A couple of weeks ago, I visited Okutama for a hike. Okutama is a beautiful mountain area with great rivers and surprisingly it’s still in the Tokyo area! For a clearer understanding, it actually only takes 90 min to Shunjuku on the Chuo-line, so it’s far but not too far.
While I was there, I came across the Shiromaru-dam fish passage. This was made in 2002 April. The entire dam is 331.8m and the fish going across are: Yamame trout, Cherry trout and Ayu fish. These fish were let out in the river by hand as an experiment to see if the pathway worked. Naturally, other fish were found utilizing the pass way such as: Japanese dace, Rhinogobius, other trouts and many more.
The stairs the leads up to the pathway have walls that are higher than the water level so that the fish can rest. In the pathway, there are small holes carved for fish to swim through as it leads to the other end of the river.