South Boulder Creek: Below Gross Reservoir to Eldorado CanyonLength of Trip: 8 miles
Gradient: 65 ft/mile
Difficulty: Class IV to V
Water Flows: June-July
Flow: 300 to 500 cfs is a good level. You must check two gauges to make sure there is enough water above and below the diversion dam. Below the dam there must be enough water to float past private property, otherwise you can not finish this run. Call 831-7135, Division 1, Station 6 for the flow at the put-in and station 7 for the take-out flow. Division 7 should be reporting 100 cfs or more to finish the run.
Scenery: A This run is all through pristine climax forest. There are numerous trails that come and go, along with some pedestrian bridges, but the run is beautiful, especially being so close to town.
Put-In: Drive west out of Boulder on Baseline road over flagstaff to Gross Reservoir, take the dirt road to below the dam. Currently the Denver Water Board does not allow boaters to put in at the bridge, so back track up the hill to a fishermans pull-out and hike down to the river.
Take-Out: Drive back to Boulder, head south on Broadway/Hwy 93 to the south side of town, take a right at the turn for Eldorado Canyon, drive into Eldorado Canyon, (a fee state park) to the picnic area at the very end, (bare left to avoid private road). You can park just inside the park area if you want to run the Class VI- section along the dirt road.
Description: This run can be done in 3 hours or take all day. It is mostly a class IV run with 3 short class V-VI rapids and a 28' dam. The rapids are fast with medium size boulders everywhere. The dam and the 3 hard rapids can all be portaged. There is quite a bit of deadfall in the river, but local boaters try to keep a boatable channel open. Good Class IV boaters should be able to run this section with portages. The first hard drop, Class V, is just below a bridge, not far beyond the put-in. We have called it the "Moist Slot". Beware that if you punch the hole, you may still end up in the right hand eddy, which has a downstream rock that has a hole that one swimmer has managed to squeeze through. Portage left. There are some fun rapids leading up to the next rapid, a Class VI-. This class VI-, I call "Hole in the Wall", for the 24" gap in the wall on the bottom right. Vertical pin or broaching is a very real possibility in this drop. A good run of this rapid puts you against the wall at the bottom. Portage left. The third drop has a nice flat pool right above it. Scout/portage right. The technical difficulty of this drop is Class V, but the screw up factor is high. Boaters boof the right hand slot and disappear along side a large boulder. I have heard that there is a log in this drop, which can not be seen at normal flows and that one boater had their boat vertically pinned. The last big drop is a 28' dam. The dam is private property, portage river left. People have run the right side, but be careful of the landing and it is questionable wether you can run the dam without trespassing.
Below the dam is a low water run, unless you're lucky and the diversion dam is not pulling water off. Below the dam is Class III-IV to the top of Eldorado Canyon. Eldorado Canyon is a class VI run, with vertical pins, possibly big holes depending on flows, and logs. It is a wild/serious run. Scout everything, and then go rock climbing instead.
The run above Eldorado canyon has been run by kayak, duckie, raft and maybe canoe. Suitable for boats that can handle Class IV creek style boating with portages. This is a great after work run, if you can run it quickly.