On April 16, 2019, President Trump signed new legislation aimed at safeguarding water shortages that could impact drinking water for 40 million Americans living in seven western states. This new legislation gives the Bureau of Reclamation authority to carry out a drought plan should water levels in Lake Mead and Lake Powell drop below critical levels. The effects of a 19-year drought have depleted water levels at Lake Mead leaving it only 37 percent full, while Lake Powell is currently 45 percent full.
The recently signed legislation will require the Lower Basin states to immediately begin saving hundreds of thousands of acre-feet of water to reduce the risk of reaching critically low reservoir levels in Mead and Powell. Heavy 2019 winter rains and above-average snowpack in the Rockies could help avert the Bureau of Reclamation from formally declaring a shortage for another year. Estimates by the Bureau’s water managers place water levels in Lake Mead at 1,084 feet above sea level by this year-end.
What are the trigger points for declared shortages on Lake Mead?
There are three tiers of shortage set in a 2007 agreement as part of the U.S. Department of Interior’s Colorado River Interim Guidelines, which calls for delivery cuts if water levels in Lake Mead drops below that level. The three tiers of shortage are set at 1,075, 1,050 and 1,025 feet. The lowest level that electricity can be generated at Lake Mead is 1,050 feet. The lake becomes a “dead pool” at 895 feet, the point where no water can be pumped from the lake.
Each tier results in larger water cuts to Lower Basin States. Under the plan signed this month by President Trump, Arizona’s total use of the river would drop by about 18 percent, or more than 500,000 acre feet during the first year of a declared shortage. Mother nature and newly signed legislation may have helped us to dodge a declared shortage in 2020. Water levels are currently at 1089-feet above sea level, recovering from the lowest levels since the Hoover Dam was built in the 1930 of 1,074.81 seen last July. The Bureau of Reclamation is scheduled to announce in August whether a shortage will be declared in January 2020. Shortage or not, under the new drought plan Arizona and Nevada may still face water cutbacks starting in 2020. If the Bureau determines in August that Lake Mead is likely to be below 1,090 feet at the start of next year, water deliveries to Arizona would be cut about 6.9 percent, and deliveries to Nevada would be cut 2.7 percent. The Bureau’s latest projections at the end of 2019 for reservoir elevation is 1,084 feet and in 2020 it’s projected to be at 1,079.55 feet.