Thanks for the welcome!
So let me tell you the outcome LOL
I started with the shop vac, after skimming up the debris that I could see.
I have a 6 gallon shop vac, it took several seconds and it was full already. 6 gallons of water was a lot to dump each time but I managed. I probably dumped 10 loads. It has wheels but my terrain is filled with walnuts, pecans, small limbs, etc., laying among the ivy so not really rake-able.
So here's the outcome...the pond is deeper than 5 inches, I probably have 5 inches of mud in the bottom. I got as much water out as I could, afraid the shop vac would get clogged with mud and pecans and walnuts that I could not see until it was too late. I have a slight amount of water on top, so I will have to hope it dries out some so I can shovel it out. It's soupy mud at the moment. I will have to measure but I'm thinking this is a 12 inch pond in the middle.
This was not a fun experience
as that pond is a breeding ground for mosquitoes. Even though I lathered in a mosquito prevention lotion, they were going inside my shirt because I was bent over and biting my face. The lotion worked amazing though as none bit my legs or arms. I also had a kiddie pool full of tadpoles that I was trying to save, which also contributed to my mosquito population. I have chickens so last year I had none.