Re: Boulder Creek, St Vrain
Never fished St Vrain Creek. So no input there.
On the other hand, my office is literally next to Boulder Creek in east Boulder. I often fish it over lunch. I have not fished it west of Boulder, but I assume that it's similar to what's in town (at least from a water level point of view).
Currently, the water level is low, but it is normally low. Most of the creek is less than 12 inches deep, although there are some pools more than 3 feet deep. And I know of at least one pool at 6 feet deep.
The fish are typically brown trouts and less than 10 inches. Although I have caught rainbows and one 14 inch brown. I've seen suckers, and a friend cought a bluegill.
The WIDTH of the creek, and the overgrowth of trees and bushes, make fishing hard. I fly fish it and in the past I've used a 9 foot, 4 weight and that worked well for mynphing. Although the 9 foot is sometimes hard to swing without hitting something. I've also used a 6' 2wt rod and while it works wonderfully for dry flies, it's terrible for nymphs. I just recently bought a 7'9" 3wt rod and I hope it'll give a better results for both dry flies and nymphing.
I have no idea how you'd fish Boulder Creek using a spinning rod. I've seen people do it, but I'm not sure what kind of success they have had. Seems to me that, aside from the rare large pool, there just isn't enough room to work a spinning rod. The creek is too shallow, too narrow, and there are too many bushes and trees. If you're not getting cought up on a branch then you're overshooting your target or hanging up on some roots or rocks.
When I fly fish, I use a 7-9 foot leader with maybe a foot or two of fly line off the tip of the 9 foot rod. Who needs to cast 60+ feet when you can only get 10-20 feet before getting caught up on something.
Boulder Creek is closed from Valmont to, I believe, 75th due to the New Zeland Mud Snail. It's even closed to joggers and dog walkers. Go in there and you can expect a fine up to $1000! Yikes. But if you fish other parts of the creek, be sure to wash your waders and stuff just to be on the safe side. Check out the post on the top of the Fly Fishing forum for instruction on how to do that.
Fishing is strictly catch and release west of 55th Street. And there are areas closed to people, so watch the signs and fences.
But the entire length of Boulder Creek (at least in town and for several miles west of town) there are bike paths. To find an area to fish just park your car, take a walk, and get your line wet.