Rafting

Rafting and white water rafting are recreational outdoor activities which use an inflatable raft to navigate a river or other body of water. This is often done on whitewater or different degrees of rough water, and generally represents a new and challenging environment for participants. Dealing with risk and the need for teamwork is often a part of the experience. The development of this activity as a leisure sport has become popular since the mid-1970s, evolving from individuals paddling 10 feet (3.0 m) rafts with double-bladed paddles to multi-person rafts propelled by single-bladed paddles and steered by a tour guide at the stern. It is considered an extreme sport, and can be fatal. The International Rafting Federation (IRF) is the worldwide body which oversees all aspects of the sport.

Classes of white water

Otherwise known as the International Scale of River Difficulty, below are the six grades of difficulty in white water rafting. They range from simple to very dangerous and potential death or serious injuries.

River

A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases a river flows into the ground and becomes dry at the end of its course without reaching another body of water. Small rivers can be referred to using names such as stream, creek, brook, rivulet, and rill. There are no official definitions for the generic term river as applied to geographic features, although in some countries or communities a stream is defined by its size. Many names for small rivers are specific to geographic location; examples are "run" in some parts of the United States, "burn" in Scotland and northeast England, and "beck" in northern England. Sometimes a river is defined as being larger than a creek, but not always: the language is vague.

Rivers are part of the hydrological cycle. Water generally collects in a river from precipitation through a drainage basin from surface runoff and other sources such as groundwater recharge, springs, and the release of stored water in natural ice and snowpacks (e.g. from glaciers). Potamology is the scientific study of rivers while limnology is the study of inland waters in general.

New Zealand

New Zealand (/njuːˈziːlənd/ new-ZEE-lənd, Māori: Aotearoa [aɔˈtɛaɾɔa]) is an island country in the southwestern Pacific Ocean. The country geographically comprises two main landmasses – that of the North Island, or Te Ika-a-Māui, and the South Island, or Te Waipounamu – and numerous smaller islands. New Zealand is situated some 1,500 kilometres (900 mi) east of Australia across the Tasman Sea and roughly 1,000 kilometres (600 mi) south of the Pacific island areas of New Caledonia, Fiji, and Tonga. Because of its remoteness, it was one of the last lands to be settled by humans. During its long isolation, New Zealand developed a distinctive biodiversity of animal, fungal and plant life. The country's varied topography and its sharp mountain peaks, such as the Southern Alps, owe much to the tectonic uplift of land and volcanic eruptions. New Zealand's capital city is Wellington, while its most populous city is Auckland.

Somewhere between 1250 and 1300 CE, Polynesians settled in the islands that were to become New Zealand, and developed a distinctive Māori culture. In 1642, Abel Tasman, a Dutch explorer, became the first European to sight New Zealand. In 1840, representatives of the British Crown and Māori Chiefs signed the Treaty of Waitangi, making New Zealand a British colony. Today, the majority of New Zealand's population of 4.5 million is of European descent; the indigenous Māori are the largest minority, followed by Asians and Pacific Islanders. Reflecting this, New Zealand's culture is mainly derived from Māori and early British settlers, with recent broadening arising from increased immigration. The official languages are English, Māori and New Zealand Sign Language, with English predominant.

Wenatchee River

The Wenatchee River is a river in the U.S. state of Washington, originating at Lake Wenatchee and flowing southeast for 53 miles (85 km), emptying into the Columbia River immediately north of Wenatchee, Washington. On its way it passes the towns of Plain, Leavenworth, Peshastin, Dryden, Cashmere, Monitor, and Wenatchee, all within Chelan County.

Tributaries include the Chiwawa River, Nason Creek, Peshastin Creek, and Icicle Creek. Its drainage basin is 1,333 square miles (3,450 km²) in area.

History

Historically the dividing line between Okanogan County and Kittitas County, the river has been in the center of Chelan County since the county's formation around 1899.

Water from the Wenatchee River and its tributaries has been diverted for irrigation since 1891, mainly for orchards. There are two small dams on the Wenatchee River, the Tumwater Canyon Dam, which sits just west of the community of Leavenworth, and the Dryden dam, a low-head dam situated just outside the town of Dryden. The Tumwater Canyon dam originally provided power to the original 2-mile (3.2 km)-long railroad tunnel used near Stevens Pass to get trains across the Cascade Mountains, it was later (starting in 1928) used to power the railroad's electrification from Wenatchee to Skykomish.

Whitewater

Whitewater, usually spelled white water in both American and British English, is formed in a rapid, when a river's gradient increases enough to create so much turbulence that air is entrained into the water body, that is, it forms a bubbly or aerated and unstable current; the frothy water appears white. The term is also loosely used 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 canoeing or whitewater kayaking.

Fast rivers

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 dependent upon both seasonal variation in precipitation and snowmelt and upon release rates of upstream dams.