This photo needs editing.
Difficulty IV(V+)
Length 7.2 Miles
Flow Range 180 - 750 CFS
Flow Rate as of: 1 hour ago 86.3 [CFS]
Reach Info Last Updated 08/07/2019 8:27 pm

River Description

South Boulder Creek from Gross Dam to Eldorado Canyon State Park is Boulder's backyard boating flave.
Lower South Boulder Creek holds three Class V+ exceptions and is a Front Range whitewater kayaking treat with remoteness and atypical Front Range creeking challenge. Mank. 
The Put-in for Lower SBC is 1/4 mile below Gross Dam. From the vehicle bridge that crosses the creek, park river-left, uphill in the developed parking turnout of the turn.
Advisory: Denver Water Board property surrounds this unique putin.
Please stick to the foot trail than runs from the turnout down to the creek. 

Launch from the cool mossy banks right away into the cold and remote feel of South Boulder Creek, Gross Reservoir to Eldorado Canyon State Park.
Wood from recent wildfires and high water will regularly load into any drop or corner.

Ramble under a footbridge, river hooks left, eddy out left for:

* Mile 0.9, Moist Slot, Drop One, Class V, the first of the three bigger drops on this run. Eddy/Scout/Portage river-left. This narrow slot on river right is setup by strong cross-current seams and folding water. Enter the Slot close to the right wall, paddle through the slot angled slightly left. The drop is about six feet on a sloping flake with a stopper hole to stuff you.
*This is a dangerous rapid. Either you feel it or shoulder your boat.

More rambling creekin' with occasional playwaves. Keep eyes peeled for mountain lions (Felis concolour) and bears as this reach holds good habitat.
Boogie-boating for about a mile until The Brain.

A channelized straight-away section of the river with picnic tables on river-left indicates that you are nearing The Brain, or Hole in the Wall rapid.
* Mile 1.7 - The Brain / Hole in the Wall, Drop Two, Class V+. Eddy/scout/portage river-left. The Brain has many ledges to stuff a boater in. When run correctly, after negotiating the setup, a good landing puts you hard against the rock in the bottom. For those who portage, seal launch from large river left boulder just after crux ... more boogie boating for about a mile, until a flat pool is reached after the river bends left.

* Mile 3.0 Bridge Falls / Martin Gulch Falls, Drop Three, Class V+. Eddy/scout/portage river-right. Recent changes in this waterfalls geology warrant scouting. Bridge Falls is filled with wood, undercuts and fast, shallow landings followed by a stomper hole. After Bridge Falls pass under a footbridge and enter a beautiful Class IV cascade into more canyon that emerges into a forebay.

*Mile 4.2, Forebay and the Dam Drop - Eddy/scout/portage river left.

The route over the Dam is right. Be four to five feet away from the right hand wall in the right hand chute. Dam Drop is about 30 feet high and on a slight angle just off vertical. After the dam drop, over half the water in the river is stolen away to the thirsty pipes of Lakewood and Denver. Prepare for about 1.3 miles of boneyard shallows (90 to 120cfs).
Attempting the de-watered section with less than a 125cfs on the lower gauge (Eldorado Canyon, 1*7*) is not recommended. Rental boats preferred.

*Mile 6.5, Take-out river-left in picnic grounds, free food for kayakers!
or *Mile 6.7, Take-out river-right upstream of the green vehicle bridge Below this bridge leads into Class V+ Eldorado Canyon and Harmon Falls.

Shuttle is about 50 minutes one way. Bumpy Boulder County backroads and dusty washboard gravel roads around Denver Water Board property.

For descriptions of Colorado runs, see Whitewater of the Southern Rockies by Stafford and McCutchen, or Colorado Rivers and Creeks by Banks and Eckert.

Lat/longitude coords are approximate, from TopoZone.

The various reaches of Boulder Creek,
Jasper Creek (Class V+/VI),
The Source (Class V),
Upper Boulder Canyon (Class V/V+),
Lower Boulder Canyon (Class IV),
Boulder Town Run (Class II/III),
North Fork Boulder (Class V+/VI),
Alto-Alto (Class IV),
Upper South Boulder (Class V+/VI),
Lower South Boulder (Class IV/V+/VI),
Eldorado Canyon (Class V+).

Spiders await you!

Rapid Descriptions


Class - II Mile - 0
Rapid Thumbnail Missing
West from Boulder on Baseline Road climb over Mt. Flagstaff to Gross Reservoir. Take left on a dirt road to below the dam. Denver Water Board does not allow boaters to put in at the bridge. Park up the hill downstream from the bridge in an obvious pull-out and hike down to the river.

Moist Slot-Drop One

Class - 5.0 Mile - 0.9
Rapid Thumbnail Missing
The Moist Slot is the first of three Class V (V+) drops on this run. Pass under a foot bridge, river hooks left, eddy out river left, then you are headed into the slot on river right. The Moist Slot drop is about 6 feet and the hole does drive you toward the right wall. Some call this rapid Hole in the Wall. Hit this hole with determination, or it will hit you, for a while. - portage river left-

Davis Gulch enters river left

Class - II Mile - 1
Rapid Thumbnail Missing
point of reference this creek/draw enters river left descending out of Walker Ranch from the North


Class - III Mile - 1.25
Rapid Thumbnail Missing
just after you seen Davis Gulch enter river left, watch for eddies and find the play wave (typically found at 350 ~ 450 cfs)

The Brain -Hole in the Wall -Drop Two

Class - 5.1 Mile - 1.7
Rapid Thumbnail Missing
The second Class V (V+) rapid of this run, the Brain just looks dumb, all water goes into an undercut rock in middle of river in the middle of the drop. After a few fun rapids upstream, the channelized lead in is straight into a pile of rocks. This rapid has a 24" slot to negotiate and this rapid could stuff you under a few rocks. A good run will put you against the wall at the bottom, or so says Eric Bader. Alternate idea: portage river left, seal-launch from rock in rapid after the junk. This rapid is ugly. The portage is easy, its your call.

Bridge Falls -Martin Gulch Falls -Drop Three

Class - IV Mile - 3
Rapid Thumbnail Missing
The third Class V or V+ rapid on this section of USB, Bridge Falls or Martin Gulch Falls. This drop used to be boofed river right, tight up against the wall, landing in a poool, then rambled down a fast shallow channel river right into the bottom hole. Wood is always a hazard here. The run is now up to you; left or right. The right side is less of a boof and more of a hazard with rocks in the landing now. The left side can be undercut and tricky, but is manageable. Very junky. Note: this rapid changed significantly in 2001: The pool has reduced in size and the entrance boulders have all moved. Take a look at this one. The hole at the bottom of this rapid will work you like a ragdoll in a planer, so for God's sake, boof with intention. Portage is river right from beach head, with a nice stone foot trail for 80 yards, then put-in above bridge and prepare for fun class IV cascade.

The Dam Drop

Class - III Mile - 4.2
Rapid Thumbnail Missing
a brainless big drop over a 25'~ 30' dam run 5' from the right hand wall point straight and lean back eddy river right Do not let anyone run center or left at low or high water, rock garden at low water and terminal recirculation at high water. Denver Water Board has a road accessing the Gauging Station and dam here. dam elevation is 6,200'

take out

Class - II+ Mile - 6
Rapid Thumbnail Missing
After running the dam, the water is stolen out of the creek and piped to the eversprawling Denver suburbia. You will pass through a patchwork of state park and homesteads along the creek in combination with splitting channels and low bridges. Take out after picnic grounds on river left in a river-right parking lot just above the green bridge that crosses the river. You are in Eldorado Canyon State Park. Harmon Falls is downstream.


default user thumbnail
Fremont Shields
15 years ago

Moist Slot rapid has a hidden (at >250 cfs) sieve on river right about 15 feet after the initial slot drop. The right side of the the entire drop and the ensuing hole are undercut, too. Be aware that accidents have occurred here when considering this drop.

Gage Descriptions

Colorado Watertalk: 303-831-7135, Division 1, Station 6 (1*6*). South Boulder below Gross Reservoir. Division 1, Station 7 (1*7*). South Boulder Creek near Eldorado Springs.

Online visit:
Colorado DWR

CRC2 website

Season is May ~ September. * Depending upon water contracts this run can fire at will.
Runnable flows start at 90 cfs on the Eldorado springs gauge (bring a rental boat!).

Recommended minimum flows are +-150 cfs on the Eldorado gauge(1*7*).

Ice plays a regular factor in the early spring.

Class IV(V+) <450cfs below Gross Res.(1*6*)

Class IV+(V+) >450cfs below Gross Res.(1*6*)

Directions Description

We have no additional detail on this route. Use the map below to calculate how to arrive to the main town from your zipcode.

Date Flow Result Factor  
2015-05-12 High Fatality Other Read More
2005-06-03 Low Fatality Other Read More



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Colorado Parks & Wildlife to Require Hunting or Fishing License at River Access

Kestrel Kunz

In an unexpected and strategic move by Colorado Parks and Wildlife (CPW), a Colorado hunting or fishing license will now be required to access State Wildlife Areas and CPW-leased State Trust Lands (effective July 1, 2020). Many of these affected areas have historically been used for paddling, hiking, rock climbing, mountain biking, camping, and other non-consumptive recreation uses. CPW's press release stated that "This rule is aimed at curtailing non-wildlife-related use of these properties", and while we understand the need to increase revenue to support management of these areas, we have a few concerns with this strategy. On July 1, American Whitewater, Colorado Mountain Club, and multiple other organizations submitted a joint letter to CPW Commissioners requesting that they reconsider the new Rule and find a more practicable and sustainable method for collecting fees for these areas.

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Opportunity to Participate in Upper Gunnison Watershed Management Plan (CO)

Kestrel Kunz

The Upper Gunnison Water Conservancy District in Gunnison, Colorado is coordinating a Watershed Management Planning effort "to help protect existing water uses and watershed health in the Upper Gunnison Basin in the face of pressure from increased water demands and permanent reductions in water supply." The current phase is focusing on Tomichi, Cochetopa, Cebolla, Taylor, and the Gunnison River above Blue Mesa. With local stewardship staff in Crested Butte, American Whitewater has joined the Watershed Management Planning Team to help represent recreational river users and quantify flow preferences and recreational opportunities on the Taylor and Gunnison Rivers. American Whitewater is very excited to be involved in this stakeholder driven process and we are asking paddlers to share their input on management priorities for the Upper Gunnison Basin. If you have experience paddling Cebolla, Taylor, or the Upper Gunnison Rivers, please fill out this quick survey! 

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AW releases Saint Vrain and Lefthand Creek Recreational Flow Study - CO

Nathan Fey

Longmont, Colorado - As part of a comprehensive Stream Management Plan for the St Vrain Creek Watershed, American Whitewater is collecting and compiling data on recreational uses, and identifying projects and strategies to improve stream health, recreation, and environmental conditions in the region. You can help with this extensive effort. Please participate in the Recreational Flow survey.


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Support Colorado River Access on Colorado Gives Day!

Kestrel Kunz

Colorado Gives Day is on December 4 this year and is fast approaching! Go here to schedule your online donation to support American Whitewater's Colorado River Access Program. All donations made to American Whitewater on Colorado Gives Day (December 4) will be put towards our River Access Program in Colorado. American Whitewater works to improve river access and public safety throughout the state by working with landowners and managers, paddlers, law enforcement, and lawmakers to understand Colorado's river access laws and the ongoing threats to public safety. Thank you for your support!

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Voluntary River Closure Proposed On the Slate River (CO)

Kestrel Kunz

Crested Butte CO - Alleged disruption to a Heron Rookery and concerned private landowners have led to a "Voluntary Closure" of the Slate River from the Gunsight Bridge to the Town of Crested Butte between March 15 and June 21 for the 2019 season. The Slate River between Oh Be Joyful Campground and Skyland Bridge, a 10.5 mile stretch, provides an incredibly scenic and unique flatwater paddling experience in the Gunnison Valley. The Voluntary clsoure is a product of the Slate River Floating Management Plan, created by a Working Group convened by the Town of Crested Butte and the Crested Butte Land Trust. The Working Group was created in direct response to pressure from the local community including conservationists and private landowners adjacent to the river, who are concerned that a recent increase in boating activity is disturbing a Heron Rookery that straddles the Slate River. 

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AW Comments on Colorado Nat'l Forest Wilderness Process

Kestrel Kunz

Today, September 5, marked the close of the public review process for the DRAFT Wilderness Evaluation Report. The Evaluation Phase is the second step of 4 different steps required in the assessment of lands that may be suitable for inclusion in the National Wilderness Preservation System (NWPS). American Whitewater thoroughly reviewed the DRAFT Wilderness Evaluation Report and submitted our comments to the Forest Service on September 4, 2018. Overall, we found that key paddling reaches throughout the GMUG area were greatly under-represented in the Polygon narratives and thus weren't acknowledged as contributing factors to the Polygon's respective Wilderness Ratings. We let the Forest Service know this, highlighting specific paddling reaches that should be added to each Polygon and which Polygons we believe should have a higher Wilderness Rating based on the high-quality recreation opportunities that each area has to offer. 

Please stay tuned as we continue to report on the GMUG Land Management Revision Process and in the meantime you can learn more about the GMUG here. (Photo of Josh King by Nick Spitzer)

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TAKE ACTION: Comment on the Arkansas Headwaters Recreation Area Management Plan

Kestrel Kunz

ARKANSAS RIVER, Colo. - The Arkansas Headwaters Recreation Area (AHRA) is revising their Management Plan for the first time since 2001. The new Draft Plan was made publicly available in October and the AHRA is accepting public comments through November 10, 2017 (next week!). In order to design effective and productive comments, American Whitewater has thoroughly reviewed the Draft Plan, discussed the Plan with our local Affiliate Clubs, attended AHRA Public Open Houses, and reached out to key members of the local paddling community. To make it easy for you to SUBMIT YOUR COMMENTS, American Whitewater staff have compiled our key concerns and comments for your review. 

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Colorado Honors the legacy of Matt Brown

Nathan Fey

Gunnison, Colorado - Last Wednesday, Matt Brown - longtime river guide, adventurer, and pillar of the Gunnison Valley community- passed away tragically after an accident in Moab. Matt was so much to so many.  At the request of his family and friends, contributions in Matt's memory can be made to American Whitewater’s River Access work in Colorado.  Matt was a strong ally and advisor in our work to protect the public’s rights to float and fish in the State.  We miss him immensely.

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Comments needed on Upper Colorado River Recreation Area Management Plan

Nathan Fey

Kremmling, Colorado - The Bureau of Land Management has released for public review and comment a set of preliminary alternatives for managing about 40 miles of the Upper Colorado River between Parshall and State Bridge - including Gore Canyon and Pumphouse. This is your chance to weigh in on whether there should be a day-use permit;  a camping permit with designated campsites in the popular stretch between Pumphouse and State Bridge; and expanding the developed Pumphouse Campground.

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Gore Fest 2017 is a few weeks away!

Nathan Fey

Bond, Colorado - American Whitewater is presenting Gore Canyon Festival - August 25-27th 2017Online registration is open and there are events for everyone, so sign up today! 

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A Successful River Cleanup on the St. Vrain (Lyons, CO)

Kestrel Kunz

On Sunday, nearly 50 people gathered on the banks of the St. Vrain River to pick up trash from the water and the shoreline. We started the day off with Hotbox Roasters coffee and donuts, and a few words about River Stewardship – the common cause that brought us all together. We found bedframes, rusty nails, lawn chairs, car doors, plastic water bottles, candy wrappers, fast food containers, and it doesn’t stop there. Our findings are likely a combination of leftover debris from the floods, illegal waste dumping along the river, and built up trash from years of careless passers-by. Thank you to all those that came out for the river cleanup! American Whitewater depends on our affiliate clubs, members, and dedicated volunteers in order to tackle our many River Stewardship projects.  

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Releases to Lower Dolores River certain in 2017.

Nathan Fey

Cortez, Colorado - Last week, American Whitewater met with local water managers, fisheries biologists, an other interests in Dolores River water, to start negotiating releases from McPhee Dam - like we do every spring.  This year, things are looking very good for the Dolores...

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Upper Colorado River Access funded by Land & Water Conservation Fund - CO

Nathan Fey

Dotsero, Colorado - A key river access point on the Upper Colorado river, once threatened with closure, has now been permanently protected through a partnership between BLM and Eagle County. 

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One more day to submit input on Colorado's Brown Canyon National Monument!

Kestrel Kunz

There is only one more day left to share what you value most in the Browns Canyon National Monument planning area! The Bureau of Land Management, U.S Forest Service, and Colorado Parks and Wildlife are working together to develop a Coordinated Management Plan for Browns Canyon National Monument. In order to design a plan that most benefits citizens and visitors of Colorado, the agencies designed an Online Survey and Mapping Tool to understand how the public interacts with the Browns Canyon planning area and what aspects of the area are most important to the public.


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New Report on Impact to San Miguel River From Proposed Reservoirs

Evan Stafford

Colorado - American Whitewater has released a new study on whitewater recreation in the San Miguel River Basin. The Colorado Water Conservation Board (CWCB) requested that Montrose County consult with American Whitewater on recreational needs and future impacts for the San Miguel River. Montrose County acquired conditional water rights to the San Miguel River in hopes of building multiple new reservoirs on BLM land. American Whitewater worked with Montrose County’s agents to assess the impact its conditional storage proposals would have on existing recreational opportunities. 

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Proposed Asphalt and Gravel Mine threatens the Upper Colorado River

Evan Stafford

A new proposal to allow the development of a 90- acre open pit mine in Eagle County at the gateway to the Colorado River has local river users asking questions. We encourage everyone to attend an Open House December 6 at 6 PM at the Gypsum Recreation Center, and to make your voices heard at the Town Council meeting where they will discuss the application on December 13 at 7 PM.


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Lyons Outdoor Games and Burning Can to Support AW

Nathan Fey

Lyons, Colorado - For the second year in a row, Oskar Blues Brewery is hosting the Burning Can Festival at this year Lyons Outdoor Games.  Burning Can, which takes place under the backdrop of Rocky Mountain National Park and the St. Vrain River, is a celebration of good beer, served in a can.  This year, All money raised from Lyons Outdoor Games recycled cans will be donated to American Whitewater. See you there!

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Final EIS for Denver Water's Moffat Project Delayed Another Year

Nathan Fey

Denver, Colorado - The U.S. Army Corps of Engineers announced that it was delaying the release of the Final Environmental Impact Statement (FEIS) for the Moffat Collection System Project on the Fraser River and South Boulder Creek, for another year.  Previously, the FEIS was scheduled to be released at the beginning of 2013 -- it has now been delayed until February of 2014.

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AW launches Flow Study for Yampa River

Nathan Fey

Colorado - American Whitewater is conducting a study of flow-recreation relationships for the Yampa Basin, and identifying specific metrics for use in the Watershed Flow Evaluation Tool. This study is intended to inform local, state, and federal planning efforts as to the full range and quality of recreational boating opportunities for the Wild and Scenic suitable Yampa River, as well as the Elk and White Rivers, and their tributaries. Your participation in the flow survey is requested.

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River Access Task Force Submits Recommendations to Colorado Governor

Nathan Fey

Colorado - On December 23, Governor Bill Ritter issued a report outlining a series of proposals for resolving disputes between landowners and rafters in Colorado. He also signed an executive order creating the River Access Mediation Commission to provide a way for some of the most contentious conflicts between boaters and property owners to be addressed. The Governor’s River Access Dispute Resolution Task Force was a 17-member group created in July of 2010 to help craft ways to sort out conflicts on Colorado rivers on a stretch-by-stretch basis as those disputes arise.

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Help Protect the Yampa River - Colorado

Nathan Fey

Colorado - Last month, the Bureau of Land Management (BLM) released their proposed management plan for the Little Snake Resource Area, encompassing over a million acres of soaring plateaus, wild and scenic rivers, and sweeping sagebrush basins.  Special interests are trying to overturn the Bureau of Land Management’s plans to protect portions of the Yampa River – one of the nation's last free flowing rivers.    Let BLM know that protections for these rivers are important to you!

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Public Hearing added for Denver Water's Moffat Collection Project

Nathan Fey

The US Army Corps of Engineers has added a public hearing on the Moffat Collection Project.  Date: December 8, 2009  Location: Keystone Conference Center (0633 Tennis Club Road, Keystone, CO, 80435)  Time: Open House 4:00 pm; Public Hearing begins at 6:00 pm

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Denver Water taking comments on Gross Reservoir Project

Nathan Fey

Colorado- While the US Army Corps of Engineers is drafting the Environmental Impact Statement (EIS) for the enlargement of Gross Reservoir in Boulder County, Colorado, Denver Water is taking comments on their proposed changes to the reservoir's FERC license, including tree removal, relocating recreation facilities, and hydropower generation.

Comments on the FERC License amendment associated with Gross Reservoir Enlargement Project are due September 29th, 2008.


Craig Irwin


John Gross


Revision #Revision DateAuthorComment
1192672 02/16/09 Craig Irwin
1199638 05/12/12 John Gross
1202946 12/22/13 Craig Irwin 20131221
1202634 09/03/13 Craig Irwin spt2013
1204249 03/03/15 Craig Irwin cd
1204272 03/05/15 Craig Irwin 201502
1212982 06/21/19 Craig Irwin updated description
1210505 11/07/18 Craig Irwin 201811
1213463 08/07/19 Craig Irwin updated description