The city of Portland is developing a GIS-based mapping tool with the goal of better understanding how sea level rise will impact the shoreline.
The process involves collecting data about a variety of coastal infrastructure within the boundary of the city’s coastal flood resilience overlay zone, such as public buildings, roadways, bridges, culverts, sewer and stormwater systems, public utilities, piers, wharves and docks, and beaches, dunes, bluffs and marshes.
The city hired consultant FB Environmental Associates and Acorn Engineering Inc., both in Portland, to conduct a visual inspection of Portland’s shoreline including Peaks Island, Great Diamond Island, Little Diamond Island, Cliff Island and Cushing Island.
The goal is to verify existing spatial data about the type and condition of natural and built shoreline. The data will inform future resilience planning and will be available to the public upon project completion.
The project is funded by a grant through the Maine Office of Community Affairs.
The project comes as the impacts of climate change become increasingly evident.
The city relies on the waterfront for recreation, economic opportunities and transportation. But like other coastal areas, Portland is facing more frequent and intense storms, sea level rise, coastal erosion and altered seasons.
Communities across the region are implementing a range of projects to address coastal flooding and increase resilience. In addition to Portland, the towns of Cape Elizabeth and Scarborough will remove a road that transects a marsh. The road removal will eliminate tide restrictions, restore saltwater marshland and enhance emergent salt marsh upstream of the restriction.
Brunswick installed living shorelines at two sites in 2020 and made small adjustments since then to test new methods for the effective use of nature-based infrastructure for reduced erosion and enhanced wave attenuation.
Falmouth completed an assessment of its town landing to develop recommendations to improve the facility and adapt to the effects of sea level rise and storm surge. South Portland has a project to evaluate hardscape solutions at six coastal sites across the city.
Portland’s coastal flood resilience overlay zone was developed in response to a future of increased coastal flooding. The city worked with the U.S. Army Corps of Engineers to model coastal flooding under a scenario of 3.9 feet of sea level rise by 2100. The zone boundary is based on that modeling. It establishes new standards for flood-resilient development in Portland’s coastal areas, such as elevation requirements for new construction within the zone.
