Standing Waves
by John Newgard
This past spring I
discovered a wave that would provide 4 minute rides, a wave that
broke in almost the exact same manner every day for 3 months, a wave
that was virtually unaffected by wind direction, a wave that never
reached shore! Dare I divulge the location of such a gem? Sure, why
not, it's located in downtown Ottawa, Ontario, on the Ottawa River.
I affectionately refer to this spot as "The Standing Wave".
There are actually
three forms of river surfing: 1) riding a tidal bore, 2) tying off to
a tree or bridge to get a board to plane on a swift current, and 3)
surfing standing waves.
A tidal bore occurs
when a relatively large tidal flood wave propagates up a river,
causing a wave (and series of trailing harmonic waves) to form.
Tidal bores can produce superb surf given the right bottom and wind
conditions.
La Dordogne River, near St. Pardon, in France.
Photo by Fabrice Colas
What happens when there are only 2 waves per day? Crowds!
Though planing on a
surfboard in a swiftly flowing river could be amusing, it is hardly
different than being towed behind a boat on a wakeboard: NOT surfing!
Now riding a
standing wave is indeed VERY similar to what we would call "surfing".
It is quite feasible to locate and surf a rideable standing wave,
providing a great means of staying in touch with your board during
the spring/summer doldrums.
Photo by Don Wallace
The author at Bates Island, Ottawa River, Ottawa, Canada.
The Physics
Contrary to what
one might expect, a standing wave does not form due to an obstruction
on the river bed, but rather, due to an abrupt increase in water
depth. Where water swiftly flows down a sloping river bed into
deeper water, the deeper water is able to resist the forcing of the
flowing water, causing a release of energy in the upstream direction
in the form of waves. Where "normal" progressive waves
move through water, standing waves are stationary relative to the
bottom. More notably, where ocean or lake surfing requires a
combination of good swell, a nicely shaped lake/sea bed, and
favorable winds to produce good waves, river surf requires only a
suitable streamflow and a favorable river bottom (I haven't yet
figured out if wind direction has much of an effect on shape). This
makes it possible to surf a river spot day after day without having
to worry about getting skunked.
- - > - - -> > |
ABRUPT INCREASE IN DEPTH |
STANDING WAVE |
CURRENT > > |
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Photo by John Newgard
Experiment
performed in the Tilting Flume at the Canadian Hydraulics Centre.
The logistics
The easiest way to
find suitable standing waves would be to make contact with local
kayakers. If there isn't a kayaking club in your area, chances are
there aren't any standing waves.
Most surfers would be able to recognize a suitable
standing wave, as it is similar in appearance to a progressive wave,
i.e. the ones we surf on the lakes or oceans. When scouting standing
waves, questions to ask yourself are: 1) "Is the wave steep
enough and high enough to be rideable?"; 2) "Does the
current look so strong that I won't be able to paddle against it to
get onto the wave?"; and 3) "Once I fall off the wave, will
I get mangled while floating downstream, and is there a suitable
place to get out of the water?" The more discerning river
surfer will also look for waves with a long crest (i.e. long wall or
shoulder) and plenty of clean face upon which to maneuver. Keep in
mind that the whitewater (or "pile" in kayaker terminology)
is very turbulent and no fun to ride. You're looking for a lot of
face or "green water", which generally means the wave won't
be steep, and so, a longboard is your best bet.
Whitewater can be
quite relentless, as it does not necessarily release you like when
you wipe out on a progressive wave. Not only can the current
continue to carry you downstream, but, worse yet, you can get caught
in "keepers", hydraulic features that churn about under the
surface and can hold you down for?well, for too long. So you've got
to get a spot wired from shore. Figure out how far out from shore
you have to paddle to get to the standing wave. Weigh this with the
current speed to guess how far upstream you'll have to jump in, then
walk an extra 50ft upstream to ensure you'll make the wave. Try to
estimate water depth based on the intensity of surface features.
Boils generally indicate deeper water, whereas violently breaking
surface waves indicate shallow spots. Locate calm spots or eddies,
typically close to shore or in the lee of obstacles such as rocks or
islands. Such features will help you make it to safety once you've
inevitably wiped out.
So now you're ready
to take the leap of faith. Stand down at water level and paddle
straight out toward the opposite bank, keeping an eye on the
approaching take-off spot. Once you're lined up, keep drifting with
the board pointed toward the opposite bank, keeping yourself in
position. At the last minute, say within 10 feet of the wave, point
the board upstream and paddle against the current. This part feels
just like catching a "normal" progressive wave, the only
difference being that, though you and the wave have roughly the same
relative speed as when you're paddling into a progressive wave, you
happen to be moving toward the wave and the wave is standing still.
Once you've caught
the wave, resist the temptation of sliding down the face on your
stomach. Instead, do your usual "pump and jump" to get to
your feet as soon as possible, crouch a bit, and make a turn. Now
simply maneuver back and forth across the face, trying to keep high
on the wave where the power is (as you would on a regular wave). For
an initial ride at a new spot, it may be worth riding on your knees.
This way you are very stable yet have good control of your board.
You can get to know the wave on your knees without having to worry
about falling too hard. Note that, once you're on your knees, it's
difficult to get to your feet, so once you decide to stand you just
have to commit to it on the take off.
You WILL fall. It
took 8 stitches to teach me to wear my bike helmet out there. To
seem responsible I'll also suggest wearing a life jacket, though I
don't wear one myself. A wetsuit and boots are handy to guard
against cuts, regardless of the temperature. Having said that, make
sure you don't feel for the bottom when you fall! Try to fall flat
and keep your legs on the surface as you retrieve your board. A
leash is handy to reel-in your board and avoid having it continue
surfing while you float away downstream.
Now remember, whitewater can be
dangerous. It is recommended that you educate yourself about
hydrotopography and consult with an experienced kayaker before heading out
on the river.
You will most
likely be sharing your standing wave with kayakers. Have no fear
though! Kayakers will respect you and you will likely find them
quite courteous. After all, you are a novelty act, a "crazy
surfer dude/chick", and so you command respect! And if you have
to wait your turn, big deal! The swell isn't going to drop, the tide
isn't changing, and there's no risk of a sea breeze coming up!
Keep surfing!
John
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