High-risk erosion areas, and why the setback moves

The state measures how fast the Great Lakes shoreline is moving inland. Where the measured recession rate is at least one foot per year, that stretch of shoreline is designated a high-risk erosion area under Part 323 of the Natural Resources and Environmental Protection Act, and a permanent structure has to sit back from the bluff by a distance derived from that rate.

This is the single highest-stakes number on the whole West Michigan shoreline, and it is also the least understood, because it is not one number. It is a calculation, and the inputs change from one stretch of beach to the next.

The setback is the recession rate multiplied by a number of years, measured landward from what the state calls the erosion reference line: a surveyed line at the top of the bluff or the landward limit of active erosion, not the water's edge.

• Thirty years is the multiplier for a typical single structure. A shoreline receding at 1.5 feet a year produces a 45-foot setback.
• Sixty years applies where the structure is larger (the threshold is based on footprint) or where the parcel is being subdivided. The same 1.5-foot rate now produces a 90-foot setback.
• The rate itself comes from EGLE's own studies of that reach of shoreline, and it is published per property on request.

So two lakefront lots a mile apart, both designated, can have setbacks that differ by fifty feet. Asking "what is the setback on Lake Michigan" has no answer. Asking "what is the projected recession distance for this parcel" does, and EGLE will tell you.

On a deep lot, a setback is an inconvenience. On a shallow one it can be the entire question. It is completely possible, and it happens every year in West Michigan, to buy a lakefront parcel of respectable acreage on which nothing new can legally be built, because the erosion setback consumes all the ground between the bluff and the road right-of-way, and the township's own front setback consumes the rest.

The arithmetic is worth doing on paper before an offer. Take the lot depth. Subtract the erosion setback measured from the reference line. Subtract the township's front-yard setback from the road. What is left is the building envelope, and if it is thirty feet deep you are not building the house in the rendering.

This is also why a vacant lakefront lot priced well below its neighbours is worth a second look rather than a fast offer. Sometimes the discount is the market being slow. Sometimes it is the envelope.

A house built before the designation, or before the current rate was measured, may sit well inside the modern setback. It can stand, because the designation does not require anyone to move a building. But it is legally nonconforming, and that status carries two consequences buyers routinely discover late.

The first is expansion: adding to a nonconforming structure generally brings the addition, and sometimes the whole building, back under the current rule. The second, and the one that matters more, is replacement. If the house is destroyed by fire, by storm or by the bluff itself, rebuilding is new construction, and new construction is subject to the setback as it stands on the day of the application, not as it stood when the original was built.

It is worth asking an insurer about that before closing, not after. A total-loss rebuild that cannot legally occur on the same footprint is a different insurance conversation than a straightforward replacement-cost policy.

Seawalls, revetments and riprap are themselves regulated under Part 323 and, where they touch the water, under the state's inland lakes and streams and Great Lakes bottomlands rules as well. Building one requires its own permit, and holding one requires maintaining it.

Engineered shore protection can change what EGLE will approve on a parcel, but it does not remove the designation and it is not cheap: a serious structure on an active Lake Michigan bluff is a six-figure proposition, and a badly designed one can accelerate erosion on the neighbouring property, which is its own kind of problem.

Great Lakes water levels run on a multi-year cycle with a range of several feet between the high and low ends of it. In the low years the beach is wide, the bluff is quiet, and every lakefront lot looks safe. In the high years, and 1986, 1997, 2019 and 2020 are the recent ones, the water reaches the toe of the bluff, the bluff fails, and Michigan loses houses.

Recession rates are measured across decades precisely because of that cycle. A calm year on the bluff is not evidence about the next ten. NOAA publishes monthly mean levels for the Lake Michigan–Huron system, and the lookup on this site reports the most recent reading from the nearest gauge alongside the erosion finding for exactly this reason.

The report shows whether the parcel intersects a designated high-risk erosion area and draws the boundary over the property. Where the state publishes the projected recession distances for that area, it reports the 30-year and 60-year figures too.

It does not compute a setback for your parcel, and it deliberately will not. That requires the erosion reference line surveyed on the ground and the current rate for that specific reach of shoreline, both of which EGLE issues per property. What the report gives you is the answer to "do I need to make that call", in about twenty seconds.

Many of the underlying erosion studies date from the 1990s. That is not a reason to discount them, since recession is measured over long periods by design, but it is a reason to ask EGLE for the study date along with the number, and the report states the vintage wherever the agency publishes it.