Figured this might apply somewhat.
Couple years back I had an accident on a motocross track with an ATV. Went over the front end off a large jump, was run over by the atv, and was dragged underneath until it stopped. I had road rash over the entire left side of my back from the butt cheek to the shoulder blade, from hard red clay. EMTs were at the track, but simply didn't have enough sterile water to even begin to clean it out. They gave me instructions of what to do at home.
First, the initial cleaning required scrubbing until I got all the dirt and clay out: no soap. Then I had the whole area irrigated with STERILE water (waterfall water still has bacteria; noticed a few mentioned that; boil water for irrigation). After that, we used a product called 2nd Skin to dress it, its like a water gel pad - semi permeable membrane. Tegaderm would be the choice for backpacking (self adhesive, stays very well, and waterproof). Replaced the dressing daily, irrigating with sterile water every time. No ointments or soap or anti-septic of any kind. The EMTs (and my general practitioner agreed) said most things will simply damage the skin, or slow the healing process (ointments will seal the wound, defeating the purpose of the semi-permeable membrane).
Wound was totally healed after about a month, scarring wasn't too bad, especially considering how deep it was (the lower left area of my back has no feeling anymore from nerve damage).