Another year, another modern-day, record low water level at Lake Mead.
The reservoir that stores Tucson and Phoenix’s drinking water from the Colorado River dropped Wednesday evening to below its previous record low level. It continued dropping Thursday and is predicted to keep dropping for at least another month.
At 7 p.m. Wednesday, Mead stood at 1,074.70 above sea level, breaking a modern-day record low level of 1,074.71 that was set on June 15, 2015. By Thursday afternoon, Mead was down to 1,074.68 and by Friday morning it was hanging at about 1,074.50.
By next month, it’s expected to drop to about 1,072 feet, before rising the rest of the year.
This week’s water levels at Mead are the lowest they’ve been since the lake at the Nevada border was filling during the Great Depression.
But given the continued drought and legacy of water use on the Colorado River, this will hardly be the last year that Mead hits a record low.
Every year, the lake goes through the same cycle. It rises in the early part of the year, drops until summertime, then rises again early the following year. As the impact of continued overuse of river water continues to mount, the record low level will keep dropping.
The levels today would be low enough to declare a formal shortage on the Colorado River if they occurred at the end of this year Because the U.S. Bureau of Reclamation doesn’t make a decision on shortages until year’s end, no shortage is likely for 2017 because the lake is expected to rise to 1,078.51 feet by Dec. 31.
A shortage would be declared if Mead were at 1,075 feet at year’s end.
A declaration of shortage is more likely at the end of 2017, by when Mead is predicted by the reclamation agency to be at 1,073 feet.
The formal shortage declaration issue could become moot, however, if Arizona and the other two Lower Colorado Basin states Nevada and California can reach agreement earlier on longer-term cuts in water deliveries to those states.
As a proposed agreement stands, Arizona would lose 192,000 acre feet annually starting next year regardless of the lake’s level. It would lose larger amounts in future years if the lake keeps dropping.
When and if a formal shortage is declared, Arizona would lose 320,000 acre feet in the first year the lake drops below 1,075 at year’s end and larger amounts when and if the lake kept dropping further.