Decadal Trends in Lake Michigan Nearshore Waves and Alongshore Sediment Transport

Session: 51. - Coastal Resilience

Cary Troy, Purdue University, [email protected]
Nicholas Olsen, Purdue University, [email protected]

Abstract

Recent shoreline changes in Lake Michigan, particularly along Wisconsin and Illinois shores, have caused concern for residents, municipalities, and scientists.  While much of the very recent beach erosion can be linked to elevated lake levels, an open question is the relationship of the increased erosion to changing winds and, in turn, waves.  This study attempts to discern long-term changes in nearshore waves and the potential alongshore sediment transport rate of sands along Lake Michigan shores, and the relationship of these changes to changing winds and waves.  Calculations are performed using the U.S. Army Corps of Engineers Wave Information Studies (WIS) output, which are validated hindcast simulations of the nearshore wave climate.  A standard wave routing procedure is used to route the hindcast nearshore waves to breaking.  Then, the well-known CERC potential alongshore sediment transport formula and its more recent updates are applied in order to infer the potential alongshore sediment transport rates.  Results are presented for several Lake Michigan shorelines, in the context of observed changes to winds and waves, highlighting both long-term sediment transport patterns as well as their interannual variability.

1. Keyword
coastal processes

2. Keyword
waves

3. Keyword
sediment transport

4. Additional Keyword
erosion

5. Additional Keyword
nearshore