Those top columns aren't necessary in my opinion, and neither is the ledge. I do like the curvature at the top. And I'm drawn to the two walkways on the face of the dam.
Very nice tones, I think I would experiment with a crop of the top vertical posts but keep the rim entering tangentially. Then crop the bottom to remove the bright rectangular shape. The eyes go to the areas of greatest contrast first and I'm not sure you want your viewer to give that area much attention. Your shot, in my opinion, is the two walkways, the ladder and steps. They form wonderful lines throughout the image. Nice work.
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