California Disadvantaged Communities (DAC) and Economically Distressed Areas (EDA), 2023

This dataset republishes California Department of Water Resources (DWR) layers for Disadvantaged Communities (DAC) and Economically Distressed Areas (EDA) at three Census geographies (Place, Tract, Block Group), with County also available for EDA. Source data are joined from American Community Survey (ACS) 2019–2023 5-year estimates onto 2020 Census geographies, and identify communities eligible for California water-related funding programs.

A community is designated Disadvantaged (DAC) when its Median Household Income (MHI) is less than 80% of the statewide MHI per California Water Code §79505.5(a). The published DAC23 field encodes this as Y / N / Data Not Available. The finer Severely Disadvantaged (SDAC) distinction (MHI < 60% of statewide) is not encoded as a separate flag in this dataset — derive it from MHI23 and the statewide MHI threshold relevant to your eligibility window.

Economically Distressed Areas (EDA) are defined per Water Code §79702(k) as a subset of municipalities with MHI < 85% of statewide MHI together with at least two of: financial hardship, unemployment ≥ 2% above statewide, or low population density.

Layers

Files are organized by the published Census geography:

Each layer is published in three formats:

• <prefix>.parquet — GeoParquet for analytical queries (DuckDB, Polars, geopandas)
• <prefix>.pmtiles — Vector tiles for web maps (MapLibre, Leaflet)
• <prefix>/hex/h0={cell}/data_0.parquet — H3 hexagonal tiling at resolution 10, hive-partitioned by H3 resolution-0 parent cell

Field Reference

DAC fields (Tract, Place, Block Group)

EDA-only fields (in addition to the geographic identifiers above)

Note: Source data are published as shapefiles, where DBF column names are capped at 10 characters. Names longer than 10 characters in the original DWR schema are truncated in the GeoParquet (e.g. Date_Record_Last_Edited → Date_Recor, Shape.STArea() → ShapeSTAre).

H3 indexing fields (added by this pipeline)

Usage

DuckDB — analytical query

DuckDB — H3 hex spatial join

MapLibre — DAC tracts overlay

PMTiles internal source-layer names by file:

Citation

California Department of Water Resources (DWR). Disadvantaged Communities and Economically Distressed Areas Mapping Tool, 2023 update. https://gis.water.ca.gov/app/dacs/

Original data layers are republished from the California Natural Resources Agency Open Data hub under the State of California's terms of use.

Data Lineage

• Source: DWR ArcGIS hosted layers, 2023 vintage, downloaded as shapefile (EPSG:4326) from the CNRA Open Data hub
• Conversion: cng-convert-to-parquet produces optimized GeoParquet
• PMTiles: tippecanoe with --drop-densest-as-needed --extend-zooms-if-still-dropping
• H3 hex tiling: cng-datasets vector at resolution 10, parent resolutions 9, 8, 0, hive-partitioned on h0

See boettiger-lab/datasets for the processing pipeline source.