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Complex Systems Modeling for Decision Making

Complex problems (e.g., climate change, social and economic justice, and sustainable resource management) are difficult to understand because of the intricate web of relationships that make causes and effects of these problems unclear. Complex systems modeling can represent the essential connections and dynamics of these systems, and in this way reveal unintended consequences of decisions and solutions through simulation.

Engaging diverse stakeholders in complex systems modeling allows researchers and decision-makers to formalize shared representations of a problem and, through the joint modeling process, design and test solutions to that problem. This approach is particularly well-suited to address complex social and environmental problems, where a diversity of values and perspectives may lead to conflict about concrete pathways forward. Participatory modeling helps elicit diverse stakeholder knowledge and harnesses this diversity to move from conflict to solutions as the collaboration strengthens relationship-building, empathy, trust, systems thinking, and collective agency for decision-making. 

Our team is creating an online collaborative whiteboard platform called that will allow teams to come together to engage in participatory complex systems modeling and jointly find concrete solutions to community problems. View here.

Zellner, M.; 2024. Participatory modeling for collaborative landscape and environmental planning: From potential to realization. Landscape and Urban Planning 247 (2024) 105063.

Elsawah, S., Filatova, T., Jakeman, A. J., Kettner, A. J., Zellner, M. L., Athanasiadis, I. N., Hamilton, S. H., Axtell, R. L., Brown, D. G., & Gilligan, J. M. (2020). Eight grand challenges in socio-environmental systems modeling. Socio-Environmental Systems Modelling, 2.

Zellner, M., & Campbell, S. D. (2020). Planning with (in) complexity: Pathways to extend planning with complex systems modelling. In Handbook on Planning and Complexity. Edward Elgar Publishing.

Zellner, M. L., Lyons, L., Milz, D., Shelley, J., Hoch, C., Massey, D., & Radinsky, J. (2020). Participatory Complex Systems Modeling for Environmental Planning: Opportunities and Barriers to Learning and Policy Innovation. In Z. Porter & L. Schmitt Olabisi (Eds.), Innovations in Collaborative Modeling: Transformations in Higher Education (pp. 189–214).

Sterling, E. J., Zellner, M. L., Jenni, K. E., Leong, K., Glynn, P. D., BenDor, T. K., Bommel, P., Hubacek, K., Jetter, A. J., Jordan, R., Schmitt Olabisi, L., Paolisso, M., & Gray, S. (2019). Try, try again: Lessons learned from success and failure in participatory modeling. Elementa (Washington, D.C.), 7(1), 9-.

Zellner, M. L., & Campbell, S. D. (2015). Planning for deep-rooted problems: What can we learn from aligning complex systems and wicked problems? Planning Theory & Practice, 16(4), 457–478.

Zellner, M. L., Lyons, L. B., Hoch, C. J., Weizeorick, J., Kunda, C., & Milz, D. C. (2012). Modeling, learning, and planning together: An application of participatory agent-based modeling to environmental planning. Journal of the Urban and Regional Information Systems Association, 24(1), 77.

Zellner, M. L. (2008). Embracing Complexity and Uncertainty: The Potential of Agent-Based Modeling for Environmental Planning and Policy. Planning Theory & Practice, 9(4), 437–457.


Landscape Green Infrastructure Design Model (L-GrID)

L-GrID is a spatially explicit, process-based model that allows for the development and exploration of scenarios to mitigate complex problems at different scales. The model can be adapted to a variety of different problems, including stormwater flooding, water quality, and urban heat islands, and different landscapes and climates. We plan to integrate the L-GrID modules for these problems within our participatory modeling platform, 

The model runs in NetLogo v. 6.2.2, a freely available software that may be downloaded from: For a guide on how to use and customize the model, click on the “Info” tab once you open the file.

L-GrID Versions

View publications at the bottom of the webpage.

Water-Use Land-Use Model (WULUM)

There is serious concern for rapidly declining groundwater levels in many parts of the country. Hydrological studies have suggested that this decline is caused by land-use changes. The Water-Use Land-Use Model (WULUM), an agent-based model that can serve as an analytical framework to understand how these processes interact and create the observed patterns of resource depletion, and suggest policies to revert the process. The agent-based model is empirically based on the case of Monroe County, Michigan, and informed with land-use and survey data and expert knowledge about the case. WULUM has been adapted for participatory modeling in other areas of the country.

View publications at the bottom of the webpage.

Integrated land-use decision-making, water-use decision-making and groundwater flow.


Hydroman is a flexible, spatially explicit model coupling human and hydrological processes to explore shallow water tables and land cover interactions in flat agricultural landscapes, modeled after the Argentine Pampas. Hydroman aligned well with established hydrological models, and was validated with water table patterns and crop yield observed in the study area. We conducted exploration of agricultural land cropping and water table interactions in the context of a changing climate. 

Hydroman is available for download from CoMSES here.

View publications at the bottom of the webpage.

Adaptive sowing decision tree. Land cover rules followed by farmers based on water table depth readings (threshold values are indicated) at different times of the cropping cycle.

Robbins Renewal and Resilience

The Village of Robbins, Illinois, and the Metropolitan Water Reclamation District of Greater Chicago (MWRD) partnered to implement a green infrastructure solution to reduce the flooding events that have plagued village residents for generations. The stormwater park would promote resilience against flooding while offering a new open space amenity, promote the health and well-being of residents, and support the economic revitalization and resilience of the community. MWRD commissioned our team to provide planning support for the various engineering, environmental, and economic development pieces of the project. The core of this effort was developing and conducting novel participatory modeling techniques that would support residents’ and local officials’ full engagement in the collaborative design and implementation planning of the park to achieve its stormwater management and economic development goals. 

View publications at the bottom of the webpage.

Group design activities with modeling clay and scale models of park elements.

Sustainability of FEW Nexus in rural-urban areas: Illinois Innovation Network

Understanding Food-Energy-Water (FEW) systems is crucial to plan for a resilient and sustainable future. This understanding may hold additional challenges in areas where large urban populations are adjacent to sparsely populated rural regions, such that distinctive linkages and drivers of dynamic change may exist between them. The trajectories of such regions may shift in response to economic and demographic trends, and to the additional challenges of a changing climate. Understanding these systems requires pooling expertise across multiple disciplines and domains within both kinds of regions. Our study approaches this complexity by convening panels of subject matter experts and employing a participatory modeling framework to generate causal loop diagrams (CLDs) of the interdependent urban-rural FEW systems, to identify potentially significant lever points in the system and novel paths towards sustainability.

View publications at the bottom of the webpage.

The final diagrams that resulted from the workshops.

Project Publications

Zellner, M.; Massey, D.; Minor, E.; Gonzalez-Meler, M.; 2016. “Exploring the Effects of Green Infrastructure Placement on Neighborhood-Level Flooding via Spatially Explicit Simulations.” Computers, Environment and Urban Systems 59(2016): 116-128.

Zellner, M.; Massey, D.; 2024. Modeling benefits and tradeoffs of green infrastructure: Evaluating and extending parsimonious models for neighborhood stormwater planning. Heliyon 10(5), 15 March 2024, e27007.

Publications on applications of L-GrID to coastal flooding and urban heat island effect are forthcoming.

Zellner, M. L., & Reeves, H. W. (2012). Examining the contradiction in ‘sustainable urban growth’: An example of groundwater sustainability. Journal of Environmental Planning and Management, 55(5), 545–562.

Zellner, M. L., & Reeves, H. W. (2010). Integrating land-use and groundwater modeling: Opportunities, challenges and implications for policy. International Journal of Operations and Quantitative Management, 16(4), 389–414. 

Zellner, M. L. (2007). Generating policies for sustainable water use in complex scenarios: An integrated land-use and water-use model of Monroe County, Michigan. Environment and Planning B: Planning and Design, 34(4), 664–686.

Zellner, M.; Garcia, G. A.; Bert, F.; Massey, D.; Nosetto, M.; 2020. “Exploring reciprocal interactions between groundwater and land cover decisions in flat agricultural areas and variable climate.” Environmental Modelling & Software 126(2020): 104641.

Zellner, M., Boria, E., Massey, D., & Keller, J. (In Press). Building Social and Environmental Capital through Participatory Modeling: The case of the Robbins Renewal and Resilience Project. UIC Justice and Community Disparities Anthology Project

Zellner, M.; Massey, D.; Rozhkov, A.; Murphy, J. T.; 2023. “Exploring the Barriers to and Potential for Sustainable Transitions in Urban-Rural Systems through Participatory Causal Loop Diagramming of the Food-Energy-Water Nexus.” Special Issue: Towards Sustainable Land-Water Interactions in the Anthropocene: The Role of Stakeholder Engagement and Participatory Modelling, Land 2023, 12(3), 551;