The White Ribbon

*This project was developed as part of Healthy Port Futures. For more detail on the process please see the HPF website.

The White Ribbon, under construction in summer 2021; Illinois Beach State Park and Hosah Park are in the background.

The White Ribbon is an innovative coastal resilience pilot project constructed in 2021, with monitoring ongoing. The feature is the result of research by our team that sought to develop a coastal protection feature that could protect rare terrestrial habitat from accelerated coastal erosion with in-water habitat features. The project was permitted, implemented, and constructed at Illinois Beach State Park and Hosah Park in Zion, IL by the Illinois Department of Natural Resources and the USACE Chicago District with funding from the EPA Great Lakes Restoration Initiative and monitoring from NOAA.

Illinois’s last beach-ridge shoreline, Illinois Beach State Park offers recreational and economic opportunities at the state’s northern border along Lake Michigan. It is home to a dynamic ecosystem where prickly pear cactus blooms in drier areas and swales sustain marshlands. The beach-ridge and interdunal wetlands provide a rare and critical habitat for many species of plants and animals, including multiple threatened or state concern species.

To protect this rare and critical habitat and recreational and economic opportunities along the coast, we set out to design with naturally occurring systems to provide aquatic habitats while slowing erosion without stopping longshore sediment transport (moving parallel to the coastline). This project represents the possibilities of a middle-ground between expensive, intensive capital projects, like armoring and breakwaters, and softer, less expensive, but more maintenance-intensive projects, like annual beach nourishment. It has the potential to work in concert with those methods or alone, which expands the range of possible approaches. While large water level fluctuations are part of the natural processes in this complex coastal ecosystem, Lake Michigan’s near record-high lake levels from 2018-2021 further worsened erosion rate, and consequently threatened public access, critical infrastructure, and important ecological areas. The underwater ridges of the design are more adaptive to the natural systems and less noticeable to the public eye than vertical breakwaters. A three-ridge system, as opposed to a submerged breakwater, is easier to construct and uses smaller stones, providing potential in-water habitat for fish.

The objective of this pilot project is to reduce the wave energy in the nearshore environment without disturbing longshore sediment movement. In this landscape erosion is simultaneously a critical threat and a fundamental process. Our concept was built on an apparent paradox– that we could achieve better outcomes over time with less control by working with the natural processes of coastal erosion. We combined physical and computational modeling to test concepts through a process that was nonlinear and iterative, yet rapid. While modern advances in computational modeling open up new possibilities in design, we still find value in working with actual water and sediment to test concepts and simulate conditions on a small scale. We tested different submerged ridge variations against physical simulations of daily, storm, and post-storm conditions. Then, computational modeling helped calibrate the size, scale, and positioning of the design before installation.

Coastal wave modeling outputs simulate the effects of the white ribbon on waves during a storm event (the dark image on the left) and calm weather with small waves (the lighter image on the right); these results indicate that the storm waves will have their energy depleted significantly (wave height decreases with the lighter colors) whereas the small waves are not effected. This suggests the feature will allow for the maintenance of nearshore sediment transport processes while minimizing the damage from storms during periods of high water.

The site will be monitored before and after implementation to test the effectiveness of this lower-cost, lower impact, and more rapid response intervention. The project will provide valuable insight into low-impact interventions, and accordingly, may offer a model for similar coastal areas struggling with eroding shorelines in the region. Michigan State University’s Theuerkauf Lab and ISGS will monitor onshore and offshore areas via high-resolution aerial photography, single-beam survey, and multiple-beam survey to determine the size, shape, location, and elevation of the land, vegetation, and shoreline position for an additional five years after placement.