There are a lot of experts on this site, but there is also no substitution for running a good old fashioned experiment.

Maybe create one or two BG spawning beds at a site you can easily observe, but doesn't have a heavy human presence disturbing the fish.

When you see BG on the beds there, do a good survey of the rest of your pond. If you don't see any other BG on beds, then you definitely have a lack of appropriate spawning habitat.