Coastal Erosion Management: Balancing Environmental and Economic Considerations

By 2050, an area the size of Connecticut along America’s coastline could be under water, valued at $35 billion. This has a range of implications for municipalities, in both the short and long-term, that need to be confronted. So how do municipalities weigh the economic costs and the environmental impacts?

Long-Term Outcomes

Sea level rise does not affect the entire coastline equally. Current infrastructure, local topography, changes in weather patterns, and other factors can either raise or lower the risk. Even heavily developed shorelines can have different risk profiles depending on the type of development and what it was built on. A home on a sheer cliff may be under threat from erosion, while one in a flatter area may be more prone to flooding damage.

The first step is to inventory what’s on the shoreline, and then develop an informed estimate of how high the sea will rise and what its impacts will be.

Developing A Realistic View of Possible Economic Impacts

Municipalities should evaluate the financial impact, including:

• Private property losses.
• Increases in public and private insurance premiums.
• Property tax revenue impacts.
• Flood insurance costs.
• Long-term budget projections.

While these will be estimates, it will answer the question of what it’ll cost to complete this work, and the cost of not doing so. This will also help determine where solutions such as living shorelines and seawalls become cost-effective

Evaluating Environmental Impacts

Rising seas erode soil and rock, drive freshwater species out of their habitats, raise the salinity of groundwater, and have a range of other environmental effects. Even for towns that have left their shorelines untouched, the risk to that protected environment can be extreme.

An environmental impact study should look closely at what lives in the natural areas, how it interacts with the environment, and what problems changes in salinity might cause in these habitats. Similarly, a hydrological and geological study can assess long term risk to species on land, and whether they’ll be driven into more developed areas or into other habitats.

These impacts will have their own costs. Recent precipitation events in Los Angeles caused nearly 400 mudslides, in part because the plants that would normally anchor the soil weren’t present due to wildfires made more intense by drier conditions.

Sea level rise is inevitable, and only by planning ahead can it be managed. With an understanding of the costs and risks, communities can better accommodate a rising ocean.