The foreman in this photo is not the onlooker on the left with his hands in his pockets but the man in the center of the team with the black and white striped shirt, using his hard hat to demonstrate some point or other.
Here's another photo of a flushing team in action. While not the most pleasant of tasks, sometimes the spray of water help alleviate the oppressive heat and humidity. Most days I was on the line I'd end up soaked in sweat so rain was refreshing. This water though, is swamp water so not the most pleasant stuff.
In the photo below two of the crew port a flushing pump through the jungle. They weren't the easiest things to carry. The coiled tube looped over the pole is the inlet hose. Others, out of the frame, have the fire hose that connected to the flushing tubes.
It didn't take a lot of horsepower to make the holes in which we set the explosives and hydrophones - just a water pump and a couple of guys with pipe wrenches. Water was relatively easy to come by. In most cases the crew only had the dig a sump one or two feet deep and place the filtered end of the inlet hose into the sump.
After the surveyor cut his line, a 'bridging crew' would follow along behind and cut smaller trees to form a walkway, or bridge. Typically three poles wide and nailed together, it made walking the lines considerably easier for the rest of us and in most cases kept our feet dry also. It also meant that relatively few people were actually tromping across the jungle floor.
Most of my LVL work was to determine and map the boundary of the organic material to the first two distinct layers of sand. Consequently, most of my shots would only be sunk a couple of meters into the organic layer. The main crew, however, needed their shots placed down in to the sand - about six meters down.