I've fished that stretch before Silverwood and have managed a few decent cats. There seems to be more bait in the water here out west. Whether it's do to the more shallow sided duct or numerous pumping stations I'm not sure. But I do best in the turbid water before and after the gates.
Have you tried drifting your bait as you walk along the duct. I'll have someone drop me off and walk a few mile stretch drift liver or mackeral. I've found this produces much better for the kitty fish.
I've seen some huge grass carp out this way munching algae on the sides and basking in the sun. The largest stripers I have read about have come outta the duct along I-5 south of Quail lake.

Tight Lines,
Bank Pounder