The gardens close on November 1st. The water will be turned off then. All garden debris needs to be removed and hauled to the compost facility nearby. If you do haul it to the back of the gardens, it must go to the far far back, not just to the first line of trees.
Failure to clean up your plot means you may not be allowed to rent again next year.
The river is forecast to rise this weekend but the projected crest is far below the level where it hits the gardens. That said, if you have crops still there, watch the forecast.