Anyone have any idea what are all of these seemingly randomly constructions that are popping up around Danshui? Looks like they dig a big hole and lower this giant steel tube into the ground, then puts a huge cap on it. Any idea what they are doing?
By the rivers? Lots of bike and pedestrian bridges going in around where I am (south) and look like that. Could also be sewage. Hard to say based on your description. 
Not just by the rivers, but in seemingly random places, like one on that big (Zhongshan street?) main road by Zhuwei MRT and Hongshuling MRT station. They would dig the big hole and put that big tube in, then leave, and the same construction would start up elsewhere. It’s really affecting traffic on that street given the Taiwanese driving style…
Sounds like sewage lines.
Yeah, it’s sewage. At least the ones in Hongshulin are.
So I hope this means that Danshui riverwalk and the river itself won’t be smelling like crap because all sewage will be going to a water treatment plant rather than straight into Danshui/Keelung river like it used to… and also an end to smelly open drainage ditch and sewers…
That is worth the traffic problem due to its construction. I really hope this means that Taipei will look and smell cleaner. I sure hope they deal with the HUGE number of scooters and vehicles that are illegally parked.
Danshui is does have some of the more stinky sewers/drains. I do hope they are fixing it up! (I am not trying to start a competition on where is more stinky!)