Have the recent downpours in Las Vegas affected the water level in Lake Mead?
Naturally, when it rains, it’s better for Lake Mead than when it doesn’t, so the question is, how much better?
Unfortunately, very little.
In December 2010, southern Nevada was pummeled by rainstorms over a six-day period, recording four inches of precipitation, more than half the annual average in less than a week. Flash floods wreaked havoc; roads and parks were closed all over the region; an avalanche warning was issued for Mt. Charleston, which added 60 inches of snow and lost power; and it took weeks to clean up the mess left by the torrential downpours.
How much water was added to Lake Mead? Nearly half a billion gallons — upwards of 1,400 acre-feet, enough to supply 1,400 homes with water for an entire year.
And how greatly did that affect the lake level? According to a Water Authority spokesperson at the time, the lake’s surface level was raised by a whopping two-tenths of an inch.
In other words, it would have required around a month of similar torrents to raise the lake level an inch, which obviously isn’t much of a dent in the nearly 150 feet the lake has dropped in the current drought.
The good news is, above average snow melt in Wyoming, Colorado, and Utah from the heavy snows of last winter, plus the lowest downriver demand in 25 years from ongoing conservation efforts, have combined to keep Lake Mead safe from a federal water-shortage declaration.
Last month, the U.S. Bureau of Reclamation projected that Lake Mead will avoid a shortage in 2018 and 2019, as the additional runoff from the Colorado watershed upriver has allowed more water than usual to be released by Lake Powell into Lake Mead.
Lake Mead’s surface level is expected to rise at least five feet by the end of this year — which would take five years or so of constant storms to match via rainfall.
