Numerical Models as Sustainable Groundwater Management Tools: The Role of Sensitivity Analysis in Data Gap Reduction

Trevor Jones wearing a blue button up collard shirt smiling

Trevor Jones
Senior Hydrogeologist – Dudek

Wednesday, February 15, 2023
1pm – CLS 422
watch Trevor’s talk

The development of Groundwater Sustainability Plans (GSPs) across California has provided local Groundwater Sustainability Agencies (GSAs) with the opportunity to re-evaluate their current groundwater monitoring networks and identify areas of improvement to support long-term sustainable management. In basins where aquifer or site-specific data are limited, GSAs are challenged by the need to acquire additional data with the fiscal impacts that construction and implementation of new projects may have on local groundwater users.
While the implementation of data acquisition projects ultimately relies on site-specific requirements, access limitations, and funding availability, the initial identification of beneficial projects can be aided by targeted groundwater modeling analyses and assessments. These analyses fall into a suite of methods referred to as sensitivity analyses, which aim to identify key drivers of uncertainty in the understanding of basin conditions. Sensitivity analyses are relatively inexpensive to perform and can be designed to answer targeted questions associated with predictions that guide basin management. The results from these analyses can then be used by GSAs to develop prioritized project lists and locations that provide the largest reduction in the overall uncertainty in the understanding of basin conditions.
This talk highlights the use of a numerical model sensitivity analysis to support identification and implementation of projects in the Montecito Groundwater Basin. In this basin, interactions between groundwater in the principal aquifer and the coast are uncertain, and projected conditions associated with seawater intrusion are informed by uncertain model predictions. To better constrain these predictions throughout GSP implementation, the local GSAs has pursued projects to acquire additional groundwater quality and level data. Dudek has supported the GSA’s project selection process by performing a numerical model sensitivity analysis to identify key properties and regions that contribute to uncertainty in predictions of seawater intrusion. This sensitivity analysis employed advanced statistical techniques to both design and analyze Monte Carlo simulations based on the original, calibrated numerical model. This presentation will highlight the technical framework utilized for development of the sensitivity analysis and will present key results and insights that inform ongoing project implementation in the basin.