Maybe it’s the fact that water doesn’t work very well as bronze. Or that it looks more like fire or mud than water. Or that a sudden flood of water rushing through the gate to destroy everything in its path is kind of morbid. Whatever it is, something about “Flood Wave” by Ann Klefstad and Jeffery Kalstrom — a 2001 sculpture at the entrance to Harriet Island Regional Park — creeps me out. There’s just something about a flood wall predicting its own failure that doesn’t sit well with me.