San Joaquin, California, US

6. Millerton Lake Bottom (Kerchoff #2 PH to Millerton Reservoir)

Can Opener

Can Opener
Photo by Paul Martzen taken 11/05/05 @ 900 cfs ?

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; formerly called Squaw Leap Rec Area) provides access to the start of the run. BLM Map of area

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.  Google map


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.

Elevations:
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.   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. Unfortunately this information is always 2 days behind, and the inflow data is a 24 hour average so it is not the actual inflow at any time. 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 Auberry and Prather have excellent mexican food. There is also Thai food in Auberry.  Primitive, free camping is available at SJRGRA but bring water.

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 are under serious investigation. One site is about one mile upstream of the confluence with Finegold Creek and could have a maximum size of around 2.1 million ac/ft. One site is downstream of Temperance flat and could be as big as 2.7 million ac/ft. The third site is upstream of Squaw Leap about halfway through the Patterson Bend section. This would only contain 1.4 million ac/ft. Despite their size maximum annual yield is only 200,000 ac/ft. All of these reservoirs will bury the Patterson Bend section and will also bury some or all of the Horseshoe Bend section. The study has maps and updates on the proposal.

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

Upper San Joaquin Basin Storage Investigation

Paul Martzen