Had a business trip near Boulder this spring and came across Boulder creek via wandering around town. There is a nice little whitewater park about a five minute walk from the popular area (were folks balance flaming chairs on their nose and play guitar upside-down). The park has cemented in boulders that focus the water to produce potentially year round waves to practice surfing etc. there is a set of maybe five+ of these, with variable wave surfing difficulty; each has a recovery pool after it. The park starts where the mountains shoot straight up into the sky and ends maybe 1.5miles down creek, where it begins to take natural form of chaotic boulders and continuous rapids for maybe 1/4 mile. after that it mellows out with some waves (level dependent probably); I took out at the university, watch out for the dam just before that, looks like it can be run on the right. i think I ran it at 500-700cfs; my memory is vague at this point; it was raining an cool many hardshellers out paddling the creek. Did an involuntary surf at the most powerful and last rapid of the park situated just before a bridge and after where the creek returns to natural chaotic type continuous rapids; the raft was real close to being completely vertical for a good 5 seconds held between the reverse flow of the wave and natural flow (similar to a low head dam effect i think). had to paddle like hell to get out of it, it was awesome after that was continuous rapids thru small boulders/rock, enough to near completely exhaust me, pulled over into a micro eddy near the bank to take a rest grasping onto a root to hold position; had to manually pull left hand fingers off of paddle, they would not let go; a first for me.
There is a bike/walk path all along the creek ideal for taking a look at the rapids to size them up and potentially observe others negotiate them; not to mention walking back to your vehicle after rafting the creek. A road (119 Boulder Canyon Dr.) follows the creek as well, going up into the mountains where additional exploration is possible, it appeared to be continuous type rapids with many boulders, which at the moment I find difficult. If I had more time I would have; but I took a short trip to Bunea Vista Area for a paddle festival at Arkansas river instead and paddled the white water park there as well and Browns Canyon.