ILLINOIS BEACH STATE PARK


OVERVIEW
PURPOSE
CONCEPT
DESIGN
PROCESS
MONITORING

This study is designed to test the effectiveness of lower-cost, lower impact and more rapid response intervention in slowing down the erosion rate of targeted coastal shoreline without obstructing the longshore drift or impacting the experience of the coast.  Through the intentional expansion of long-term hydrological and biological monitoring efforts, this project will provide valuable insight and information about the effects of a lower impact intervention.  In turn, this pilot project provides the opportunity to offer a model for nearby coastal areas that are dealing with similar rapidly eroding shorelines and subsequent critical habitat loss.   Regionally, there are many comparable sites to IBSP that will be able to utilize the knowledge generated through this study. 

Healthy Port Futures, in partnership with Illinois Department of Natural Resources (IDNR), will direct the design of a pilot project at Illinois Beach State Park, and work closely with USACE- Chicago District, Michigan State University and The Illinois State Geological Service (ISGS), on the implementation and monitoring of the project, respectively. 

The objective of the project is to develop a low-cost and low-impact intervention to reduce erosion and upland habitat loss in a targeted area, and to maintain or improve the experiential qualities of the coast. This project positions itself 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, thereby expanding the range of possible approaches. Healthy Port Futures developed these ideas through research, physical modeling and iterative design.  The project was later refined through computational modeling in collaboration with partner engineering firm, Anchor QEA.

The valuable Beach Ridge Plain at the Illinois Beach State Park is eroding at an unprecedented rate, due primarily to climate shifts and the associated increase in storm activity

One of the last remaining natural shorelines in the state, Illinois Beach State Park is located in the Zion Beach Ridge Plain, a slow migratory complex that has shifted southward over thousands of years through erosive and accretive processes.  This 3000-acre park, managed by IDNR, supports important wetland, dune, and savanna habitats.  These critical habitats are home to many important endemic and/or endangered plant and animal species, including four federal and sixty state listed species.  

The strong northeastern waves erode the northern portion of the ridge while the southward littoral drift transports and deposits the sediment in the south. Overtime, these processes have built up the unique curvilinear ridge-and-swale topography which support the upland black oak savannas and the lowland wetlands. However, recent shifts in weather patterns and various anthropogenic forces have rapidly increased the erosional process of this region, erasing what took thousands of years to develop in less than half a century.

Lake Michigan’s current near record high lake levels have further exacerbated the erosion rate, and consequently threaten public access, critical infrastructure, and important ecological areas. To protect against loss of critical infrastructure and habitat, IDNR is under an effort to identify and implement sustainable strategies to more effectively manage the shoreline erosion. To this end, HPF was enlisted to help develop an innovative, lower-cost, more rapid-response intervention to slow the immediate threat to important ecological areas from the rampant erosion caused by high lake levels.

The objective of this pilot project is to reduce the wave energy in the nearshore environment while maintaining a modified longshore drift, reducing costs, and minimizing visual impacts. The intervention is designed to dissipate high energy waves in targeted areas to protect identified nearby critical upland habitat, while allowing low energy waves to build and transport sediment behind the feature.  We aim to do this through the creation of a feature that functions as a horizontal field of low ridges, rather than a more vertical wall such as a breakwater. 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.

DESIGN PRINCIPLES

[DESIGN PRINCIPLES DIAGRAM]

DYNAMISM: A recognition of the geologic migratory ridge-swale complex and the cyclical water levels in the lake that contribute to a rich and topographically complex system. 

EXPANSION OF RIDGE AND SWALE: An expanded shore-zone scope that includes the rich, varied, and important habitat types that inhabit the lacustrine upland and nearshore habitats.

 SLOW NOT STOP:  An emphasis on lower impact design that will modify and choreograph coastal process rather than inhibit them.

DESIGN RESEARCH COLLABORATION: A concerted effort to relate findings to regional needs and future projects.


The topographic feature that characterizes the Illinois Beach State Park is the beach ridge plain. This landscape is composed of a series of shore-parallel sand ridges with wetlands between them. The habitat created by the beach ridge, in particular the interdunal panne wetlands that develop between them, is incredibly rare and a priority conservation area for federal and state agencies. But as a dynamic system, the coastal conditions of the park are continually shifting, with a present-day net erosion on the north area of the park and a net gain in the southern area. This process is exacerbated by climate change and the increased intensity of storms that fuel the longshore transport process. As the landscape erodes, habitats that took thousands of years to develop are washed away in months or years.

The strong northeastern waves erode the northern portion of the ridge while the southward littoral drift transports and deposits the sediment in the south. Overtime, these processes have built up the unique curvilinear ridge-and-swale topography which support the upland black oak savannas and the lowland wetlands. However, recent shifts in weather patterns and various anthropogenic forces have rapidly increased the erosional process of this region, erasing what took thousands of years to develop in less than half a century.

Lake Michigan’s current near record high lake levels have further exacerbated the erosion rate, and consequently threaten public access, critical infrastructure, and important ecological areas. To protect against loss of critical infrastructure and habitat, IDNR is under an effort to identify and implement sustainable strategies to more effectively manage the shoreline erosion. To this end, HPF was enlisted to help develop an innovative, lower-cost, more rapid-response intervention to slow the immediate threat to important ecological areas from the rampant erosion caused by high lake levels.

HPF took an iterative approach to rapidly produce and explore various concepts through a combination of physical and computational modeling. This approach is common in landscape architecture, though applying to a sediment-and-water system was more complex.

In concept development, water table experiments were conducted to test out the effectiveness of a variety of broad basic ideas in supporting the overall project concept. Namely, to create intervention that would allow for daily beach-building waves while reducing detrimental storm waves. Physical modeling is a bit unusual these days, with the power of computational means readily available. However, we find it critical in the idea-generating process to design with the intelligence of water and sediment itself, not mere representations of it. These water table conditions were not intended to be calibrated to the particular wave conditions Illinois Beach State Park, but rather were used to intuitively and responsively test the concept objectives in general conditions.  Each iteration went through a series of specific wave conditions meant to glean insight into its response to daily and storm conditions. 

  • The series involved the following sequence of conditions: A long period of small waves representing daily conditions were introduced to the system, followed by;
  • A short period of larger waves representing storm conditions, following by;
  • A long period of small waves representing daily conditions

This series allowed for HPF to study the response of different iterations to daily, storm, and post-storm conditions.   Through this method, the field condition of a series of submerged ridges was developed.

Physical modeling aided in the overall design of the intervention while computational modeling helped calibrate the size, scale, and positioning of the design.  AnchorQEA, a coastal engineering firm, worked with HPF to develop a computation wave modeling and longshore sediment transport approximation (CERC) of the design.  The computation modeling went through a series of iterations as well to tune it to both the site conditions and to meet the outlined goals.

Monitoring is a vital part of the pilot project and will serve to understand the effect of the intervention on the topo-bathymetry, vegetation, wave conditions, and biological communities.  Monitoring will be conducted through Michigan State University and ISGS collaboration, and Stantec. Through an ongoing effort by MSU Theuerkauf Lab and ISGS, onshore and offshore areas will be monitored 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 post placement.  Additionally, Stantec will place wave buoys to measure the wave conditions offshore of the structure.


Monitoring is a vital part of the pilot project and will serve to understand the effect of the intervention on the topo-bathymetry, vegetation, wave conditions, and biological communities.  Monitoring will be conducted through Michigan State University and ISGS collaboration, and Stantec. Through an ongoing effort by MSU Theuerkauf Lab and ISGS, onshore and offshore areas will be monitored 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 post placement.  Additionally, Stantec will place wave buoys to measure the wave conditions offshore of the structure.

This study is designed to test the effectiveness of lower-cost, lower impact and more rapid response intervention in slowing down the erosion rate of targeted coastal shoreline without obstructing the longshore drift or impacting the experience of the coast.  Through the intentional expansion of long-term hydrological and biological monitoring efforts, this project will provide valuable insight and information about the effects of a lower impact intervention.  In turn, this pilot project provides the opportunity to offer a model for nearby coastal areas that are dealing with similar rapidly eroding shorelines and subsequent critical habitat loss.   Regionally, there are many comparable sites to IBSP that will be able to utilize the knowledge generated through this study.