This worries me....

This is pretty much how it's done.

The dredging equipment has a tremendous amount of force and to build a shield over the pipeline that could stand up to it just isn't going to happen.

Anytime someone digs in the ground they are supposed to call for utility locates..in this case the sign is a great notice. This could just as easily have been a fiber optic communication line, water, or sewer pipeline.