Revenue streams never go away. Government becomes dependent on that revenue and continuing to collect is it easier than re-shuffling other revenue around or choosing what to de-fund so the revenue gets kept.
Get used to your drought surcharge. It's not going anywhere.
Edit: Based on the popularity of this comment one would think government revenue streams go poof all the time. If anybody has evidence of this I would like to know more about is to I can advocate for replicating those circumstance in my state.
Edit: Is this interpretation incorrect or just inconvenient?
I see what you did there.