Southeastern Lake Ontario
Last week, we explored several embayments along Lake Ontario, specifically the eastern region between Sodus Bay and Sandy Point. The southeastern shoreline’s unique geological features have shaped the ecological and social uses of the area, and its rapidly shifting morphology creates a unique set of sedimentation issues for the region. This area serves as a case study in the connections and conflicts between ongoing geological processes and subsequent patterns of human useages.
Alternating drumlin bluffs and baymouth barriers comprise the region of Lake Ontario between Sodus Bay and Oswego. These bluffs nourish the nearshore and offshore zones through erosive actions of wave notching, slumping, and gullying. Clays and silts are suspended and fluxed offshore as the prevailing longshore drift disperses coarser materials, sand and gravel, eastwards along the shore. The traveling sand and gravel are the building materials for the baymouth barriers, which act as important protection for the neighboring bays, ponds, and marshes (Pinet, 1998).
Small communities anchored in recreational boating and fishing surround several of these bays (Sodus Bay, East Bay, Port Bay, Blind Sodus Bay, and Little Sodus Bay). An estimated 2000 boat slips and 20 boat launches exist between the five bays (F-E-S Associates, 2000), with a majority of clustered around the largest bay, Sodus Bay. However, these recreational activities are reliant on a consistent channel. Jetties and other structures have been built to divert the coarser material from entering the boat channels, but subsequently and paradoxically, these same structures serve to block the continual re-nourishment of the barriers. Last year, in Port Bay, the DEC reconstructed a barrier which had been eroded to the point of being easily breached by a nor’easter (Buchiere, 2017), depositing over a foot and a half of sediment in some parts of the bay, endangering property as well as important spawning and nursery habitat.
Dredging regimes are dependent on the resources and needs of the community as well as the geologic features of the area. For example, Sodus Bay and Little Sodus Bay, are substantially larger bays, and contend with sandier material. These communities dredge in mid-sized amounts, about 15,000 cy every five years. In comparison, the smaller communities in the other bays, dredge about 1,500 cy every year. In Port Bay, the operation consists of dredging the channel out each year and placing the material back on the eastern barrier, thus providing a simple, but heavy-handed mechanism to bypass the interrupted longshore drift. These smaller operations may provide important opportunities to explore alternate ways to deal with sediment erosion and accretion in unwanted areas that require less human capital.
Buchiere, S. (2017) “Steps Taken to Restore Narrow Bar of Land Separates Port Bay from Lake Ontario”. Finger Lakes Times. https://www.fltimes.com/news/steps-taken-to-restore-narrow-bar-of-land-separates-port/article_6b15767c-d353-11e6-b301-c7d9567c418e.html. Accessed March 8, 2019.
F-E-S Associates. (2000) “Regional Dredging Management Plan Final Report”. Prepared for New York Department of State: Division of Coastal Resources. http://web.co.wayne.ny.us/wp-content/uploads/Planning/Projects/RDMP-Final-Report.pdf . Accessed March 8, 2019.
Pinet, R. P. (1998) “Resolving Environmental Complexity, Southeastern Lake Ontario, NY. In Welby, C. W. and M. E. Gowan. A Paradox of Power: Voices of Warning and Reason in the Geosciences. Geological Society of America.