Rio Las Palmas: Cañon la Presa
class III-IV
length: 23 miles
gradient: 30 ft/mile
drainage area: 530  sq. miles (put-in), 800 sq. miles (take out)
elevation: 280 m = 924 ft (put-in), 70 m = 230 ft (take-out)
minimum flow: 1000 cfs
optimum flow: 3000 cfs
shuttle: 36 miles
     From Tijuana go on Highway 2 to toward Tecate.  Make a right turn
toward Presa Rodriguez several miles after leaving populated area
("presa" means "dam").  You can park a couple hundred feet above the
reservoir (river right), about 1 mile from the dam.  To get to the
put-in, go back to Highway 2 and continue to Tecate (20 miles), then
turn right onto Highway 3 toward Ensenada.  16 miles on this road and
you're at Valle Las Palmas, the town where you can find a spot to
put-in.  We put-in on the major northern tributary just before getting
to town at Puente Las Palmas ("puente" means "bridge").  Alternatively,
if you want to put-in at mile 7.0, heading on Highway 2 to Tecate from
the take-out, turn right on a dirt road 8 miles from Presa Rodriguez
(toward El Dorado).  Eight miles down this dirt road (which climbs over
an ~800 ft pass) will leave one at the river.  It may be difficult to
drive down this road after or during a rainstorm.  Also access may be
inhibited by the ranchers in the area.

     The Tijuana River is one of the three largest river systems in the
Southern California region, along with the Santa Ana and Santa Clara
Rivers.  It runs through the city of Tijuana in Baja California
(Mexico), where it picks up a disgusting amount of sewage and pollution,
before crossing back over to the US to empty into the Pacific Ocean just
south of Imperial Beach.  The two major streams that create Rio Tijuana
are Cottonwood Creek from the north (whose primary drainage area is in
the US, where it is dammed creating Barrett Reservoir and Lake Morena)
and Rio Las Palmas to the south (which is dammed just east of Tijuana by
Presa Rodriguez).  The water impounded by Presa Rodriguez is the
drinking water for the city of Tijuana.  Rio Las Palmas above the lake
has little chance for pollution - only from the small town of Valle de
las Palmas, and of course the numerous ranches in the area.  The water
still flows chocolate like all Southern California rivers, due to
rampant erosion.  Rio las Palmas is the largest river in the Southern
California region that flows through a gorge the magnitude of Canon la
Presa.  It carries adequate flow to boat after good storms in the winter
time.  The drainage area is so large and at an average of 4000 ft
elevation, that this river system picks up much more precipiation than
the coastal lowlands during storms, and water flows pretty good for
several days following a large storm.
     On February 15, 1998 Preston Holmes and I put-in for a first
descent of Canon la Presa.  Having been hasseled by cops on the US side
several times the past week, we were looking forward to some worry-free
wilderness brownwater kayaking in Baja.  A major storm had struck the
previous afternoon/evening, dropping about 2-3 inches of rain in the
upper elevations of San Diego County, and probably just south of the
border as well.  We put in on the tributary just north of Valle de las
Palmas on approximately 800 cfs.  A gauge under the bridge read about
0.5 meters (?).  It looked like this tributary and the main river had
not gone more than a foot higher in the recent past.  Perhaps the
previous week’s storms were only getting the ground satuated, and this
last one was the first to really start water flowing at good levels.
Though raining slightly all day, we had a good omen at this time when
there was a small break in the clouds which gave us sunshine as we got
ready to put-in.
     It was a couple miles down to the confluence with the main river.
There were some riffles in this first little stretch, and some shallow
areas where we got stuck on sand.  In general it flowed pretty quickly.
There were a few trees along the banks here, but nothing threatening.
After the confluence, the volume of water flowing was over fourfold our
initial amount, and we didn’t get stuck for the next 10 miles down to
the start of the canyon (class II). There was only one fallen tree that
required a little maneuvering to avoid (near the canyon) - otherwise the
riverbed was free of obstructions - especially in the canyon.  It was
also very wide, giving the feel of being on a very large river.  Ranches
are passed the entire way in the valley, and we even had a chopper
circle over us.  Fear gripped me as I thought we might actually live out
a dream Preston had about us being thrown in Mexican jail for running
the river, but the chopper soon went away.  Though it returned a little
later, I don’t think they spotted us the second time.  It didn’t have
any kind of government markings on it anyway, so they were probably just
interested people flg around.  Big sand waves were found on the entire
run (up to 8 vertical feet, often crashing for several seconds) and I
had a blast surfing them in a loaned boat (Fusion).  The chocolate water
moved us along quickly, and we were at the canyon entrance within 2.5
hours of launching (i.e. around 3 pm).  A good stream enters on the left
just before the canyon entrance.  Things pick up in the canyon proper
(don’t be fooled by a large hill on the right a couple miles before the
real canyon entrance).  Within a mile we paddled through a couple class
IIIs and one long class IV ("Looks Can Be Deceiving") which we scouted
from the right.  I mentioned to Preston as he peeled out into this rapid
that the water always feels much bigger than it looks from the bank.
There were a couple huge holes lurking in that rapid that we failed to
recognize from our scout at the top.  One can see on the video Preston
floating up and down over the huge waves, disappearing from view in each
trough.  Just downstream from this rapid is another, "Big Bopper" -
which is now the largest in the canyon, of about IV+/V- difficulty.  A 6
ft pourover drop at the top starts this long one, with two other large
holes just below.  I listened to Preston and we both portaged (there was
a good compromise being accomplished on this trip between my crazy
attitude and the safe-and-sane way Preston boats).  We both agreed that
it was runnable, but I didn’t mind portaging it on a first descent.
Preston was worried about not being able to see anything after getting
the thick water in his eyes in the middle of it.  Just below Big Bopper
is "Little Bopper", which we both ran.  The water moved swiftly through
many class IIs and IIIs after this, and at least two other class IVs.
Things begin to really pick up about 3 miles from the canyon mouth, in
the Las Palmas Gorge.  Two class IVs are encountered just before
reaching the high water level of the reservoir about 2 miles from the
mouth.  Before the dam was raised in the last 2 decades, this would have
been the most exciting stretch, two miles with average gradient of 80
fpm (as compared to the 30 fpm gradient in the rest of the canyon).  We
had hiked into the gorge the previous summer to check out what the drops
would be like.  It was then we found that this last part was entirely
coverd with silt laid down when the reservoir was full.  Impressive
rapids had been buried after being drowned by the lake, very reminiscent
of the Grand Canyon and Lake Mead.  The silt banks along the canyon were
falling into the river as we floated down this very fast stretch to the
reservoir.   It seemed the reservoir was still 60-80 ft below capacity.
If full, you’d have to paddle 3-4 miles out.  As we had it, water took
us to within a mile of my truck.  A rainbow and some sunshine greeted us
as we paddled on the lake. We were at the take-out exactly on schedule,
just after 5 pm, and back in La Jolla for a pizza dinner by 8 pm.  It
was an absolutely amazing run, a gem of whitewater just south of the
border, unknown to the paddling community!

0.0     Put-in at the town of Valle las Palmas
2.0     Arroyo Hondo (?) enters on the right; drainage area 160 sq mi (this
is the one we put-in on)
6.0     El Dorado (R), a small village.  A dirt road into here offers an
alternate put-in.  The road reaches the river at mile 7.0, and shortens
the shuttle to 16 miles (8 dirt).
9.0     The river divides into two channels that separate widely (sand in
between) for the        next 2 miles.
12.0    Entrance to Cañon la Presa.  The next seven miles have an average
gradient of 25 fpm.
19-21   Las Palmas Gorge where the river drops at an average gradient of
80 fpm.
21.5    Canyon opens up.
23.0    Reservoir created by Presa Rodriguez.  Take-out on the right at
Highway 2.

Rocky Contos
jcontos@ucsd.edu