In EffetsCumulatifsNavigation/ceanav: Research compendium for project on the assessment cumulative effects of marine vessel activities in the St. Lawrence

Bank integrity

Several environmental stressors of anthropogenic and natural origins are added to the natural geomorphological mechanisms that govern the dynamics of bank erosion. With respect to anthropogenic pressures, the factors exerting a particular impact on bank erosion are: wave action caused by marine traffic, flow management, dredging, bank artificialization, and coastal infrastructure and activities [@bernier2020; @bernier2021]. Climate change may also impact bank erosion by altering flood dynamics and water flows [@bernier2020; @bernier2021]. In our assessment, shipping and dredging are the stressors related to marine vessel activities with an established link to bank erosion. This means that we considered bank vulnerability to erosion from the other environmental stressors identified in our study to be zero.

The vulnerability scores assigned to shipping and dredging were directly informed by the data used to characterize bank integrity in the study area, which provides a characterization of bank susceptibility to erosion by dividing bank state into three erosion index levels, with the third level identifying banks that are not vulnerable to erosion [@bernier2020; @bernier2021]. We also distinguished between natural and artificial banks, assigning a higher value to natural banks (see Full Picture of the Study Area).

We can thus classify the categories of banks based on the magnitude of their vulnerability, for which we assigned a relative vulnerability score decreasing by 10% intervals:

1. Natural - Active (EI = 2): 1.
2. Artificial - Active (EI = 2): 0.9.
3. Natural - Semi-vegetated (EI = 1): 0.8.
4. Artificial - Semi-vegetated (EI = 1): 0.7.

No comparison was made to distinguish the vulnerability of the banks to shipping from that of dredging; we instead opted to assign them similar vulnerability values (Table \@ref(fig:bergevuln)).

knitr::include_graphics("./figures/figures-vulnerability/berge.png")

EffetsCumulatifsNavigation/ceanav documentation built on April 17, 2023, 1:02 p.m.