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
Williston Lake is a reservoir created by the W. A. C. Bennett Dam and is located in the Northern Interior of British Columbia, Canada; the lake fills the basin of the upper Peace River, backing into the Rocky Mountain Trench, where the Parsnip and Finlay met at Finlay Forks to form the Peace. The lake includes three reaches, the Peace Reach, the Parsnip and Finlay Reaches, which are the lowermost basins of those rivers, covers a total area of 1,761 km2, being the largest lake in British Columbia and the seventh largest reservoir in the world; the reservoir is fed by the Finlay, Ingenika, Parsnip, Manson and Nabesche Rivers and by Clearwater Creek, Carbon Creek, other smaller creeks. Several provincial parks are maintained on the shore of the lake, including Muscovite Lakes Provincial Park, Butler Ridge Provincial Park, Heather-Dina Lakes Provincial Park and Ed Bird-Estella Provincial Park; the following rivers empty into the Williston Reservoir: Finlay River Omineca River Ingenika River Ospika River Parsnip River Manson River Nation River Clearwater Creek Nabesche River Carbon Creek Williston Lake was created in 1968 by the building of the W. A. C. Bennett Dam on the Peace River, which flooded the aboriginal-territorial home of the Tsay Keh Dene First Nation.
The reservoir was named after the Honourable Ray Gillis Williston, at the time the Minister of Lands and Water Resources. BC Hydro. Williston Reservoir BC Hydro. Peace-Williston Fish and Wildlife Compensation Program "Williston Lake". BC Geographical Names
In hydrology, the inflow of a body of water is the source of the water in the body of water. It can refer to the average volume of incoming water in unit time, it is contrasted with outflow. All bodies of water have multiple inflows, but one inflow may predominate and be the largest source of water. However, in many cases, no single inflow will predominate and there will be multiple primary inflows. For a lake, the inflow may be a river or stream that flows into the lake. Inflow may be speaking, not flows, but rather precipitation, like rain. Inflow can be used to refer to groundwater recharge; the dictionary definition of inflow at Wiktionary
Tagish Lake is a lake in Yukon and northern British Columbia, Canada. The lake is about 2 km wide, it has two arms, the Taku Arm in the east, long and in British Columbia and Windy Arm in the west in Yukon. The Klondike Highway runs along Windy Arm south of Carcross. Bennett Lake flows into Tagish Lake, so the northern portion of Tagish Lake was part of the route to the Klondike used by gold-seekers during the Klondike Gold Rush. On January 18, 2000, a carbonaceous chondrite meteorite now known as "Tagish Lake", fell on the frozen surface of the Taku Arm. A number of fragments were recovered and studied by researchers from the University of Calgary, University of Western Ontario, NASA; the lake is named for the Tagish people. Tagish means fish trap in an Athabascan language. Other sources translate Tagish as "it is breaking up". Tagish lies in the path of migratory swans that come every spring to wait out the melting of the more Northern Lakes. Tagish is home to the Southern Lakes with trophy fishing
Bute Inlet is one of the principal inlets of the British Columbia Coast. It is 80 km long from the estuaries of the Homathko and Southgate Rivers at the head of the inlet, to the mouth, where it is nearly blocked by Stuart Island, it averages about 4 km in width. Bute Inlet is in a spectacular wilderness setting and is one of the most scenic waterways in the world. In the upper reaches of the inlet mountains rise 9000 feet above sea level. Bute Inlet is a spectacular wilderness, visited by few people. In more recent years tourists are travelling from around the world to view grizzly bears in a natural setting and explore the wilderness of Bute Inlet. Bute Inlet took its name from John Stuart, 3rd Earl of Bute, Prime Minister of Great Britain from 1762 to 1763, his grandson Charles Stuart was a master's mate on Vancouver's Discovery. Bute Inlet had an interesting role in the early history of the Colony of British Columbia. Entrepreneur Alfred Waddington sought to build a route to the Cariboo goldfields, shorter and easier than the existing routes via the Fraser Canyon and the Douglas Road.
In competition with the projected Cariboo Wagon Road, still under construction at that time, Waddington got a license from the colonial government to undertake the construction of a wagon road from the head of Bute Inlet via the Homathko River to the Chilcotin Plateau, thence east across the Fraser to the Cariboo Goldfields. The plan was that steamers from Victoria would voyage to the head of the inlet, travellers would take what was to be a toll road overland from there, he was granted a townsite at the head of the inlet and commenced construction up the Grand Canyon of the Homathko from there. Conflict with warriors of the Tsilhqot'in Nation ensued when Waddington's foreman threatened smallpox on the warriors, working as labourers due to famine in their country, over the mountains on the inland side of the range. Discussing his threats that night, the warriors, led by Klatsassin of the Xeni Gwet'in of Nemaia Valley near Chilko Lake, rose up and slaughtered Waddington's work party. Three men made it to civilization despite severe injuries.
As a result of their reports, expeditions were launched by troops from Victoria and a posse of volunteers from the Cariboo and a long bait-and-wait game ensued known to history as the Chilcotin War of 1864. It ended with the surrender on terms of amnesty by Klatsassin, betrayed and hung at Quesnellemouthe; the Bute Inlet route was considered for the mainline of the Canadian Pacific Railway, which would have seen extensive blasting down the west shore of the inlet and a series of bridges to reach Vancouver Island near Campbell River via Seymour Narrows. This route was passed over in favour of the Fraser Canyon route to a new port-city at Burrard Inlet, to become the city of Port Moody, British Columbia; the residual political impact of the Chilcotin War was one factor dissuading the CPR from using Bute Inlet. Bute Inlet is located in the Coast Land District, Range 1 and is part of the Sunshine Coast Forest District of the Coast Forest Region, headquartered in Powell River, the Lower Mainland Ministry of Environment Region, headquartered in Surrey.
It is within the mainland portion of the Strathcona Regional District, which has only municipal powers such as sewage and building permits on non-Indian Reserve lands in rural areas. The inlet lies in the overlapping traditional territories and land claims of the Homalco, Kwiakah and We Wai Kai First Nations. Bute Inlet in British Columbia is a classic fjord formation formed during the Holocene by glacial erosion. Bute Inlet is one of the deepest fjords in British Columbia with its depth of 660 metres, with a sill of 220 metres; the majority of freshwater entering the inlet, ~95%, is supplied by the Homathko river and the Southgate river at the head of the fjord. An underwater channel system is incised in the fjord basin sediments which carries sediment to the fjord. Homathko Estuary Provincial Park Bute Inlet, Long Term Trends in Deep Water Properties of BC Inlets and Oceans Canada - Pacific Region Map hydropower project in Bute Inlet
The Thompson River is the largest tributary of the Fraser River, flowing through the south-central portion of British Columbia, Canada. The Thompson River has the South Thompson River and the North Thompson River; the river is home to several varieties of Pacific salmon and trout. The area's geological history was influenced by glaciation, the several large glacial lakes have filled the river valley over the last 12,000 years. Archaeological evidence shows human habitation in the watershed dating back at least 8,300 years; the Thompson was named by Fraser River explorer, Simon Fraser, in honour of his friend, Columbia Basin explorer David Thompson. Recreational use of the river includes whitewater angling; the South Thompson originates at the outlet of Little Shuswap Lake at the town of Chase and flows 55 kilometres southwest through a wide valley to Kamloops where it joins the North Thompson. Highway 1, the Trans-Canada Highway and the mainline of the Canadian Pacific Railway parallel the river.
Little Shuswap Lake is fed by the Little River, which drains Shuswap Lake, fed by several rivers and creeks. The North Thompson originates at the toe of the Thompson Glacier in the Cariboo Mountains west of the community of Valemount and flows south towards Kamloops and the confluence with the South Thompson. For most of its length, the river is paralleled by Highway 5, the Canadian National Railway; the North Thompson passes by several small communities, the most notable being Blue River, Clearwater & Barriere. The North Thompson picks up the Clearwater River at the town of Clearwater; the Clearwater, the North Thompson's largest tributary, drains much of Wells Gray Provincial Park. A notable feature along the North Thompson is Little Hells Gate, a mini-replica of the much larger rapid on the Fraser downstream from the mouth of the Thompson. About 17.4 kilometres upstream from the small town of Avola, the river is forced through a narrow chute only about 30 feet wide creating a rapid that resembles the Fraser's famous rapid.
At Kamloops, the combined Thompson River river flows 15 kilometres from the confluence of the North and South Thompson Rivers before reaching Kamloops Lake, 30 kilometres in length, ending at the town of Savona. From there it flows in a meandering course westwards through a broad valley area. At Ashcroft, the Thompson Canyon begins and the river turns southwestward to its confluence with the Fraser; the river is paralleled by the Trans-Canada Highway, the Canadian Pacific Railway and the Canadian National Railway. From Ashcroft to Lytton, the river is confined within Thompson Canyon, making for spectacular scenery; the Thompson River joins the Fraser River in Lytton. There is a striking stretch of dark black cliffside just downstream from Ashcroft and visible from the Logan Lake-Ashcroft highway is named the Black Canyon. Just below the town of Spences Bridge was the site of a major rail disaster in the early 20th Century. Communities along this section are Bighorn, Shaw Springs, Goldpan; the Thompson River valley has existed in some form for at least 50 million years.
Geologists believe water from the river flowed northward, through the Cariboo region entering what is the modern-day Peace River drainage basin and ending up in the Arctic Ocean. This flow direction is estimated to have ended 2 million years ago, as the Pleistocene era of heavy glaciation began. During the era of massive glaciers in the Thompson River valley, water from the area drained eastward, through the Shuswap Lake area into what is now the Columbia River drainage; this flow direction was influenced by large ice buildups in the Thompson valley, which created extensive glacial lakes. Two large glacial lakes, Glacial Lake Thompson and Glacial Lake Deadman, occupied much of the modern river's course from 13,000 BCE to 10,000 BCE; these deep, ribbon-shaped lakes held large volumes of water. The lake stretched from Spences Bridge in the west to the eastern reaches of Shuswap Lake, as well as far up the northern reaches of the North Thompson river valley; the last large glacial lake, Lake Deadman, was drained by a catastrophic ice dam failure, called a jökulhlaup, in about 10,000 BCE.
This event released as much as 20 cubic kilometres of water southwest into the Fraser River system depositing sediments as far away as the Salish Sea, more than 250 kilometres away. From this point, the Thompson waters stopped flowing eastward into the Columbia River system, the river became a tributary of the Fraser; because of large deposits of glacial silt and gravel in the lower Thompson River valley, large landslides are common. The area downstream from the town of Ashcroft is prone to landslide events. Several of them have obstructed the river, caused large, temporary lakes. An 1880 slide caused the formation of a short-lived lake over 14 kilometers long with a maximum depth of 18 meters; these slides have caused major damage to the rail lines and farming operations in the river valley. Heavy irrigation has been blamed for some of the events; the Interior region of British Columbia was first populated after the retreat of the continental ice sheets of the last ice age. The ice moved out of the Thompson River region 11,000 BCE, migration by the ancestors of the Nlaka'pamux and Secwepemc people is thought to have occurred soon after.
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