Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Better freshwater forecasts to aid drought-plagued west

Even at the best of times, the West's water supplies are fraught with political, economic and environmental wrangling. When devastating droughts occurred in the 1970s and the 2000s, farmers and fish alike suffered. Yet the ability to predict stream flows in the Western United States at seasonal lead times – months or longer – is scarcely better today than it was in the 1960s.

Forecasting models that incorporate high-powered computers and satellite data may soon modernize the way Western states manage freshwater supplies. Several such models are currently under development. Dennis Lettenmaier, professor of civil and environmental engineering at the UW, will describe the role of science in Western water management Friday in San Francisco at the American Association for the Advancement of Science annual meeting.

A half-century ago, resource managers would ski or hike to mountain stations and measure the amount of water stored in the snowpack. They took a metal tube and inserted it in the snow, then weighed the tube to calculate how much water it contained. Today's electronic systems automate this process, but use a similar principle, Lettenmaier said.

"If you know how much snow is on the ground in the spring, you have a pretty good idea of how much runoff will occur during the spring and summer," Lettenmaier said. "That's something that's been used for a long time. The question is: can we do better than that?"

A new generation of hydrologic forecasting models integrate not only scattered, ground-based measurements of snow depth, but also satellite measurements of snow extent. The University of Washington's West-Wide Seasonal Hydrologic Forecast System is an example of such a model. It recalculates conditions every day using weather data and satellite images. UW's model incorporates atmospheric climate forecasts and produces forecasts of stream flow for up to a year into the future.

The overall aim is to provide computerized water forecasts equivalent to modern weather-prediction models. The new forecast methods incorporate a wealth of other climate information to produce results earlier in the season, more accurately and for situations that are outside the norm. These methods recalculate conditions every day by incorporating satellite images of snowcover and computing the influence of that day's temperature and precipitation.

Forecasts based on physical processes avoid the problems inherent in statistical forecasting methods that rely on historical patterns. For example, after unusually heavy snowfall in the Southwest in 2003, traditional forecast models predicted that the spring and summer runoff in Utah's Virgin River would be as much as 10 times its normal rate, values that didn't seem believable. In the case of drought, snow levels in 1977 were so low that forecasted runoff for some California streams was negative.

"It's a classic problem of extrapolating a line out past the end of the observations," Lettenmaier said. When current conditions don't look like anything previously seen, methods that are too closely related to historic patterns can fail.

Water managers are beginning to feel a crunch related to climate change, Lettenmaier said. Springtime melt now starts some 20 days earlier than a half-century ago, which is "pretty unequivocally" seen as a signature of climate change, he said. The shift results in a bigger gap between when the fresh water flows down from the mountains and when it actually is most needed in the height of summer. Climate change constitutes an additional challenge, on top of factors such as population movement, agriculture changes and water use changes, that managers must contend with.

Knowing the amount of water ahead of time lets people prepare for droughts or flooding. Building more reservoirs would help, in particular to handle earlier runoff, but the West is unlikely to see any more dams built, Lettenmaier said. Instead, people can use forecasts to decide which crops to plant, whether to drain reservoirs to prepare for flooding and how to allocate water resources early in the season.

Hannah Hickey | EurekAlert!
Further information:

More articles from Ecology, The Environment and Conservation:

nachricht Dispersal of Fish Eggs by Water Birds – Just a Myth?
19.02.2018 | Universität Basel

nachricht Removing fossil fuel subsidies will not reduce CO2 emissions as much as hoped
08.02.2018 | International Institute for Applied Systems Analysis (IIASA)

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Alliance „OLED Licht Forum“ – Key partner for OLED lighting solutions

Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, provider of research and development services for OLED lighting solutions, announces the founding of the “OLED Licht Forum” and presents latest OLED design and lighting solutions during light+building, from March 18th – 23rd, 2018 in Frankfurt a.M./Germany, at booth no. F91 in Hall 4.0.

They are united in their passion for OLED (organic light emitting diodes) lighting with all of its unique facets and application possibilities. Thus experts in...

Im Focus: Mars' oceans formed early, possibly aided by massive volcanic eruptions

Oceans formed before Tharsis and evolved together, shaping climate history of Mars

A new scenario seeking to explain how Mars' putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million...

Im Focus: Tiny implants for cells are functional in vivo

For the first time, an interdisciplinary team from the University of Basel has succeeded in integrating artificial organelles into the cells of live zebrafish embryos. This innovative approach using artificial organelles as cellular implants offers new potential in treating a range of diseases, as the authors report in an article published in Nature Communications.

In the cells of higher organisms, organelles such as the nucleus or mitochondria perform a range of complex functions necessary for life. In the networks of...

Im Focus: Locomotion control with photopigments

Researchers from Göttingen University discover additional function of opsins

Animal photoreceptors capture light with photopigments. Researchers from the University of Göttingen have now discovered that these photopigments fulfill an...

Im Focus: Surveying the Arctic: Tracking down carbon particles

Researchers embark on aerial campaign over Northeast Greenland

On 15 March, the AWI research aeroplane Polar 5 will depart for Greenland. Concentrating on the furthest northeast region of the island, an international team...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

Virtual reality conference comes to Reutlingen

19.03.2018 | Event News

Ultrafast Wireless and Chip Design at the DATE Conference in Dresden

16.03.2018 | Event News

International Tinnitus Conference of the Tinnitus Research Initiative in Regensburg

13.03.2018 | Event News

Latest News

New 4-D printer could reshape the world we live in

21.03.2018 | Life Sciences

Alliance „OLED Licht Forum“ – Key partner for OLED lighting solutions

21.03.2018 | Trade Fair News

Physicists made crystal lattice from polaritons

20.03.2018 | Physics and Astronomy

Science & Research
Overview of more VideoLinks >>>