My cat won't stop scratching the carpet

I don't want to declaw her, because I know it is painful. She has 2 scratching posts, one that is flat and carpet and one that is slanted and horizontal. I have even put catnip on them. She will sit on them and all, but keeps on scratching the carpet mostly and sometimes the couch. The couch isn't all that nice, but I plan on getting a new couch in a few years, and will probably still have her. How can I get her to stop scratching. I have tried the water bottle, and clipping her nails. All I have succeeded in doing, however, is that she scratches and then runs for her life, because she knows that a water bottle will follow her scratch. She goes and hides under the bed. help!