Massachusetts flood risk datasets for developed and populated areas, 1997 - 2025

These datasets are intermediate files generated in the production of the flood risk indicator for MassEnviroScreen. See the MassEnviroScreen technical documentation for more detailed descriptions about the flood risk indicator, processing, and originating datasets.

File name

Description

Fields

ma_blkgrp20devFloodAgg.zip
A zipped shapefile for display in a GIS. This file consists of census 2020 block group polygons for Massachusetts with attributes describing the population, buildings, and area exposed to flood risk, as well as other supporting a details. 

GEOID: Census block group geographic identifier

NAME: Census block group name

BGpop: 2020 census population of the block group

DevArea_sqm: Developed area of the block group in square meters

DevFldArea: Developed area of the block group that intersects with an area subject to flood risk

PopFlood: Population estimated to reside within developed areas of block group that intersect with areas subject to flood risk

BldgFlood: Buildings within developed areas of block group that intersect with areas subject to flood risk

BG_bldgCnt: Count of buildings within the census block group

PopFloodPct: Percent of the block group population estimated to reside within developed areas of block group that intersect with areas subject to flood risk

BldFloodPct: Percent of buildings within developed areas of block group that intersect with areas subject to flood risk

CLIMpctilFLD: Percentile score for flood risk indicator

ma_blkgrp20devFloodAgg.csv
A Comma Separated Values (CSV) file for display in a spreadsheet (e.g., Excel) or database. This file consists of records of census 2020 block groups for Massachusetts with attributes describing the population, buildings, and area exposed to flood risk, as well as other supporting a details. 
See field descriptions for ma_blkgrp20devFloodAgg.zip

ma_block20devFlood.zip
A zipped shapefile for display in a GIS. This file consists of polygons representing the developed areas of 2020 census blocks that intersect with flood risk areas. 

GEOID: Census block geographic identifier

DevFldArea: Developed area of the block that intersects with an area subject to flood risk

bldg_cnt: Buildings within developed areas of block that intersect with areas subject to flood risk

DevArea: Developed area of the block in square meters

floodProp: Proportion of the census block that is developed and intersects with flood risk areas

NAME: Census block name

P1_001N: Census 2020 population of the block

GEOID_BG: Census block group geographic identifier

PopFlood: Estimated population of the block within the developed areas subject to flood risk

flood2026MA.zip
A zipped shapefile for display in a GIS. This file consists of polygons representing FEMA-identified Special Flood Hazard Areas as well as areas within 200 meters of a stream for areas lacking FEMA flood maps for entire state of Massachusetts.