I haven't anchored ther since sandy , but, most of the storm damage to the waterways was done further south. I believe the anchorage is still viable just be sure to check for shoaling at the entrance. Also, you can anchor outside the mooring field at Atlantic highlands municipal marine and take advantage of the breakwater.
All that is necessary for the triumph of evil is that good men do nothing. Edmund Burke
Shoaling is much worse since Sandy. Low tide is an adventure if you draft is 3+. Good news is Sandy Hook Marina marina is opening (to some degree) this spring. Marina is located on Highlands shore immediately as you enter Shrewsbury River. Its possible the dredges you saw were those working at the marina. Also, the dredging companies often move the dredges to the protected waters inside the Hook. Link to the marina: Sandy Hook Bay Marina - A Premier Resort Marina
I live in Highlands, on the river, can answer any other questions you may have
That's unfortunate. So where is everyone going for the weekend now? Highlands can fill up pretty quick, Rockaway is nice but what else is there? I really don't know much about Richmond but recall it was pretty full.
Sounds likeI'm going to get familiar with the East River again!