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.
SEI experts analyse how water efficiency and storage methods can help Rwanda meet its sustainable development and economic growth goals.
- SEI briefs
- Climate
- Governance
- Economy
- Water
- 21 March 2023
- Africa
- Eastern Africa
- Rwanda
This study analyses how managed aquifer recharge might affect irrigated agriculture in California's Kings Groundwater Basin during drought.
- Journal articles
- Climate
- Governance
- Water
- 28 May 2022
- California
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
- Other publications
- Climate
- Governance
- Water
- 21 March 2023
- Africa
- Asia
- Oceania
- Europe
- Americas
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 Bolivia'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
- Senior Scientist
- SEI US
- @ahuberlee
- Senior Scientist
- SEI US
- Senior Scientist
- SEI US
- Scientist
- SEI US
- Senior Scientist
- SEI US
- @cyoung_sei
- WEAP and Operations Associate
- SEI US
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
SEI is designing water allocation models that explicitly represent every water right and assess the impact of in-stream flow requirements on water users.
- Project
- Water
- 2017
- California