Over thousands of years, waves have pushed sand from southern Wisconsin, grain by grain to the shores of Illinois Beach. However, little sand now comes from Wisconsin due to beach protection measures and harbor jetties that divert sand into deep water. Waves continue to move sand southward, but because there is little replenishment from Wisconsin, the remaining beach deposits in Illinois are eroding, endangering structures and wildlife habitat.
Sand is periodically dredged from Waukegan Harbor and brought back to the North Unit to replenish and protect the beach. Without this intervention, Lake Michigan will continue to erode the shoreline, threatening the delicate ecosystems of the park.
At right, see the shoreline at the Illinois Beach State Park office recede from 2010 to 2015.
The graphic below shows how the shoreline in Illinois Beach State Park’s North and South units have changed from 1994 to 2015.
For more information on erosion and erosion control, read “Coastal Erosion Along the Illinois Coastal Zone”
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Waves and currents have carried sand from the southern Wisconsin Lake Michigan shoreline to Illinois Beach State Park for thousands of years. However, very little sand is transported here from Wisconsin today due to Wisconsin’s beach protection measures and harbor jetties. With lake currents continuing to move Illinois Beach sand southward and little sand arriving from Wisconsin to replace it, our remaining beaches are eroding. Notice how the beach sand has moved further south over time in the aerial photographs of Illinois Beach State Park shown below. Beach erosion endangers buildings and structures, unique landforms, and ecological habitats.
Replenishing the beach
Sand is periodically purchased or dredged from Waukegan Harbor, North Point Marina, and Pleasant Prairie Marina, and brought to the North Unit to replenish and protect the beach. Without intervention, the North Unit shoreline will continue to erode away.