Return to Threeway Tunnel
I hadn't been here in about three and a half years, but there was always this nagging issue of a couple of side tunnels I had never gotten around to exploring on any of the previous expeditions.  Granted, the last time we went below in here, it took more than six hours just to get to the end of the main tunnel and back with all there was to see.  Explorer Phil hadn't been through this one before, so it was a good opportunity to load up the bikes and check it out.
One, two, threeway.  Both the center and left tunnel lead to the same system; they run parallel until they converge.  I've only done the one on the right once on my first trip here.  It's probably worth another visit at some point if only for GPS readings to see what it runs beneath, but we didn't have time for that on this trip.
Sekt, Shares, and...
...Soler.
More funnies from Soler right near the entrance.
Phil looking awesome in your near-death experience.
Phil standing atop the retaining wall.  I'm not sure what purpose this structure serves.  There isn't one of these in the parallel (i.e., center) tunnel, so it doesn't really retard the flow significantly.  It just makes it a pain to get the bikes over in order to get to the side tunnel here (to the right) which was one of the main reasons I returned for this expedition.
A Phil's-eye view of the entrance to said side tunnel.
The "end' of the side tunnel where it turned out to be a junction with another part of the system: two parallel tunnels that ran both up- and downstream from here...
...as you can see in this alternate view.
However, as the plywood barrier in the previous shot suggests, there's nothing upstream.  These have both been sealed off.
We headed downstream a ways until we found this side tunnel...
...and I was able to get a GPS reading of where we were at this point.
From here onward in the main tunnel it was a long, straight shot.

Oh, look, an 8' auger.  No idea what this was for.  There was another slightly shorter one behind me and to the left out of the frame.
Eventually the gravel made it hard to bike along here, so we switched over to the other side where there was more water but less debris.
One of the only side tunnels along here.  It led to a chute that went straight up with no rungs.
Eventually there was just plain too much water and it was almost impossible to bike any farther, so we switched sides yet again (only without the bikes this time) and walked still farther downstream.

We never seemed to get any closer to an end, but the water kept getting deeper and deeper, little by little, so we doubled back.  This is a mystery for another time... and another means of transportation like as in a boat.
Continue to Part II