| Variable | Meaning | Weight |
|---|---|---|
| I | Impervious surface % | 0.363 |
| Dd | Pipe length density | 0.493 |
| Di | Inlet density | 0.492 |
| Do | Outlet density | 0.015 |
| E | Elevation risk | 0.279 |
Neighborhoods adjacent to the combined sewer area AND at lower elevation than the combined sewer zone median (305.9 ft) receive a darker color — combined sewer overflow sewage flows downhill into them (2002 Vine City, 2012 Peoplestown).
EJ score = 0.4×flood_risk + 0.35×(pct_Black/100) + 0.25×(1−income/100k). Top EJ = High risk + majority Black + below city median income ($68k).
Validates impervious surface as dominant urban flood risk predictor. doi:10.1007/s11069-020-04480-0
Establishes DCIA as strongest runoff predictor. doi:10.1016/j.ecolind.2020.106929
Sewer surcharge produces manhole overflows; supports no-outlet penalty. doi:10.1080/1573062X.2024.2446528
1 inch of rain = 35M gallons into Intrenchment Creek. Informs live precipitation thresholds. americanrivers.org
Validates PCA methodology for objective factor weighting. doi:10.1080/19475705.2023.2240943
Click any neighborhood on the map or in the list below for flood risk details, contributing factors, demographics, and specific actions to take.
COMBINED One pipe carries both stormwater and raw sewage. During heavy rain it overflows — untreated sewage discharges directly into creeks. Shown as dashed dark teal on the map. Neighborhoods inside the CSO area are colored dark teal; those at lower elevation adjacent to it are teal-blue.
Clean Water Atlanta: consent decree historySANITARY A separate pipe carries only sewage. SSOs occur when pipes fail or block — also a Clean Water Act violation. Shown as dashed blue on the map.
Consent Decree ProgramThe Intrenchment Creek / Custer Avenue drainage area from RedOutline_Project.shp. Shown as a dashed rose outline on the map. This watershed is subject to the 2024 Custer Ave Multi-Benefit Capacity Relief Project under federal consent decree.
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