According to information issued by the National Bank, any banknote that has been damaged during the floods or in any other way can be exchanged for a banknote of the same value. However, this is subject to the condition of the banknote being damaged.
If your banknote is not badly damaged, you can get a replacement of the same value on the same day. For severely damaged notes, the bank will need to assess the value of the note before it can determine the value of the replacement note.
If you have only half a banknote left, then you will definitely not be able to exchange it for the original value. If your banknote is only torn at the corners or the colour has fallen off, you will be able to exchange it for a banknote of the same value.