120-8 Land subsidence modeling in the Central Valley of California: are complex models always needed?

Session: Land Surface Subsidence: Processes, Impacts, and Ongoing Challenges

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Determining the appropriate level of complexity needed in a groundwater model to answer specific management questions remains a challenging task. Over-simplification can lead to uncertainty underestimation or bias in simulated responses to groundwater stresses.  On the other hand, overly complex models typically suffer from numerical instability, extreme computational demand, and long development and simulation times.

Within the context of groundwater management in the Central Valley of California, land subsidence resulting from groundwater withdrawals is a well-known management issue and groundwater models are commonly used to evaluate land subsidence under various possible future groundwater withdrawal scenarios.  Models used in the Central Valley of California range from simple one-dimensional equilibrium compaction models to three-dimensional integrated surface-water/groundwater numerical models that include many facets of the hydrologic cycle with a high degree of spatial and temporal resolution. 

In this talk, we will discuss tradeoffs associated with using simple and complex models to support land subsidence management in the Central Valley of California. These tradeoffs include 1) the cost of developing the model, 2) the ability to represent critical processes that affect land subsidence at appropriate scales, and 3) the ability to assimilate historical land subsidence observations with the intent to identify important factors for conducting model-based land-subsidence analyses to support groundwater management.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

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