While I can't relate to your flooded garden, I do feel for you.

I live in drought ridden CA and am struggling to just water my vegetables enough. I have raised beds which dry out quicker, though I have spend a decade adding compost and growing cover crop to add to the soil every winter. I heavily mulch with 4 - 6 inches of straw to help retain the moisture, but my garden is not as happy as previous years when I was less concerned with the amount of water it got.

It is strange how our weather is so different. We never get any rain in the summer, and didn't get much last winter either.