International scale of river difficulty
The international scale of river difficulty is an American system used to rate the difficulty of navigating a stretch of river, or a single rapid. The scale was created by the American Whitewater Association to evaluate rivers throughout the world, hence international in the title, it should not be confused with the internationally used whitewater scale, published and adapted by a committee of the International Canoe Federation ICF. The grade reflects the technical difficulty and skill level required associated with the section of river; the scale is of use to various water sports and activities, such as rafting, whitewater canoeing, stand up paddle surfing, whitewater kayaking. There are six categories, each referred to; the scale is not linear, nor is it fixed. For instance, there can be difficult grade twos, easy grade threes, so on; the grade of a river may change with the level of flow. A river or rapid will be given a numerical grade, a plus or minus to indicate if it is in the higher or lower end of the difficulty level.
While a river section may be given an overall grading, it may contain sections above that grade noted as features, or conversely, it may contain sections of lower graded water as well. Details of portages may be given. A summary of river classifications as presented by the American Whitewater Association: Classifications can vary enormously, depending on the skill level and experience of the paddlers who rated the river. For example, at the 1999 International Conference on Outdoor Recreation and Education, an author of a paddling guide pointed out that there is too much variation in what is covered by the Class I designation, proposed making further distinctions within the Class I flat water designations and Class I+ moving water designations, with the goal of providing better information for canoeists, instructors leading trips, families with young children; the grade of a river or rapid is to change along with the level of the water. High water makes rapids more difficult and dangerous, although some rapids may be easier at high flows because features are covered or washed out.
At spate/flood stage rapids which are easy can contain lethal and unpredictable hazards. Conversely, some rapids may be easier with lower water levels when dangerous hydraulics become easier to manage; some rivers with high volumes of fast moving water may require little maneuvering, but will pose serious risk of injury or death in the event of a capsize. Degree of difficulty
Bethel Census Area, Alaska
Bethel Census Area is a census area in the U. S. state of Alaska. As of the 2010 census, the population is 17,013, it therefore has no borough seat. Its largest community is the city of Bethel, the largest city in the unorganized borough. According to the U. S. Census Bureau, the census area has an area of 45,504 square miles, of which 40,570 square miles is land and 4,934 square miles is water, its territory includes the large Nunivak Island in the Bering Sea. Its land area is comparable to that of Kentucky, which has an area of under forty thousand square miles. Kusilvak Census Area, Alaska - northwest Yukon-Koyukuk Census Area, Alaska - north Matanuska-Susitna Borough, Alaska - east Kenai Peninsula Borough, Alaska - southeast Lake and Peninsula Borough, Alaska - south Dillingham Census Area, Alaska - south Alaska Maritime National Wildlife Refuge Bering Sea Wilderness Lake Clark National Park and Preserve Lake Clark Wilderness Togiak National Wildlife Refuge Togiak Wilderness Yukon Delta National Wildlife Refuge Nunivak Wilderness As of the census of 2000, there were 16,006 people, 4,226 households, 3,173 families residing in the census area.
The population density was 0 people per square mile. There were 5,188 housing units at an average density of 0/sq mi; the racial makeup of the census area was 12.53% White, 0.38% Black or African American, 81.93% Native American, 1.05% Asian, 0.06% Pacific Islander, 0.19% from other races, 3.85% from two or more races. 0.87% of the population were Hispanic or Latino of any race. There were 4,226 households out of which 51.00% had children under the age of 18 living with them, 50.20% were married couples living together, 15.20% had a female householder with no husband present, 24.90% were non-families. 19.90% of all households were made up of individuals and 2.80% had someone living alone, 65 years of age or older. The average household size was 3.73 and the average family size was 4.41. In the census area the population was spread out with 39.80% under the age of 18, 9.70% from 18 to 24, 28.90% from 25 to 44, 16.40% from 45 to 64, 5.20% who were 65 years of age or older. The median age was 25 years.
For every 100 females, there were 113.20 males. For every 100 females age 18 and over, there were 112.80 males. Bethel Census Area is one of only 38 county-level census divisions of the United States where the most spoken language is not English and one of only 3 where it is neither English nor Spanish. 63.14% of the population speak a Yupik language at home, followed by English at 34.71%. Crow Village Georgetown Napaimute Umkumiute List of Airports in the Bethel Census Area Nunathloogagamiutbingoi Dunes Census Area map, 2000 census: Alaska Department of Labor Census Area map, 2010 census: Alaska Department of Labor
Stony River, Alaska
Stony River is a census-designated place in Bethel Census Area, United States. The population was 54 at the 2010 census, down from 61 in 2000. Native inhabitants are mixed Yup ` ik ancestry of Alaska Native. Stony River village is the modern contact point between Yu'pik Eskimo and three distinct Athabaskan peoples: Deg Hit'an, Dena'ina, Upper Kuskokwim. Today there is considerable multilingualism in Stony River village between Yu'pik and three distinct Athabaskan languages; the Stony River CDP is located at 61°47′15″N 156°35′28″W on an island in the Kuskokwim River at the mouth of the Stony River 140 miles northeast of Bethel. According to the United States Census Bureau, the CDP has a total area of 4.9 square miles, of which 3.1 square miles is land and 1.8 square miles, or 36.71%, is water. Stony River first appeared on the 1970 U. S. Census as an unincorporated village, it was made a census-designated place in 1980. As of the census of 2000, there were 61 people, 19 households, 14 families residing in the CDP.
The population density was 16.8 people per square mile. There were 25 housing units at an average density of 6.9/sq mi. The racial makeup of the CDP was 14.75% White, 78.69% Native American, 6.56% from two or more races. There were 19 households out of which 52.6% had children under the age of 18 living with them, 47.4% were married couples living together, 5.3% had a female householder with no husband present, 26.3% were non-families. 21.1% of all households were made up of individuals and none had someone living alone, 65 years of age or older. The average household size was 3.21 and the average family size was 3.64. In the CDP, the population was spread out with 39.3% under the age of 18, 13.1% from 18 to 24, 29.5% from 25 to 44, 11.5% from 45 to 64, 6.6% who were 65 years of age or older. The median age was 24 years. For every 100 females, there were 117.9 males. For every 100 females age 18 and over, there were 131.3 males. The median income for a household in the CDP was $20,714, the median income for a family was $20,714.
Males had a median income of $8,750 versus $0 for females. The per capita income for the CDP was $5,469. There were 38.9% of families and 38.7% of the population living below the poverty line, including 36.7% of those under 18 and none of those over 64. Stony River Airport History of Stony River
Google Earth is a computer program that renders a 3D representation of Earth based on satellite imagery. The program maps the Earth by superimposing satellite images, aerial photography, GIS data onto a 3D globe, allowing users to see cities and landscapes from various angles. Users can explore the globe by using a keyboard or mouse; the program can be downloaded on a smartphone or tablet, using a touch screen or stylus to navigate. Users may use the program to add their own data using Keyhole Markup Language and upload them through various sources, such as forums or blogs. Google Earth is able to show various kinds of images overlaid on the surface of the earth and is a Web Map Service client. In addition to Earth navigation, Google Earth provides a series of other tools through the desktop application. Additional globes for the Moon and Mars are available, as well as a tool for viewing the night sky. A flight simulator game is included. Other features allow users to view photos from various places uploaded to Panoramio, information provided by Wikipedia on some locations, Street View imagery.
The web-based version of Google Earth includes Voyager, a feature that periodically adds in-program tours presented by scientists and documentarians. Google Earth has been viewed by some as a threat to privacy and national security, leading to the program being banned in multiple countries; some countries have requested that certain areas be obscured in Google's satellite images areas containing military facilities. The core technology behind Google Earth was developed at Intrinsic Graphics in the late 1990s. At the time, the company was developing 3D gaming software libraries; as a demo of their 3D software, they created a spinning globe that could be zoomed into, similar to the Powers of Ten film. The demo was popular, but the board of Intrinsic wanted to remain focused on gaming, so in 1999, they created Keyhole, Inc. headed by John Hanke. Keyhole developed a way to stream large databases of mapping data over the internet to client software, a key part of the technology, acquired patchworks of mapping data from governments and other sources.
The product, called "Keyhole EarthViewer", was sold on CDs for use in fields such as real estate, urban planning and intelligence. Despite making a number of capital deals with Nvidia and Sony, the small company was struggling to make payroll, employees were leaving. Fortunes for the company changed in early 2003 when CNN received a discount for the software in exchange for placing the Keyhole logo on-air whenever the map was used. Keyhole did not expect it would amount to more than brief 5 or 10 second prerecorded animation clips, but it was used extensively by Miles O'Brien live during the 2003 invasion of Iraq, allowing CNN and millions of viewers to follow the progress of the war in a way that had never been seen before. Public interest in the software exploded and Keyhole servers were not able to keep up with demand. Keyhole was soon contacted by the Central Intelligence Agency's venture capital firm, In-Q-Tel, the National Geospatial-Intelligence Agency, for use with defense mapping databases, which gave Keyhole a much-needed cash infusion.
Intrinsic Graphics was sold in 2003 to Vicarious Visions after its gaming libraries did not sell well, its core group of engineers and management transitioned to Keyhole with Hanke remaining at the head. At the time, Google was finding that over 25% of its searches were of a geospatial character, including searches for maps and directions. In October 2004, Google acquired Keyhole as part of a strategy to better serve its users. Google Earth's imagery is displayed on a digital globe, which displays the planet's surface using a single composited image from a far distance. After zooming in far enough, the imagery transitions into different imagery of the same area with finer detail, which varies in date and time from one area to the next; the imagery is retrieved from satellites or aircraft. Before the launch of NASA and the USGS's Landsat 8 satellite, Google relied on imagery from Landsat 7, which suffered from a hardware malfunction that left diagonal gaps in images. In 2013, Google used datamining to remedy the issue, providing what was described as a successor to the Blue Marble image of Earth, with a single large image of the entire planet.
This was achieved by combining multiple sets of imagery taken from Landsat 7 to eliminate clouds and diagonal gaps, creating a single "mosaic" image. Google now uses Landsat 8 to provide imagery with greater frequency. Imagery is hosted on Google's servers, which are contacted by the application when opened, requiring an Internet connection. Imagery resolution ranges from 15 meters of resolution to 15 centimeters. For much of the Earth, Google Earth uses digital elevation model data collected by NASA's Shuttle Radar Topography Mission; this creates the impression of three-dimensional terrain where the imagery is only two-dimensional. Every image created from Google Earth using satellite data provided by Google Earth is a copyrighted map. Any derivative from Google Earth is made from copyrighted data which, under United States Copyright Law, may not be used except under the licenses Google provides. Google allows non-commercial personal use of the images as long as copyrights and attributions are preserved.
By contrast, images created with NASA's globe software World Wind use The Blue Marble, Landsat, or USGS imagery, each of, in the public domain. In version 5.0, Google introduced Historical Imagery. Clicking the clock icon in the toolbar opens a time slider, which marks the tim
A river mouth is the part of a river where the river debouches into another river, a lake, a reservoir, a sea, or an ocean. The water from a river can enter the receiving body in a variety of different ways; the motion of a river is influenced by the relative density of the river compared to the receiving water, the rotation of the earth, any ambient motion in the receiving water, such as tides or seiches. If the river water has a higher density than the surface of the receiving water, the river water will plunge below the surface; the river water will either form an underflow or an interflow within the lake. However, if the river water is lighter than the receiving water, as is the case when fresh river water flows into the sea, the river water will float along the surface of the receiving water as an overflow. Alongside these advective transports, inflowing water will diffuse. At the mouth of a river, the change in flow condition can cause the river to drop any sediment it is carrying; this sediment deposition can generate a variety of landforms, such as deltas, sand bars and tie channels.
Many places in the United Kingdom take their names from their positions at the mouths of rivers, such as Plymouth and Great Yarmouth. Confluence River delta Estuary Liman
The Alaska Range is a narrow, 650-km-long mountain range in the southcentral region of the U. S. state of Alaska, from Lake Clark at its southwest end to the White River in Canada's Yukon Territory in the southeast. The highest mountain in North America, Denali, is in the Alaska Range, it is part of the American Cordillera. The range is the highest in the world outside Asia and the Andes; the range forms a east-west arc with its northernmost part in the center, from there trending southwest towards the Alaska Peninsula and the Aleutians, trending southeast into the Pacific Coast Ranges. The mountains act as a high barrier to the flow of moist air from the Gulf of Alaska northwards, thus has some of the harshest weather in the world; the heavy snowfall contributes to a number of large glaciers, including the Canwell, Black Rapids, Yanert, Eldridge, Ruth and Kahiltna Glaciers. Four major rivers cross the Range, including the Delta River, Nenana River in the center of the range and the Nabesna and Chisana Rivers to the east.
The range is part of the Pacific Ring of Fire, the Denali Fault that runs along the southern edge of the range is responsible for a number of earthquakes. Mount Spurr is a stratovolcano located in the northeastern end of the Aleutian Volcanic Arc of Alaska, USA which has two vents, the summit and nearby Crater Peak. Parts of the range are protected within Wrangell-St. Elias National Park and Preserve, Denali National Park and Preserve, Lake Clark National Park and Preserve; the George Parks Highway from Anchorage to Fairbanks, the Richardson Highway from Valdez to Fairbanks, the Tok Cut-Off from Gulkana Junction to Tok, Alaska pass through low parts of the range. The Alaska Pipeline parallels the Richardson Highway; the name "Alaskan Range" appears to have been first applied to these mountains in 1869 by naturalist W. H. Dall; the name became "Alaska Range" through local use. In 1849 Constantin Grewingk applied the name "Tschigmit" to this mountain range. A map made by the General Land Office in 1869 calls the southwestern part of the Alaska Range the "Chigmit Mountains" and the northeastern part the "Beaver Mountains".
However the Chigmit Mountains are now considered part of the Aleutian Range. Denali Mount Foraker Mount Hunter Mount Hayes Mount Silverthrone Mount Moffit Mount Deborah Mount Huntington Mount Brooks Mount Russell Neacola Mountains Revelation Mountains Teocalli Mountains Kichatna Mountains Central Alaska Range/Denali Massif Eastern Alaska Range/Hayes Range Delta Mountains Mentasta Mountains Nutzotin Mountains Mentasta Lake to Kitchatna Mountains: Scott Woolums, George Beilstein, Steve Eck, Larry Coxen by skis: first traverse. 375 miles in 45 days. Canada to Lake Clark: Roman Dial, Carl Tobin, Paul Adkins by mountain bike and packraft: first full length traverse. 775 miles in 42 days. Tok to Lake Clark: Kevin Armstrong, Doug Woody, Jeff Ottmers by snowshoe and packraft: first foot traverse. 620 miles in 90 days. Lake Clark to Mentasta Lake: Gavin McClurg by paraglider and foot: first vol-biv traverse. 466 miles in 37 days. Summit Lake, Alaska Churkin, M. Jr. and C. Carter.. Stratigraphy and graptolites of an Ordovician and Silurian sequence in the Terra Cotta Mountains, Alaska Range, Alaska.
Washington, D. C.: U. S. Department of the Interior, U. S. Geological Survey
Alaska is a U. S. state in the northwest extremity of North America, just across the Bering Strait from Asia. The Canadian province of British Columbia and territory of Yukon border the state to the east and southeast, its most extreme western part is Attu Island, it has a maritime border with Russia to the west across the Bering Strait. To the north are the Chukchi and Beaufort seas—southern parts of the Arctic Ocean; the Pacific Ocean lies to southwest. It is the largest U. S. state by the seventh largest subnational division in the world. In addition, it is the most sparsely populated of the 50 United States. Half of Alaska's residents live within the Anchorage metropolitan area. Alaska's economy is dominated by the fishing, natural gas, oil industries, resources which it has in abundance. Military bases and tourism are a significant part of the economy; the United States purchased Alaska from the Russian Empire on March 30, 1867, for 7.2 million U. S. dollars at two cents per acre. The area went through several administrative changes before becoming organized as a territory on May 11, 1912.
It was admitted as the 49th state of the U. S. on January 3, 1959. The name "Alaska" was introduced in the Russian colonial period when it was used to refer to the Alaska Peninsula, it was derived from an Aleut-language idiom. It means object to which the action of the sea is directed. Alaska is the northernmost and westernmost state in the United States and has the most easterly longitude in the United States because the Aleutian Islands extend into the Eastern Hemisphere. Alaska is the only non-contiguous U. S. state on continental North America. It is technically part of the continental U. S. but is sometimes not included in colloquial use. S. called "the Lower 48". The capital city, Juneau, is situated on the mainland of the North American continent but is not connected by road to the rest of the North American highway system; the state is bordered by Yukon and British Columbia in Canada, to the east, the Gulf of Alaska and the Pacific Ocean to the south and southwest, the Bering Sea, Bering Strait, Chukchi Sea to the west and the Arctic Ocean to the north.
Alaska's territorial waters touch Russia's territorial waters in the Bering Strait, as the Russian Big Diomede Island and Alaskan Little Diomede Island are only 3 miles apart. Alaska has a longer coastline than all the other U. S. states combined. Alaska is the largest state in the United States by total area at 663,268 square miles, over twice the size of Texas, the next largest state. Alaska is larger than all but 18 sovereign countries. Counting territorial waters, Alaska is larger than the combined area of the next three largest states: Texas and Montana, it is larger than the combined area of the 22 smallest U. S. states. There are no defined borders demarcating the various regions of Alaska, but there are six accepted regions: The most populous region of Alaska, containing Anchorage, the Matanuska-Susitna Valley and the Kenai Peninsula. Rural unpopulated areas south of the Alaska Range and west of the Wrangell Mountains fall within the definition of South Central, as do the Prince William Sound area and the communities of Cordova and Valdez.
Referred to as the Panhandle or Inside Passage, this is the region of Alaska closest to the rest of the United States. As such, this was where most of the initial non-indigenous settlement occurred in the years following the Alaska Purchase; the region is dominated by the Alexander Archipelago as well as the Tongass National Forest, the largest national forest in the United States. It contains the state capital Juneau, the former capital Sitka, Ketchikan, at one time Alaska's largest city; the Alaska Marine Highway provides a vital surface transportation link throughout the area, as only three communities enjoy direct connections to the contiguous North American road system. Designated in 1963; the Interior is the largest region of Alaska. Fairbanks is the only large city in the region. Denali National Park and Preserve is located here. Denali is the highest mountain in North America. Southwest Alaska is a sparsely inhabited region stretching some 500 miles inland from the Bering Sea. Most of the population lives along the coast.
Kodiak Island is located in Southwest. The massive Yukon–Kuskokwim Delta, one of the largest river deltas in the world, is here. Portions of the Alaska Peninsula are considered part of Southwest, with the remaining portions included with the Aleutian Islands; the North Slope is tundra peppered with small villages. The area is known for its massive reserves of crude oil, contains both the National Petroleum Reserve–Alaska and the Prudhoe Bay Oil Field; the city of Utqiagvik known as Barrow, is the northernmost city in the United States and is located here. The Northwest Arctic area, anchored by Kotzebue and containing the Kobuk River valley, is regarded as being part of this region. However, the respective Inupiat of the No