Scientists develop new tool to forecast drought and water flow in the Colorado river — ScienceDaily

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A team of scientists at Utah State University has developed a new tool to forecast drought and water flow in the Colorado River several years in advance. Although the river’s headwaters are in landlocked Wyoming and Colorado, water levels are linked to sea surface temperatures in parts of the Pacific and Atlantic oceans and the water’s long-term ocean memory. The group’s paper, “Colorado River water supply is predictable on multi-year timescales owning to long-term ocean memory” was published October 9 by Communications Earth and Environment, an open-access journal from Nature Research.

The Colorado River is the most important water resource in the semi-arid western United States and faces growing demand from users in California, Arizona, New Mexico, Colorado and Utah. Because water shortages in the Colorado River impact energy production, food and drinking water security, forestry and tourism, tools to predict drought and low water levels could inform management decisions that affect millions of people.

Current drought forecasts focus on short-term indicators which limits their usefulness because short-term weather phenomena have too great an influence on the models.

“This new approach is robust and means that water managers, for the first time, have a tool to better estimate water supply in the Colorado River for the future,” Robert Gillies, professor in USU’s Department of Plants, Soils and Climate (PSC) and director of the Utah Climate Center, said. “The model can be run iteratively so every year a new forecast for the next three years can be created.”

In addition to ocean memory, water flows are impacted by land systems — including soils, groundwater, vegetation, and perennial snowpack — which play important roles in tempering the effects of short-term precipitation events. The researchers hypothesized that multi-year predictions could be achieved by using long-term ocean memory and associated atmospheric effects and

Most of Mass. under severe or extreme drought conditions, National Drought Monitor says

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Most of Massachusetts is currently under “severe” or “extreme” drought conditions, the National Drought Monitor said Thursday.

An updated map released by the monitor Thursday said southeastern Massachusetts and the Cape and Islands were in the extreme drought category, as was a stretch of the northern part of Middlesex County.

The monitor describes extreme drought as a level that can bring significant crop and pasture losses, as well as “water shortages or restrictions,” according to its website.

Among the Massachusetts communities enacting restrictions Thursday was Cohasset.

Town officials said Thursday in a statement that a drought warning was “currently in effect for all residents,” and that the warning carries “stricter mandatory outdoor water restrictions” than those previously imposed on Sept. 1 due to “abnormally dry conditions.”

The stricter measures that took effect Thursday, the statement said, include a prohibition on using irrigation systems. In addition, officials said, a “handheld hose for ornamental plants and vegetable gardens is allowed daily, only between the hours of 5 p.m. and 9 a.m. Monday-Saturday. No watering is allowed on Sunday.”

Meanwhile, most of central Massachusetts, southern Middlesex County, and Essex County in the northeastern part of the state were under “severe” drought conditions Thursday, according to the monitor.

The monitor says severe drought conditions can result in water shortages and some water restrictions, and crop or pasture losses are “likely.”

Lesser drought conditions were reported elsewhere in New England too.

According to the map, extreme drought conditions were being reported in northeastern Connecticut; the southern tip of Maine, as well as parts of Somerset County in the western part of the state and Aroostook County in the northeastern region; and the southeastern part of New Hampshire.

In addition, the monitor said, virtually all of Rhode Island was under extreme drought conditions Thursday. Governor Gina

Redefining drought in the US corn belt — ScienceDaily

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As the climate trends warmer and drier, global food security increasingly hinges on crops’ ability to withstand drought. But are scientists and producers focusing on the right metric when measuring crop-relevant drought? Not exactly, according to new research from University of Illinois scientists, who urge the scientific community to redefine the term.

“Plants have to balance water supply and demand. Both are extremely critical, but people overlook the demand side of the equation, especially in the U.S. Corn Belt,” says Kaiyu Guan, principal investigator on two new studies, Blue Waters professor in the Department of Natural Resources and Environmental Sciences and the National Center for Supercomputing Applications at Illinois.

The demand Guan refers to is atmospheric dryness, often expressed as vapor pressure deficit (VPD). The drier the air, the more moisture is sucked out of pores, or stomata, in plant leaves. Plants have to open stomata to take in carbon dioxide as their food, but if they sense the atmosphere is too dry, they’ll close pores to avoid drying out. Keeping stomata closed too long leads to reductions in photosynthesis, plant growth, and grain yield.

The kicker? Plants shut down stomata due to atmospheric dryness even when there’s an adequate supply of moisture in the soil.

“If you only consider rainfall and soil moisture, which is how most people think about drought, that’s mostly describing the supply side. Of course if you have low soil moisture, plants will be stressed by how much water they get. But the supply is often pretty sufficient, especially here in the U.S. Corn Belt,” Guan says. “However, the demand side from the atmosphere can also severely stress plants. We need to pay more attention to that drought signal.”

Guan’s two recent studies used multiple technological approaches, including field measurements, various sources of satellite data,