Thanks to "Il Draino" for the location info.
Here's the drain entrance. You can see me there, cause I made use of the u-beat timer feature on the camera. Other photos have just the other two members of our group :
Some photos inside the drain :
Here we've found an outlet into a river, which one of our party checked out:
And we're mapping out the drain ...
We can see a light off in the distance ...
And we're moving along ...
Eventually we escaped to the surface via a manhole ...
And looked back at the entrance of Lake Ginninderra. We could not figure out where the drain opened, we imagine it is below water level.
Having done this by day, we retraced our steps, looking for the openings we identified while below ground. This is the advantage of draining during the day. We found three openings above ground :
The following photo of a grill corresponds to the bit of daylight we moved towards in an earlier photo :
The following photo corresponds to the opening into a river, where one of our party was silhouetted earlier :