The Drunken Lizard Pub

So I enter Grimhold...I head for the maintenance shed...I take the stairs down into the catacombs to explore...I discover two switches for primary water flow...one is busted, the other is stuck...I head west over a long bridge...I discover a lever in an area with water almost completely surrounding it, which I hit...I then go south-west in order to do battle with a beastie who, after-wards, leaves me a goblin key...I head west from his area, I climb the stairs, yadda-yadda and I'm home free out the other side and into a brand new spankin' forest map. So...after all of that...how come I end up scratching my head in the name of uncertainty? How come I feel as though I was supposed to get the water flowing in order to fill in the fissures contained within some of the maps? If I "was" supposed to get the water flowing...what did I miss?

There are two ways across the rift cutting through Tangletree Forest:

1) Open the secondary water valve, which will release the security gates above, allowing you to walk across the rift.

-or-

2) Upon crossing the Goblin Bridge (over the rift) on the maintenance level, you can climb a ladder and appear on the other side of the rift, on the Grimmhold top level.

Doing option #1 actually finishes a quest, earning XP and making it quicker to pass through Grimmhold. Option #2 is convenient if you skipped Grimmhold on the East side and traveled all the way around to the West side via the "northern route". You can still get down into the Maintenance level from the west side even without getting the quest to open the water valve.