There is an excellent article in the 2005 newsletter of the Mountain Federation of Valencia. This contains detailed topos and directions for the Barranco del Infierno, Barranco del Sant and Barranco de Mela. I am currently trying to arrange to get an English version of this article.
Barranco del Infierno
There is a gorge called the Barranco del Infierno that is fully equipped for canyoning. Basically it is 'normally' a dry gorge that is fully bolted where required.
Directions to the gorge:
Turn off the the motorway at the Denia turning, and head in the opposite direction to Sagra. From there take the road to Pego. As you descend towards Pego take a turn on the left toward Val de Ebo, this goes up a long hill, with lots of bends (up to about 450m). At the top is an obvious white building that looks like a replica windmill, 20m after this turn left on to a dirt track, follow this track for 4km, it alternates between tarmac and dirt. After 4 km there is turn right signed Les juvees denmig. 100m down there is a parking area by some old buildings. If you miss this turn you reach the end of the road at a well and small parking area, turn around and come back and you'll spot the correct turn after 250m or so.
From the correct Parking area head downhill (it is to left immediately before the shady tree) along a marked footpath, this is the PRV147. This goes down past the the Font de Reinos (spring - the last drinking water), and after about 20mins or so you will reach a streambed in the bottom of the valley. Turn left and you will soon be at the first pitch.
Kit requirements for Barranco del Infierno: Harness, Cowstails (via ferrata shock absorbers not required), short rope for abseils (25m is fine), abseil device. Trainers are fine. Based on dry weather - wouldn't attempt it if the river is flowing.
Technical descent consists of about 10 short abseils, a couple of via-ferrata type sections, a few scrambling bits, and some interesting walking. Almost all the gear is good, normally 2 bolts with connecting chain, but one short pitch had just an old peg.
Timings - 30mins walking descent into gorge, 2hrs in technical section, 45 mins for walk out. Based on competent party of 2, not hurrying but with no hold-ups.
Directions to leave the gorge:
After a final pool traverse carry on walking down the streambed until you reach a T junction. Turn left and follow the riverbed for 20 minutes, until a well made mule track crosses the river. Turn left up hundreds of zig-zags (this is the PRV147 again) until you reach the well at the end of the road mentioned earlier. Carry on up the road and turn left to the parking space.
Thanks to Robin Symonds for all these details.
It would appear that the amount of water in the canyon varies greatly. I suppose that should come as no big surprise. I have had reports ranging from "they spent a lot of time with their lower halves under very very cold 'wet' water" to "we stayed completely dry". I certainly would be cautious during the rainy season, it really can rain in Spain, especially in October, and flash floods are worth considering - drownings have occurred. However most of the time don't be put off taking a camera you just may have to hold it above your heads.
Thanks to Affenmagic for the last tip.
There is a decent looking guide to the barranco published here:http://deco.alc.upv.es/cuevasalicante/pdf/infern%20022.pdf
It contains very detailed topos and maps as well as some nice photos.
The Barranco de Meli in the Guadalest valley would appear to offer plenty of sporting fun with several short abseils, some easy scrambles and some short jumps into pools.