In the parks the state rule usually applies. CA law states that any size fixed blade not openly work on your belt is a FELONY. Oddly, a concealed firearm without a CCW is a misdemeanor in most areas(Some locales are much stricter)

The other odd thing is there is no size restriction on fixed blades as long as they are openly carried on the belt. There is a guy here in town who is known for carrying a sword on his daily walk. The cops all know him because people call him in all the time, but unless he brandishes it there isn't anything they can do to him.

I would consider myself lucky and buy a new knife.