Sociohydrology modeling for complex urban environments in support of integrated land and water resource management practices

This paper argues that a systems' thinking and explicit modeling approach is needed to address noted weaknesses (in terms of practicality and usefulness) in integrated water resource management. A process of coupling complex regional land use, economy, and water system interactions in integrated modeling is demonstrated with proof-of-concept applications to two urban cases (Chicago and Stockholm). In this uniquely coupled systems model, urban land use scenarios are considered a complex urban system represented by dynamic systems models of land use, economics, and water with a focus on urban environments that include drivers and system feedbacks with implications focused on urban water systems. The integrated model results reveal that the physical availability of land for economic activities (forecasted via a bottom-up land use change model) and their locations differ sharply from top-down sectoral-based economic forecasts. This shows that both human systems (economic and land use planning) and natural systems (land use limitations and associated water implications) need to be considered in order to accurately account for system(s) impacts. For example, flood zone regulations divert land use to other locations, whereas land cover changes can greatly affect the water infiltration characteristics of land surfaces and thereby alter hydrological outcomes. Our results indicate that modeling social and natural processes using a systems approach can provide a more comprehensive understanding of coupled causal mechanisms, impacts, and feedbacks in applications of integrated water resource management.