William More about water - this time, not where it comes from but where goes. Mark Twain is purported to have said regarding the American West, “Whisky is for drinking; water is for fighting over.” As an Angeleno, I understand this.
Even in water-rich Japan, when it comes to irrigation, all must be assured their fair share. Herein comes the “Enkei Bunsui” (円形分水, or cylindrical diversion). This device serves two purposes: to slow water flow by forcing a stream to surge upward into a basin; and to create a visually calculable division of water.
Several of these devices remain in Japan. Google 円形分水 for photos. One is in Yabe, to divert a stream’s flow into three, two divisions into the uplands and one through Tsujunkyo, which in turn irrigates the plateau to the south. No visit to Tsujunkyo is complete without a visit to this ingenious device. I’ve never jumped into it, but I suppose it would not be particularly dangerous.
Photo: ①Waterflow on the left is the incoming stream, which is forced upward to slow the flow and then divided. ②A map showing diversion through Tsujunkyo to the Shiroito Plateau. ③Water flushed from Tsujunkyo to remove sediment from its center.