A waterfall is an area where water flows over a vertical drop or a series of steep drops in the course of a stream or river. Waterfalls occur where meltwater drops over the edge of a tabular iceberg or ice shelf. Waterfalls are formed in the upper course of a river in steep mountains; because of their landscape position, many waterfalls occur over bedrock fed by little contributing area, so may be ephemeral and flow only during rainstorms or significant snowmelt. The further downstream, the more perennial a waterfall can be. Waterfalls can have a wide range of depths; when the river courses over resistant bedrock, erosion happens and is dominated by impacts of water-borne sediment on the rock, while downstream the erosion occurs more rapidly. As the watercourse increases its velocity at the edge of the waterfall, it may pluck material from the riverbed, if the bed is fractured or otherwise more erodible. Hydraulic jets and hydraulic jumps at the toe of a falls can generate large forces to erode the bed when forces are amplified by water-borne sediment.
Horseshoe-shaped falls focus the erosion to a central point enhancing riverbed change below a waterfalls. A process known as "potholing" involves local erosion of a deep hole in bedrock due to turbulent whirlpools spinning stones around on the bed, drilling it out. Sand and stones carried by the watercourse therefore increase erosion capacity; this causes the waterfall to recede upstream. Over time, the waterfall will recede back to form a canyon or gorge downstream as it recedes upstream, it will carve deeper into the ridge above it; the rate of retreat for a waterfall can be as high as one-and-a-half metres per year. The rock stratum just below the more resistant shelf will be of a softer type, meaning that undercutting due to splashback will occur here to form a shallow cave-like formation known as a rock shelter under and behind the waterfall; the outcropping, more resistant cap rock will collapse under pressure to add blocks of rock to the base of the waterfall. These blocks of rock are broken down into smaller boulders by attrition as they collide with each other, they erode the base of the waterfall by abrasion, creating a deep plunge pool in the gorge downstream.
Streams can become wider and shallower just above waterfalls due to flowing over the rock shelf, there is a deep area just below the waterfall because of the kinetic energy of the water hitting the bottom. However, a study of waterfalls systematics reported that waterfalls can be wider or narrower above or below a falls, so anything is possible given the right geological and hydrological setting. Waterfalls form in a rocky area due to erosion. After a long period of being formed, the water falling off the ledge will retreat, causing a horizontal pit parallel to the waterfall wall; as the pit grows deeper, the waterfall collapses to be replaced by a steeply sloping stretch of river bed. In addition to gradual processes such as erosion, earth movement caused by earthquakes or landslides or volcanoes can cause a differential in land heights which interfere with the natural course of a water flow, result in waterfalls. A river sometimes flows over a large step in the rocks. Waterfalls can occur along the edge of a glacial trough, where a stream or river flowing into a glacier continues to flow into a valley after the glacier has receded or melted.
The large waterfalls in Yosemite Valley are examples of this phenomenon, referred to as a hanging valley. Another reason hanging valleys may form is where two rivers join and one is flowing faster than the other. Waterfalls can be grouped into ten broad classes based on the average volume of water present on the fall using a logarithmic scale. Class 10 waterfalls include Paulo Afonso Falls and Khone Falls. Classes of other well-known waterfalls include Kaieteur Falls. Alexander von Humboldt "Father of Modern Geography" Humboldt was marking waterfalls on maps for river navigation purposes. Oscar von Engeln Published "Geomorphology: systematic and regional", this book had a whole chapter devoted to waterfalls, is one of the earliest examples of published works on waterfalls. R. W. Young Wrote "Waterfalls: form and process" this work made waterfalls a much more serious topic for research for modern Geoscientists. Ledge waterfall: Water descends vertically over a vertical cliff, maintaining partial contact with the bedrock.
Block/Sheet: Water descends from a wide stream or river. Classical: Ledge waterfalls where fall height is nearly equal to stream width, forming a vertical square shape. Curtain: Ledge waterfalls which descend over a height larger than the width of falling water stream. Plunge: Fast-moving water descends vertically, losing complete contact with the bedrock surface; the contact is lost due to horizontal velocity of the water before it falls. It always starts from a narrow stream. Punchbowl: Water descends in a constricted form and spreads out in a wider pool. Horsetail: Descending water maintains contact with bedrock most of the time. Slide: Water glides down maintaining continuous contact. Ribbon: Water descends over a long narrow strip. Chute: A large quantity of water forced through a narrow, vertical passage. Fan: Water spreads horizontally as
Hydrography is the branch of applied sciences which deals with the measurement and description of the physical features of oceans, coastal areas and rivers, as well as with the prediction of their change over time, for the primary purpose of safety of navigation and in support of all other marine activities, including economic development and defence, scientific research, environmental protection. The origins of hydrography lay in the making of charts to aid navigation, by individual mariners as they navigated into new waters; these were the private property closely held secrets, of individuals who used them for commercial or military advantage. As transoceanic trade and exploration increased, hydrographic surveys started to be carried out as an exercise in their own right, the commissioning of surveys was done by governments and special hydrographic offices. National organizations navies, realized that the collection and distribution of this knowledge gave it great organizational and military advantages.
Thus were born dedicated national hydrographic organizations for the collection, organization and distribution of hydrography incorporated into charts and sailing directions. Prior to the establishment of the United Kingdom Hydrographic Office, Royal Navy captains were responsible for the provision of their own charts. In practice this meant that ships sailed with inadequate information for safe navigation, that when new areas were surveyed, the data reached all those who needed it; the Admiralty appointed Alexander Dalrymple as Hydrographer in 1795, with a remit to gather and distribute charts to HM Ships. Within a year existing charts from the previous two centuries had been collated, the first catalogue published; the first chart produced under the direction of the Admiralty, was a chart of Quiberon Bay in Brittany, it appeared in 1800. Under Captain Thomas Hurd the department received its first professional guidelines, the first catalogues were published and made available to the public and to other nations as well.
In 1829, Rear-Admiral Sir Francis Beaufort, as Hydrographer, developed the eponymous Scale, introduced the first official tide tables in 1833 and the first "Notices to Mariners" in 1834. The Hydrographic Office underwent steady expansion throughout the 19th century; the word hydrography comes from the Ancient Greek ὕδωρ, "water" and γράφω, "to write". Large-scale hydrography is undertaken by national or international organizations which sponsor data collection through precise surveys and publish charts and descriptive material for navigational purposes; the science of oceanography is, in part, an outgrowth of classical hydrography. In many respects the data are interchangeable, but marine hydrographic data will be directed toward marine navigation and safety of that navigation. Marine resource exploration and exploitation is a significant application of hydrography, principally focused on the search for hydrocarbons. Hydrographical measurements include the tidal and wave information of physical oceanography.
They include bottom measurements, with particular emphasis on those marine geographical features that pose a hazard to navigation such as rocks, shoals and other features that obstruct ship passage. Bottom measurements include collection of the nature of the bottom as it pertains to effective anchoring. Unlike oceanography, hydrography will include shore features and manmade, that aid in navigation. Therefore, a hydrographic survey may include the accurate positions and representations of hills and lights and towers that will aid in fixing a ship's position, as well as the physical aspects of the sea and seabed. Hydrography for reasons of safety, adopted a number of conventions that have affected its portrayal of the data on nautical charts. For example, hydrographic charts are designed to portray what is safe for navigation, therefore will tend to maintain least depths and de-emphasize the actual submarine topography that would be portrayed on bathymetric charts; the former are the mariner's tools to avoid accident.
The latter are best representations of the actual seabed, as in a topographic map, for scientific and other purposes. Trends in hydrographic practice since c. 2003–2005 have led to a narrowing of this difference, with many more hydrographic offices maintaining "best observed" databases, making navigationally "safe" products as required. This has been coupled with a preference for multi-use surveys, so that the same data collected for nautical charting purposes can be used for bathymetric portrayal. Though, in places, hydrographic survey data may be collected in sufficient detail to portray bottom topography in some areas, hydrographic charts only show depth information relevant for safe navigation and should not be considered as a product that portrays the actual shape of the bottom; the soundings selected from the raw source depth data for placement on the nautical chart are selected for safe navigation and are biased to show predominately the shallowest depths that relate to safe navigation.
For instance, if there is a deep area that can not be reached because it is surrounded by shallow water, the deep area may not be shown. The color filled areas that show different ranges of shallow water are not the equivalent of contours on a topographic map since they are drawn seaward of the actual shallowest depth portrayed. A bathymetric chart does show marine topology accurately. Details covering the ab
Saskatchewan is a prairie and boreal province in western Canada, the only province without a natural border. It has an area of 651,900 square kilometres, nearly 10 percent of, fresh water, composed of rivers and the province's 100,000 lakes. Saskatchewan is bordered on the west by Alberta, on the north by the Northwest Territories, on the east by Manitoba, to the northeast by Nunavut, on the south by the U. S. states of North Dakota. As of late 2018, Saskatchewan's population was estimated at 1,165,903. Residents live in the southern prairie half of the province, while the northern boreal half is forested and sparsely populated. Of the total population half live in the province's largest city Saskatoon, or the provincial capital Regina. Other notable cities include Prince Albert, Moose Jaw, Swift Current, North Battleford and the border city Lloydminster. Saskatchewan is a landlocked province with large distances to moderating bodies of waters; as a result, its climate is continental, rendering severe winters throughout the province.
Southern areas have warm or hot summers. Midale and Yellow Grass near the U. S. border are tied for the highest recorded temperatures in Canada with 45 °C observed at both locations on July 5, 1937. In winter, temperatures below −45 °C are possible in the south during extreme cold snaps. Saskatchewan has been inhabited for thousands of years by various indigenous groups, first explored by Europeans in 1690 and settled in 1774, it became a province in 1905, carved out from the vast North-West Territories, which had until included most of the Canadian Prairies. In the early 20th century the province became known as a stronghold for Canadian social democracy; the province's economy is based on agriculture and energy. Saskatchewan's current lieutenant governor is the current premier is Scott Moe. In 1992, the federal and provincial governments signed a historic land claim agreement with First Nations in Saskatchewan; the First Nations received compensation and were permitted to buy land on the open market for the bands.
Some First Nations have used their settlement to invest in urban areas, including Saskatoon. Its name derived from the Saskatchewan River; the river was known as kisiskāciwani-sīpiy in the Cree language. As Saskatchewan's borders follow the geographic coordinates of longitude and latitude, the province is a quadrilateral, or a shape with four sides. However, the 49th parallel boundary and the 60th northern border appear curved on globes and many maps. Additionally, the eastern boundary of the province is crooked rather than following a line of longitude, as correction lines were devised by surveyors prior to the homestead program. Saskatchewan is part of the Western Provinces and is bounded on the west by Alberta, on the north by the Northwest Territories, on the north-east by Nunavut, on the east by Manitoba, on the south by the U. S. states of North Dakota. Saskatchewan has the distinction of being the only Canadian province for which no borders correspond to physical geographic features. Along with Alberta, Saskatchewan is one of only two land-locked provinces.
The overwhelming majority of Saskatchewan's population is located in the southern third of the province, south of the 53rd parallel. Saskatchewan contains two major natural regions: the Boreal Forest in the north and the Prairies in the south, they are separated by an aspen parkland transition zone near the North Saskatchewan River on the western side of the province, near to south of the Saskatchewan River on the eastern side. Northern Saskatchewan is covered by forest except for the Lake Athabasca Sand Dunes, the largest active sand dunes in the world north of 58°, adjacent to the southern shore of Lake Athabasca. Southern Saskatchewan contains another area with sand dunes known as the "Great Sand Hills" covering over 300 square kilometres; the Cypress Hills, located in the southwestern corner of Saskatchewan and Killdeer Badlands, are areas of the province that were unglaciated during the last glaciation period, the Wisconsin glaciation. The province's highest point, at 1,392 metres, is located in the Cypress Hills less than 2 km from the provincial boundary with Alberta.
The lowest point is the shore of Lake Athabasca, at 213 metres. The province has 14 major drainage basins made up of various rivers and watersheds draining into the Arctic Ocean, Hudson Bay and the Gulf of Mexico. Saskatchewan receives more hours of sunshine than any other Canadian province; the province lies far from any significant body of water. This fact, combined with its northerly latitude, gives it a warm summer, corresponding to its humid continental climate in the central and most of the eastern parts of the province, as well as the Cypress Hills. Drought can affect agricultural areas during no precipitation at all; the northern parts of Saskatchewan – from about La Ronge northward – have a subarctic climate with a shorter summer season. Summers can get hot, sometimes above 38 °C during the day, with humidity decreasing from northeast to southwest. Warm southern winds blow from the plains and intermontane regions of
Athabasca Falls is a waterfall in Jasper National Park on the upper Athabasca River 30 kilometres south of the townsite of Jasper, Alberta and just west of the Icefields Parkway. A powerful, picturesque waterfall, Athabasca Falls is not known so much for the height of the falls, as it is known for its force due to the large quantity of water falling into the gorge. On a cold morning in the fall, when river levels tend to be at their lowest, copious amounts of water flow over the falls; the river'falls' over a layer of hard quartzite and through the softer limestone below carving the short gorge and a number of potholes. The falls can be safely viewed and photographed from various viewing platforms and walking trails around the falls. Access is from the nearby parking lot. Highway 93A takes off from the nearby Icefields Parkway, crosses the falls on the way north to the town of Jasper. White water rafting starts below the falls to travel downstream on the Athabasca River to Jasper, it is a width of 60 ft. Explore Jasper.
Cold Lake (Alberta)
Cold Lake is a large lake in Central Alberta and Northern Saskatchewan, Canada. The lake straddles the Alberta/Saskatchewan border, has a water area of 373 km2, it is one of the deepest lakes in Alberta with a maximum depth of 99.1 m. It is a major ice fishing lake, it is major stop for many migrating birds, is home to one of the largest warbler populations in Alberta. A surface of 248 km2 lies in the province of Alberta; the city of Cold Lake is located on the shore. Excepting the western shore, the lake is surrounded by protected areas such as the Cold Lake Provincial Park in Alberta and the Meadow Lake Provincial Park in Saskatchewan; the Cold Lake 149 A and B indian reserve of the Cold Lake First Nations are established on the western and southern shores respectively. Cold Lake House was a trading post built by the Montreal traders in 1781 near the present Beaver Crossing, Alberta south of Cold Lake; the Martineau River flows from Primrose Lake into Cold Lake, which in turn discharges through the Cold River in Waterhen River, a major tributary of Beaver River.
Fish species include walleye, yellow perch, northern pike, lake trout, lake whitefish, burbot, white sucker and longnose sucker. Both Alberta and Saskatchewan angling licenses are valid on the entire lake. Fish Species of Saskatchewan Meadow Lake Provincial Park http://gateway.ca.gov.ab.ca/siteinformation.aspx?id=22
South Saskatchewan River
The South Saskatchewan River is a major river in Canada that flows through the provinces of Alberta and Saskatchewan. For the first half of the 20th century, the South Saskatchewan would freeze over during winter, creating spectacular ice breaks and dangerous conditions in Saskatoon, Medicine Hat and elsewhere. At least one bridge in Saskatoon was destroyed by ice carried by the river; the construction of the Gardiner Dam in the 1960s, lessened the power of the river by diverting a substantial portion of the South Saskatchewan's natural flow into the Qu'Appelle River. By the 1980s many permanent sandbars had formed due to the lowering of the level of the river. From the headwaters of the Bow River, the South Saskatchewan flows for 1,392 kilometres. At its mouth at Saskatchewan River Forks, it has an average discharge of 280 cubic metres per second and has a watershed of 146,100 square kilometres, 1,800 of which are in Montana in the United States and 144,300 square kilometres in Alberta and Saskatchewan.
The river originates at the confluence of the Bow and Oldman Rivers near Alberta. The waters of these two rivers, in turn, originate from winter snowpack and rainfall in the Rocky Mountains near the British Columbia and Montana border. Glacier melt contributes about 2% of the annual flow, with most of that contribution during July and August; the Red Deer River is a major tributary of the South Saskatchewan merging 16 kilometres east of the Alberta-Saskatchewan border. The Lake Diefenbaker reservoir was created with the construction of the Gardiner and Qu'Appelle River dams in Saskatchewan. Water from the South Saskatchewan flowing through the dams provides 19 percent of the hydro-electricity generated by SaskPower. Downstream from the dam the river flows north through Saskatoon and joins the North Saskatchewan River east of Prince Albert at the Saskatchewan River Forks — thus forming the Saskatchewan River. For 60 kilometres near Saskatoon, the Meewasin Valley Authority is responsible for conservation of the river environment.
Numerous lakes in the Saskatoon area were formed by oxbows of the South Saskatchewan River, most notably Moon Lake and Pike Lake. A 2009 report, produced by WWF-Canada which analysed the river flow on 10 major Canadian rivers reported that the South Saskatchewan River was the most at risk. Climate change and urban infrastructure water use, dams producing hydroelectricity, have all combined to reduce the flow of the South Saskatchewan River by 70 percent. Developers and governments have been cautioned to protect and restore the river with sustainable projects and limit water diversion. Dickson Dam regulates water supply downstream on the Red Deer River. Mary Headworks System manage water flow downstream of the Oldman River; the proposed Meridian dam 30 kilometres west of Leader and 95 kilometres north east of Medicine Hat was cancelled due to project costs outweighing the irrigation benefits. Bow River Oldman River Seven Persons Creek Red Deer River Teepee Creek Landing Creek Smith Creek Valentine Creek Pine Lake Creek Brightwater Creek Beaver Creek Fish Creek Swift Current Creek Partial list McLean Island Wilson Island Yorath Island Sections of the riverbank along the South Saskatchewan River are prone to slumping.
Since its founding, the city of Saskatoon has dealt with a number of slope failures. Controlling riverbank development was a factor in establishing the Meewasin Valley Authority in 1979. Fish species include walleye, yellow perch, northern pike, lake trout, rainbow trout, lake whitefish, lake sturgeon, quillback, longnose sucker, white sucker and shorthead redhorse. List of crossings of the South Saskatchewan River List of longest rivers of Canada List of rivers of Alberta List of rivers of Saskatchewan Partners for the Saskatchewan River Basin Fish Species of Saskatchewan South Saskatchewan River – Encyclopedia of Saskatchewan
The Brazeau River is a river in western Alberta, Canada. It is a major tributary of the North Saskatchewan River; the river was named for a linguist associated with the Palliser Expedition. The river originates in the heights of the Canadian Rockies from Brazeau Lake and flows east through the Rocky Mountains foothills until it merges into the North Saskatchewan River between Drayton Valley and Rocky Mountain House at Brazeau Forks; the upper course runs eastwards from Jasper National Park into Brazeau Canyon Wildland Provincial Park. The O'Chiese First Nation is established at the confluence with Nordegg River; the total length of the river is 210 kilometres. The river, various other local geographic features, were named after Joseph Brazeau, a Missouri-born fur trader working for the Hudson's Bay Company in the area between 1852 and 1864; the Brazeau River has long been seen as a potential site for hydroelectric power generation. The earliest scheme to harness the power of the river was hatched in 1913 and involved a dam and storage on Brazeau Lake.
The potential power generation was estimated at 5,000 to 10,000 kVA, power would have been transmitted to Edmonton and Calgary, both 400 kilometres from the generator. The plan was scuttled after the discovery of a large underflow at Brazeau Lake, precluding its use as a storage facility; the 99 square kilometres Brazeau Reservoir was created on the lower course through the construction of the Brazeau Dam. Its hydroelectric power plant is Alberta's largest with a capacity of 355 MW and an annual production of about 394,000 MW⋅h of electrical energy. An unusual feature of this hydroelectric development commissioned in 1965 is a pump system capable of lifting water from the reservoir into the 20-kilometre long canal leading to the power plant so that it can operate at low reservoir water levels. Boulder Creek Four Point Creek Brazeau Lake John-John Creek Upper Longview Lake Job Creek Whisker Creek, Whisker Lakes, Job Lake, Leah Lake, Samson Lake Isaac Creek Race Creek Southesk River Southesk Lake Thistle Creek Chimney Creek Marshybank Creek Marshybank Lake Canyon Creek Moosehound Creek Cardinal River Blackstone River Elk River Nordegg River Geography of Alberta List of Alberta rivers