I think another poster, who lives in the area, has said they can't understand why the police are just focusing on the CCTV and, as you say, there are only certain areas covered by it. The poster said there are other ways of leaving the area.
Personally I think she has probably entered the water, but it then begs the question why it has taken over a week to find nothing so far.
Must be awful for her family.
It's a tough job trying to find people underwater in zero visibility. I believe an experienced diver with specialist equipment has volunteered his services. I don't know how fast moving it is in that area, but if it is it could move a person over a fair distance quite quickly.