photo: Gilly Elor in The Metro in San Agustin. Photo by Kasia Biernacka.

Exploration in Sistema Huautla has been ongoing for the last 50 years. There have been countless expeditions during that period, which pushed the system to its current length and depth. This has resulted in many books and trip reports being created that describe this exciting journey. Here we will focus mainly on summarizing the expeditions, relevant to connecting Sistema Huautla with its resurgence, and point the curious reader towards more detailed reading.

Diving in Sistema Huautla started during the 1979 San Agustin expedition, when it became increasingly evident that the only way to go deeper in the system was to dive or climb. Most of the cave diving expeditions in the system from that time on were led by Dr. Bill Stone, an engineer who has been continuously developing techniques for sump diving in deep caves, such as the development of the CIS Lunar rebreather. Dr. Bill Stone led multiple cave diving expeditions into Sistema Huautla and the resurgence area in the Santo Domingo Canyon until 2001, when he turned his attention to the nearby Cueva Cheve system.

Noel Sloan discusses a dive plan with Ian Rolland and Kenny Broad (back to camera) on the deck at Devil's Eye spring during rehearsal dives for the 1994 San Agustin expedition. Photo by U. S. Deep Caving Team/Bill Stone.

After the 2001 trip nothing happened in the sumps of Sistema Huautla until 2013, when British caver Chris Jewell planned a trip into San Agustin to dive sump 9. With the help of strong team, he and British cave diver Jason Mallinson made a series of dives in the final sump.  This trip suddenly sparked interest in the region again, which led to the creations of an American-lead expedition,  Proyecto Espeleológico Sistema Huautla (PESH). This organisation had the aim to continue exploration in Sistema Huautla, which is still going on strong to this day.

In 2014 Andreas Klocker and Zeb Lilly joined PESH as both dry cavers and cave divers. Both were new to Mexican caving, but they quickly realised the exploration potential beyond the many sumps. This led to Andreas and Zeb planning the 2015 trip to Redball Canyon, during which they dived multiple sumps and climbed several hundred metres vertically. They were heading towards the surface to find out where one of the last remaining unknown streams in San Agustin emerged from. On this expedition they were also joined by David Bardi and Sandy Varin, both fellow caving buddies of Andreas' from Australia. It was this expedition where the idea for "The Huautla Resurgence Project" was born, with the goal of connecting Sistema Huautla with its resurgence. The Huautla Resurgence Project had its first successful expedition in 2016.

Derek Bristol climbing into Redball Canyon. Photo by Kasia Biernacka.