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River Ecology
River ecosystems are flowing waters that drain the landscape, and include the biotic (living) interactions amongst plants, animals and micro-organisms, as well as abiotic (nonliving) physical and chemical interactions of its many parts.Angelier, E. 2003. Ecology of Streams and Rivers. Science Publishers, Inc., Enfield. Pp. 215.”Biology Concepts & Connections Sixth Edition”, Campbell, Neil A. (2009), page 2, 3 and G-9. Retrieved 2010-06-14. River ecosystems are part of larger watershed networks or catchments, where smaller headwater streams drain into mid-size streams, which progressively drain into larger river networks. The major zones in river ecosystems are determined by the river bed's gradient or by the velocity of the current. Faster moving turbulent water typically contains greater concentrations of dissolved oxygen, which supports greater biodiversity than the slow-moving water of pools. These distinctions form the basis for the division of rivers into upland and lo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stream In The Redwoods
A stream is a continuous body of surface water flowing within the bed and banks of a channel. Depending on its location or certain characteristics, a stream may be referred to by a variety of local or regional names. Long large streams are usually called rivers, while smaller, less voluminous and more intermittent streams are known as streamlets, brooks or creeks. The flow of a stream is controlled by three inputs – surface runoff (from precipitation or meltwater), daylighted subterranean water, and surfaced groundwater (spring water). The surface and subterranean water are highly variable between periods of rainfall. Groundwater, on the other hand, has a relatively constant input and is controlled more by long-term patterns of precipitation. The stream encompasses surface, subsurface and groundwater fluxes that respond to geological, geomorphological, hydrological and biotic controls. Streams are important as conduits in the water cycle, instruments in groundwater ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lentic Ecosystems
A lake ecosystem or lacustrine ecosystem includes biotic (living) plants, animals and micro-organisms, as well as abiotic (non-living) physical and chemical interactions. Lake ecosystems are a prime example of lentic ecosystems (''lentic'' refers to stationary or relatively still freshwater, from the Latin ''lentus'', which means "sluggish"), which include ponds, lakes and wetlands, and much of this article applies to lentic ecosystems in general. Lentic ecosystems can be compared with lotic ecosystems, which involve flowing terrestrial waters such as rivers and streams. Together, these two ecosystems are examples of freshwater ecosystems. Lentic systems are diverse, ranging from a small, temporary rainwater pool a few inches deep to Lake Baikal, which has a maximum depth of 1642 m. The general distinction between pools/ponds and lakes is vague, but Brown states that ponds and pools have their entire bottom surfaces exposed to light, while lakes do not. In addition, some lake ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deposition (geology)
Deposition is the geological process in which sediments, soil and rocks are added to a landform or landmass. Wind, ice, water, and gravity transport previously weathered surface material, which, at the loss of enough kinetic energy in the fluid, is deposited, building up layers of sediment. Deposition occurs when the forces responsible for sediment transportation are no longer sufficient to overcome the forces of gravity and friction, creating a resistance to motion; this is known as the null-point hypothesis. Deposition can also refer to the buildup of sediment from organically derived matter or chemical processes. For example, chalk is made up partly of the microscopic calcium carbonate skeletons of marine plankton, the deposition of which has induced chemical processes (diagenesis) to deposit further calcium carbonate. Similarly, the formation of coal begins with the deposition of organic material, mainly from plants, in anaerobic conditions. Null-point hypothesis The null ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Erosion
Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is distinct from weathering which involves no movement. Removal of rock or soil as clastic sediment is referred to as ''physical'' or ''mechanical'' erosion; this contrasts with ''chemical'' erosion, where soil or rock material is removed from an area by dissolution. Eroded sediment or solutes may be transported just a few millimetres, or for thousands of kilometres. Agents of erosion include rainfall; bedrock wear in rivers; coastal erosion by the sea and waves; glacial plucking, abrasion, and scour; areal flooding; wind abrasion; groundwater processes; and mass movement processes in steep landscapes like landslides and debris flows. The rates at which such processes act control how fast a surface is eroded. Typically, physical erosion procee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geomorphology
Geomorphology (from Ancient Greek: , ', "earth"; , ', "form"; and , ', "study") is the scientific study of the origin and evolution of topographic and bathymetric features created by physical, chemical or biological processes operating at or near Earth's surface. Geomorphologists seek to understand why landscapes look the way they do, to understand landform and terrain history and dynamics and to predict changes through a combination of field observations, physical experiments and numerical modeling. Geomorphologists work within disciplines such as physical geography, geology, geodesy, engineering geology, archaeology, climatology, and geotechnical engineering. This broad base of interests contributes to many research styles and interests within the field. Overview Earth's surface is modified by a combination of surface processes that shape landscapes, and geologic processes that cause tectonic uplift and subsidence, and shape the coastal geography. Surface processes co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Baseflow
Baseflow (also called drought flow, groundwater recession flow, low flow, low-water flow, low-water discharge and sustained or fair-weather runoff) is the portion of the streamflow that is sustained between precipitation events, fed to streams by delayed pathways. It should not be confused with groundwater flow. Fair weather flow is also called base flow. Importance Baseflow is important for sustaining human centers of population and ecosystems. This is especially true for watersheds that do not rely on snowmelt. Different ecological processes will occur at different parts of the hydrograph. During the baseflow ascending limb, there is frequently more stream area and habitat available for water-dependent species, spawning salmon for example. During the recession limb which in California is from May to October, there is increasingly less stream area, indigenous species are more adept at surviving in low flow conditions than introduced species. Geology Baseflow is derived from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Discharge (hydrology)
In hydrology, discharge is the volumetric flow rate of water that is transported through a given cross-sectional area. It includes any suspended solids (e.g. sediment), dissolved chemicals (e.g. CaCO3(aq)), or biologic material (e.g. diatoms) in addition to the water itself. Terms may vary between disciplines. For example, a fluvial hydrologist studying natural river systems may define discharge as streamflow, whereas an engineer operating a reservoir system may equate it with outflow, contrasted with inflow. Theory and calculation A discharge is a measure of the quantity of any fluid flow over unit time. The quantity may be either volume or mass. Thus the water discharge of a tap (faucet) can be measured with a measuring jug and a stopwatch. Here the discharge might be 1 litre per 15 seconds, equivalent to 67 ml/second or 4 litres/minute. This is an average measure. For measuring the discharge of a river we need a different method and the most common is the 'area-velocity' method. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Snowmelt
In hydrology, snowmelt is surface runoff produced from melting snow. It can also be used to describe the period or season during which such runoff is produced. Water produced by snowmelt is an important part of the annual water cycle in many parts of the world, in some cases contributing high fractions of the annual runoff in a watershed. Predicting snowmelt runoff from a drainage basin may be a part of designing water control projects. Rapid snowmelt can cause flooding. If the snowmelt is then frozen, very dangerous conditions and accidents can occur, introducing the need for salt to melt the ice. Energy fluxes related to snowmelt There are several energy fluxes involved in the melting of snow. These fluxes can act in opposing directions, that is either delivering heat to or removing heat from the snowpack. Ground heat flux is the energy delivered to the snowpack from the soil below by conduction. Radiation inputs to the snowpack include net shortwave (solar radiation including ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sinuosity
Sinuosity, sinuosity index, or sinuosity coefficient of a continuously differentiable curve having at least one inflection point is the ratio of the curvilinear length (along the curve) and the Euclidean distance (straight line) between the end points of the curve. This dimensionless quantity can also be rephrased as the "actual path length" divided by the "shortest path length" of a curve. The value ranges from 1 (case of straight line) to infinity (case of a closed loop, where the shortest path length is zero or for an infinitely-long actual path). Interpretation The curve must be continuous (no jump) between the two ends. The sinuosity value is really significant when the line is continuously differentiable (no angular point). The distance between both ends can also be evaluated by a plurality of segments according to a broken line passing through the successive inflection points (sinuosity of order 2). The calculation of the sinuosity is valid in a 3-dimensional space (e. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thalweg
In geography and fluvial geomorphology, a thalweg or talweg () is the line of lowest elevation within a valley or watercourse. Under international law, a thalweg is the middle of the primary navigable channel of a waterway that defines the boundary line between states. Also under international law, thalwegs can acquire special significance because disputed river borders are often deemed to run along the river's thalweg. Etymology The word ''thalweg'' is of 19th-century German origin. The German word (modern spelling ) is a compound noun that is built from the German elements (since Duden's orthography reform of 1901 written ) meaning ''valley'' (cognate with ''dale'' in English), and , meaning ''way.'' It literally means "valley way" and is used, with its modern spelling , in daily German to describe a path or road that follows the bottom of a valley, or in geography with the more technical meaning also adopted by English. Hydrology In hydrological and fluvial landforms, th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Overlander Falls
Overlander Falls is a waterfall on the Fraser River in Mount Robson Provincial Park, British Columbia, Canada. It is popular for kayakers. The falls are reached by a short walking trail which starts on the Yellowhead Highway east of the Mount Robson visitor centre. The waterfall is named for the Overlanders expedition of 1862. A group of 175 men and 1 woman from Ontario travelled across the prairies and through the Rocky Mountains, intending to reach the Barkerville or Cariboo goldfields. Just west of Overlander Falls, the group split. About half continued down the Fraser River, eventually reaching Barkerville in late fall of 1862, but over a year had elapsed since Billy Barker's gold strike and there were no claims left to stake. The other half abandoned their dreams of gold and rafted down the North Thompson River to Fort Kamloops. Metcalf, Vicky (1970). ''Journey Fantastic: With the Overlanders to the Cariboo'' See also *Rearguard Falls *Overlander Mountain Overlander ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cooplacurripa R
Cooplacurripa Station is a pastoral lease that operates as a cattle station in Cooplacurripa, New South Wales. It is situated approximately north of Gloucester and west of Kendall. The Cooplacurripa River runs through the property, which is situated in a high rainfall valley area. It is one of the largest cattle stations on the eastern seaboard. The Australian Agricultural Company has had links with the property dating back as far as 1846. In 1950 the property was acquired by Ivan Norrie Livermore when it occupied an area of . Over two years at a cost of 35,000 pounds he destroyed an estimated 500,000 rabbits; subsequently the property was soon able to support a herd of 10,000 cattle. The property was acquired by the Bydand Pastoral Company in 2003. The deal also involved the Australian Agricultural Company taking the stock and leasing the land for six years. The deal was worth 18.5 million. The Bydand Pastoral Company placed the property on the market in 2012 for leasi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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