Clark County, NV, May 21, 2018
As the General Manager for the Southern Nevada Water Authority (SNWA) between 1991 and 2014, Pat Mulroy warned that low snow packs in the mountains could cause reservoirs like Lake Mead to crash.
This winter the Colorado River Basin experienced one of the driest seasons on record. Paul Miller, a hydrologist with the Colorado Basin River Forecast Center said. “This entire water year has been characterized by way below-average precipitation; it’s bad everywhere”.
Tom Buschatzke, Director of the Arizona Department of Water Resources reported that the entire Southwest has experienced the warmest, driest winters on record. He warned that the lack of snowpack runoff in the Colorado River System will likely continue into the spring.
In February 2017, Federal water managers put the possibility of Lake Mead falling below the trigger line of 1,075 at 50-50.
On March 19, The U.S. Bureau of Reclamation (BOR) projected that Lake Mead could fall as much as 11 feet (3 meters) by the end of the year. Such a drop could trigger a requirement for water Nevada managers to reduce Colorado river water use by 4 percent and Arizona 11 percent. [i]
On May 15, Lake Mead was at 7.78 mean sea level (msl) feet above the trigger point of 1,075 msl.
The BOR’s latest projections put inflow into Lake Mead at 42 percent of its average between now and July.
The Southern Nevada Water Authority (SNWA) projects that when Lake Mead hits the 1,075 msl trigger point, users of that Colorado River resource will need to reduce consumption by 13,000 Acre Feet Yearly (AFY) . At 1,050 msl, the reductions rise to 17,000 AFY and at 1,025 msl the reduction reaches 20,000 AFY. Generally, one-acre foot of water is enough to serve a family of five.
Under the 1922 Colorado River Compact and the Boulder Canyon Project Act (BCPA) Nevada is limited to 300,000 Acre Feet Yearly (AFY) of Colorado River water (includes Virgin and Muddy River tributaries).
The SNWA is entitled to 272,205 AFY [ii] of the total 300,000 AFY. Leaving only 21,205 AFY (7%) available for consumption by others.
On May 7th users of Colorado river water consumed 283,000 AFY (94%) of the total.
On that same day, SNWA used 251,000 AFY (84%) of the daily amount. All other users took 32 AFY (11%).
Limitations to Colorado river consumers in Clark County is measured in two ways. First, drought limitations as measured by inflow and outflow to Lake Mead. Second, consumption as measured by limits under the 1922 agreement. Both measurements tell the same story: The Colorado River is crashing.
On May 9th, Brenda Burman, U.S. Bureau of Reclamation (BOR) Commissioner called upon the Colorado River basin water managers to put real and effective drought contingency plans in place before the end of the year.
Burman said, “drought and low flows continue on the Colorado with no end in sight, so it’s up to those who rely on the river to stave off a coming crisis.”
“We need action and we need it now. We can’t afford to wait for a crisis before we implement drought contingency plans,” Burman said. She called on the basin managers to “put real — and effective — drought contingency plans in place before the end of this year.”
Ben Franklin was right: “You learn the value of water when the well runs dry.”
[i] In response to the severe Colorado River Basin drought conditions, the Secretary of the Interior in 2007 issued a Record of Decision for Colorado River Interim Guidelines for Lower Basin Shortages and Coordinated Operations for Lake Powell and Lake Mead. The Interim Guidelines define the availability of Colorado River water for use in the lower basin based on Lake Mead’s water surface elevation.
Per the Interim Guidelines, the Secretary of the Interior would base a shortage declaration on projections of Lake Mead water levels as determined by the U. S. Bureau of Reclamation’s Colorado River modeling efforts. The projection forecast is determined annually in August.
[ii] Southern Nevada Water Authority, “Water Resource portfolio, chapter 3 pg. 21.
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