# Teaching Aquitard Concepts With Field‐Based High‐Resolution Head Profile Learning Activities

## TL;DR

This paper introduces classroom and field activities focused on aquitards to enhance hydrogeology education and improve understanding of groundwater processes.

## Contribution

The paper provides novel classroom and field-based learning activities centered on aquitards to supplement limited textbook coverage.

## Key findings

- Classroom activities help students understand the relationship between vertical gradients and hydraulic conductivity.
- Field exercises using high-resolution head profiles improve student intuition about aquitard characteristics.
- Comparing high- and low-resolution profiles highlights uncertainties in aquitard delineation.

## Abstract

Aquitards play critical roles in a variety of hydrogeologic processes. Despite their importance, coverage of aquitards in introductory hydrogeology textbooks is generally limited. This paper provides examples of classroom and field activities designed with an aquitard focus for instructors wishing to supplement textbook content. These activities emphasize high‐resolution head profiles. Examining head profiles prompts students to think about how aquitards influence head with depth and conversely how these plots can be used to delineate and characterize aquitards. During a classroom activity, students explore the connection between changes in vertical gradient and changes in hydraulic conductivity by sketching conceptual head profiles based on given boundary conditions and several aquifer/aquitard scenarios. In a companion field exercise, students measure high‐resolution head profiles using CMT multilevel systems at an outdoor learning laboratory. Students compare the high‐resolution head profiles to lower resolution profiles they obtain from clusters of conventional wells. The field exercise provides students with a tactile experience that can help build intuition for vertical head changes, practice interpreting aquitards from head profiles, and an example of how lower resolution head profiles may create uncertainty in aquitard delineation and vertical gradient estimates. A paleosol at the site forms a prominent aquitard providing a unique basis for discussions about the geology of aquitards and characteristics influencing aquitard integrity. Regardless of the approach used, incorporating more aquitard content into hydrogeology courses at all levels will be beneficial for future hydrogeologists tackling a range of issues from sustainable water supplies to waste disposal.