Tunnel Run (Ralston Powerhouse to Greenwood)
California – US
- Class
- IV- to IV
- Length
- 16.5 Mile(s)
- Gradient
- 23 FPM
- Put-in elevation
- 1,088 Feet
- Take-out elevation
- 827 Feet
- Typical season
- January to December
Current Flow
404 CFS
Gauge height: 8.58 FT
Reading from Jul 10, 2026 10:00 PM
▼ -50.00/hr (12h) ▼ -25.00/hr (24h)
Don't bother
- Primary gauge
- MIDDLE FK AMERICAN R NR OXBOW PH Gauge detail & alternatives Live gauge ↗
Recommended levels
| Minimum | 700 |
| Average | 1,800 |
| Maximum | 3,000 |
Recommended use
- Kayaking
- Rafting
- Canoeing
- SUP
- Packrafting
- Fishing
Struck-through craft are not recommended for this run.
Flow history — last 6 days
No gauge history recorded in the last 6 days.
Photos
No photos added for this run yet.
Description
For those without the skill or equipment to run this on their own, this could be one of the best commercial trips in CA. This area is not nearly as crowded as the South Fork but still offers year round boating due to dam controlled flows coming out of the Oxbow reservoir.
This is a longer run but can easily be done in a day (including shuttles). For those wanting to make a weekend out of this, overnighters are possible along most of the river due to BLM controlled land. Only problem with overnighters is the amount of gear you need to bring and portage through the portage section of this run.
The portage is the least fun aspect of this run but is still worth it. Heavy gear and boats will be a real pain so pack light. You can also have an adventurous sole run the boat down the portage chute while the others walk it. Either way, make sure to plan appropriately for a successful portage here.
The fishing and side hikes found in this canyon also warrant doing this run as an overnighter. Lots of mines and historic gold rush era equipment to explore and think about.
Most of this run is solid class III but handful of IV's with a class V portage, length and remoteness make this overall run a solid IV.
Rapids
| # | Rapid | Class | Recommended flow | Description | Scout |
|---|---|---|---|---|---|
| 1 | Panic Alley Rapid | III | 700–3,000 | What better way to start your run than with an immediate class III wave romp to get your juices flowing? |
Read and run |
| 2 | Last Chance Rapid | III | 700–3,000 | This rapid is right above the Tunnel Chute. A simple wave hole with minimal flatwater below here doesn't leave a lot for boaters to eddy out left or right just before Tunnel. |
Best choice for someone never running this before would be to eddy out above Last Chance and scout Last Chance and Tunnel all at the same time. |
| 3 | Tunnel Chute | IV+ | 700–3,000 | Tunnel Chute is a man made rapid. This rapid was dynamited by gold miners to bypass a large loop in the river. Consequentially, this rapid is really rocky and swimming the whole thing could get you banged up pretty good. Most commercial raft trips run this and most people familiar with the river run this as well. |
Scout left or right (preferrable above Last Chance) |
| 4 | Kanaka Falls (Cartwheel Rapid) | IV | 700–3,000 | After a couple miles of entertaining, straight forward class III water you get to Kanaka Falls. This is a boulder strewn rapid drop. Waves and holes down the chute. |
Scout on river left. Portage or run. |
| 5 | Upper Ruck-A-Chucky (Chunder) Rapid | IV- to IV | 700–3,000 | A lot of class I and II water lead up to this point where things start to get interesting again. This is a class IV ledge drop. If you have a yardsale here you have a good chance of runny ruck-a-chucky below. Be confident in running this and practice appropriate safety standards. |
Scout and/or portage on river right. |
| 6 | Ruck-A-Chucky | V+ to VI | 700–3,000 | This is the recommended portage on the tunnel run. Many undercut rocks and class V+ to VI water makes this a very hazardous rapid. Many accidents involving gear and human bodies has occurred here. The only possible route down is straight down the center. Too right or too left can have serious consequences. |
Scouting and portage trail on river right. |
| 7 | Lower Ruck-A-Chucky | III+ to IV | 700–3,000 | This is right below ruck-a-chucky. Run the chute down the middle moving right to left. |
|
| 8 | Driver's Ed Rapid | III to IV | 700–3,000 | Run towards the left |
|
| 9 | Catapult Rapid | III to IV- | 700–3,000 | Big hole and waves on the left where a big boulder splits the river. At higher flows there is a sneak on the right. |
Read and run |
| 10 | Shareen's Dream Rapid | III+ | 700–3,000 |
Access
| Type | Name | Elevation | Camping | Water | Boat ramp | Vehicle access | Description |
|---|---|---|---|---|---|---|---|
| Put-In | Ralston Powerhouse | 1,088 Feet | No | No | No | All Vehicles | Putin just below the Oxbow dam where you can see the water release out of the powerhouse. Get here by turning off of Highway 49 and following the mosquito ridge road to the dam. |
| Take-Out | Cash Rock Access | 827 Feet | No | No | No | 4WD Only | A 4WD road switch backs down to the river. This should only be used in emergencies. |
| Take-Out | 4WD Access | 808 Feet | No | No | No | 4WD Only | Another 4WD access on river right. Again this should probably only be used in an emergency. |
| Take-Out | Old Greenwood Bridge Access | 727 Feet | No | No | No | All Vehicles | Take out on river right. |
Camps
No river camps added yet.
Permit
No permit is required, or permit info hasn't been added yet.
Fishing
No fish species have been associated with this run yet.
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Community Run Notes
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