Johnnies may be the choice class IV/IV+ creek in Alabama. It is the upper end of class IV creeking with one V, Gorilla Constrictor. Room between rapids exists, but there ain't much. This is a super run, and is a favorite of many. Multiple runs per day are often de rigeur. I know it has been run in 19 minutes, but when I'm on it, it takes longer.
The first drop is the easiest on the river. The second rapid is called two out of three because if you go left, you may find a pin spot. In fact, this was the exact ratio when we ran left one time. So I like right, even though it is very tight and likes to collect trees. There is a short warmup section of III+/IV-, then things get pretty steep. Soon you will see the top of a shallow slide, which leads into a big slide best run center to slightly left of center. The first time you run it, as you crest the big slide, you will get a rush. Gorilla Constrictor follows the pool after the big slide. You don't want me of all people to tell you how to run GC - if you are worthy, you'll figure it out.
The runout of GC is runnable above +1" via a seal launch below the final slide of GC. Below this level, you'll have to lower your boat over a rock to put in the pool below GC. Just after that is a right to left curve leading into a sticky short slide run either left or right. Next is Cliff Right, which features an eddy that will make your head spin followed by a drop with a rock right in the middle at lower levels. You then ride it out against or heading away from the river right wall. Pins and pain are possible in this rapid. The next drop, Meltdown, used to smack you against the left wall, but has undergone a series of significant changes, most recently in summer 2021. Enter the rapid driving right over the curler and off the right side of the obvious hump, which has a rock hiding in the center and left. A couple slightly longer and cool rapids follow. One is a follow the current down the left side, another (Bastard) ends up on river right with a neat boof very similar to seven foot falls. The last rapid is very unstable and now has a tree in it on the left. Finally you drop into LRC just above Canyon Mouth Park.
You may be interested in running Upper Johnnies as a warm-up or easier alternative, depending on where you put-in.
Thanks to the folks at Streambeam, Johnnies now has an online gauge which is in the same location as the bridge gauge which has been in use for a long time. The correlation between the Streambeam and bridge gauges is not one-to-one, but is very linear and reliable. On the online gauge, -0.5 ft. is the minimum, it gets good at -0.1 ft., and high around 0.6 ft. The online gauge and more correlation information can be accessed via the link below.
The bridge gauge is painted on the put-in river right piling. I believe very (very) low is -6". 0" (top of the step) is sweet. Medium high is 2-4", and 4" is pretty padded out and getting high. Over 4", I have no good insight for you, you are on your own. Johnnies essentially gets harder the higher it is, though a lot more rocks come into play at low water. As a rule, you want about 2100-2200 cfs in LRC to do this, though the StreamBeam gauge is dialed in at this point.