Wotta Canyon is a short canyon tributary of Birrabang Brook. It features several abseils through a fairly low quality section of canyon, with a couple of deep wades or short swims.
Park at the Mt Wilson turn off on Bells Line of Rd, and walk back along the Bell Rd to the top of the hill to the east. Follow the fire trail south and drop into the creek down one of the spurs, aiming for MGA519842. There is a rough track down the spur to the east. Following the creek for a short distance brings you to the start of the canyon.
The canyon starts with a 4m drop from slings around a slightly dodgy tree into a waist deep pool. Then a 5m wade through chest deep water to the start of the next abseil. This is about 10m, from an even more dodgy set up, a rope sling around a couple of tree ferns. Safer is to do the first two drops as one using the original slings, although you probably need about a 50m rope. Then the third abseil is about 7m, but the anchor is high on a tree some 10m back from the drop, so you'll probably need at least 40m of rope. The start is tricky as the abseil is completely overhung, and the anchor a long way back.
That's pretty much it for the canyon. Walk down the creek to the junction with Birrabang Brook, and then exit up Birrabang. You can climb out in a number of places between MGA517852 and MGA519852. Climb the spur to the north and find the track that leads back to Bells Line of Road.
Alternatively, scramble on the left hand side of the first main gully on the right after the canyon section finishes, and from there up to the ridge.