As our climate changes and coastal areas become more populated, we will undoubtedly face new and worsening challenges in our coastal environments. The water quality of estuaries and bays along our coastlines depends on the ability of these systems to transport and flush water-borne material in an efficient and timely manner. Some materials in particular that are problematic for our coastline include harmful algal blooms (HABs), microplastics, and bacterial pollution. What materials like these have in common is that their abundance in a particular region depends on the circulation patterns of the water. However, in regions where the flow interacts with complex topographic features, such as islands, headlands, channel constrictions, and bathymetric variations, these circulation patterns become very complex. In order to predict how material is transported, we must first understand and be able to replicate how complex coastal features can impact local circulation patterns. Numerical hydrodynamic models, which solve theoretical equations to estimate the motion of water, are incredibly powerful tools that we can use to better understand circulation patterns, and ultimately material transport.<\/p>\n\n\n\n
Frenchman Bay, Maine, with its numerous estuaries, islands, and extensive tidal flats, is an exemplary complex coastal system presently facing environmental challenges. In recent years, regionally novel species of harmful algal blooms (HABs) have been detected in Frenchman Bay (personal communication with the MEDMR) and elsewhere in the Gulf of Maine (Bates et al. 2018). HABs are fast-growing algae that can produce toxins under some conditions. When people consume animals like shellfish that feed on these algae, it can lead to illness. For this reason, toxic HABs force the Maine Department of Marine Resources (MEDMR) to make extensive closures of coastal zones to aquaculture farming and shellfish harvesting to ensure public health and safety. Frenchman Bay\u2019s aquaculture, fishing and shellfish harvesting industries are a major source of revenue for the state of Maine, and these closures threaten the economic stability of those industries and the wellbeing of those who rely on them.<\/p>\n\n\n\n
While we are still learning about the conditions that lead to the initiation and growth of HABs, like all water-borne material, the transport of HABs in coastal waters depends on the local hydrodynamics. By improving our understanding of the transport of water-borne materials in complex regions like Frenchman Bay, we can begin to refine the monitoring and management practices surrounding these blooms.<\/p>\n\n\n\n
As a first step, our team has developed a three-day forecast of \u201cparticle\u201d transport in Frenchman Bay. This video forecast provides a tool for informing where material might go in the bay depending on conditions that influence the regional circulation patterns including winds, tides, salinity, and streamflow. Our forecast encompasses the region around Mount Desert Island, home to Acadia National Park. <\/p>\n\n\n\n