They arrived in Thailand and began the process of pushing through the flooded passages toward the team’s presumed position. The diving conditions they encountered were extreme by any standard. The passages between Sam Yaek and the deeper chambers were filled with chocolate-colored water — dark, full of suspended sediment, and carrying current. Visibility was zero. The passages were tight, requiring equipment to be removed and pushed through separately at certain points. Navigation was by touch alone, following the guideline they were laying as they went.
By June 28, the flood had progressed to the point that the main passage was sumped approximately 200 meters from the entrance itself. The scale of the water volume in the cave was becoming clear. This was not a situation that would resolve with a few pumps and a few days of dry weather. The cave was substantially flooded for a distance of kilometers, through multiple sumps, with more water entering through the mountain’s fissures with every rain event.
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## Parallel Approaches: Pumping and Drilling
While the diving team was attempting to push through the flooded system, engineers and logistics teams were working on the other approaches to the problem.
Water extraction was the most straightforward concept: if the water could be removed from the cave faster than it was entering, the flooded sections would eventually become passable on foot or with minimal swimming. The challenge was the volume. The Tham Luang cave system was receiving water from an enormous catchment area — the entire Doi Nang Non range was channeling rainfall into the limestone below, and the capacity of the cave to absorb that water had been reached. Pumping it out required industrial-scale equipment: large-capacity pumps capable of moving thousands of liters per hour, pipeline systems to carry that water away from the cave entrance, and the sustained mechanical capacity to run continuously.