OUR PLACE · EVIDENCE & EVERYDAY QUESTIONS
West Georgia’s September 2009 flood
What the local measurements tell us—and what “100-year flood” really means.
A regional disaster, measured locally
The National Weather Service dates the disaster to September 15–22, 2009, after days of prolonged rain. The Douglas County Water and Sewer Authority recorded 21.03 inches in 24 hours during September 20–21. That is one location’s measurement, not a rainfall total for every town in West Georgia. [1]
NWS reports ten deaths in Georgia and a revised property-damage estimate of about $500 million. Portions of I-20, I-75 and I-85 closed. Those figures describe the wider disaster, not Haralson County alone. Behind the measurements were families, homes and livelihoods; this account keeps the focus on understanding the record. [1]
Four familiar waterways
The table below transcribes four USGS station records. Gauge height uses each station’s own reference level. It is not the depth over a road, and comparing heights between different stations does not tell us which neighborhood had deeper water. Peak flow measures how much water passes a point each second. [2]
Notice the dates: the Chattahoochee peak near Whitesburg came two days after the listed Dog River and Carrollton peaks. These records describe different locations and times, not one simultaneous regional crest. [2]
| Station | Peak date | Gauge height | Flow (ft³/s) |
|---|---|---|---|
| Dog River, GA 5 near Fairplay | Sept. 21 | 33.8 ft | 59,900 |
| Sweetwater Creek near Austell | Sept. 22 | 30.8 ft | 31,500 |
| Chattahoochee near Whitesburg | Sept. 23 | 29.84 ft | 60,900 |
| Little Tallapoosa, U.S. 27 Carrollton | Sept. 21 | 17.05 ft | 6,520 |
“100-year” is a probability, not a timetable
A 100-year flood is a magnitude estimated to have a 1% chance of being equaled or exceeded in any given year at a specified location. A 500-year flood corresponds to a 0.2% annual chance. Having one this year does not guarantee a long break before the next. [3]
Assuming independent years and a constant 1% annual chance, the chance of at least one such event in 30 years is 1 − 0.99³⁰, or about 26%. This calculation is an illustration, not a prediction for your home. Estimates can change as records improve or watershed conditions change. [3]
What we can still learn
An old flood photograph is most useful when it comes with a date, a location and the photographer’s account of what it shows. A flooded road in one picture cannot establish the water depth at a different house. Nor does an old image define today’s flood boundary or a suitable drainage design.
We have not established a Bremen-specific rainfall total or complete Haralson County damage tally for this event. Contemporary newspapers, county road-repair files and permission-cleared family photographs could fill that gap. Submit a copy with its provenance rather than an unexplained screenshot. This article reports historical conditions, not current road or river safety.
Sources and limits
Sources reviewed October 13, 2026. This first edition uses published records; it is not a new field inspection. Bracketed numbers link claims to the sources below. Substantive corrections will be dated here.