GSA Annual Meeting in Indianapolis, Indiana, USA - 2018

Paper No. 96-52
Presentation Time: 9:00 AM-6:30 PM


ARGYILAN, Erin P., Dept. of Geosciences, Indiana University Northwest, 3400 W. Broadway, Gary, IN 46408 and WIBLE, Randi Jean, Indiana University Northwest, 3400 W. Broadway, Gary, IN 46408

This project was developed to address the knowledge gap that exists between the public and geoscientists, pertaining to shoreline dynamics to better inform shoreline management decisions. Shorelines are dynamic systems that experience ongoing change in response to short-term weather conditions and longer-term variations in lake-level and sediment supply. Throughout the Holocene, the southern shoreline of Lake Michigan received littoral drift generated by the erosion of bedrock bluffs and glacial deposits in the northern margin of the lake. Northwest Indiana was created by ongoing shoreline progradation and the development of paralic landforms and associated landscapes. However, human development of the shoreline, including the installation of hard structures that began in the early 1800’s, has dismembered the geologically established littoral drift cells into multiple smaller cells. Although all parts of the ~70 km southern shoreline experience the same lake-level, the shoreline response is highly variable. Shoreline reaches that occur within short distances (<10km) exhibit strikingly different shoreline behavior. This project observes three shoreline reaches associated with hard structures that have developed between the Michigan-Indiana state line and Gary, Indiana. Each reach exhibits erosional shoreline behavior in the east and depositional shoreline behavior in the west. Multiple sites were selected within each reach for photomonitoring. Photographs are acquired monthly by re-occupying the same locations and using a camera, tripod, and a “Rule of Thirds” grid drawn on laminated photos to ensure continuity. Shoreline photos are placed within the context of our understanding of shoreline behavior gathered from analysis of historical aerial photographs.