San Joaquin - Mendota Pool to Merced River Confluence

San Joaquin, California, US


Mendota Pool to Merced River Confluence

Usual Difficulty I (for normal flows)
Length 74 Miles
Avg. Gradient 1 fpm
Max Gradient 1 fpm

Fishing near Firebaugh

Fishing near Firebaugh
Photo by Paul Martzen taken 03/31/07

Gauge Information

Name Range Difficulty Updated Level
cdec-SDP 200 - 8000 cfs I 00h46m 181 cfs (too low)
cdec-SJN 100 - 2000 cfs I 93d12h15m 94 cfs (too low)
cdec-JBP 200 - 4000 cfs I 1y127d21h15m 83 cfs (too low)
usgs-11254000 200 - 6000 cfs I 00h46m 245 cfs (running)
usgs-11261500 400 - 8000 cfs I 01h16m 861 cfs (running)
Near end

River Description

This section is flatwater and especially suited for canoes and touring kayaks.    There is playboat potential at the outflow from the Mendota Pool dam, but there are usually lots of fishing lines from people up on the dam.   The reach is of particular interest because of its historic and political significance. 

The flow situation here is unusual. Friant dam normally diverts all of the water that would flow in this section. Most San Joaquin river water is diverted south to Tulare and Kern counties via the Friant Kern Canal, and some is diverted north through the Madera Canal.

To provide water to Mendota and Firebaugh area farms, water from the Sacramento and Feather rivers, is pumped out of the Sacramento - San Joaquin delta, into the Delta Mendota Canal. This water reenters the San Joaquin River at Mendota Pool immediately above the put-in.   Water then flows down the river to various irrigation diversions, till there is no more. The river is empty and dried up by the time it crosses highway 152.    It is an expensive process, but worth it to the farmers, since your federal tax money pays for much of the real costs.

A settlement agreement in 2006 between the Bureau of Reclamation and various environmental groups, lead by the Natural Resources Defense Council (NRDC), mandates that sufficient flows be returned to this river so that it does not dry up and that salmon may once again swim up the river to spawn.    In accordance to the agreement, restoration test flows began in October 2009.    In the spring of 2010,  water once again flowed from Friant all the way to the confluence with the Merced and on to the San Joaquin/Sacramento Delta.   Several long sections of river which were usually dry for the last 60 years, now have low but steady flows. 

Between Mendota and Sack Dam, the river flows past farmland.  North of Highway 152 the river flows through the Merced and San Luis wildlife refuges and through the Great Valley Grasslands State Park. 

Put in: There is a wide, dirt boat ramp just downstream of Mendota Pool Dam.   There is plenty of Parking.   From Highway 180 on the north side of Mendota, take Bass Road past Mendota Pool park, to the dam. 

Take Out: There appears to be informal public access on the east side of the river on Hills Ferry Road at the confluence with the Merced River.   There is a nice public park on river left just downstream of the highway bridge in Firebaugh.   View the map tab for locations of other possible access locations. 

Mendota Pool to Firebaugh is a pleasant 10 mile float  suitable for beginners.   The scenery is nice, though the riparian zone appears to be narrow along most of this distance.   Still, there is lots of wildlife to see.   With 1300 cfs the trip will take around 3 hours for a kayak or canoe. 

Other Information Sources: 
San Joaquin River Restoration Project 
San Joaquin River Restoration: CA DWR page
Dept of Fish & Game: Restoration pdf 
Revive the San Joaquin
Save the San Joaquin  
Merced National Wildlife Refuge 
San Luis National Wildlife Reguge
Great Valley Grasslands State Park
Firebaugh's Ferry
A minimart in Firebaugh at a main intersection of highway 33, has a large and informative display about the history of the area. 


StreamTeam Status: Not Verified
Last Updated: 2011-01-18 22:38:28

Rapid Summary

Mile Rapid Name Class Features (Legend)
0.0Mendota Pool DamN/APutin Photo
2.4Gauge below MendotaN/A
7.5Firebaugh Wasteway confluenceN/A
9.8Firebaugh ParkN/AAccess Photo
22.0Sack DamN/APortage
23.0Gauge near Dos PalosN/A
30.6Highway 152N/A
36.3Small DamN/APortage
36.8Chowchilla Bypass - ConfluenceN/A
43.7Sandy Mush RoadN/AAccess
46.3Small DamN/APortage
59.0Highway 165 - Lander AveN/AAccess
67.0Fremont Ford State Rec AreaN/AAccess
74.0Merced River Confluence - Hills Ferry RoadN/ATakeout

Rapid Descriptions

Mendota Pool Dam (Class N/A)

Put-in below Mendota Pool

Put-in below Mendota Pool
Photo by Paul Martzen taken 03/31/07 @ 100 ? very low

There is easy access for launching boats just downstream of the dam. 

Gauge below Mendota (Class N/A, Mile 2.4)

A Bureau of Reclamation gauging station is on river left.   Water in this section is usually pumped from the delta, via the Delta-Mendota Canal.   During the winter and spring flows can come from Friant, from Pine Flat via the Kings, pumped out of Tulare Lake or perhaps from west side creeks.  

The gauge is housed in a vertical corrugated pipe with a solar panel on top.   The cable crossing just downstream is used to measure the actual streamflow and calibrate the river level gauge. 

Firebaugh Wasteway confluence (Class N/A, Mile 7.5)

The Firebaugh Wasteway channel comes in from the left.  It appears to be a drain of some kind.   It probably carries treated waste water from the Firebaugh sewage treatment plant.   Looks like it can be flushed out with water from the Delta-Mendota Canal. 

Firebaugh Park (Class N/A, Mile 9.8)

Firebaugh Park

Firebaugh Park
Photo by Paul Martzen taken 03/31/07

The concrete remains of the old rotary bridge on the right side of the channel, signal this access point.   Take out or launch next to the white gazebo on river left. 

Sack Dam (Class N/A, Mile 22.0)

A small dam backs up the river, allowing diversion of most of the flow into the Arroyo Canal on the left. 

Sack Dam  Sack Dam is 5-foot-high low-head structure used to divert water from the San Joaquin River into Arroyo Canal. Diversions to Arroyo canal are usually limited to 600 cfs, but range from 0 to 800 cfs (Reclamation 2009b). Recently, changes in groundwater use are causing subsidence between the Eastside Bypass and the San Joaquin River. The San Luis Canal Company (SLCC) reports recent subsidence of Sack Dam at rates exceeding 0.5 foot per year (SLCC 2013)

Gauge near Dos Palos (Class N/A, Mile 23.0)

This gauge measures the flow below Sack Dam.   This section was normally dry after the construction of Friant Dam.  The San Joaquin Restoration process might bring dependable flows back to this section of river.  As of 2014 the river remains dry in this section till the Merced confluence.

Highway 152 (Class N/A, Mile 30.6)

It may be possible to access the river under this bridge, but there are likely to be fences blocking the way.

Small Dam (Class N/A, Mile 36.3)

There is a small dam just south of W. Washington Road and about 1/2 mile before the confluence with the Eastside Bypass.    Might be easier to portage on river right.   There may be public acces to the river from the road here as well. 

Chowchilla Bypass - Confluence (Class N/A, Mile 36.8)

The Chowchilla Bypass rejoins the river here.   Or rather, the river joins the bypass.   The channel is pretty much a straight ditch after this for a long ways. 

Sandy Mush Road (Class N/A, Mile 43.7)

There may or may not be public access at this road crossing.

The Merced National Wildlife Refuge is on the east side of the river and to the south of the road. 

Small Dam (Class N/A, Mile 46.3)

Portage on either side, but it may be better on river left. 

Highway 165 - Lander Ave (Class N/A, Mile 59.0)

There may be access at this bridge.   The west side of the road is the  boundary of the Great Valley Grasslands State Park. 

Fremont Ford State Rec Area (Class N/A, Mile 67.0)

This state park provides parking and river access.  It is on the west side of the river just south of the highway 140 bridge.   This is now part of the Great Valley Grasslands State Park. 

Merced River Confluence - Hills Ferry Road (Class N/A, Mile 74.0)

There appears to be public river access on the south side of Hills Ferry Road, just east of the bridge.   The Merced River enters on the right.

User Comments

Users can submit comments.
May 23 2011 (2801 days ago)
Paul MartzenDetails
On the morning of April 21, 2011, two men accosted a paddler at the small dam at mile 46. The men,
representing land owners, told the paddler that the land and river were private property and that
they would not allow him to continue downstream. The paddler went back upstream to Sandy Mush Road
and called to get picked up by friends. The paddler did not get the name or contact information
from the landowner. American Whitewater believes that this section of the San Joaquin is legal to
float and that it is legal to portage any dams that need to be portaged. Land owners do not have
any legal right to prevent boaters from paddling on the river or from portaging obstructions.
Diplomatically assert your right to float. Private land owners can not legally stop you. Only a
sheriff's officer or other police officer can legally detain you. Politely continue on your way,
but get their name and contact information. If an officer of the law does come and detain you, do
what ever they say, but explain your understanding that the river is a legally navigable waterway.
Get the name of the officer so that we can follow up. Then contact American Whitewater.
May 23 2011 (2801 days ago)
JSmith (153112)
I have been planning a trip down the San Joaquin River. My understanding has always been that
navigation of waters below the high water mark is permitted. These people are claiming that the
water is being "diverted" into the flood ways lying on their property. Can someone please advise me
if it is legal for me to continue on down the river in this section? If i am contacted by these
guys, i want to have a good knowledge of navigation laws to support us! thanks!