Community Water Model

Opensource model to examine how future water demand will evolve in response to socioeconomic change and how water availability will change in response to climate.

The Community Water Model allows the assessment of water supply and human and environmental water demands at both global and regional levels. 

 The hydrological model is open source and has been designed to link to other models, enabling the analysis of many different aspects of the water-energy-food-ecosystem nexus. 


  • CWatM represents one of the new key elements of IIASA’s Water program to assess water supply, water demand and environmental needs at global and regional level

  • CWatM is open source and flexible to link in different aspects of the water energy food nexus

  • CWatM will be coupled to existing IIASA models, including EPIC, MESSAGE, GLOBIOM and Global Hydro-Economic Model

  • The vision for the short to medium term is to introduce a water quality component

 The model is the first step towards developing a next-generation global hydro-economic modeling framework, that can explore the economic trade-offs among different water management options, encompassing both water supply infrastructure and demand management. 

The integrated modeling framework will consider water demand from agriculture, domestic, energy, industry, and the environment. It will also take into account the investment needed to alleviate future water scarcity, and provide a portfolio of economically optimal solutions. In addition, it will be able to track the energy requirements associated with the water supply system; for example, pumping, desalination, and inter-basin transfer.  

Rising population and growing economic development mean that water demand is expected to increase significantly, especially in developing regions. At the same time, climate change will have global, regional, and local impacts on water availability. Ensuring this changing supply can meet the increasing demand, without compromising the aquatic environment from which it is derived, is a huge challenge.  Accurate assessment of water supply, human water demand and the water demand of the environment required to maintain this supply, is essential to devise and assess potential strategies to overcome this challenge. 

The Community Water Model is the first step towards developing an integrated modelling framework, which will be able to provide vital information to decision and policy makers.

CWatM design

CWatM will be designed for the purpose to assess water availability, water demand and environmental needs. It includes an accounting of how future water demands will evolve in response to socioeconomic change and how water availability will change in response to climate.

CWatM - Water related processes included in the model design

CWatM outputs

CWatM can be run at daily resolution globally from 5’ to 0.5° or separately for any basin or any region.

Example output from CWatM - Global potential discharge

Example output from CWatM - Global potential evaporation

Short to medium vision

The development of the Community Water Model is the foundation block of the Integrated Modelling Framework.

The next steps towards creating an integrated modelling framework include:

  • Adding water quality (e.g., salinization in deltas and eutrophication associated with mega cities)
  • Qualitative and quantitative measures of transboundary river and groundwater governance into an integrated modelling framework
  • Coupling existing IIASA models to CWATM:


Wada Y , Flörke M, Hanasaki N, Eisner S, Fischer G, Tramberend S , Satoh Y, van Vliet M, et al. (2016). Modeling global water use for the 21st century: Water Futures and Solutions (WFaS) initiative and its approaches. Geoscientific Model Development 9: 175-222. DOI:10.5194/gmd-9-175-2016.

Burek P , Satoh Y, Fischer G, Kahil MT , Scherzer A, Tramberend S , Nava LF , Wada Y , et al. (2016). Water Futures and Solution - Fast Track Initiative (Final Report). IIASA Working Paper. IIASA, Laxenburg, Austria: WP-16-006

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Last edited: 09 October 2019


Peter Burek

Research Scholar


T +43(0) 2236 807 1090


Yoshihide Wada

Acting Program Director


T +43(0) 2236 807 241


CWATM homepage and manual

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Burek P , Satoh Y, Greve P, Kahil T , & Wada Y (2017). The CommunityWater Model (CWATM) / Development of a community driven global water model. In: European Geosciences Union (EGU) General Assembly 2017, 23–28 April 2017, Vienna, Austria.

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