Water Supply Forecast Shows Record Snow in Northern Parts of West, Parched in Southwest

USDA Blog Post:

Posted by Spencer Miller, Natural Resources Conservation Service, on April 14, 2014 at 1:00 PM

Streamflow in the West consists largely of accumulated mountain snow that melts and flows into streams as temperatures warm. (NRCS photo)

March storms increased snowpack in the northern half of the West but didn’t provide much relief for the dry southern half, according to data from the U.S. Department of Agriculture’s National Water and Climate Center (NWCC) in its April 2014 water supply forecast.

According to the Natural Resources Conservation Service (NRCS), most of Idaho, Montana, Wyoming, and northern parts of Colorado and Utah are expected to have near normal or above normal water supplies, according to the forecast.  Far below normal streamflow is expected for southern Oregon, California, Arizona, New Mexico, southern Utah and western Nevada.

Early April is commonly regarded as the transition from snow accumulation to snowmelt, making the April 1 water supply forecast of key importance for planning, according to NWCC hydrologist Cara McCarthy.

“Many water managers, reservoir operators, irrigation districts and hydroelectric power companies make significant strategic decisions based on the April forecasts,” McCarthy said.

In states where snowmelt accounts for the majority of the seasonal water supply, information about snowpack serves as an indicator of future water supply. Streamflow in the West consists largely of accumulated mountain snow that melts and flows into streams as temperatures warm. NRCS scientists analyze the snowpack, air temperature, soil moisture and other measurements taken from remote sites to develop the water supply forecasts.

For the second consecutive month, many snow telemetry, or SNOTEL, sites in Montana, Wyoming, and parts of Idaho, Washington, and Oregon received two to three times the normal amount of precipitation. The Cascade Mountains in Washington went from extremely dry in January to a normal snowpack currently and Montana and Wyoming snowpack is now at record levels.

“There’s flooding potential in the Missouri River basin,” McCarthy said. “These areas will be most vulnerable if snow melts rapidly during a hot spell, or if there’s extreme rain while the streams are swollen with snowmelt.”

NRCS’ streamflow forecasts are one of the tools used to assess drought conditions. USDA is partnering with western states to help mitigate the severe effects of drought on agriculture.

Since 1939, NRCS has conducted snow surveys and issued regular water supply forecasts. Since the late 1970s, NRCS has been installing, operating and maintaining an extensive, high-elevation automated system called SNOTEL, designed to collect snowpack and related climatic data in the western U.S. and Alaska.

The center will continue to monitor and forecast water supplies for the next two months. View the April Snow Survey and Water Supply Forecast map or view information by state. And to learn more about how NRCS is helping private landowners deal with drought, visit NRCS’ drought resources. You can also visit USDA’s disaster and drought information page.

Watch the April water supply forecast: https://www.youtube.com/watch?v=LoK5Vdd3NUc

Jointly Developed Watershed Assessment Model Being Used in Yosemite National Park

USDA Blog Post:

Posted by Tara T. Weaver-Missick, USDA-Agricultural Research Service Information Staff, on December 3, 2013 at 3:00 PM

Bridalveil Falls, Yosemite National Park, California (USDA-NRCS photo by Ron Nichols).

This post is part of the Science Tuesday feature series on the USDA blog. Check back each week as we showcase stories and news from USDA’s rich science and research portfolio.

An award-winning watershed assessment tool, the Automated Geospatial Watershed Assessment (AGWA), was deployed to assess potential Rim Fire threats in Yosemite National Park in California.  The park experienced a devastating fire that began on August 17, 2013, and took several months to contain. The fire burned more than 400 square miles in and around the park, cost $125.8 million to date, and is considered one of the largest wildfires in California’s history.

BAER (Burned Area Emergency Response) is a multi-agency group that includes USDA’s Forest Service and others, and is responsible for identifying potential threats such as downstream flooding and developing plans to rehabilitate and restore burned areas. BAER teams use AGWA to target immediate efforts to prevent threats to people, wildlife and the land.  Using AGWA combined with the burn severity map produced by BAER teams, experts can rapidly pull together information on pre- and post-fire conditions. For example, knowing where to apply mulch after a fire can reduce runoff and erosion and can help minimize downstream risks from fire induced land cover and soil changes.

AGWA has already been successfully used for post-fire BAER team watershed assessments following fires in Arizona, New Mexico, California, Idaho and Washington.  AGWA was jointly developed by scientists with the USDA Agricultural Research Service (ARS) Southwest Watershed Research Center in Tucson, AZ, the U.S. Environmental Protection Agency (EPA), and the Universities of Arizona and Wyoming.

ARS researchers and their partners originally developed the computer model as a multipurpose computer system and software tool designed for managing and analyzing water quantity and quality to help keep our Nation’s watersheds cleaner. AGWA uses nationally available data sources to rapidly establish and execute results from two ARS-developed watershed models, the Kinematic Runoff and Erosion Model (KINEROS2) and the Soil and Water Assessment Tool (SWAT).  It enables the user to visualize and compare model results to understand the impact of a certain practice on a given landscape.

How we manage activities that take place on crop production areas, rangelands, pastures, forests, meadows, and urban areas influences the quantity and quality of water available for domestic, industrial, agricultural and ecological uses. You can learn more about AGWA at www.tucson.ars.ag.gov/agwa.