April 1, 2001 | By Jim Lively
and Patty Cantrell
Great Lakes Bulletin News Service
Not all Great Lakes shoreline is the same, so not all structural setbacks need be the same. Setback distances from sensitive shoreline resources — sand dunes, bluffs, coastal wetlands, beaches, forested areas, or combinations of these — can range from 25 feet to more than 100 feet. Where you build determines what you need to do.
It is the nature of sand dunes to move. Lakeshore winds constantly shape and reshape these shifting mountains of sand. Only grasses, bushy plants, tree roots, and deadfall keep sand dunes in place long enough for anyone to recognize them.
It is important to set structures at least 35 feet to more than 100 feet back from the crest of the “foredune,” or most lakeward dune. This distance helps protect stabilizing vegetation and natural habitat from construction disturbance, stormwater runoff, and vehicle traffic. It also protects property owners from sand that can shift and cover up structures.
Some dunes in your area may fall under the state’s category of “critical dunes.” The state has created an atlas of critical dune areas and protects them under Michigan’s Sand Dune Protection and Management Act. Communities should identify state-protected critical dunes. Builders must apply to the state for permits. The community can still ensure enforcement of critical dune protections by adopting the provisions of the state permit into its shoreline protection approval process. This allows local officials to take action on noncompliance.
The practice of draining and filling wetlands to place homes closer to the Great Lakes is a serious threat to coastal wetlands, which are highly valuable to both humans and wildlife.
Countless species of fish and wildlife breed or live in coastal wetlands, which are rich in food and full of shelter. Coastal wetlands also reduce flooding from storms and rising Great Lakes water levels because they can absorb large volumes of water. And wetlands maintain high Great Lakes water quality by filtering sediments and pollution that could flow out from inland activities.
Coastal wetlands are another good reason for communities to consider basing their overlay zone boundary on a resource inventory. Fixed-distance boundaries may not catch the smaller wetlands, which are farther from the shoreline but critical to healthy fish and wildlife populations.
Structures should sit at least 25 feet back from the edges of both year-round and seasonal wetlands to ensure that these bodies of water and plants can serve their vital functions.
Towering walls of gravel, clay, and sand line many Great Lakes shores and stand as monuments to the Ice Age glaciers that once covered the region. These steep bluffs are highly erodible both at their base, from waves and high water levels, and at their tops, from clearcutting, construction, and stormwater runoff. Bluffs can literally erode out from under homes. Bluff erosion also threatens fish and wildlife because clay and silt falls into the water, burying spawning beds and depriving aquatic life of oxygen and light.
Set structures at least 50 feet to 100 feet back from steep bluffs to protect homes, wildlife, and water quality.
Michigan’s Shorelands Protection and Management Act protects some high-risk erosion areas. Communities should identify state-protected bluffs and erosion sites when drawing their overlay zone boundary. Builders in those areas must apply to the state for permits. The community can ensure enforcement of shoreland protections by adopting the provisions of the state permit into its shoreline protection approval process.
Whether sandy or rocky, Great Lakes beaches are a special place for both people and animals. They provide unique habitat for such species as the piping plover, an endangered shore bird, and Pitcher’s thistle, a threatened flower. They also give children, families, and lovers an opportunity to spend the day building sandcastles, playing in the waves, or watching the sun set on the vast inland sea.
Property owners may still enjoy priceless views of the beach and direct access to the water under the setback requirements of a shoreline protection overlay. The buffer zone in between is a place for wild grasses and bushes, but property owners can also thin trees for a filtered view of the water. Observation areas and other places for human activity are also allowed. The overlay’s aim is to make them fit into the natural landscape.
Structures near beaches should sit at least 75 feet back from the ordinary high water mark. This distance gives people and animals the chance to enjoy a natural beach setting free of the driveways and backyards that belong to a different kind of place.
In many areas of the Great Lakes, forests reach all the way out to the water, much like they did in the days before logging cleared vast tracts of Michigan land. Only a few feet of space separates the lake from mature trees in these areas of forested shoreline.
Keeping this forested edge intact is important for protecting the shoreline’s wildlife populations, its soil, and its “north woods” look and feel.
Setting structures back from the forested edge maintains a distinct woodland habitat for such large birds as eagles and osprey, as well as upland wildlife, such as deer and fox. The trees’ root systems are also key to keeping the shoreline itself intact because they hold coarse soils in place.
Homeowners can selectively cut trees or trim branches to create a filtered view of the water without destroying the tree canopy.
Set structures at least 25 feet back from the edge of the tree line to protect habitat, prevent erosion, and preserve the natural, forested shoreline setting.