Mark, I have been fishing the Jordan River (as well as Stillwater like Utah Lake and DC) for the past 5 years with Carp as my target.
I fished a small canal right next to Smith's that sounds like what you got. A lot of moss and muck. It is part of the Jordan River.
This canal is very shallow and about 10' wide.
I also fish the river coming into it
I use four flies most times. They are Rainy's Hex, Popcorn ball, then a Dog Biscuit that was introduced to me here, and lastly the Tadpole in White, Olive and Midnight fire. I fish a dry dropper with either the Dog Biscuit or the tadpole as a dry and ALWAYS the popcorn ball as a dropper.
With water really mucky, I use a small Thingamabobber, with the dry on a 10" tag right below the indy, and the popcorn ball 20" to 24" below the indy. REALLY fun hooking two at once with the smallest being 24"....