Potential challenges for the restoration of Biscayne Bay (Florida, USA) in the face of climate change effects revealed with predictive models

Abstract

Estuaries and coastal areas worldwide are rapidly changing, especially those adjacent to urban centers. Physical and ecological stresses are exacerbated by climate change (CC) and sea level rise (SLR). In this research, a salinity transport model for Biscayne Bay is presented. The model is used to estimate salinity under various scenarios of altered precipitation, increased salinity/temperature, and SLR. The simulated scenarios (based on prior studies and existing literature) assumed increases of 1.5 °C in temperature, and 0.6 PSU in ocean salinity. Current precipitation was varied from −10% to +10%. SLR varied from +0.46 m to +2.18 m. The highest increase in bay salinity (worst-case scenario) occurred for 10% decrease in precipitation, and +2.18 m SLR. The lowest increase in salinity (mildest scenario) occurred for 10% increase in precipitation, and +0.46 m SLR. In the mildest scenario, a 50% increase in baseline freshwater inputs is needed to maintain currently observed Bay salinities. For the worst scenario, a 300% freshwater increase would be required. Current Everglades Restoration plans to restore the Bay salinity to “natural” conditions must consider the potential CC-induced effects simulated in this research. Present efforts may not be sufficient to even maintain current salinity conditions in Biscayne Bay. Increasing urban vegetation (urban greening), artificial groundwater recharge with treated wastewater, and decreasing water consumption, are proposed as management measures for reinforcing current and future restoration efforts.