The chain was going to be in the water regardless, because unless you're really carrying a lot of speed bikes don't float over water. Sure it would have been better environmentally to stay home and not venture out at all, but I actually like to see some of said environment and a dirt bike is a fun way to do so (and it even has less of an environmental impact than a 4wd).
It's where Jerrabattgulla fire trail crosses Jerrabattgulla creek, in Tallaganda state forest. It's a nice little green section around there surrounded by drier more scrubby country on the way in and out.