C+S April 2022 Vol. 8 Issue 4 (web)

Figure 3 - High-tide flooding in Boston, Massachusetts (March 2018).

Newburyport, Massachusetts These new flood resilience initiatives do not appear solely in local zoning codes or building codes. Further up the Massachusetts coast - line, the City of Newburyport has also experienced chronic coastal flooding issues. In an effort to minimize future flood-related dam - age, the City of Newburyport revised the local Wetlands Protection Regulations to include updated flood-resistant design requirements. The updated regulations consider the same future flood scenario as the Boston zoning provisions (100-year flood event with 40 inches of sea level rise) but do so through the regulatory jurisdiction of the local Conservation Commission. Concluding Remarks The prevalence of enhanced flood regulations is likely to increase in concert with the projected effects of climate change on future flood events and the inherent uncertainty of those projections. These local regulations are implemented by municipalities using various avenues, as discussed above, and can have significant impacts on projects. It is easy to imagine a scenario where a prospective development project gains traction, only to later discover the more stringent local flood requirements, creating a major or even fatal disruption to the project. These requirements are often manageable but require early identifica - tion and careful planning for successful implementation.

flood elevation or 1.5 feet above the highest finished grade immedi - ately adjacent to the structure, whichever is higher. Boston, Massachusetts Concerns about increased coastal flooding due to sea level rise also drove Boston, Massachusetts, to recently adopt more stringent flood- resistant design standards. However, Boston sought to first establish a target sea level rise scenario and better define the local flood extents and elevations for that scenario. Many guidance tools and policies for sea level rise are based on the approach of linear superposition in which a projected sea level rise quantity is added directly to a present- day flood elevation and compared with the local topography to deter - mine future flood extents. However, as this approach does not consider changes to the dynamic coastal processes with elevated sea levels, it may not accurately reflect the future flood conditions. Therefore, Bos - ton utilized a flood risk model, independent from the FEMA FIRMs and FEMA flood studies, to develop a map of future flood conditions considering rise. This map, intended to represent flood conditions dur - ing a 100-year storm event in 2070 with 40 inches of sea level rise, forms the new Coastal Flood Resilience Overlay District (CFROD). A new article of the Boston Zoning Code, Article 25A, regulates the CFROD, requiring buildings to be designed to this future flood eleva - tion plus 1 foot of freeboard.


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