I can.
To answer your first question, I wish I could give you comprehensive numbers. I cannot. This sort of thing is difficult to sort out. In my position, I am often asked by my engineering friends how much all of this environmental and regulatory stuff is costing us. It's difficult to answer that question. In most cases, accommodating navigation is not a problem. It automatically happens. We are trying to accommodate flood flows and similar circumstances, and engineers are personally liable for any public hazards they create. So it's not as if these things would be totally ignored if there were no act.
What was the second question?