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 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 the CWATM

Example output from the CWATM

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:

Processes included in the Community Water Model


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

Print this page

Last edited: 06 June 2017


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

Search all Water Programms publications

International Institute for Applied Systems Analysis (IIASA)
Schlossplatz 1, A-2361 Laxenburg, Austria
Phone: (+43 2236) 807 0 Fax:(+43 2236) 71 313