Southern Nevada set for ‘lean water year’
Jeniffer Solis
(Nevada Current) Water officials have raised concerns about anticipated water levels in Southern Nevada this summer, following a disappointing winter snowpack that threatens to stall progress made during last year’s wetter-than-average season.
Snowpack in the Upper Colorado River Basin, which provides streamflow for the two largest reservoirs in the United States — Lake Mead and Lake Powell — has underperformed this winter, reinforcing long-term drought challenges facing the west.
Snowpack is a crucial source of water for Nevada and the West. As snowpack melts, it recharges ecosystems and replenishes reservoirs that provide drinking water for millions of people and irrigation water for millions of acres of farmland.
Despite two consecutive decent water years, both reservoirs could see gains reversed, according to the monthly Nevada Water Supply Outlook Report from the Department of Agriculture Natural Resources Conservation Service.
“Southern Nevada should expect a lean water year with less than normal streamflow predicted for the Virgin River and the Colorado River inflow to Lake Powell,” reads the report.
According to the report, the Upper Colorado Basin’s snowpack only reached 89% of the historical median this April, which is considered the month when the snowpack reaches its highest snow water total before melt begins.
That could spell trouble for water levels in Lake Mead and Lake Powell which are already suffering deficits due to drought impacts and high water demands.
Water officials estimate that streamflow for Lake Powell will be at about 74% of the historical median, according to the report. Lake Powell’s water levels directly affect Lake Mead because streamflow to Lake Powell is eventually released to Lake Mead.
Combined storage in Lake Powell and Lake Mead as of March is down 691,000 acre-feet compared to the same time last year, or enough water to supply 1.3 million households. Both reservoirs combined are at 33% of capacity as of April.
Snowpack in Southern Nevada’s Spring Mountains has also underperformed this winter, hitting only 30% of its historical median. Snow melt from Spring Mountains is the largest source of groundwater for Southern Nevada and provides some limited water to Lake Mead.
However, Spring Mountains did receive much needed rain in March, hitting about 229% of the historical median as of March.
Despite deficits in Southern Nevada, other parts of the state are looking at a more robust water year. Snowpack in the Eastern Sierra is about normal at 105% of median, compared to 134% at this time last year.
Snowpack in several basins that supply water for the Reno-Sparks area — including the Walker River, Carson River, Truckee River and Lake Tahoe basins — are at about normal as of April. Combined all four basins hit nearly 98% of their historical median.
Snowpack is well above normal in other parts of Northern Nevada, especially in regions along the Oregon-Nevada border.
That snowmelt will also help bolster already healthy reservoirs in northern Nevada. Most reservoirs in northern Nevada were near normal to well above normal storage as of March, according to the report.
Snowpack in the Humboldt, Owyhee, Snake, Clover-Franklin basins — largely located in Elko County — reached well above normal snowpack at 122% to 151%.
The Humboldt Basin has now seen three consecutive winters with snow water peak amounts above normal. There hasn’t been a three-year period with better consecutive snowpacks in the Humboldt Basin since the mid-1980s. The Humboldt Basin is a major course of water for Humboldt, Elko, Lander, and Eureka counties
Snowpack in the Northern Great Basin, located largely in Humboldt County, also reached well above normal at 151% median as of early March. Precipitation in March in the Northern Great Basin was also about normal at 96%.
Snowpack in Eastern Nevada — which covers the majority of White Pine County and part of Eureka County — improved dramatically from 55% in early March to 86% by early April.
While March significantly improved snowpack in Eastern Nevada, snowpack in the region is still below the historical median, hitting 86% of median. Snowpack in the region was also not distributed evenly.
“Eastern Nevada is a mixed bag with better mountain snowpack conditions near Austin, Eureka and Ely, but well below normal snow in Great Basin National Park,” read the report. “It should be noted that snow percentages in Eastern Nevada vary widely from site to site ranging from twice normal to less than 50%.”
Above normal rain also helped improve conditions in Eastern Nevada, reaching well above normal at 182% in March,
Above normal precipitation in March also reduced drought severity on the US Drought Monitor Map in Elko, Churchill, Lander and Eureka counties over the last month. But areas of extreme and exceptional drought in southern Nevada remain unchanged from last month.
Dry conditions in Southern Nevada followed a pattern of drought throughout the Southwest this winter, according to the latest National Water and Climate Center report from the Natural Resources Conservation Service.
The Southwest experienced a snow drought and precipitation deficit this season, with well-below normal streamflow from snow melt expected for the spring and summer period, according to the National Water and Climate Center report.
Above-normal springtime temperatures are also causing a rapid melting of high-elevation snowpacks across the entire West, which could impact streamflow as snow melts before it’s most needed in the summer.
In Nevada, snowmelt started early due to a week of warm temperatures in late March. Daily average air temperature at snow monitoring sites across Nevada peaked at 48 degrees Fahrenheit on March 26th, very close to a record for that date.
Those conditions are expected to continue in Nevada in the long term. The National Weather Service predicts there is a 40 to 50% chance most of Nevada will see above average temperature from April through June, according to the National Water and Climate Center report. Climate scientists predict Nevada will also see below average precipitation during that same period.