation will be reduced by 512 KAF, while Nevada’s allocation will be reduced by 21 KAF and Mexico’s allocation will be reduced by 80 KAF. Tier 1 restrictions will be in place as long as Reclamation’s future forecasts indicate that Lake Mead water levels will remain between 1.075 and 1,050 ft MSL.

Lake Mead drought comparisons. Source: National Park Service.

At 1,050 ft MSL Tier 2A restrictions go into place, followed by Tier 2B restrictions at a lake level of 1,045 ft MSL.

With the current projections for Lake Mead water levels, Tier 2 restrictions could come sooner, rather than later. Tier 2B restrictions at a water level elevation of 1,050 ft MSL would entail curtailment of 592 KAF of Arizona’s entitlement, 25 KAF of Nevada’s entitlement, and 108 KAF of Nevada’s entitlement. Tier 2B curtailments would for the first time affect California’s 4.4 MAF entitlement by reducing it by 200 KAF. The other downstream states (Arizona and New Mexico), plus Mexico, would also be hit with further curtailments, 640 KAF of Arizona’s entitlement, 27 KAF of Nevada’s entitlement, and 154 KAF of Nevada’s entitlement. This represents approximately 23 percent of Arizona’s allocation under the Compact, 9 percent of Nevada’s allocation, 4.6 percent of California’s entitlement, and 10 percent of Mexico’s allocation. 

So what do the Tier 1 restrictions under the DCP mean for the Upper Basin States (Colorado, Wyoming, Utah, and New Mexico)?

On May 20, 2019, the Upper Basin States signed the Demand Management Storage Agreement (DMSA). The fundamental purpose of the DMSA is to conserve water consistently over the years and store that water in the unfilled portions of the Upper Basin reservoirs (Lake Powell and Flaming Gorge, Blue Mesa, and Navajo Reservoirs). If established by the states, an Upper Basin DCP Demand Management Program would likely entail willing seller/buyer agreements allowing for temporary paid reductions in water use that would provide for more storage volume in Lake Powell. The demand management program contemplates there will be willing water users such as farmers, ranchers, industries, cities, and towns that would temporarily reduce their water consumption, thereby keeping more water in rivers and reservoirs. One possibility would be alternative transfer methods (ATM), similar to the discussion in the LWS blog of December 2020.

Map of the Colorado River Basin. Source: USGS.

Water conserved through this program would be delivered to the Colorado River water “bank account” in Lake Powell. However, there is no mandate to establish a demand management plan, nor have conditions related to the DMSA been developed at this point. With the increased pressure on all of the water resources of the Colorado River Basin, the Upper Basin States need to discuss whether temporary and voluntary measures can be developed to conserve water through reduced consumptive uses of Colorado River water, as voluntary measures could become less voluntary and more mandatory if conditions in the Colorado River Basin continue to worsen with time.

The DCP has many complex conditions associated with its implementation. This is just a quick summary of some of the terms of the plan under Tier 1 restrictions and beyond, which may not be that far off. However, if you are interested in learning more about the details of the DCP, there are a number of resources that can be found on the Bureau of Reclamation website.

If you have any water resources issues, LWS can help. For more information on this subject or any Western water rights issue, please contact us for help at 303-350-4090 or by email.

Bruce Lytle, P.E.: bruce@lytlewater.com

Chris Fehn, P.E., P.G.: chris@lytlewater.com

Anna Elgqvist, EI: anna@lytlewater.com

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