Groundwater Exchange Pools and Urban Water Supply Sustainability: Modeling Directed and Undirected Networks

E. Porse, K. Mika, R. Williams, M. Gold. W. Blomquist, S. Pincetl


Groundwater basins are important sources of water supply and storage for many cities. Groundwater exchange pools offer
additional opportunities for utilizing these common pool resources, but their potential role in urban water management is not clear,
and modeling such exchanges can be challenging. This paper presents an analysis of the potential for groundwater basin exchange pools
to contribute to urban water supply sustainability. Building on an existing model of urban water management in Los Angeles, the analysis
assesses the potential for groundwater exchange pools to reduce scarcity and demonstrates a method for modeling two-way (undirected)
flows within a directed-network model using linear programming. Results indicate that exchange pools can help alleviate shortages
from operational changes (reduced imported water) in Los Angeles, but providing more parties with access to storage improves their
effectiveness. Exchange pools could potentially provide 6–12% of total supplies and reduce shortages as much as 86%. Considerations
for organizing exchange pools are discussed to explore policy implications for managing common pool resources. The analytical
method for embedding undirected network flows within a larger directed-network model has wide applicability for water resource systems
analysis applications, including modeling water markets and interbasin transfers. 

Published Work | 2018 | Journal of Water Resources Planning and Management

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