Since 1904 there is a river gauge in this stream "near Austell" (actually in Lithia Springs), at latitude 33°46'22"N, longitude 84°36'53"W. The watershed area at this point is 246 square miles or 637km². It is 857 feet or 261.2 meters above mean sea level. The flood stage at this point is 10.0 feet or 3.05 meters. The identifier for this gauge is AUSG1.
Major flooding occurred here in July 2005, after Hurricane Dennis dumped enormous amounts of rain across its watershed, just after being soaked by Hurricane Cindy a few days before. It rose to one of its highest levels ever, flooding dozens of homes even well beyond what was considered the 100-year flood plain. About 15 inches or 38cm of rain fell at the gauge before it was ruined by the flood.
The record flood was 20 feet or 6.1 meters in July of 1916. Base flow is around 2.7 feet or 0.8 meters.
Major tributaries include: