The canyon section of the South Fork Boise runs for 21 miles from Danskin Bridge to
Neal bridge through a deep, committing, vertically walled canyon. The run contains
many fun, long and technical rapids with beautiful desert canyon scenery. Flows are
fed by Anderson Ranch dam, which provides an extended season
for rafts and kayaks. At standard summer releases of 1,600 CFS, expect to spend around
5 hours on the river.
From Danskin Bridge, the run starts with a few miles of fast moving class I, winding through an open canyon bottom of cow pastures, with brush lined banks and the occasional island. There is a primitive road on river left leading to two working cattle ranches. After the second ranch house, marked by a large island on a right hand bend, the river enters a deep, walled canyon, and the gradient increases.
From the canyon entrance to Steamboat Rock (see above photo) the rapids are mostly
fast moving, fun class II's, linked by sections of swiftwater. Not far below Steamboat
Rock, the rapids build into longer, technical class III drops, with one fairly
significant class IV (Buffalo Creek) thrown in. Most drops in this section,
with the exceptions of Devil's Hole and Buffalo Creek,
are read and run, though don't run anything blind as the run is prone to collect wood.
While there is a rudimentary portage trail at Buffalo Creek, carrying a raft
around it would be extremely difficult and time consuming. Lining it is not a good
Originating from bottom of Anderson Ranch Reservoir, the water temps on South Fork
are extremely cold year round. The rapids are long, and in the the calmer sections
the current moves very quickly. Even in summer, swims can be long and cold. With
the vertical canyon walls, and steep talus banks, there is no way to walk downriver
if a swimmer is separated from their boat. The river
is also home to healthy populations of rattlesnake, and poison ivy. The South Fork is a
very committing run, with potentially high consequences for the unprepared. Boaters,
especially rafters, should have solid class IV skills, and propper cold weather gear
during the early season.
Standard summer release flows from Anderson Ranch reservoir are around 1,600 CFS, though in the early season, it can run much higher. I wouldn't want to take a raft down at flows much below 1,600 cfs, but it could be run much lower in a kayak. Check the below link to Bureau of Reclamation under planning tools for current status of Anderson Ranch Reservoir. Note that difficulty of the run increases with higher flows.
|Ave Gradient:||25 fpm|
|Min Level:||1,600 CFS|
|Season:||May - Sep|
Best access to the put in is via the city of Mountain Home off of Interstate 84.
From Mountain Home head North on state hi-way 20 towards Sun Valley for roughly
15 miles. Watch for a small sign on the West (left) side of the road that says
"Prairie". Continue towards Prairie until you reach the river. Cross the bridge
and continue downstream following the signs to Danskin access. Danskin has a good
boat ramp, and parking.
To get to the take out, continue go back to the Danskin turn off and continue to the town of Prairie. From Prairie, take the Blacks Creek road (FR 189) to the river at Neal Bridge. There is a primitive boat ramp at Neal Bridge and limited parking. Do not block the boat ramps when you park! To return to I-84 from Neal Bridge, continue South on Blacks Creek road until you hit the interstate, roughly 20 miles East of Boise.
Given the length of the run and the long, dirt road shuttle, the best option is to hire a shuttle service. Boise River Canyon Shuttle Service (208-868-3255) of Prairie runs a top notch operation with a convenient, secure key drop at Danskin Bridge. Its well worth the price. Call for details.
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Copyright Todd Hoffman 2009 - All Rights Reserved