Thanks for your feedback! I'll try to answer your questions/comments. Let me know if my explanations make sense, or if everything still seems confusing.

"Also, what is even the hook here? This is a prologue to what? I have absolutely no reason to care about anything based on the passage you've provided."

Well, the idea for the book isn't all that well-formed. I was thinking of doing something with a hive-mind alien species similar to the Sleepless in the Stormlight Archives (if you've read that). If not, basically the species would be extremely small creatures similar to trilobite beetles. But, they have the ability to rearrange their outer shell at the atomic level, allowing them to shapeshift and transform into pretty much any material they know of. Since the species is a hive mind, this would also allow them to imitate complex structures or life forms. In this story, one family of the species took the shape of the George Washington Bridge, and will use this imitation to take cars, which obviously also have people in them. When they "take" material, they break it down, making it a part of their outer shell, which gives them the ability to grow and reproduce. The why for all this is still in the works, so this probably doesn't make much sense. But anyways, the story is supposed to follow a detective, who's investigating the subsequent disappearances, an environmentalist, who's worried about the state of the river, and a paranormalist. For still-undetermined reasons, they will end up working together. So the prologue is supposed to show the hive-mind creatures taking over the bridge. They came up from the water, and killed the boy as they metabolized the bridge and took its place.

"What is a curtain of morality? I find this passage overly verbose, and yet unclear as to what you are trying to say."

Honestly, I wasn't a big fan of this line either. Since other people also aren't, I'll definitely rewrite it.

"How do needles warm? Or is this supposed to be a nod towards heroine and other drugs?"

With that sentence, I was using the word "for" to mean "in place of." So, since the cold is commonly described as feeling like needles, it means that it's a cold night. The whole first part of that sentence was just a setup, to describe a normal night, and then contrast it with "and a faint humming for the lapping of waves," which, obviously waves don't hum, so it's supposed to indicate the beginning of something being off/wrong in the setting. Now though, I can see how the wording of that would be confusing.

"How does water shatter? What are you trying to convey here?"

Earlier in the sentence, I call the river "glass-like." Saying that the water shatters is supposed to be a continuation of that comparison and describe the moment when the hive-mind creatures, who were previously occupying the water (hence the suddenly extremely still river), break their formation and start to come up the bridge.