Featured Research

from universities, journals, and other organizations

Better Freshwater Forecasts To Aid Drought-plagued West

Date:
February 20, 2007
Source:
University of Washington
Summary:
Western droughts wreak social, economic and environmental havoc. Yet the ability to predict drought at seasonal lead times -- months or longer -- has scarcely improved since the 1960s. Computer simulations aim to improve freshwater forecasts.

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.

Related Articles


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.


Story Source:

The above story is based on materials provided by University of Washington. Note: Materials may be edited for content and length.


Cite This Page:

University of Washington. "Better Freshwater Forecasts To Aid Drought-plagued West." ScienceDaily. ScienceDaily, 20 February 2007. <www.sciencedaily.com/releases/2007/02/070218140343.htm>.
University of Washington. (2007, February 20). Better Freshwater Forecasts To Aid Drought-plagued West. ScienceDaily. Retrieved December 22, 2014 from www.sciencedaily.com/releases/2007/02/070218140343.htm
University of Washington. "Better Freshwater Forecasts To Aid Drought-plagued West." ScienceDaily. www.sciencedaily.com/releases/2007/02/070218140343.htm (accessed December 22, 2014).

Share This


More From ScienceDaily



More Earth & Climate News

Monday, December 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Lava Inches Closer to Highway

Raw: Lava Inches Closer to Highway

AP (Dec. 21, 2014) Officials have opened a new road on Hawaii's Big Island for drivers to take care of their daily needs if encroaching lava from Kilauea Volcano crosses a highway and cuts them off from the rest of the island. (Dec. 20) Video provided by AP
Powered by NewsLook.com
Could Cheap Oil Help Fix U.S. Roads?

Could Cheap Oil Help Fix U.S. Roads?

Newsy (Dec. 21, 2014) As falling oil prices boost Americans' spending power, the U.S. government is also gaining flexibility from savings on oil. Video provided by Newsy
Powered by NewsLook.com
Raw: Scuba Diving Santa Off Florida Keys

Raw: Scuba Diving Santa Off Florida Keys

AP (Dec. 20, 2014) A scuba diving Santa Claus explored the waters of the Florida Keys National Marine Sanctuary. Dive shop owner Spencer Slate makes the dive each year to help raise money for charity. (Dec. 20) Video provided by AP
Powered by NewsLook.com
Obama: Better Ways to Create Jobs Than Keystone Pipeline

Obama: Better Ways to Create Jobs Than Keystone Pipeline

AFP (Dec. 19, 2014) US President Barack Obama says that construction of the Keystone pipeline would have 'very little impact' on US gas prices and believes there are 'more direct ways' to create construction jobs. Duration: 00:47 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins