Dreamflows Glossary Of Terms
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 Glossary of River-Running Terms

The definitions given here apply to whitewater paddling.  Most entries are serious, but some are just for fun.  For more general definitions, consult your favorite dictionary.

acre-foot (AF)
The volume of water required to cover one acre to a depth of one foot.  An acre-foot equals 43,560 cubic feet, or approximately 325,851 U.S. gallons.  Reservoir storage is typically measured in acre-feet; large reservoirs have capacities of several million AF.  An acre-foot is enough to produce a smidge more than half a cfs of flow for a day.  Put another way, figure that releasing 500 cfs for 24 hours requires 1000 acre-feet.
The act of combining a powerful paddling stroke with forward hip action to lift the nose of a hardshell kayak.  Often used to facilitate a flat landing off a drop or to clear undesirable river obstacles and hydraulics.  The paddler may cleverly employ river features such as waves, rocks and pour-overs to enhance the amount of lift generated.  If you're running Class V in a hardshell and can't boof, expect many highly memorable paddling trips.
A small and light human-powered boat, pointed at both ends, propelled with a single-bladed paddle.  Open canoes have an open cockpit, i.e. have no sprayskirt.  Two-person canoes are common.  A whitewater canoe can look just like a kayak, with a sprayskirt, and in fact is often a modified kayak.  Major differences are that the paddler kneels instead of sits, and wields a one-bladed paddle.  However, in some regions, the distinction between the two is ignored, and kayaks are called canoes anyway.  A one-person whitewater canoe is termed a C1, while a two-person is termed a C2.  Whitewater kayakers are always deeply impressed when they see a C1 running Class V, giving rise to the expression "half the paddle, twice the man".
What happens when something goes wrong on the river.  It usually results in swimmers plus a yard sale of boat, paddle, and assorted gear like water bottles and sponges floating downstream.
An inflatable craft, typically made of very durable rubber, which has two pontoons, held together with some kind of frame.  The catarafter sits in a seat and operates two (very long) oars in a manner similar to an ordinary rowboat.  However (in the right hands) the craft is fast and nimble, and is suitable for running hard, technical whitewater.  Larger catarafts optionally carry one, or perhaps even two, passengers.
This is short for "cubic feet per second" and measures the total volume of water flowing past a particular point in a river or stream.  One cfs corresponds to one cubic foot of water flowing past the given point each second.  See river flow.
A small stream, often a seasonal (i.e. intermittently-running) tributary of a river.  In general creeks are smaller in width and volume than rivers, but this is by no means a rule.  For instance, puzzle over this one: in Arizona, Thunder River feeds Tapeats Creek, which in turn flows into the Colorado River.
Mike Ward writes: «A website devoted to informing, teasing, depressing, amusing and second guessing the Californian boating community about the amount of water flowing in the rivers of the Golden State, and similarly exotic destinations in the western region.  Operated by the benevolent but curmudgeonly South African/Brit/American by the name of Chris Shackleton, who is often heard wailing "It's just an estimate!!" as he drops into the boat-eating hole that "shouldn't have been there at this flow".  The site offers a wide range of flow information, and depending on the watershed in question, a similarly wide range of likely accuracy.»  Dreamflows was described in the Sacramento Bee newspaper as having "almost too much information".  This can be verified by the fact that 90% of the website's functionality is not accessed by 90% of the users.
The height, above mean sea level, of an object.  For a river gauge, elevation is the height, above mean sea level, of the bottom of the gauge.  For a reservoir, the elevation of the reservoir is the height, above mean sea level, of the surface of the water in the reservoir.
feebled (verb)
Used to describe the running of a drop in a sloppy or tentative way, as in "He feebled the entry to Skyscraper, and really got worked, heh, heh, heh".
gauge (or gage) height
This measures the height of water in a river or stream, relative to some (usually arbitrary) datum.  In the United States, gauge heights are typically measured in feet.  The datum is usually a little below the bottom of the river at that point, though sometimes they get that wrong and negative gauge heights are possible.  See river flow.
gauge (or gage) datum
The bottom (i.e. zero point) of the gauge.  Thus, if a hypothetical river gauge were reading 2.31 feet, and the elevation of its datum is 432 feet, then the surface of the river (at that point in space and time) is 434.31 feet above mean sea level.  Note that gauge datum remains fixed, while gauge height changes with river flow.
Gold Country Paddlers
An informal paddling club whose main purpose appears to be entertaining the rest of us.  They love to hunt in packs; group sizes of fifteen or more are common.  They get in each other's way a lot, and carnage is common (major source of the above-mentioned entertainment).  The leader is generally the one furiously blowing his whistle.
A small and light human-powered boat, pointed at both ends, propelled with a double-bladed paddle.  In general the paddler sits down inside the kayak, and a sprayskirt keeps water out.  There are many different categories of kayak, including touring kayaks, hardshell whitewater kayaks, and inflatables. Within each category there are typically several sub-categories; for instance the most popular kinds of hardshell whitewater kayak are playboats, river-runners, slalom boats and creekers. A one-person whitewater kayak is termed a K1, while a two-person is termed a K2.  One-person hardshell creekers are great for running really sick whitewater; it's best to be young, fearless, and a little crazy too.
A euphemism for getting drunk while telling ridiculously improbable river-running stories around a campfire.  Kayakers generally start yawning around 8pm, especially in Grand Canyon, but most everyone else seems capable of partying all night.
A flat-bottomed inflatable human-powered boat, with a series of inflatable tubes running all the way around the side, typically made of very durable rubber.  A typical raft has a guide, and a crew.  The guide sits at the back, performs the major steering functions, and calls instructions to the crew.  Ignoring the guide's instructions is common, and is usually - but not always - a mistake.  Each member typically has a paddle similar to a canoe paddle.  A raft with three occupants is termed an R3, as you'd expect if you've read up on canoes and kayaks.  However, most rafts are designed to carry six, eight or more paddlers, and are in that case generally described by the length of the boat (e.g. a 14-footer).  Some rafts are fitted with an oar frame in the manner of a cataraft, except that instead of resting on pontoons, the frame rests on the raft's side tubes.
rating table
A rating table is a conversion chart that translates gauge height to river flow.  For instance: a gauge height of 1.12 feet (on some arbitrary river) might correspond to 814 cfs.  The relationship is generally non-linear, with flows increasing exponentially with gauge height.  This makes creating an accurate rating table difficult, since it generally isn't practical to sit by the side of the river for several years, taking measurements, until every possible gauge height occurs.  Rather, the calibrator goes to the gauge and measures the gauge height and corresponding flow at that particular point in time.  They come back again later at a different flow, and after a few (four or five, say) measurements, they connect the points that they measured.  The curve that they choose is usually either a quadratic or cubic function.  However, the actual relationship between gauge height and river flow is almost never a perfect quadratic or cubic.  What's more, on a typical river, the river bed (and hence the relationship between gauge height and river flow) changes with every major flow event, and sometimes it changes during normal flows too.  For this reason, reputable agencies like the USGS continue to monitor the gauge, and apply local adjustments (called "shifts") to the rating table as necessary.  The rating table therefore changes dynamically, and at any given point in time is sure to have inaccuracies.  If properly maintained, however, it is usually acceptably close.  If not properly maintained, Dreamflows gets a lot of email about how inaccurate the gauge is.
reservoir elevation
This measures the height of water in a reservoir relative to some datum point, usually mean sea level.  Therefore, in general, reservoir elevations are the height of the water in the reservoir above sea level, and not the height of water above the bottom of the reservoir.
river flow
This measures the total volume of water flowing past a particular point in a river or stream.  In the United States, river flow is typically measured in cfs.  As a very rough guide: typical boatable flows in a small creek might be 250 cfs; in a medium river 1500 cfs; in a large river 10,000 cfs.  However, gradient is a major factor too - in general, the higher the gradient, the harder it is to navigate a given river at a given flow.  Craft type also plays a major part - generally canoes and inflatable kayaks like less water than hardshell kayaks, while rafts like more.  In a river or stream, flow is usually computed from gauge height, using a rating table.
river left
The left-hand side of the river or stream as it would appear to an observer who is facing downstream.  It's a relative term, though, the exact position being determined from the context.  For instance "river left of the hole" could still be physically on the right half of the river, while "she ran river left" without a qualifier just means toward the left side of the river.  Taking "the far left technical route" is a euphemism for portaging on river left.
river right
The right-hand side of the river or stream as it would appear to an observer who is facing downstream.  See river left for the rest of it.
Could just be river folk in the next campsite (see party).  However "rowdy" when applied to rivers means very busy whitewater.  It's a notch short of sick, but still requires full concentration to run successfully.
Used to describe truly impressive whitewater, e.g. "That run's totally sick, dude".  To really get the point across, hold your index and little fingers out while clenching your other fingers loosely to your hand, and make a light downward stabbing motion.
Technically, this is a cascade of falling water at a vertical or almost vertical drop in a river or stream.  In river-running usage, however, many "waterfalls" aren't even nearly vertical - it seems that almost any impressive cascade of water qualifies.

Please send any comments, corrections, additions or suggestions for improvement you may have to chris@dreamflows.com