Whitewater
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- This page discusses whitewater rapids. For the controversy involving the Whitewater Development Corporation and former U.S. President Bill Clinton, see Whitewater (controversy).
- For other uses, see Whitewater (disambiguation). For the Whitewater River, see Whitewater River (disambiguation)
Whitewater is formed in a rapid, when a river's gradient drops enough to form a bubbly, or aerated and unstable current; the frothy water appears white. The term is also used loosely to refer to less-turbulent but still agitated flows.
The term "whitewater" also has a broader meaning, applying to any river or creek itself that has a significant number of rapids. The term is also used as an adjective describing boating on such rivers, such as whitewater kayaking.
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[edit] Rapids
Four factors, separately or in combination, can create rapids: gradient, constriction, obstruction and flow rate. Gradient, constriction and obstruction are streambed topography factors and are relatively consistent. Flow rate is dependant upon both seasonal variation in precipitation and snowmelt and upon dam release rates upstream.
[edit] Streambed topography
Streambed topography is the primary factor in creating rapids, and is generally consistent over time. Increased flow, as during a flood or high rainfall season can make permanent changes to the streambed by displacing rocks and boulders, by deposition of alluvium or by creating new channels for flowing water.
[edit] Gradient
The gradient of a river is the rate at which it loses elevation along its course. This loss determines the river's slope, and to a large extent its rate of flow. Shallow gradients produce gentle, slow rivers while steep gradients are associated with raging torrents.
[edit] Constriction
Constrictions can form a rapid when a river's flow is forced into a narrower channel. This pressure causes the water to flow more rapidly (hence the name) and to react differently to riverbed events (rocks, drops, etc.)
[edit] Obstruction
A boulder or ledge in the middle of a river or near the side can obstruct the flow of the river, and can also create a "cushion"; a "drop" (over the boulder); and "hydraulics" or "holes" where the river flows back on itself--perhaps back under the drop--often with fearful results for those caught in its grasp. (Holes, or hydraulics, are so-called because their foamy, aerated water provides less buoyancy and can feel like an actual hole in the river surface.) If the flow passes next to the obstruction, an eddy may form behind the obstruction; although eddies are typically sheltered areas where boaters can stop to rest, scout or leave the main current, they may be swirling and whirlpool-like. As with hydraulics (which pull downward rather than to the side and are, essentially, eddies turned at a 90-degree angle), the power of eddies increases with the flow rate.
[edit] Stream flow rate
A fourth factor, a marked increase or decrease in flow can create a rapid, "wash out" a rapid (decreasing the hazard) or make safe passage through previously-navigable rapids more difficult or impossible. During "flood" (highly increased flow), scouting rapids and hazards which were formerly "safe" becomes much more crucial for a safe descent. Flow rate is typically measured in Cumecs (cubic-meters-per-second), or in CFS (cubic-feet-per-second) depending on the country.
[edit] Classification of whitewater
The most widely used grading system is the International Grading System, where whitewater (either an individual rapid, or the entire river) is classed in six categories from class I (the easiest and safest) to class VI (the most difficult and most dangerous). The grade reflects both the technical difficulty and the danger associated with a rapid, with grade I referring to flat or slow moving water with few hazards, and grade VI referring to the hardest rapids which are very dangerous even for expert paddlers, and are rarely run. Grade-VI rapids are sometimes downgraded to grade-V or V+ if they have been run successfully. Harder rapids (for example a grade-V rapid on a mainly grade-III river) are often portaged, a French term for carrying. A portaged rapid is where the boater lands and carries the boat around the hazard.
A rapid's grade is not fixed, since it may vary greatly depending on the water depth and speed of flow. Although some rapids may be easier at high flows because features are covered or "washed-out," high water usually makes rapids more difficult and dangerous. At flood stage, even rapids which are usually easy can contain lethal and unpredictable hazards. (Briefly adapted from the American version[1] of the International Scale of River Difficulty[2].)
- Class 1: Very small rough areas, requires no maneuvering. (Skill Level: None)
- Class 2: Some rough water, maybe some rocks, small drops, might require maneuvering. (Skill Level: Basic Paddling Skil)
- Class 3: Whitewater, medium waves, maybe a 3-5 ft drop, but not much considerable danger. May require significant maneuvering. (Skill Level: Experienced paddling skills)
- Class 4: Whitewater, large waves, rocks, maybe a considerable drop, sharp maneuvers may be needed. (Skill Level: Whitewater Experience)
- Class 5: Whitewater, large waves, large rocks and hazards, maybe a large drop, precise maneuvering (Skill Level: Advanced Whitewater Experience)
- Class 6: Whitewater, typically with huge waves, huge rocks and hazards, huge drops, but sometimes labeled thusly due to largely invisible dangers (i.e., a smooth slide that creates a near-perfect, almost inescapable, hydraulic, as at Woodall Shoals/Chattooga). Class 6 rapids are considered hazardous even for expert paddlers using state-of-the-art equipment, and come with the warning "danger to life or limb." (Skill Level: Expert)
[edit] Features found in whitewater
On any given rapid there can be a multitude of different features which arise from the interplay between the shape of the riverbed and the velocity of the water in the stream.
[edit] Strainers
Strainers are formed when an object blocks the passage of larger objects but allows the flow of water to continue - like a big strainer. These objects can be very dangerous, because the force of the water will pin an object or body against the strainer and then pile up, pushing it down under water. Strainers are formed by many different objects, like storm grates over tunnels, trees that have fallen into a river ("log jam"), bushes by the side of the river that are flooded during high water, or rebar from broken concrete structures in the water. In an emergency it is often best to try and climb on top of a strainer so as not to be pinned against the object under the water. If you are in a river, swimming aggressively away from the strainer and into the main channel is your best bet. If you cannot avoid the strainer, you should swim hard towards it and try to get as much of your body up and over it.
[edit] Sweepers
Sweepers are trees fallen or heavily leaning over the river, still rooted on the shore and not fully submerged. Its trunk and branches may form an obstruction in the river like strainers. Since it is an obstruction from above, it often does not contribute to whitewater features. But it should be mentioned here because in fast water sweepers can pose a serious hazard to paddlers.
[edit] Hydraulics
Hydraulics, often referred to as "holes", "souse-holes", or "stoppers", are formed when water pours over the top of a submerged object, causing the water downstream to flow back over the top of the water which rushes over the submerged object. Hydraulics can be dangerous: a boater may become stuck in the recirculating water. In high volume water, hydraulics will aerate the water, possibly to the point where it may even lose the capacity to carry any water crafts.
Some of the most dangerous types of hydraulics are formed by lowhead dams (weirs), underwater ledges, and similar types of obstruction. In lowhead dams, the hydraulic has a very symmetrical character - there's no weak point - and where the sides of the hydraulic are often blocked by a man-made wall, making it impossible to slip off the side of the hydraulic. Lowhead dams are insidiously dangerous because their danger cannot be easily recognized by people who have not studied whitewater.
[edit] Waves
Waves are formed in a similar nature to hydraulics and are sometimes also considered hydraulics as well. Waves are noted by the large smooth face on the water rushing down. Sometimes a particularly large wave will also be followed by a "wave train", a long series of waves. These standing waves can be smooth or, particularly the larger ones, can be breaking waves (also called "whitecaps" or "haystacks").
Because of the rough and random pattern of a riverbed, waves are often not perpendicular to the river's current. This makes them challenging for boaters since a strong sideways or diagonal wave can throw the craft off.
In fluid mechanics, waves are classified as laminar, but the whitewater world has also included waves with turbulence ("breaking waves") under the general heading of waves.
[edit] Pillows
Pillows are formed when a large flow of water runs into a large obstruction, causing water to "pile up" or "boil" against the face of the obstruction. Pillows can be dangerous because sometimes the object that forms the pillow is undercut and so paddlers can be swept underwater - possibly to be entrapped. Pillows are also known as Pressure Waves.
[edit] Eddies
Eddies are formed, like hydraulics, on the downstream face of an obstruction. Unlike hydraulics, eddies swirl on the horizontal surface of the water. Typically, they are calm spots where the downward movement of water is partially or fully arrested - a nice place to rest or to make one's way upstream. However, in very powerful water, eddies can have powerful, swirling currents which can flip boats and from which escape can be very difficult.
[edit] Whitewater craft
There are many different types of whitewater craft that people use to make their way down a rapid, preferably with finesse and control. Here is a short list of them.
Whitewater kayaks differ from sea kayaks and recreational kayaks in that they are specialized to deal with moving water better. They are often shorter and more maneuverable then sea kayaks and are specially designed to deal with water flowing up onto their decks. Most whitewater kayaks are made of plastics these days, although some paddlers (especially racers and "squirt boaters") use kayaks made of fiberglass composites. Whitewater kayaks are fairly stable in turbulent water, once the paddler is skillful with them; if flipped upside-down, the skilled paddler can easily roll them back upright. This essential skill of whitewater kayaking is called the "Eskimo Roll," or simply "Roll." Kayaks are paddled in a low sitting position (legs extended forward), with a two-bladed paddle. See Whitewater kayaking.
Rafts are also often used as a whitewater craft; more stable than typical kayaks, they are less maneuverable. Rafts can carry large loads, so they are often used for expeditions. Typical whitewater rafts are inflatable craft, made from plastic - much like an air mattress. See Whitewater rafting.
Catarafts are constructed from the same materials as rafts. They can either be paddled or rowed with oars. A specialized cataraft, designed without any metal frame, is a Shredder. It is manufactured by Inflatable Technologies in Ohiopyle, Pa. A Shredder is specifically designed to be paddled. It is usually paddled by a two person crew, though highly skilled paddlers are able to negotiate extreme whitewater in a Shredder paddled as a solo boat. Typical catarafts are constructed from two inflatable pontoons on either side of the craft which are bridged by a frame. Oar propelled catarafts have the occupants sitting on seats mounted on the frame. Virtually all oar powered catarafts are operated by a boatsman with passengers having no direct responsibilities. Catarafts can be of all sizes. Many are smaller and more maneuverable than a typical raft.
Canoes are often made of fiberglass, kevlar, plastic or a combination of the three for strength and durability. They may have a spraycover, resembling a kayak, or "open," resembling the typical canoe. This type of canoe is usually referred to simply as an "open boat." Whitewater canoes are paddled in a low kneeling position, with a one-bladed paddle. Open whitewater Canoes have large airbags to prevent the boat from being swamped by big waves and holes. Like kayaks, whitewater canoes can be righted after capsizing with an Eskimo Roll.
C1s are similar in construction to whitewater kayaks, however are paddled in a low, kneeling positon. They employ the use of a one-blade paddle, usually a little shorter than used in a more traditional canoe. They will have a spraycover, essentially the same type used in kayaking. Like kayaks, whitewater canoes can be righted after capsizing with an Eskimo Roll.
McKenzie River dory or "Drift Boat" by some. A more traditional "hard sided" boat. The design is characterized by a wide, flat bottom, flared sides, a narrow, flat bow, a pointed stern, and exteme rocker in the bow and stern to allow the boat to spin about its center for ease in manuvering in rapids.
[edit] Academic explanation of whitewater events
- See: fluid dynamics
[edit] North American whitewater rivers
[edit] Canada
Canadian whitewater rivers are characterized by the dramatic difference between the high water spring run-off and the summer low water volume. The classification of rapids therefore changes from spring to summer.
- Lachine Rapids, Montreal
- Ottawa River, Ontario
- Kananaskis River, Alberta Canadian Rockies Rafting
- Bow River - Horseshoe Canyon, Alberta Canadian Rockies Rafting
- Rouge River, Quebec
- Missinaibi River, Ontario
- Fraser River, British Columbia
- Alsek, British Columbia - Alaska
- Bloodvein River, Manitoba
- Kicking Horse River, British Columbia Canadian Rockies Rafting
- Wellandvale/Twelve Mile Creek, Ontario in planning stage Niagara Whitewater Park Association
- South Nahanni River, Northwest Territories
- Capilano River
- Chehalis River
- Chilliwack River
- Coquitlam River
- Mamquam River
- Cheakamus River
- Elaho River
[edit] United States
[edit] Eastern rivers
Rivers in the eastern section of the United States are usually considered "technical," which means that due to lesser water volume, rafters and kayakers must often direct their craft through boulder-strewn sections of river, through narrow channels and shoals. This requires a degree of "river reading" skill, paddling precision, and understanding of hazards such as undercut rocks and strainers.
[edit] Northeast
The following are some of the rivers in the northeast that are popular.
- Black River, New York - Class 3-5; http://www.americanwhitewater.org/rivers/id/1255/
- Contoocook River, New Hampshire - Class 3-4
- Dead River, Maine - Class 3-5
- Deerfield River, Vermont and Massachusetts - Class 2-5
- Delaware River, New York - many sections of this river can be paddled with the best sections being in New York; class 1-2.
- Esopus Creek, New York - Class 2-3
- Farmington River, Massachusetts and Connecticut - Class 3
- Housatonic River, Connecticut - Class 1-5
- Hudson River, North Creek, New York - Class 4
- Kennebec River, Maine - mostly Class 2-4, one Class 5 rapid
- Lehigh River, Whitehaven to Jim Thorpe, Pennsylvania - a 24 mile run, through a beautiful gorge; Class 3, in high water this is a class 4 run.
- Mongaup River, New York - Class 3; a 2 mile section can be paddled from the base of a dam to the Delaware River.
- Nescopeck Creek, Pennsylvania - Class 2-3
- Penobscot River, Maine - Class 3-5
- Rockaway River, Boonton, New Jersey - Class 4; only a 1 mile section can be paddled but the gradient is a 120 feet for the mile, with the staircase rapids along Rt. 287 reaching 40 feet drop in a quarter of a mile.
- Ten Mile Creek, New York - Class 1-2; about 10 miles can be paddled; in early spring one can start at Big Indian.
- Youghiogheny River, Pennsylvania - Class 3-4
[edit] Southeast
Some signature streams in the Southeastern United States include:
- James River, Richmond, Virginia - The only urban whitewater in North America. Class 4 rapids.
- Nantahala River, Bryson City, North Carolina - a relatively gentle river, with the final rapid having the propensity to send paddlers in for a cold, exhilarating swim; suitable for beginners.
- Toccoa/Ocoee River, Polk County, Tennessee - 1996 Olympic Canoe/Kayak Whitewater Slalom Competition was held on this world-class river; a special section was contructed for the venue, but the "lower" Ocoee is the classic ride that is almost continuously whitewater.
- New River (West Virginia), Thurmond, West Virginia - the next step up; its rapids are larger than those of the Ocoee, though they are separated by long flatwater pools.
- French Broad River, Asheville, North Carolina - featuring a long run of varying difficulty, from flatwater runnable in a canoe to class IV rapids near Hot Springs, North Carolina and the border with Tennessee. The main drawbacks are that the water tends to be muddy or polluted and it is a natural flow river.
- Nolichucky River, Erwin, Tennessee
- Chattooga River, Georgia / South Carolina - sports huge rapids, big drops, and thunderous power; this river can be a challenge for even experts; the Chattooga was one of the rivers used for the filming of the 1973 adventure movie, Deliverance.
- Gauley River, Summersville, West Virginia - has huge rapids, especially at the "Fall Drawdown" (when the reservoir is drained) is a world-class ride; many of them listed as Class V; the Upper Gauley, from Summersville to Mason's Branch, is the tougher section; the Lower Gauley, from Koontz' Flume to Swiss, is still a Class-IV river with significant hazards; navigating the Upper and Lower Gauley in a single day is called "the Gauley Marathon," twenty-four miles of big rapids and paddling.
- Green River (North Carolina), Asheville, North Carolina - the Green Narrows is the steepest "creek run" with regular activity in the Eastern U.S; with a gradient that reaches 600 feet/mile over one short section, The Narrows is a series of blind waterfalls and tight slots; regular, predictable releases from the Tuxedo Hydro Plant upstream draw paddlers on a regular basis.
- Russell Fork River - located in Breaks Interstate Park on the border of Kentucky and Virginia, this river drops 150 feet per mile in the Russell Fork Gorge, which has been described as a continuous forty-five degree waterfall; it has dangerous rapids, even experienced paddlers have died in its many undercut rocks, and there have been many close calls; for the most experienced rafters and kayakers only.
[edit] West Coast rivers
In the western United States, the more noted rivers, such as the Grand Canyon have much greater water volume and therefore require a different set of paddling skills. Western rafters also navigate many small, low volume rivers, some with much steeper descents than eastern rivers; however, since the mountains are newer in the west, the hazard from undercut rocks, a problem in the east, is replaced by more frequent log jams precipitated by logging activities near the rivers.
The big-water rivers usually do not require the precision paddling of smaller rivers, but have larger rapids and longer wilderness trips due to the greater length and water flow of the big rivers. The smaller rivers and creeks boated by most rafters offer many one- or two-day trips with difficulty levels from I to VI.
In the West, some paddlers start on the American in California and work their way up to the Rogue and Illinois in Oregon, the Tuolomne (California), the Salmon in Idaho, the Snake, and then the big-water rivers like the Green and Colorado through the Grand Canyon (Arizona), the Fraser in British Columbia, and many Alaskan streams.
[edit] Washington
All Washington Rivers & Descriptions on ProfessorPaddle.com
The most popular runs in Washington are listed below.
- Green III-IV
- Wenatchee III
- Skykomish III-IV
- Skookumchuck Narrows III-IV
- Snoqualmie III-IV
- Icicle Creek V+
- Tumwater Canyon V
[edit] Colorado and Utah
- Cache La Poudre - Colorado's only federally designated Wild and Scenic River contains sections appropriate for every level of expertise including an easy Class II section, several Class III and Class-IV sections, as well as some Class V. There is a Class VI waterfall that is very dangerous because the last drop is unrunnable. The water pours off a slab into a 2-foot-wide crack and grinds anything that goes into it.
- Colorado River
- Gore Canyon - a Class-IV reach with two significant Class-V rapids. The first Class V, Gore Rapid, is tighly surrounded by several large Class-IV rapids. Most of the water flows to the river-left side of the rapid, where a very nasty and very sticky hydraulic runs into a large rock. The second Class-V Rapid, Tunnel Rapid, is mostly comprised of a single large ledge. On the right side of the rapid is a very nasty and very sticky hole that is bordered by a large rock on the left preventing people from exiting. On the left side of the ledge, the water is redirected right back into the large hole. The water is redirected by an undercut rock.
- I-70 Section - Class-III big water, pushy at times.
Cataract Canyon Varies in class from III to V. At over 50,000 cubic feet per second (1400 m³/s), Cataract Canyon becomes class V. The first 48 miles (77 km) from Potash boat ramp are flat water. Four miles (6 km) after the confluance of the Green and Colorado rivers Cataract Canyon begins. Major John Wesley Powell navigated the rapids in 1869 and gave Cataract Canyon its name. Cataract Canyon slices its way through Canyonlands National Park. Prior to becoming a National Park in 1964, Canyonlands and particularly Cataract Canyon was a "no man's land". French trapper Denis Julien made his way up the canyon in 1836 and left his inscription near the confluence or the Green and Colorado Rivers.
Spring runoff from the Uinta, Wasatch, and the western fronts of the Rocky Mountains combines to create some of the most exciting whitewater in North America. Flows have been gauged at over 110000 Cubic feet per Second in 1984. This is much larger than in the Grand Canyon where water is released from the Glen Canyon Dam and therefore regulated. In an average year Cataract Canyon will peak at 35,000 cubic feet per second (1000 m³/s) which creates 32 rapids (depending on water levals in Lake Powell). At over 50,000 cubic feet per second (1400 m³/s) the rapids from rapid 14 through rapid 24 form some of the most awe inspiring whitewater in North America.
- Arkansas River - a big river, with many sections ranging from Class I to V, very popular with kayakers and with commercial rafting companies.
[edit] Idaho
- Lochsa River
- Salmon River
- Payette River (Main)
- Payette River, North Fork
[edit] Montana
- Clarks Fork of the Yellowstone
- Gallatin - Gallatin River
[edit] Wyoming
- Snake River
[edit] European whitewater rivers
[edit] United Kingdom
Whitewater rivers in the UK are typically low volume and technical. In England and Wales rivers are typically less than 20 m³/s, and some are run with less than 1 m³/s (usually these involve skidding the kayak down steep rockslides and small waterfalls). In Scotland there are also a few bigger volume (up to about 50 m³/s) rivers.
Almost all runs in England and Wales need recent rain to be at a paddleable level, and many can only be run immediately after heavy rain. In Scotland some bigger rivers can be run for weeks after rain although as with the rest of the country, most need recent wet weather. The paddling season is year-round but the rivers are more often runnable in winter (the wettest months of the year being December and January). Exceptions to this include rivers which have artificialy maintained flows from reservoirs. On these rivers flow may increase in dry weather as more water is released. The Afon Tryweryn is one example in Wales.
Most runs offer only a few kilometres of whitewater; often several rivers can be run on a wet day. Some rivers consist of only a single rapid. Only a few rivers (such as the Findhorn and Spean in the Scottish Highlands) have more than a days' worth of paddling, and most of this tends to be grade III or less.
There is no natural whitewater in the (mainly flat) south and east of England. Here whitewater paddlers often go playboating at man made weirs. Hurley weir on the River Thames west of London is probably the most popular. There are several artificial whitewater courses, where water is pumped or diverted though a concrete channel containing obstacles to create rapids. There is a 28 m³/s artificial whitewater course on the Trent at Holme Pierrepont in Nottingham (at the National Watersports Centre), a 5 m³/s course on the Tees in Teesside, and smaller courses on the Nene at Northampton, and at Cardington.
Commercial rafting is limited to artificial whitewater courses (where it often provides the majority of the courses' income) and a few of the bigger and more reliable rivers, in particular the Afon Tryweryn and the Orchy.
There are several sites off the west coast of Britain where strong tidal currents channeled between islands create big volume sections of whitewater. These include the Bitches in Pembrokeshire in Wales, and the Falls of Lora on the west coast of Scotland.
Legal access to whitewater is a big issue in England and Wales. The public are only allowed access to a tiny proportion of the available whitewater, and often this is restricted to a few months or even a few days per year. This limits commercial operations and the activities of clubs, but many individual kayakers still paddle illegally. Rivers are almost all private and access must be agreed with all of the riparian owners (the owners of the land either side of the river) and the owners of the fishing rights, otherwise canoeing or kayaking there is trespass (although landowners can do little other than tell trespassers to leave their property). Agreements rarely exist as there is no incentive for the owners of rivers to let anyone else use them. In Scotland, like most of the rest of the world, access to whitewater is legal and has never been illegal. It has been enshrined in law in the recent Scottish Land Reform act. The Right to Roam act in England explicitly excluded rivers. The British Canoe Union is running the Rivers Access Campaign to raise awareness and bring about changes in the law to permit public access to all inland rivers in England and Wales.
[edit] Alps
Popular whitewater rivers in the Alps are mainly medium volume glacier-fed rivers with long continuous rapids and few big drops. The season is short (two or three months in early summer when the snow and glaciers are melting) but the whitewater is reliable in this period. Tourists come from around Europe to kayak and raft--the most popular centres are Briançon in the French Alps, and the area around Landeck in Austria.
[edit] Whitewater in Norway
Norwegian whitewater rivers are typically steep pool-drop rivers with many waterfalls, and are run mainly by experienced kayakers. There are also bigger (sometimes glacier-fed) rivers which are sometimes rafted. The season lasts all summer, although some rivers only run after recent rain.
Norwegian waterfalls regularly feature on extreme kayaking videos.
[edit] See also
[edit] External links
- White water rafting in India
- Norwegian Whitewater
- Irish Whitewater river guide
- American Whitewater--US River Inventory
[edit] Books
- William Nealy, Kayak: A Manual of Technique. Menasha Ridge Press. (1986) ISBN 0-89732-050-6.
