Many regions are facing formidable freshwater management challenges. Allocation of limited water resources, environmental quality and policies for sustainable water use are issues of increasing concern. Conventional supply-oriented simulation models are not always adequate.
Over the last decade, an integrated approach to water development has emerged that places water supply projects in the context of demand-side issues, water quality and ecosystem preservation and protection. WEAP incorporates these values into a practical tool for water resources planning.
WEAP is distinguished by its integrated approach to simulating water systems and by its policy orientation. WEAP places the demand side of the equation – water use patterns, equipment efficiencies, reuse, costs and allocation – on an equal footing with the supply side – streamflow, groundwater, reservoirs and water transfers. WEAP thus provides a laboratory for examining alternative water development and management strategies.
WEAP is comprehensive, straightforward and easy-to-use, and attempts to assist rather than substitute for the skilled planner. As a database, WEAP provides a system for maintaining water demand and supply information. As a forecasting tool, WEAP simulates water demand, supply, runoff, streamflows, storage, pollution generation, treatment and discharge, and instream water quality. As a policy analysis tool, WEAP evaluates a full range of water development and management options, and takes into account multiple and competing uses of water systems.
To see a full list of publications that use WEAP – including those produced outside of SEI – see the publications page of the external WEAP website.
Urban and agricultural growth in Bolivian dry forests are putting pressure on groundwater and surface water supply. SEI research seeks to quantify the problem.
- SEI briefs
- Governance
- Land
- Water
- 24 January 2022
- South America
- Bolivia
This article discusses how different climate scenarios affect the water-energy nexus in California, employing the WEAP modelling tool.
- Journal articles
- Climate
- Energy
- Governance
- Water
- 29 September 2021
- United States of America
- California
SEI researchers quantified the impact of irrigation and climate variability on the fluctuation of water levels in Lakes Titicaca and Poopó by applying WEAP.
- Journal articles
- 23 September 2021
This study demonstrates how incorporating social factors into water modelling can lead to a more equitable water supply.
- Journal articles
- Water
- 19 August 2021
- Cambodia
- Other publications
- Water
- 26 March 2021
- Mekong
This study finds that water management is a larger threat to rice and ecosystems than the warming temperatures of climate change.
- Journal articles
- Water
- 9 February 2021
- Cambodia
This article provides insights from a case study testing the Tandem framework for the co-design of climate services in Colombia's Campoalegre River Basin.
- SEI briefs
- Climate
- Water
- 24 September 2020
- Colombia
Investigadores de SEI presentan avances sobre la modelación estratégica utilizando el Sistema de Evaluación y Planeación del Agua (WEAP)
- SEI working papers
- Water
- 1 December 2019
- Bolivia
SEI built WEAP models for seven major river basins, enabling the exploration of policies and investments under various climate futures.
- SEI briefs
- Water
- 15 October 2019
- Sub-Saharan Africa
The Sacramento Water Allocation Model, known as SacWAM, mimics one of the most complex water systems in the US.
- SEI briefs
- Water
- 7 May 2019
- California
Policy-makers can now model the effect of management options on the availability of habitat and the viability of aquatic species.
- SEI briefs
- Water
- 6 May 2019
- California
RDS helps stakeholders create a shared mental model of available opportunities and potential trade-offs for various objectives.
- SEI briefs
- Water
- 6 May 2019
- California
SEI researchers used the Gridded Meteorological Ensemble Tool for a water balance study in Bolivia, marking the first time the tool was applied outside the US.
- SEI briefs
- Water
- 7 March 2019
- Bolivia
This paper describes the development of poverty-related indicators in SEI's Water Evaluation And Planning (WEAP) tool.
- SEI working papers
- Water
- 1 August 2018
- Colombia
An overview of the development scenarios for Rwanda SEI researchers co-created with stakeholders and explored using the LEAP and WEAP tools.
- SEI reports
- Water
- Energy
- 31 May 2018
- Rwanda
- Sub-Saharan Africa
This study examines how the continued development of hydroelectric dams could affect one of the largest wetland systems in South America.
- Journal articles
- Water
- 8 May 2018
- Colombia
This paper evaluates a coupled water planning and crop model for irrigated agriculture that researchers deployed in Yolo County, California.
- Journal articles
- Water
- 2 October 2017
- United States of America
This document draws on SEI experience with WEAP and LEAP to provide guidance for mainstreaming gender and social equity issues into modelling studies
- Other publications
- Energy
- Water
- Gender
- 30 April 2017
- SEI reports
- Climate
- Energy
- Water
- 28 December 2016
- Middle East and North Africa
- Journal articles
- Water
- 2 November 2016
- California
- SEI briefs
- Energy
- Water
- 11 September 2015
- Colombia
- Journal articles
- Energy
- Water
- 21 July 2015
- United States of America
- Journal articles
- Energy
- Water
- Land
- 6 February 2015
- Ethiopia
SEI Senior Scientist Laura Forni explains why gender and income inform inequities in access to irrigation water in a rural Cambodian watershed.
- Feature
- Gender
- Governance
- Water
- 11 January 2022
- South-eastern Asia
- Cambodia
SEI Senior Scientist Chuck A. Young explains why California saw severe water shortages this year and how better forecasting can help alleviate those challenges.
- Feature
- Water
- Climate
- Governance
- 29 November 2021
- California
- United States of America
SEI's flagship water modelling tool helped a San Jose-area water district identify an opportunity to help protected steelhead in the wake of dam construction.
- Feature
- Water
- 25 August 2021
- California
This perspective suggests how to better integrate water modelling into policymaking in countries of the Asia-Pacific.
- Perspective
- Water
- Governance
- 23 August 2021
- Asia
The eWRIMS Analyzer transforms California’s water rights data into accessible reports on monthly water use in each watershed.
- Feature
- Water
- 18 August 2021
- United States of America
- California
This World Water Day, six researchers share insights on the value of water and lessons learned on how to equitably manage and protect this valuable resource.
- Perspective
- Water
- Climate
- Health
- Governance
- 22 March 2021
- Africa
- Europe
- EU
- United States of America
- Asia
SEI's Marisa Escobar, Alison Dyke, and Hector Angarita introduce the new SEI Initiative on Water Beyond Boundaries.
- Feature
- Water
- 22 March 2020
- United States of America
- Colombia
- Mekong
The Mara River is a crucial water source for farms, villages and ecosystems. Researchers and stakeholders are working together to ensure it remains sustainable.
- Perspective
- Water
- 19 August 2019
- Kenya
- United Republic of Tanzania
SEI is working with the U.S. Department of Energy and the California and Chinese governments to help policy-makers plan for resilient water and energy systems.
- Feature
- Water
- Energy
- 23 May 2019
- California
- China
SEI's Charles Young and Stantec's Andy Draper won for their work on an unprecedented water model of the Sacramento-San Joaquin Delta.
- Feature
- Water
- 26 April 2019
- California
SEI researchers Felipe Benavides and Jeanne Fernandez reflect on a recent tour of Boliva's Tupiza watershed, where residents have "lost everything."
- Perspective
- Water
- Health
- 21 March 2019
- Bolivia
SWARM, a new platform for water management, combines hydrological modelling and stakeholder input to improve river basin management in Southeast Asia.
- Perspective
- Climate
- Water
- 13 March 2019
- Asia
- South-eastern Asia
An innovative water management exercise fostered hands-on learning in Cambodia at a workshop held through the Sustainable Water Partnership.
- Perspective
- Water
- 18 October 2018
- Cambodia
- Feature
- Water
- Governance
- Land
- 25 August 2016
- United States of America
21 of California’s groundwater basins and sub-basins are critically overdrafted. We must break entrenched positions and find sustainable solutions.
- Perspective
- Water
- Governance
- 3 November 2015
- California
- Feature
- 2 September 2015
Laura Forni explains how a large-scale scenario exercise could help decision-makers find the best way to allocate limited water resources.
- Feature
- 27 August 2012
- Afghanistan
- SEI US Water Program Director
- SEI US
- @MEscobar_Agua
- Centre Director
- SEI Latin America
- @dpurkey1
- Scientist
- SEI US
- Scientist
- SEI US
- Senior Scientist
- SEI US
- @ahuberlee
- Senior Scientist
- SEI US
- Senior Scientist
- SEI US
- Scientist
- SEI US
- Senior Scientist
- SEI US
- Senior Scientist
- SEI US
- @cyoung_sei
The Sacramento Water Allocation Model enables policy-makers to weigh difficult trade-offs in water use, by simulating a complex water system in the US.
- Project
- Water
- 2014
- California
SEI adapted WEAP to assess the needs of chinook salmon and steelhead trout in the Santa Clara Valley Water District.
- Project
- Water
- 2015
- California
SEI worked with the Yolo County Flood Control and Water Conservation District to produce a Stormwater Resources Plan.
- Project
- Water
- 2017 - 2018
- California