I've never seen the Watercourse in Tainan tourist, business, or historical publications. Even after going there and asking locals about it, I could get no information. I figure it's like a lot of places all over the world, it's no longer part of daily life, it's off the beaten path, it belonged to an older generation, and so it becomes forgotten. I stumbled across the Watercourse based on a recommendation from my nephew; he'd read something about it in Chinese on-line, so he thought I might be interested. Fong Ta was right!
Sometimes, those are the most interesting sites because they give real insight as to how people used to live. Much of Taiwan's historical locations are based on the Chinese influence. Valid, from a Chinese perspective and the view of most Chinese who came to Taiwan in the late 1940s. However, for those who had long family roots in Taiwan, the Japanese era still rings loudly in their memories. This small site can show the influence of the Japanese in the lives of those in the Tainan area.
The nearby city of Sin Hua is worth visiting while already in Tainan because the main street is lined with Japanese-era one and two-story buildings and homes. Just those make the visit there worthwhile. Add to those, just one, two, and three blocks away are neighborhoods of the one-story brick Fuchian-style homes that were prominent all over Taiwan until the 1960s and '70s. You can wander to your heart's content.
While already in Sin Hua, the short drive to get to the Watercourse is worthwhile. Were I civil engineer, I'd make it a point to go there. Were I into Japanese-era life in Taiwan, I'd make it a point to go there. Were I satiated with the temples and shrines of Tainan and had half a day available, I'd go to Sin Hua and then the Watercourse.
Well, what is it? It's the water treatment facility built by the Japanese just before World War One. It was used until the 1970s. You can wander around the old buildings and ponds. Many of the sites are identified in English; an English brochure is available near the entrance. This is not the top-visited location for tourists so you may have the place all to yourself. You can take pictures and snoop around everything without being disturbed.