If you put your time in, you will for sure be catching Steelies in the Coquitlam. Keep in mind it is a fragile system, and it can not take a lot of pressure. The Steelhead Hatchery program has not continued as far as I know, but there is, and always has been a run of wild Steelhead there.
Especially for a local fisherman, this would be a good system to learn, and explore. If you can learn how to fish the silty water properly, and watch the water conditions closely, you will do fine in no time. Keep in mind there are upper river boundaries and the lower tidal boundary as well. Check your regs for further info.
I would not recommend this system for others to try because like I said it is fragile, but since you live close by, it will be worth your effort. There are also large dolly/bull trout throughout the system as well as Salmon, and cutties.
A good way to find holding fish in silty conditions is to cover the water carefully with a spinner or spoon.
If you find fish are checking out your gear, but not quite getting hooked well, then it's time to toss in some bait through the same water(check your regs on bait usage) and you should find yourself with a hookup.
Take care, and tight lines!