My wife wanted to show you what I constructed to keep the leaves out of the pond. The pictures are a little dark, but you should get the idea. I stole the idea myself from a garden center in NJ.
The pond is about 8' by 12'. The cover is constructed from grey plastic 1/2" electrical conduit sold at any home center like Lowes or the BORG for about $2 each. I needed 6. The conduit is nested together to make the needed lengths, and cut to size. It is simply slipped over small pieces of rebar that are hammered into the ground. I think I used 2' long rebar, x6, at also less than $2 each. Then you stretch the netting over the top, and I used cable ties to tie the netting to the conduit, and also to tie the pieces of conduit together where they cross. Then I used landscaping ground stakes to tie the netting to the bround (so the birds don't climb underneath and get trapped). Keeps 100% of the leaves out. Air flowing through the netting does a pretty good job of keeping the leaves from staying on the netting. It was a little tricky stretching the net under the Japenese lace-leaf maple tree that covers 1/4 of the pond.
This is the second year I have used the same set-up. I keep it under the deck during the rest of the year. It has saved my wife huge amounts of time daily removing leaves from the pond.