Exposure Analysis

Exposure refers to the physical location of the asset located in an impacted area. Because the Greenway runs parallel to the coastline of Downtown Boston, its probable exposure to sea level rise and storm surge flooding is significant.

Using the State of Good Repair asset management database, an exposure analysis was conducted for each of the assets. This was a spatial analysis conducted in ArcMap using data outlined in Table 2 below.

To understand future flood-risks, data was utilized from the most recent Massachusetts Coastal Flood Risk Model (MC-FRM) developed by Woods Hole Group for MassDOT. This model expanded on the original BH-FRM for the entire Massachusetts coastline using updated storm and climate data.

There was no quantitative data available for groundwater flooding, winter weather, or wind. For these assets the sensitivity of the asset is the sole indicator of vulnerability.

All Greenway assets are considered ‘exposed’ to extreme heat during a heat wave, though geolocated surface temperature data was available. A more granular analysis could be conducted looking at localized urban heat island impacts. However, this was not done as a part of this climate vulnerability assessment. The best available climate hazard exposure data is listed in Table 2.

Table 2: Data Used for Analysis

Data Description Source, Year Application

Ground Elevation Elevation of asset LiDAR, 2013 The elevation of each asset will help determine its vulnerability to different hazards.

Critical Elevation Elevation of critical component of asset Kleinfelder, 2020 Based on site walks, some assets have critical components that are at a higher elevation than the ground elevation of the asset. This is the elevation at which inundation would compromise the functionality of the asset, and therefore this is the elevation at which the asset would become vulnerable.