Freshwater management challenges are increasingly common. Allocation of limited water resources between agricultural, municipal and environmental uses now requires the full integration of supply, demand, water quality and ecological considerations.

WEAP, the Water Evaluation And Planning system, is a user-friendly, robust software tool that takes an integrated approach to water resources planning. It provides a unique framework for water assessment and planning and is used to represent current water conditions in a given area and to explore a wide range of demand and supply options for balancing environment and development.

WEAP is widely disseminated to water analysts throughout the world in both governmental and NGO settings. SEI conducts training workshops in integrated water planning relying on WEAP as a conceptual framework and practical approach for organizing information and supporting decision-making.

Download the WEAP brochure (PDF, 265kb)

Visit the WEAP website

New version of WEAP adds powerful 'nexus' capabilities

WEAP 3.3, showcased at World Water Week in Stockholm, adds a major new feature: the ability to link seamlessly with SEI's energy and climate mitigation planning software, LEAP, for integrated analysis of water-energy trade-offs (the "nexus"). Used together, the two systems can model evolving conditions in both water and energy systems and show the cross-sectoral impacts of different policy choices.

"With this new dynamic linkage to LEAP, WEAP modelers can now create much more powerful and integrated models to explore both the impact of the energy system on the water system and the water system's impact on the energy system," says Jack Sieber, developer of WEAP.

The new version of WEAP also adds a new function and wizard to help estimate and model environmental flows, incorporating the methodology of the Global Environmental Flow Calculator (GEFC), which was developed by the International Water Management Institute (IWMI). This addresses a different set of nexus issues – the need to ensure that sufficient water is provided to support healthy ecosystems.

WEAP also includes several new features that make it more powerful and versatile:

• Interactive wizard for exploring, comparing and selecting individual time series from one or more CSV text files.

• Numerous optimizations to speed up calculations and display for both data and results.

• Structural changes to WEAP's built-in linear program (LP) solver increases its robustness, and allows for solving much more complex models.

• Several new result reports and additions to WEAP's powerful Application Programming Interface (API).

In addition, now that the WEAP website has been translated into 21 languages, SEI will be working with partners and volunteers to add new language translations to the WEAP software in the coming months.

To learn more or to download WEAP 3.3, visit www.weap21.org.