Record Breaking Snow Accumulation Brings Opportunities and Challenges for Nevada

By Christopher Rose, James Komar and Jeff Anderson Natural Resource Conservation Service

Winter 2023 produced one of the biggest snowpacks ever measured across the Sierra Nevada, the Great Basin and the Colorado basin. The Carson and Walker basin snowpacks broke alltime records based on SNOTEL data back to 1981. Peak amounts were second highest in the Upper Humboldt, Lake Tahoe and Truckee basins, as well as in Eastern Nevada. The Lower Humboldt and Owyhee snowpack ranked third highest. The Upper Colorado Basin’s peak snow water tied 1997 for the best winter since 1986.

Each winter field staff from USDA’s Natural Resources Conservation Service and cooperators from other state and Federal agencies venture out on skis, snowshoes, and snow machines to take readings and maintain equipment at the 85 SNOTEL (Snow Telemetry) weather stations across Nevada and the eastern Sierra. Snowpack, precipitation, air temperature and soil moisture are monitored at the stations and snow surveyors also collect snow tube measurements at an additional 40 snow courses. The data is used by hydrologists at the NRCS National Water and Climate Center to produce seasonal streamflow forecasts for the region’s water managers and water users. Water Supply Outlook Reports are also used by state and Federal agencies, Tribes, individuals, and organizations to make decisions regarding irrigation allocations and agricultural production, fish and wildlife management, municipal and industrial water supply, flood control, power generation and recreation. NRCS provides technical and financial assistance to farmers and ranchers that can assist them with becoming more resilient to extreme weather conditions including droughts and high-water years.

Water Supply Summary

This winter’s record-breaking snow accumulation finally relented in April allowing the snowpack to ripen and begin to melt. Snowpacks reached their maximum water content across Nevada’s basins between April 7-10 with amounts ranging from 169-382% of the normal peak amounts. April’s sunny skies and near record temperatures towards the end of the month ramped up snowmelt allowing a few of the lowest elevation SNOTEL sites across the state to melt out by May 1. By June 1, most

NRCS SNOTEL sites below 7,500 feet elevation in the Sierra and below 8,000 feet elevation in Northern Nevada had melted out. As of June 1, significant snow remains at higher elevations and melt will continue into June or July and perhaps even August at the deepest locations.

Water year precipitation on June 1 was 112-197% of median across Nevada. Most SNOTELs south of Interstate 80 have recorded October through May precipitation totals that rank above the 80th or 90th percentile compared to historic data.

Reservoir storage will be excellent this summer. In the Truckee Basin, Stampede, Prosser, and Boca reservoirs are all expected to fill once flood control operations are complete. Lake Tahoe’s water level could rise to within a few inches of its legal limit based on current forecasts but may not fill to its legal limit. In the Carson Basin, there is more than enough water to fill Lahontan multiple times. Mangers have drawn Lahontan down and excess water is being released into the desert. In the Walker basin Topaz and Bridgeport reservoirs will also fill once peak flows pass. In the Lower Humboldt Basin, Rye Patch Reservoir should also fill based on streamflow forecasts. In the Owyhee Basin, Wildhorse Reservoir is unlikely to fill based on streamflow forecasts. In the Colorado basin, since the beginning of April Lake Powell has risen over 37 feet and Lake Mead has risen over 8 feet. This is a storage increase of over 2.8 million acre-feet in April and May. The Colorado basin hasn’t seen a snowpack this large since 1997, but it would take a string of similar winters to refill these reservoirs.

Streamflow Forecasts

Nearly all streamflow forecasts for April-July period are more than twice median, and more than a quarter of the forecasts are for more than four times median. The median is the middle value of the 1991-2020 dataset. It represents a volume that is exceeded by half the years. The median is considered more representative of “normal” than the average since the median doesn’t get skewed upward by a handful of large years. A forecast for 300% of median means the total streamflow volume during the April-July period is expected to be three times the median. Spring precipitation will play a big role in where this year’s volume ends up. NRCS streamflow forecasts are intended for water supply planning, they provide a total volume of runoff expected during the spring snowmelt runoff period. Snowmelt has already caused flooding this spring and high flows will continue. The NRCS seasonal forecasts are volumetric and do not provide guidance on peak discharge magnitude or timing. To track flooding potential, use the 5-day forecasts on the NOAA California-Nevada River Forecast Center website (www.cnrfc.noaa.gov) and click on the stream gage of interest.

FIGURE standing above the top of the snow course marker at Willow Flat snow course in the Walker Basin. The April 1 measurement this winter was 425% of median, coming in at 91 inches deep and contained 37.4 inches of water content. This measurement blew away the previous record from 1969 which contained 29 inches of water content. Credit: Jeff Anderson

FIGURE 4

Streamflow Forecasts ‐ State of Nevada Overview

May 1, 2023

Rangeland Conditions

The increase in precipitation this year has improved conditions on the range. As seen below, in 2022, all of Nevada was in the severe to exceptional drought category while this year, approximately 20 percent of the state, mostly in the south, is in any type of drought.

Plant green-up progressed across the state below the snow line. Native wildflowers had an amazing bloom at low to midelevations. The native shrub, desert peach (Prunus andersonii) provided a beautiful display of pink flowers in western Nevada. Other early growing shrubs such as bud sagebrush (Picrothamnus desertorum) and spiny hopsage (Grayia spinosa) are also in flower. Native perennial bunchgrasses (needlegrasses, squirreltail, basin wildrye) received much needed winter moisture across Nevada and had a slow start due to colder than normal temperatures. Cheatgrass (Bromus tectorum) set seed at lower elevations where moisture was available across the state and some hillsides stayed green longer than usual. For additional detail about what’s happening with vegetation, the Rangeland Analysis Platform (RAP) provides monitoring and context to evaluate current or past management strategies and develop new ones.

RAP allows producers to visualize and analyze vegetation data and see trends at pasture, ranch, watershed and broader scales. The web-based application can provide a 16-day aboveground biomass production estimate and track changes in bare ground and annual herbaceous, shrub, tree vegetation cover. Other features include assessing fire probability and annual invasive abundance, and comparison of historical imagery of an operation using side by side comparisons sourced from the United State Geological Survey. This link allows you to access the app and view tutorials on how to use the program https:// rangelands.app/.

NRCS assistance to increase resiliency of operations

As mentioned earlier, NRCS has a variety of tools available to farmers and ranchers to allow them to adapt to changing climate conditions while supporting their operations. Applications are accepted for all programs year round.

• Conservation Technical Assistance helps to analyzes natural resource concerns on the land and works with producers to develop objectives to address them.

• The Environmental Quality Incentive Program (EQIP) provides financial assistance to address the natural resource issues.

• The Conservation Stewardship Program (CSP) rewards good stewardship of the land.

See appendix for more information

Over the next three years, there will be an additional $30 million available in EQIP and CSP under the Inflation Reduction Act to help producers adopt practices designed to help them become more resilient to the changing climate.

To find out more about NRCS programs, visit www.nrcs. usda.gov/conservation-basics/conservation-by-state/nevada

To find your nearest local NRCS office, visit: https://offices.sc.egov.usda.gov/locator/app

How youtube.com/ watch?v=gWm5TeASLY8

The 82nd Nevada Legislative Session might have had the highest number of legislative proposals dealing with water of any past sessions (there wasn’t any official search of the archives, but there were a lot of water bills this legislative session). Of the total of water-related legislative ideas on the table, there were a high number of very good ones, aimed at addressing some serious concerns facing Nevada. Unfortunately, most of these solid proposals didn’t make it through to enactment into law. In some cases, legislative concepts receive support from some and opposition from others. The results of these different perspectives aren’t always an end. Throughout the legislative process there are discussions to try to work through disagreements over policy. There’s give and take, as well as breakthroughs that build from the differences to form even better ideas. There are also times when those supporting a bill can out-maneuver opposition or overpower those on the other side to gain passage. Frequently those who oppose a bill have the advantage and the legislation doesn’t make it by not making it through the numerous hurdles that pop-up and keep it from going forward.

As we saw again in the 2023 Nevada Legislature, passing a bill to gain a change in law is not easy and there are times when even strongly supported legislative ideas don’t make it.

Perhaps one of the best examples of widely supported legislation that didn’t get passed is SB 176.

The purpose for SB 176 was to deal with Nevada’s growing number of over-appropriated and overpumped groundwater basins. It is estimated that of the state’s 256