This photo needs editing.
Difficulty III
Length 3 Miles
Gauge N/A
Flow Range
Reach Info Last Updated 08/22/2018 5:16 pm

River Description

The Millerton Lake Bottom run is a short introduction to the main stem San Joaquin River.  It is a good introduction. It has a classic San Joaquin feel with a deep and relatively narrow channel, banks of amazingly sculpted granite and big powerful drops. It is also runnable most years for a few months, typically August, September, October and November, with big flows ranging up to 5,000 cfs. This section of the San Joaquin is usually hidden beneath Millerton reservoir, but each summer the level of the lake gets lower as outflows exceed inflows. By the end of summer up to 3 miles of river can be revealed. Flows are provided into the river from an underground PG&E powerhouse.

The San Joaquin River Gorge Recreation Area (SJRGRA) provides access to the start of the run.

Getting There:
From Fresno, take highway 168 through Prather. Continue east for 2 or 3 miles, then turn left off of highway 168 onto Auberry Road heading north to the town of Auberry. Go through Auberry till the road splits by the school. Veer left onto Powerhouse Rd. After just 2 or 3 more miles turn left onto Smalley Rd and follow it to the SJRGRA.

From the north, take highway 145 from Madera through Friant to Auberry road. Turn left onto Auberry Road and drive east on Auberry Rd to the junction with highway 168 at Prather. Continue on as described above.

Put-in: Once at Squaw Leap go all the way to the West end of the road at a gate and park. Carry your boats over the gate and down the road to the water (big switchback), or hike the trail which drops down more directly to the river. As you approach the gate turn right into the lower parking area. The trail starts at the right hand side of this lower parking area. The river elevation is about 220 feet below the parking area.

Take-out: Here is the complication. There is no easy public take out at this time. You have 3 options. 1) Boat as far downstream as you want, then carry your boat back upstream across the lake bottom, or, boat and carry back upstream to the put-in. This option is excellent exercise, but still gets used occasionally. 2) Leave a car at Sky Harbor and 2a) paddle 9 miles across the reservoir. 2b) hitch a ride from a powerboat. 3) Get access down Wellbarn Rd. to Temperence Flat which is 2 miles downstream of the put-in by 3a) going with a local who has access or 3b) calling and writing Millerton State Park (559- 822-2332) and bugging them to allow access for paddlers to use this wonderful little section of river.

Even if you do get vehicle access to Temperence Flat, the driving distance and time between Temperance flat and SJRGRA is ridiculously long. A combination hiking & driving shuttle works best.   Drive an empty shuttle vehicle down Wellbarn Road to the take out, while other vehicles with boaters and gear drive to the put-in. The driver of the take-out vehicle then hikes across the lake bottom or along the Millerton trail to the put-in. The take-out driver/hiker will arrive at the put-in within a reasonable time after everyone else. At the end of the run, the drivers of the put-in vehicles hike back across the lake bottom to their vehicles while boats are loaded on the take-out vehicle and driven out.

There is an excellent and popular hiking and riding trail on the south side of the reservoir. It comes close to the reservoir high water mark just downstream of the first rapid. Hiking on the trail is probably easier and faster than in the lake bottom. However there is a fork at a gate in a fence. One fork heads downhill along the fence (going upstream), then traverses near the reservoir high water mark. Finally it climbs up to the powerhouse access road. This lower trail is faster and more direct than the upper trail. The upper trail climbs high above the parking area and eventually ends up at the main junction and camping area 1.5 miles further away. It is easy to miss the small spur trail that drops from the main trail to the parking area at Kerchoff #2.

581' Millerton Reservoir high water mark.
540' Put-in at powerhouse outlet.
520' TurboWave rapid, class 3. Followed by Can Opener rapid, class 3.
500' Temperance Flat rd access. Mile 2 +-
480' Below last class 3 rapid.
470' Lowest possible level of reservoir. Mile 3 +-

Millerton Elevation Level page shows the exact elevation, on the hour and every 15 minutes (type in MIL for the gauge identifier).   Notice the hourly fluctuations in the reservoir elevation caused by differences between inflow and outflow.  Click on the graphing button at the bottom of the page to more easily see patterns.  During late summer and fall, when there are no other significant inflows to Millerton, the graph usually shows an obvious daily fluctuation. Daily rises in the graph indicate when the powerhouse is on, while declines indicate when the powerhouse is off. Longer term rise and fall in the graph indicates whether outflows are larger or smaller than inflows over the longer term.

There should be a delay of several hours between the powerhouse starting up and change in reservoir elevation reading at Friant Dam , 15 miles away. So there is probably flow from the powerhouse at the put-in a few hours before the graph registers an upward change. This will be updated when a more accurate estimate of the time delay can be made.

Millerton website has reservoir elevations, calculated inflows and outflows as well as other information. The actual inflow will be around 20 or 30 cfs while the powerhouse is off and up to 5,000 cfs while the powerhouse is on.

You can get an estimate of actual flows by comparing the daily average inflows with the amount of time the powerhouse is on. Multiply the daily average flow x 24, then divide by the estimated time the powerhouse was actually on.  Outflows from the powerhouse often fluctuate a few times during a daily release. You might start off with low flows and end with high flows or vice versa.

Other info: Gasoline, groceries and dining are available at Auberry, Prather and Friant. Velasco's in Prather has excellent mexican food. There is also Thai food in Auberry.  Primitive camping is available at SJRGRA and campgrounds have drinking water.  There is a small museum and office at the SJRGRA.

Information about Millerton Reservoir State Rec Area is available at Millerton SRA .   Check out the recreation area boundaries around the Temperance Flat area by looking at this NE-Millerton-map.pdf

Temperance Flat Dam Proposal:  
This area of the San Joaquin is presently under study for several potential large dam and reservoir sites. See: Upper San Joaquin Basin Storage Investigation Three sites were under serious investigation. As of 2014, the final selected site is about one mile upstream of the confluence with Finegold Creek and would have a maximum size of around1.4 million ac/ft.  Despite the large size maximum annual yield is less than 100,000 ac/ft. This reservoir will bury the Patterson Bend, Squaw Leap and the Millerton Bottoms sections. The study has maps and updates on the proposal. 

Draft EIS is out September 2014.  

As of 2018 dam proponants have formed the San Joaquin Valley Water Infrastructure Authority and are working hard to get federal and state taxpayers to fund this project. 

PG&E Kerchoff Project - FERC Relicensing:
Flows for this reach come from the PG&E Kerchoff #2 powerhouse.  The FERC license for this powerhouse expires in 2022.  The relicensing process typically starts about 4 years ahead of time, so will likely start in 2018.  In this process, AW will advocate for scheduled releases from Kerchoff Dam to facilitate whitewater boating in Patterson Bend and Squaw Leap.  We will also advocate for real time flow information below Kerchoff #2 when Millerton is low enough for boating in the Millerton Bottoms section.

Other Information Sources: 
San Joaquin River Gorge Recreation Area
BLM Map of area
Millerton State Recreation Area
Friant Dam Statistics
Millerton DailyReport - pdf

Upper San Joaquin Basin Storage Investigation

Rapid Descriptions

First drop

Class - II+ Mile - 0.6
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This is the first significant drop on the run.  Although it is not big, it has several odd and tricky ledge holes.   Scout from either side, but probably a bit easier to scout on the river left.   The main line is from the right back towards the center.   There can be a shallow sneak route down the left edge.


Mileage and location marker are close, but approximate.

Turbo Wave

Class - III+ Mile - 1
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At high flows this forms a huge and very fast wave.    At lower flows, rocks show or form holes.   The conservative line is down the right edge.   Scouting is easiest from the river left, but requires clamboring over large boulders.   This is an impressive drop, short but very steep.

Can Opener

Class - III+ Mile - 1.2

Following Turbo Wave, float a short narrow channel.   Where the channel opens up again it suddenly drops over a small waterfall.  The Can Opener rock kicks up an impressive spray in the center of the falls.  A narrow line is just to the right of the Can Opener.   At some flows you can also boof the falls a bit further to the right.   This is the most difficult rapid on the run. 


There is an easy take out for scouting on river right. 

Wave Train

Class - II Mile - 1.5
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This is the longest rapid on this run, consisting of good sized waves and laterals with large eddies on either side.  It offers interesting play at many flows.   One time I saw a full sized creek boat do a mystery move while trying to surf in this rapid.  The canyon is opening out into the Temperance Flat basin at this rapid. 


The mileage is a rough estimate while the coordinates are close but approximate. 


Class - III Mile - 2.4
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After a long section of slow flat water the river picks up speed with a fairly long class 1 to 2 lead in.  Suddenly it plummets down a steep but clean ramp.    This is the last of the big class 3 drops in this section and though it is the easiest, it may have the most vertical of them all.   Unfortunately it appears out of the lake for the shortest duration and may not show at all in some years. 


The mileage is just an estimate at this time, while the location marker is also very approximate.   The actual location could be a few hundred yards upstream or downstream. 

Last Fling

Class - II Mile - 3
Rapid Thumbnail Missing

This rapid only appears when the reservoir is at its very lowest level, so it seldom shows up.   It is a small rapid, but at many flows, there is a great nose stand wave in the middle of the rapid, with a good service eddy as well. 


No Gage

Gage Descriptions

This section is runnable every Autumn and has 3 good rapids exposed once the Millerton Elevation Level, is 510 feet or less. More rapids are revealed as the elevation drops lower.  Click on the graph link at the bottom of the elevation page to more easily see patterns of change.  This elevation chart is the only online way of estimating when the powerhouse is on or off. It can also provide a rough estimate of flow when compared to outflow figures at Millerton DailyReport - pdf. On this page, both inflow and outflow figures are 24 hour averages. The actual inflow will vary considerably during the day as the powerhouse is turned on or off, and ramped up or down. Actual inflow can range from 0 up to 5,000 cfs. The total average outflow tends to be fairly stable from hour to hour, so just assume that the outflow today is about the same as yesterday. Look at the daily fluctuations in the elevation graph. If the graph is level, the powerhouse is releasing the same flow as the reservoir outflow. If the gragh is going up, the powerhouse is releasing more than the reservoir outflow. If the graph is going down the powerhouse may be off or only releasing a small amount.

The Millerton Daily data page shows how much average flows have fluctuated for several past days. It is always two days behind in reporting.

From January 1997 to February 1998, the Bureau of Reclamation reported real time hourly inflows to Millerton.  This made it much easier to decide when to float on the river, because the actual flow was known.  AW is hoping to reinstate this hourly inflow report so that the Millerton run can be better utilized. 

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.

No Accident Reports




Paul Martzen


Revision #Revision DateAuthorComment
1197829 06/16/10 Paul Martzen minor updates
1197633 05/10/10 Paul Martzen
1193985 02/16/07 Paul Martzen n/a
1203724 10/14/14 Paul Martzen Temperance Flat Dam - update
1210267 08/22/18 Paul Martzen updated some links