This year in particular it sure seemed that there were more anglers than ever fishing well into October, and knowingly or otherwise affecting brown trout that were getting ready to, on spawning beds or during a spawning event. Yes, there are spawning brown trout within the open portion, quite a lot.
I also believe that the browns within the city deserve a break for at least a few months of the year, especially after the hardships that occur during spawning. And really, do you really want to go fish for the skinny post-spawn slugs?
With closing the river at 22x upstream, this would leave a very large portion of the river open to access, and still allowing plenty of access for anglers who want to pursue fish well into the winter