ENVIRONMENTAL SEQUENCE STRATIGRAPHY (ESS): GEOLOGY-FOCUSED CONCEPTUAL SITE MODELS AS A BEST PRACTICE FOR GROUNDWATER PROJECTS

Geology defines the permeability architecture that largely controls the aquifer characteristics of groundwater basins. Geology is the foundation for all groundwater basin assessments including hydrogeologic conceptual models (HCMs), water budgets, groundwater models, and groundwater monitoring networks. However, historically the groundwater industry has marginalized the geology and the focus of groundwater basin management has been on the hydrology. For instance, little to no emphasis is placed on depositional environments and facies models that define the permeability architecture controlled by the geology. Moreover, simplifying assumptions of homogeneous and isotropic aquifer conditions are typically applied to otherwise complex geologic conditions. Environmental Sequence Stratigraphy (ESS) applies best geologic practices from the petroleum industry to address these subsurface geologic complexities by optimizing the use of existing lithology data to construct an improved HCM and define the permeability architecture that controls groundwater occurrence. This technical approach was recognized by the U.S. Environmental Protection Agency (EPA) in their 2017 Groundwater Technical Issue Paper, Best Practices for Environmental Site Management: A Practical Guide for Applying Environmental Sequence Stratigraphy to Improve Conceptual Site Models.

This presentation will cover the following topics:

1. Outline the components of a robust, geology-focused CSM, showing how it differs from the “industry standard”, and explain why it is beneficial to all groundwater projects, big and small (geology is “scaleable”);
2. Present the processes and workflow required to incorporate an ESS-based CSM into a groundwater project;
3. Present case studies of both groundwater remediation and groundwater resources projects.