Gauge Description:

The river can be run (sans-portage) as low as minus 12 on the Adako Bridge gauge. -3" to +6 inches are the preferred levels. Anything over a foot puts you into a class 5 day with big ledge holes. The gorge has been run much higher.

Wilson Creek is a tributary of Johns river, and the gauge is about 7 to 8 miles below the confluence. If the Johns river gauge is over about 750 cfs the river might be running.   According to the wilsonvisual database, when the Johns flow is between 750 & 800,  visuals have ranged from -3" to +8".

According to Regional Streamkeeper Chris Bell:
"Runnable when Johns River is at least 300 cfs and rising; 400-500 cfs on Johns River corresponds to approximately 0 on the painted Wilson Creek gauge. Keep in mind that Wilson Creek is a tributary to Johns River, and that the Johns River reading is a clue as to what was happening in the Gorge about twelve hours earlier."
 

The Johns River gauge is ~6 hours below the Gorge put-in.  Depending upon season & conditions, it takes ~8 to 14 hours for rain at Grandfather Meadows to reach the Johns gauge.

Note added by Garrick Taylor:

Go to either http://www.boatingbeta.com/cgi-bin/myflows.cgi or http://syotr.org/?s=l to find a virtual gauge based on an AFWS gauge located on Wilson Creek.  This virtual gauge is far more accurate than relying on the USGS gauge on the Johns River.