Shoreline erosion is the property-owner consequence of the lake-level cycle, and Chris Izworski tracks erosion patterns because no other shoreline process drives more property-owner investment, regulatory action, and policy debate on the Great Lakes. The 2019 to 2020 high water cycle exposed shoreline that had not seen modern record levels in three decades, prompted hundreds of millions of dollars in private and public shoreline-protection investment across the basin, and re-set the regulatory and engineering baseline for how shoreline change is anticipated and managed. This page covers what erosion actually is on the Great Lakes, where it matters most, and what property owners can practically do about it.
What it is: the net retreat of the shoreline position over time, driven by wave action, lake-level cycle, ice action, and the underlying geology.
What it is not: short-term beach narrowing during a single high cycle, which can reverse during the next low cycle.
Where it matters most: bluff shorelines (southwest Michigan, Sunrise Side, Lake Ontario south shore), sand-spit features (Presque Isle, Long Point), and engineered shorelines during storm-plus-high-water events (Chicago, Buffalo, Toronto).
Time scale: single storms can produce dramatic short-term retreat; cycle-scale change (multiple years) is more meaningful for property planning.
Reference cycles: 1986 high, 1999 to 2013 low, 2019 to 2020 high on the upper Great Lakes; 2017 and 2019 highs on Lake Ontario.
Erosion on the Great Lakes is the product of three forces operating on three timescales. Lake level (months to decades) sets the baseline elevation at which wave action attacks the shoreline. Wave climate (hours to days) determines the energy delivered to the shoreline at any given time. Ice action (weeks to months) acts during winter freeze and breakup, with ice push and ice ride producing distinctive shoreline damage that wave action does not. Sediment supply, the underlying bedrock or sediment, and human-built structures all modify the response of the shoreline to these forces.
The interaction between lake level and wave climate is the central reality property owners need to internalize. A storm during a low water cycle delivers wave energy to a shoreline that is set back from active wave attack. A similar storm during a high water cycle delivers the same wave energy to a shoreline that is fully exposed, often to portions of the bluff or back-beach that have not been wave-active for years or decades. The 2019 to 2020 high cycle produced damage on shorelines that property owners had reasonably treated as stable through the prior low cycle.
Bluff shorelines are the most exposed property type during high water cycles. Southwest Michigan from Stevensville through Saugatuck is the most prominent example, with multi-foot bluff retreat documented at hundreds of properties during 2019 and 2020. See Southwest Michigan. The Sunrise Side of Michigan from Tawas north through Alpena is another major bluff segment, see Sunrise Side. The Lake Ontario south shore from Rochester east through Oswego experienced comparable damage during the 2017 and 2019 cycles. See Eastern Basin and Thousand Islands.
Sand-spit and barrier features respond to the same forces but with different geometry. Presque Isle at Erie, Pennsylvania, and Long Point on the Ontario Lake Erie coast are the two most distinctive examples. These features are inherently dynamic, with sand transport along the spit driven by long-shore current. High water cycles narrow the back-beach and increase overwash during storm events. See Eastern Basin and Long Point.
Engineered shorelines at urban waterfronts (Chicago, Buffalo, Toronto, Cleveland) experience erosion differently. The shoreline does not retreat in the normal sense because hardened revetments, breakwaters, and seawalls prevent it. Instead, the erosion expression is wave run-up, revetment overtopping, and damage to the engineered structures themselves. The 2019 storm-plus-high-water combination at Chicago drove substantial revetment damage along the public lakefront. See Chicago Lakeshore.
Dune systems at Indiana Dunes, Sleeping Bear, and the southwest Michigan coast respond to erosion forces through dune scarp retreat and active sand transport. The dynamic character of the dunes means short-term shoreline change can be dramatic, but the longer-term trajectory depends on overall sediment supply. See Indiana Dunes, Sleeping Bear, and Southwest Michigan.
Property owners facing active shoreline erosion have several options, each with regulatory, engineering, and cost considerations.
Hard armor includes seawalls, revetments, and bulkheads designed to resist wave attack. Hard armor is effective at preventing further bluff retreat at the protected property, but it does shift wave energy to adjacent unprotected property and can accelerate erosion downdrift. Hard armor is the most common shoreline-protection approach in densely developed shoreline segments and is typically required for high-value bluff property in active erosion zones.
Living shoreline approaches use sand nourishment, vegetation, and softer engineering to absorb wave energy rather than reflect it. Living shoreline is more appropriate for shoreline segments with adequate sediment supply, lower wave climate, and longer planning timescales. Some Great Lakes shorelines are well-suited to living-shoreline approaches and others are not.
Setback and managed retreat remove structures or land use from the active shoreline rather than attempting to defend it. This is the option of last resort for most property owners but is increasingly part of the regulatory and insurance conversation along the most actively eroding shorelines.
The regulatory framework around shoreline protection varies by state and lake. Michigan EGLE administers shoreline alteration under NREPA Parts 325 and 303. Ohio operates through ODNR Coastal Management. New York applies the Coastal Erosion Hazard Area framework through NYSDEC. Ontario uses Conservation Authorities and the Ministry of Natural Resources and Forestry. See Ordinary High Water Mark for the related regulatory line that governs much of this permitting.
For current readings, see the live dashboard. For sub-region-specific erosion context, see Southwest Michigan, Sunrise Side, Eastern Basin and Thousand Islands, and Indiana Dunes. For the regulatory context that governs shoreline-protection permitting, see Ordinary High Water Mark and Save Our Shoreline. For the property-owner-focused decision framework, see Property Owner Guide.