What do you need to do after activating the generator in Blast Pit?

I'm playing the Blast Pit chapter of Half Life 1, and I can't continue or go back to the previous area.

I have already started the generator by activating the two switches on the top.

If I try to go back, this electrified water is going to kill me instantly (even with 100 health).

What do I need to do to continue the level?

You have to crawl over the pipes that run across the wall to the right side of it by placing one of the blue boxes (that can be found underneath the cranes (and barnacles)) next to the larger box at the end of the hallway, or drag those blue boxes over the electrified puddle to get across.