The occurrence of extreme water levels and storms during the last 6 years on Lake Michigan resulted in critical shoreline erosion for both residential and public property. Municipal infrastructure and the safety of the public were at high risk. The bluff composition is primarily glacial till with less than 12% sand. The narrow beaches are primarily sand. The regulatory permitting process is complex and comprised various project locations in Wisconsin.
In the last 2 years, GZA has completed over 40 shoreline assessment studies to quantify the severity of damages and prioritized the repairs to be performed with construction cost estimates. The GZA services also included data collection (topographic and bathymetric survey, soil borings), coastal analysis (water levels, offshore waves, wave transformation-computer modeling and desktop, overtopping rates), geotechnical analysis (slope stability), bluff drainage, selection of a permanent vegetation cover, design development, regulatory permitting, preparation of construction plans, bid assistance, and construction observations. The projects were constructed in 2020 and 2021, and some new sites are under construction in 2022. The restoration of lost habitat was one of the project priorities.
The GZA project team provided all services in-house, and carefully planned and designed the proposed improvements, providing shoreline protection and stable bluff slopes with native plants/revegetation.