IGUaNA Module 3: Evaluating the Health of an Urban Wetland Using Electrical Resistivity

External URL: https://www.iris.edu/hq/inclass/lesson/iguana_module_3_evaluating_the_health_of_an_urban_wetland_using_electrical_resistivity

This module emphasizes how electrical resistivity is used as a proxy for measuring salinity in a wetland just outside of New York City, and how the presence of an indicator species is used as a proxy for ecosystem health. Comparing these data illustrates how cities impact the environments around them.

IGUaNA Module 3: Evaluating the Health of an Urban Wetland Using Electrical Resistivity Open Intermediate Open Resource This module introduces students to the fundamental principles and uses of electrical resistivity, with a focus on an environmental application. Students explore the characteristics and environmental setting of Harrier Meadow, a saltmarsh just outside of New York City. They investigate the relationship between electrical resistivity and physical properties of the soil in the marsh. Students also discover how variations in survey configuration parameters control investigation depth (how far into the ground the signals sense) and spatial resolution (what size objects can be detected). Finally, students learn about and then perform geophysical inversion, which is the process of estimating the geophysical properties of the subsurface from geophysical observations. In the final unit of the module, students evaluate the extent to which the geophysical dataset and direct physical measurements support the hypothesis, introduced in Unit 1, accounting for the distribution of Pickleweed in Harrier Meadow. This module is intended to require approximately 2-3 weeks of class time. Teaching material includes PowerPoints that may be used in lectures or provided for self-guided learning, exercises, and handouts that ask students to synthesize what they learn from the exercises. In addition, multiple choice and short answer questions can be given to students as homework, on quizzes, or on exams.   Keypoints: A great fit for courses in Geology Environmental Science Environmental Studies Earth Science Earth System Science Geophysics