The main theory is that his accident had something to do with his dog. It’s possible tha this dog went in the canal and he went in to get it out. Once you go into the Coachella you can not simply crawl or walk out. The canal wall is cement, pitched at a 60 degree angle and is covered in algae from the water’s surface to the bottom. You have to be calm and expert enough make it to a ladder. If you miss the ladder you will get sucked into a Siphon. Richard had gone through a siphon.
Thanks for the update!