California has embarked on a historic journey to achieve groundwater sustainability with the passage of the Sustainable Groundwater Management Act (SGMA) by the California Legislature in 2014. A specific legislative requirement is the development of a hydrogeologic conceptual model; such a model provides the information about the subsurface architecture needed for generating a groundwater model and for quantifying the water balance. There is widespread recognition of the need to acquire more subsurface data so as to reduce the uncertainty in the conceptual models. But the currently deployed, traditional methods of characterizing aquifers through the drilling of wells with testing and logging are slow, expensive and insufficient in terms of data coverage.
The MUDP-funded project (GAP) was part of a larger project, made up of ten work packages that allowed us to develop the optimal workflow for the use, in California, of AEM data to develop a hydrogeologic conceptual model. In the MUDP project, we included four work packages, that represent the research and development components of the ten in the larger project. The main body of this report contains descriptions of these four work packages. The deliverable from the larger project, the set of recommendations describing the optimal workflow, is presented in the Appendix.
The GAP project has created the foundation for a large-scale procurement from the State of California Department of Water Resources (DWR) for mapping of the Californian geology in all high and medium priority groundwater basins. The first large scale project was tendered out in autumn 2020 requesting use of advanced AEM technology similar to SkyTEM.