This year has been a dry one for states in the Intermountain region. With precipitation levels below the average, the importance of the snowpack for intermountain ag producers has never been clearer.
The year’s new water year started Oct. 1. Lucas Zukiewicz, water supply specialist for the Montana Natural Resources Conservation Service (NRCS) Snow Survey, told WLJ the snowpack is conceptually thought of as a big reservoir in the mountains. Most ag producers in the region rely on the snowpack’s melt throughout the year.
Montana
Zukiewicz said about 60-65 percent of the state’s diverted water use goes directly to agriculture.
“Our agricultural production across the state is pretty intrinsically tied to our seasonal snowpack, whether you’re right up against the mountains running cows where you transition out into the Plains, or you get further east to the larger rivers that provide another water source for both agriculture and stock water as well,” Zukiewicz said.
Being so far north, Zukiewicz said Montana tends to receive monsoonal moisture, which is a big producer in overall precipitation for the year. That didn’t really play out as much this year. However, a snowpack above average levels produced slightly higher stream flows, but hotter temperatures in May and June melted snowpack levels a little faster than normal, resulting in a dryer August and September.
The past two years’ snowpacks in Montana have been above average, which has set up some insulation against drier months. The U.S. Drought Monitor currently has some areas of Montana in low to moderate drought conditions.
An expected La Niсa is likely to bring cooler than normal temperatures and slightly above normal chances for precipitation this winter, Zukiewicz said. However, he noted it is still a little too early to predict what the winter will bring in terms of precipitation and snowpack.
Colorado
Russ Schumacher, Colorado state climatologist and director of the Colorado Climate Center, told WLJ ag producers’ reliance on the snowpack varies, but overall the natural reservoir is still crucial to agriculture production.
“Depending on where in the state, there are lots of reservoirs that people have built over time to store water, to try and guard against the dry years by being able to store more water from the more plentiful years,” Schumacher said. “We have a very complicated system of water rights in Colorado. Some producers have very senior water rights and don’t really have to worry too much in dry years, but then there’s plenty of other places where they don’t have those water rights, and they are much more dependent on the year-to-year snowpack and how much happens to be in the reservoirs in a given year.”
Schumacher said La Niсa typically brings cooler temperatures and wetter conditions to the northern states, drier conditions to the southern states, and Colorado sits in the middle with not as much of an influence.
Similar to Montana, Colorado has experienced above average and average snowpacks the last few years, but the past season’s snowpack melted quickly due to warmer and drier conditions. This water year was the third-driest water year on record for Colorado and most areas in the state are in some sort of abnormally dry condition with some areas in extreme and exceptional drought. In terms of the remainder of the fire season, Schumacher said prolonged cooler weather and multiple snowfalls are needed to put out the ongoing fires.
Idaho
“About 75 percent of the region’s water supply comes from snow melt, and Idaho is the second largest consumer of water for agricultural use in the West, besides California,” Erin Whorton, NRCS Idaho water supply specialist told WLJ.
A total of 70 percent of consumptive water—water that could be used for irrigation, livestock, mining, or drinking water—comes from surface water. Out of all diverted water, agriculture uses at least 86 percent, with the greatest concentration coming from southern counties that rely more on irrigation, Whorton said. She noted livestock accounts for only a small portion of the total diverted water use.
“We came into this summer with very full reservoirs,” Whorton said. “And then we had a pretty dry summer without a lot of precipitation, especially in the last few months, so our reservoir water has been very important for agricultural producers to meet their needs.”
The first week of the new water year has been very dry compared to the 30-year average. Northern Idaho has received slightly less rain compared to historical data, but hasn’t been nearly as dry as South Central Idaho.
If drier trends continue and the snowpack this winter isn’t substantial, there will be potential water curtailment for junior water right holders if this winter isn’t sufficient to refill and recharge those reservoirs, Whorton said.
Utah
Jordan Clayton, data collection officer at NRCS Utah Snow Survey, told WLJ precipitation levels in the state up until the end of March were above average, and then fell out toward the end of the month and never really recovered.
“We entered the water year at 76 percent of normal for the state of Utah, which is not horrific, but keep in mind that most, if not the vast majority, of that precipitation fell between Oct. 1 and March 31, and almost none of it came the rest of the time,” Clayton said.
Utah is relying on an above-average snowpack to get even a normal runoff response, he said. The soil is so dry right now that a larger percentage of snow that falls this winter is going to get absorbed in the watershed and won’t make it downstream into the rivers.
Roughly 98 percent of the water used in the state comes from the snowpack and La Niсa doesn’t have much of an influence on snowpack in Utah.
“We get a bit of moisture in the summer typically, but that’s not what replenishes our reservoirs and that’s not what makes sure that we have enough groundwater for our withdrawals and things like that,” Clayton said.
Wyoming
About 70 percent of Wyoming’s surface water comes from the snowpack, according to James J. Jacobs, professor of agricultural economics at University of Wyoming, and Donald J. Brosz, associate director at the Wyoming Water Resources Center. On average, about 16.3 million acre-feet of surface water are produced each year by precipitation.
Irrigation is the largest user of consumptive water, accounting for 80-85 percent of consumptive use in the state. Nearly 60 percent of farms and ranches irrigate in the state.
Like the rest of the region, Wyoming has reported drier conditions this year. Much of the state is in some sort of drought, with the central and south-central portions of the state reporting extreme drought. This will likely lead to a prolonged fire season and dry fall.
Aviva Braun and Gerry Claycomb, forecasters at the National Weather Service, reported October may see some precipitation in the second half of the month, but above-average fire risk will continue across the state.
Nevada
“Boom and bust is a pattern familiar to the Silver State. In terms of water supply, 2019 was as good as it gets, while conversely, 2020 has been mostly disappointing,” read the latest Nevada Water Supply Outlook report published this past May.
Precipitation amounts haven’t recovered from the dry fall and most basins failed to reach median peak amounts. Snowmelt began later than normal this year, but progressed rapidly. Most of the state is in extreme drought, with a small area of the southeast side of the state in exceptional drought. — Anna Miller, WLJ editor
