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Habitat Assessment

Marina Development

Map credit: Great Lakes Commission, 2004

While there is little Lake St. Clair-specific data on the impact of marina development on coastal habitat, a study on the St. Lawrence River indicated that the construction of marinas, wharves and boat launch ramps contributed to the loss of natural environments and biodiversity. A 1991 study identified three types of impacts of marinas: those stemming from the construction of the site, those associated with the effects of the structure and those resulting from the consequences of their operation .

The construction or expansion of a new marina frequently necessitates dredging. Although the issue of sediment contamination appears to be a minor consideration in the construction of a marina as compared to a commercial port, the impacts of dredging activities should not be dismissed. Indeed, these activities lead to the destruction of riparian sites that are often rich in plant communities and major spawning habitats for certain species of fish. Sediments can be swept away by the current and settle on adjacent habitats during dredging. The presence of marinas in the environment may lead to varying degrees of changes in hydrodynamics, depending on the scope of the work and in-place structures like breakwaters. These structures may also create new sediment deposition zones that are likely to modify existing habitats.

Marina operations can also disturb wildlife species when boating activity is intensive and localized. Moreover, the concentration of a high number of pleasure craft and support services (e.g., restaurants, maintenance) can generate solid and liquid pollutants that can affect the quality of the water and sediments near or within harbor areas, inasmuch as septic tanks are not emptied as per regulations. In Lake St. Clair, portions of the connecting channels and certain other sheltered portions of the Great Lakes nearshore waters are important resting and feeding areas for migrating waterfowl. Recreational boaters can flush and otherwise disturb flocks of resting and feeding birds, causing them to unnecessarily expend energy needed for migration, survival and reproduction. They can also force them to seek less favorable feeding and resting habitat or to alter their migratory schedules. To help relieve this stress, recreational boating is restricted seasonally in substantial portions of Lake St. Clair, which have been declared refuges for migrating waterfowl.

For more information, see: Coastal Habitat Plan, Section V (PDF)