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News and Media
New WEAP adds power, flexibility for water modeling
The Mekong River basin, in Thailand, is one of many sites worldwide where WEAP is being used for water systems planning. SEI PHOTO/AMANDA FENCL.
SEI has released a new version of its WEAP system (Water Evaluation And Planning) with improved analytical tools, more customisation options, and full compatibility with Windows 7, including the 64-bit version.
WEAP was created by SEI scientists more than 20 years ago and has been applied to water systems in the United States, Mexico, Guatemala, Peru, Chile, Spain, Germany, Italy, Lebanon, Israel, Egypt, Ethiopia, Benin, South Africa, and many other countries.
Provided for free to governments and nonprofits in developing nations, and for a fee to others, it is a powerful but simple and accessible tool.
“It’s always been our focus to make the model very easy to use,” says Jack Sieber, developer of WEAP and deputy director of SEI’s U.S. Center. “Anyone who knows how to use Windows or Excel should have no problems. You can also use it with a minimal amount of data, or you can add more and do groundwater modeling, for example.”
And WEAP is very transparent, Sieber notes – not a “black box” with dozens of hidden input variables. For policymakers and stakeholders who may rely on the model results, that is critical, because it allows them to see what variables drive changes in the outcomes.
New customisation options
The new release pulls together two years’ worth of upgrades and improvements, most notably to add flexibility for advanced users. “With this upgrade, the user is able to build much more complex models using our internal script editor, or they can link to other models,” Sieber says.
One recent project used Python scripts to link an external GAMS optimisation model for demand estimation and supply allocation in the Middle East. Another project built an embedded reservoir temperature model in VBScript.
“You have to give the user flexibility to come up with their own uses and ideas,” says David Purkey, director of the SEI-U.S. water program, which distributes WEAP. “This upgrade was really about advancing the technology and allowing the user to find new functionalities.”
Looking at the whole picture
The new release also builds on one of WEAP’s greatest strengths: its comprehensive approach. Historically, Purkey says, modeling tools have dealt separately with two domains: natural systems, including rainfall, snowmelt, evaporation, groundwater, etc., and built infrastructure, such as dams, diversions, and instream flow regulations. WEAP integrates both in a single analytical framework with extensive capabilities in both domains, and it allows users to consider ways to change demand, not just supply.
“You can look at different future climate scenarios and the impact on water resources,” Sieber says. “You can also look at land use changes and how water resources will be affected if cut down forests and use the land for agriculture. You can see the impact of conservation measures.”
In addition, the upgrade enhances hydropower planning capabilities, allowing users to assign supply priorities for hydropower, and change them over time or by scenario.
Another new feature, the Safe Yield Wizard, helps users optimize and evaluate tradeoffs among human and environmental water supply needs, exploring different policies for reservoir release, instream flow requirements and demand management.
SEI provides support to registered users, and it conducts periodic training workshops in integrated water planning with WEAP (next scheduled sessions: SEI-US office (Somerville, MA), Spain, Tunisia, Israel. To learn more, visit the WEAP website, www.weap21.org.
