WEAP is a software tool for integrated water resource planning and policy analysis. WEAP operates on the basic principle of water balance and integrates natural processes (evapotransipiration, runoff, etc.) and engineering aspects (reservoirs, groundwater use, etc.) water systems. WEAP was created to be a decision support tool meant to assist skilled planners. The software is very user-friendly, with a GIS-based interface enabling easy visualization of system components and simulation results. (WEAP website, 2011). Specifically, we have used the MABIA method to simulate climate change scenarios. The MABIA Method is a daily simulation of transpiration, evaporation, irrigation requirements and scheduling, crop growth and yields, and includes modules for estimating reference evapotranspiration and soil water capacity.
WEAP has previously been used as a water balance database, used to record water demand and supply information; a scenario generation tool, simulating water supply and demand, runoff, storage, pollution generation, and more; and as a policy analysis tool, evaluating a range of water development and management options. For more details on previous research using the WEAP model, see: http://weap21.org/index.asp?action=205
This toolbox entry has been labelled with the following tags:
| Sector: | water management | |
| Spatial scale: | sub-national | |
| Temporal focus: | future | |
| Onset: | slow | |
| Role in decision process: | diagnostic | |
| Level of skills required: | modest | |
| Data requirements: | modest | |
| Adaptation tasks: | Appraise regulation options; Potential impact projection; Residual impact projection |
Key Strengths:
The model can run daily, monthly or yearly time steps and provide results on supply requirements, unmet demands, ecological flows, reservoir operations, groundwater storage, hydropower generation, the evolution of soil moisture, evapotranspiration rates, etc. (Sieber and Purkey, 2007). In geographical terms, the model is applicable at sub-national scales.
Key inputs are data required to calibrate the model and accurately describe the water system under study, as well as data and trends to be used in scenario analysis (economic, demographic, hydrological, technological, etc.)
Key outputs of the model are scenario-based long-term effects of policy changes on a water system. The model is presented as assisting in providing answers to questions such as, What if population growth and economic development patterns change? What if reservoir operating rules are altered? What if groundwater is more fully exploited? What if water conservation is introduced?
An intuitive graphical interface provides a simple yet powerful means for constructing, viewing and modifying the system and its data. The main functions--loading data, calculating and reviewing results--are handled through an interactive screen structure that prompts the user, catches errors and provides on-screen guidance. The expandable and adaptable data structures of WEAP accommodate the evolving needs of water analysts as better information becomes available and planning issues change. In addition, WEAP allows users to develop their own set of variables and equations to further refine and/or adapt the analysis to local constraints and conditions. (WEAP website, 2011)
The tool is very user-friendly, and no technical knowledge of programming is required, however, a background in hydrology, water policy, or other related disciplines is desirable. The only technical requirement is a computer running Microsoft Windows. The tool is free to use with registration to the WEAP website.
The WEAP website http://weap21.org/ has published examples, tutorial videos, and a users guide on its website.
An online list of Applications of the WEAP model can be found here: http://weap21.org/index.asp?action=205
Hervé Lévite, Hilmy Sally, Julien Cour, "Testing water demand management scenarios in a water-stressed basin in South Africa: Application of the WEAP model," Physics and Chemistry of the Earth 28 (2003) pp. 779-786, doi:10.1016/j.pce.2003.08.025.
Blanco, I., (2010). Economic-hydrologic analysis of water management strategies for balancing water for nature and water for food. Implications for the Guadiana River Basin, in Spain. PhD Thesis. Universidad Politécnica de Madrid, Madrid.
Blanco-Gutiérrez, I., Varela-Ortega, C., Purkey, D., (accepted, in press). Integrated assessment of policy interventions for promoting sustainable irrigation in semi-arid environments: a hydro-economic modeling approach. Journal of Environmental Management.
Purkey, D., Joyce, B., Vicuna, S., Hanemann, M.W., Dale, L.L., Yates, D., Dracup, J.A., 2008. Robust analysis of future climate change impacts on water for agriculture and other sectors: a case study in the Sacramento Valley. Climate Change 87, 109-122.
Sieber, J., Purkey, D., 2011. User Guide for WEAP21 (Water Evaluation And Planning System). Stockholm Environment Institute. Available online from www.weap21.org
Varela-Ortega, C., Blanco-Gutiérrez, I., Swartz, C. H., & Downing, T. E., 2011. Balancing groundwater conservation and rural livelihoods under water and climate uncertainties: An integrated hydro-economic modeling framework. Global Environmental Change, 21(2), 604-619.
Yates, D., Purkey, D., Sieber, J., Huber-Lee, A., Galbraith, H., West, J., Herrod-Julius, S., Young, C., Joyce, B., Rayej, M., 2009. Climate driven water resources model of the Sacramento Basin, California. Journal of Water Resources Planning and Management 135(5), 303-313.
Yates, D., Sieber, J., Purkey, D., Huber-Lee, A., 2005. WEAP21-A Demand-, priority-, and preference-driven water planning model -- Part 1: Model characteristics. Water International 30, 487-500.
Young, C.A., Escobar-Arias, M.I., Fernandes, M., Joyce, B., Kiparsky, M., Mount, J.F., Mehta, V.K., Purkey, D., Viers, J.H., Yates, D., 2009. Modeling the hydrology of climate change in California? Sierra Nevada for subwatershed scale adaptation. JAWRA Journal of the American Water Resources Association 45, 1409-1423.
The WEAP Website http://weap21.org/
The case study pool contains the following steps that were performed applying the described entry:
weADAPT case studies identified for this toolbox entry:
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Finding Points of Engagement to Integrate Climate Change Adaptation into Water Management Planning
The main lesson learned in the NCAP Guatemala project pertain to assessing the appropriate points of engagement for introducing climate change considerations into policy setting and decision making processes... | |
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Mali NCAP project
Like other Sub-Saharan countries, Mali has been subject to an unprecedented drought since the seventies. To seek solutions to such problem, different studies were conducted under the NCAP project in Kiban, Diouna, and Massabla to understand the use of water resources by different population groups and sectors... | |
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Linking Water Scarcity with Climate Change
The main goal of the Yemen NCAP project was to mainstream priority adaptation activities that would build resilience against increasing water scarcity among vulnerable communities, sectors, and ecosystems in three representative area... | |
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Research On Possible Micro-finance System For Landscape Protection In The Upper Tana
WEAP modelling work focused on water management planning, and in so doing identified the need for better understanding the behavioural aspects of the various actors operating in the basin and how they might respond to a Green Water Credits scheme... | |
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SEI Supports Management Entities In Making Tough Management Choices
The El Dorado Irrigation District (EID) agency, U.S. Forest Services, Sacramento Municipal Utility District, and others are tasked with balancing a complex set of management objectives SEI worked with the EID, a public agency responsible for water management, to develop an application of the Water Evaluation and Planning System... |
Available related training material
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WEAP
Training material for WEAP |
