When coastal wetlands are protected from erosion, have adequate sediment supply, and have access to landward migration pathways, they will have high resilience to climate change impacts. To evaluate coastal wetland resiliency to climate change, we examined one aspect of climate change: sea level rise. Using coastal wetland distributions throughout the Bay and the amount of sediment in the surrounding water, resilience of coastal wetlands to current and near future sea levels was determined. Total suspended solids (TSS) data from the Chesapeake Bay Program’s monitoring stations and current and projected sea level rise rates from the Baltimore tide gauge were used. Taken together, these parameters determine if there would be enough sediment in the water to build coastal wetlands as fast as the sea levels will be rising. For 4 millimeters of sea level rise per year, a TSS value of 9 mg/l is needed. For 6 mm of sea level rise per year, a TSS value of 15.5 mg/l is needed.
With current sea level rise rates (4 mm/year), the majority of the regions in Chesapeake Bay have moderate to very good coastal wetlands resiliency scores. The Lower Western Shore, which has a D, is the only region to have a poor score. Five regions scored A or A- and five regions scored in the B range. Under future sea level rise rates (6 mm/year), coastal wetlands will be less resilient. There are no regions that scored an A, and seven regions scored B’s. Two regions scored D’s and one scored an F. More analysis is needed to address the following concerns: the model used to determine thresholds is only theoretical; TSS measurements directly in coastal wetlands rather than in open water are preferable; and, the current analysis assumes TSS stays the same in future scenarios.
