Water Quality Modeling

Water quality modeling for water availability/scarcity assessment, water-energy-land-environment nexus analysis and identification of cost-effective solutions under long-term changes.

© Siegi232

© Siegi232


Water quality issues pose increasing risks to human health, water security and ecosystem functioning worldwide. Water quality is an important consideration in both water supply and environmental quality. In this context, water quality modeling is added as a new component into IIASA’s Water Program to assess the long-term impacts of future changing socio-economic and climatic conditions on water quality and water resources, and to identify potential solution options. 

Two main lines of ongoing activities

1. Water quality modeling using the MARINA model (Strokal et al., 2016), mainly in collaboration with the Water Systems and Global Change Group, Wageningen University & Research, Netherlands.


  • The nutrient export model MARINA is soft-linked to other IIASA models to explore basin-scale nexus solutions.

  • A global gridded water quality model is being developed (currently for nutrients, next steps including sediment transport and salinity).

  • The model is intended to be open source, modular and will be coupled with existing IIASA models, including CWATM and ECHO.

MARINA was originally developed for China to quantify nutrient export to seas (Strokal et al., 2016) and recently up-scaled to the world for multiple pollutants in rivers from point sources. As part of on-going IIASA projects, the MARINA model is used to quantify current and future nutrient export to coastal waters for selected large river basins (e.g., Zambezi, Indus, Yangtze) under different socioeconomic development and climate change pathways. To this end, the model is soft-linked to other IIASA models (CWATM, ECHO, GLOBIOM, EPIC, etc.) to explore basin-scale nexus solutions. The model linkages (Figure 1) and some example outputs (Figure 2) for the Zambezi river basin are shown below. 

2. Development of a global gridded water quality model (currently for nutrients, next steps including sediment transport and salinity)
The model is intended to be open source and will be coupled with CWATM and ECHO. To facilitate the coupling with these models, it is designed as a flexible modular process-based parsimonious model with a mixture of empirical or mechanistic process descriptions. This is part of our efforts to develop a next-generation global hydro-economic modeling framework that can explore the economic trade-offs among different water management options, encompassing both water infrastructure and management of water demand and water resources.

Figure 1 The MARINA model is soft-linked to CWATM and ECHO at IIASA’s Water Program to explore economically-optimal water management solutions for selected river basins.

Figure 2 Illustrative example of the MARINA output for annual river export of total dissolved nitrogen by source (TDN, kg/km2/yr) for the Zambezi river basin. The figure illustrates the increase in river export of TDN to sea between 2010 and 2050 (business-as-usual scenario), the increasing share of anthropogenic nitrogen sources and high spatial variability in the Zambezi basin (Tang et al., in preparation).

Relevant Publications

Strokal M, Kroeze C, Wang M, Bai Z, Ma L, (2016). The MARINA model (Model to Assess River Inputs of Nutrients to seAs): Model description and results for China. Sci. Total Environ. 562, 869–888. DOI: 10.1016/j.scitotenv.2016.04.071

Tang T, Strokal M, van Vliet MTH, Seuntjens P, Burek P, Kroeze C, Langan S, & Wada Y (2019). Bridging global, basin and local-scale water quality modeling towards enhancing water quality management worldwide. Current Opinion in Environmental Sustainability 36: 39-48. DOI:10.1016/j.cosust.2018.10.004.

Tang T, Strokal M, Wada YBurek PKroeze Cvan Vliet M, & Langan S (2018).Sources and export of nutrients in the Zambezi River basin: status and future trend. In: International Conference Water Science for Impact, 16-18 October 2018, Wageningen, Netherlands.

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Last edited: 15 March 2021


Ting Tang

Research Scholar Water Security Research Group - Biodiversity and Natural Resources Program


Yoshihide Wada

Principal Research Scholar Water Security Research Group - Biodiversity and Natural Resources Program

International Institute for Applied Systems Analysis (IIASA)
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