My dad had a good way of explaining what to pick up and what could remain in place. Imagine you are driving along in your car at 120 mph. If the object would fly off the hood of your car, it's likely to become air borne during a storm.
I would skip the plywood on the pond, unless you could nail or preferably screw it down. I took all my tall potted plants (irises mostly) and put them on their sides. Some parts of my garden are protected by a line of trees that act as a wind break, so my heavier lotus tubs went there, snug against a fence and a line of trees. The smaller lotus tubs came inside. They all managed ok.
I took my trickle filters down...just because Ididn't want to be fishing out lava rock and bioballs from the bottom of the pond.
I took the nets off...I was afraid they would just blow into the pond and gill net the fish. But now I have a million leaves in the pond. Like hurricane Andrew, Gustav defoliated some trees (my poor rose bushes are completely naked!) and I have a whole compost pile worth of leaves in the bottom of the pond right now. So it's a toss up...to net or not to net.
If you don't have a safe overflow point, you can drain a bit of water off to allow for rain water to accumulate. That way the fish won't wash out.
I took all my decorative doodads and brought them in. Gazing ball, strawberry jars....anything top heavy. Birdfeeders. anything like that.
One site I went to suggested a partial (25%) water change, to make sure you have fresh, clean oxygenated water going into the storm. I wish I had done that.
I also wish I had completely cleaned my filters before the storm, too. I think a lot of the muck from the filter wound up in the pond when things got tipped over.
The other thing is a generarator. For us, it ran a small window unit a/c, the fridge and the fish. We lived in one room, but hey, it was a lot cooler than it was for the aftermath of Katrina and Rita!
I would check at Lowe's for those solar powered aerators. Anything that will disturb the surface of the water will add oxygen in the event power is out for any length of time. My dad has a large (acre sized) bass pond and the words of wisdom for low oxygen situations is to back a bush hog over to the pond edge and run it...anything to churn the water. We were fixing to take the lilies out and run the weed eater in the water...if thing got really dire. Btw....the lilies suffered no ill consequences. They were blooming their little hearts out right through the winds and rain and sludgey water.
I am watching Ike close. My mom and step-dad have opted to hunker down and stay in Houston. They are stocking up on canned goods and pet food and drinking water and they were able to get a generator to run the window unit in their bedroom.
I will be keeping you in my thoughts and prayers!!!