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It looks like some sort of weir. You can see the rack-and-pinion arrangement at the top which will raise or lower gates on the high side to control the flow of water. See the high-water marks on the sides? Sometimes the flow here is much greater
The shapes on the low side are such that water flowing from the high side to the low side dissipates as much energy moving around them as possible and so the flow through the pool nearest to the camera is relatively still. This is to avoid erosion from turbulent water downstream.
I’d say that some care has been taken to make this more beautiful than it needs to be, but these sorts of arrangements often are very agreeable to look at even if purely functional. The way they work leads to a certain sort of symmetry.