Document Type

Article

Publication Date

5-2021

Abstract

Over the past 7 weeks, our group has worked with Laura Sewall of the Phippsburg Comprehensive Planning Committee to create a methodology for assessing properties’ risk to the impending effects of sea-level rise and storm surge, as well as provide recommendations and examples to the Committee on dealing with the socioeconomic effects of these issues. Because Phippsburg is a very large town compiled by 9 distinct villages, we decided to look at a specific area that is densely developed and particularly vulnerable to the effects of sea-level rise and provide risk assessments for the properties that inhabit it. We chose Popham Beach to be that area because it was both particularly accessible to us for data collections and it potentially contained the greatest number and most vulnerable properties of any other village.

We surveyed about 84 different houses along the coast of Popham and we found there was a very concerning number of houses and buildings which were not only at-risk for future extreme SLR scenarios, but at-risk for current highest annual tide and storm surge occurrences. Some of these very vulnerable homes were even newly built, and as the number of people moving to Phippsburg continues to increase, the number of homes vulnerable to SLR and storm surge flooding is also predicted to increase. We created maps using data from the Maine GeoLibrary to visualize which homes are located in parcels projected to be affected by Sea-level rise and using an elevation methodology based around “first-floor elevation”, we were able to find which homes would be vulnerable to sea-level rise and storm surge, and there were an alarming number of them in this particular example. Under a 10.9ft SLR scenario by 2100, 49% of properties will be flooded, with many being projected as dangerously close to flooding. Despite the 10.9ft SLR scenario once being labeled an “extreme” scenario, SLR scenarios have continued to shift towards the more extreme end as annually recorded SLR measurements continue to accelerate faster than expected. Also, 92% of properties are at-risk from flooding via a category 4 hurricane. These properties typically included homes that had both a high first-floor elevation as well as a high topographical elevation, and even despite these homes being somewhat resistant to the flooding effects of category 4 hurricanes, the wind speed itself could harm homes that are built on mountains and don’t have a particularly stable foundation.

Although their effects have continued to accelerate, sea-level rise and storm surge are no new occurrences. Many other low-lying coastal communities have had to deal with their effects. There is a series of interconnecting effects that must be planned for in order for residents to avoid displacement. As people are forced out of coastal communities they will be forced to move inland and build new homes, which also typically coincides with an increase in property prices. Since Phippsburg has many multi-generational homes that get by from fixed incomes, these long-term residents will have a difficult time relocating and can very well be priced out from the town they’ve lived in forever. Based on our sea-level rise and storm surge risk assessments we have crafted some recommendations to the Comprehensive Planning Committee to ensure that this does not occur. These include the tactical use of voluntary managed retreat to avoid a steep tax burden on the residents of Phippsburg when homes inevitably begin to move, the alteration of zoning laws to find a middle ground between preserving the rural nature of Phippsburg and allowing for denser development to prevent further increases in housing costs for residents, and the future implementation of affordable housing options in Phippsburg for people as sea-level rise indirectly makes the cost of housing too high to handle. Nonetheless, the perspective of Phippsburg residents is of utmost importance and they should remain to have a choice in where 2 they live, but current and potential residents deserve to know how this very real threat will affect their homes and investments in the future, and there should be a great deal of collaboration and planning before it is too late.

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