Why does my dog scratch at certain areas on our carpet ?

We have a 14 year old er spaniel and recently have noticed her scratching (nesting) in certain areas of our living room carpet which is probably destroying the carpet in spots not to mention, is driving us up the wall. She starts off in one area ,then proceeds to another area to another. It is a routine now with a definte pattern. We have tried everything we can think of to deter her but she still continues.Any advice would be grateful and thank you in advance . Also she has no health concerns again thank you .