We ended up in that 4 pipes' chamber ( on the top of the plan ) I did know where it lead but never expected to be able to get in...

Incredible gift that was given to me...(The guys from "La Forge" are well aware of our explorations and I feed them regularly about our findings..)
We clearly see the three water gates in the brick pipe that passes under the pumping station...those 4 pipes you'll see next and also that big pump controleman is showing on his gallery...and also a bit of what's beyond the wooden gate ! oooooooh !

Plan by : R.P./J.L. 7-4-70