Upland and lowland are conditional descriptions of a plain based on elevation above sea level . In studies of the ecology of freshwater rivers , habitats are classified as upland or lowland.
18-646: Low country is a large lowland . Specific uses are: Predominantly, South Carolina Lowcountry in the United States of America Low Countries , a historical region in Europe, although rarely used in this context see also Netherlands (terminology) Low Country, and old term for the Scottish Borders plus far Northern England region Low Country (album) [REDACTED] Topics referred to by
36-1040: A riffle and pool structure and cooler water temperatures. Rivers with a course that drops in elevation very slowly will have slower water flow and lower force. This in turn produces the other characteristics of a lowland river—a meandering course lacking rapids , a river bed dominated by fine sediments and higher water temperatures. Lowland rivers tend to carry more suspended sediment and organic matter as well, but some lowland rivers have periods of high water clarity in seasonal low-flow periods. The generally clear, cool, fast-flowing waters and bedrock and coarse sediment beds of upland rivers encourage fish species with limited temperature tolerances, high oxygen needs, strong swimming ability and specialised reproductive strategies to prevent eggs or larvae being swept away. These characteristics also encourage invertebrate species with limited temperature tolerances, high oxygen needs and ecologies revolving around coarse sediments and interstices or "gaps" between those coarse sediments. The term "upland"
54-619: A new one ( avulsion (river) ). A braided river may form as small threads come and go within a main channel. The intensity and frequency of both drought and rain events are expected to increase with climate change. Floods , or flood stage , occur when a stream overflows its banks. In undisturbed natural areas, flood water would be able to spread out within a floodplain and vegetation of either grassland or forest , would slow and absorb peak flows. In such areas, streambeds should remain more stable and exhibit minimal scour. They should retain rich organic matter and, therefore continue to support
72-597: A rich biota ( river ecosystem ). The majority of sediment washed out in higher flows is "near-threshold" sediment that has been deposited during normal flow and only needs a slightly higher flow to become mobile again. This shows that the streambed is left mostly unchanged in size and shape over time. In urban and suburban areas with little natural vegetation, high levels of impervious surface , and no floodplain, unnaturally high levels of surface runoff can occur. This causes an increase in flooding and watershed erosion which can lead to thinner soils upslope. Streambeds can exhibit
90-727: Is also used in wetland ecology , where "upland" plants indicate an area that is not a wetland. The generally more turbid , warm, slow-flowing waters and fine sediment beds of lowland rivers encourage fish species with broad temperature tolerances and greater tolerances to low oxygen levels, and life history and breeding strategies adapted to these and other traits of lowland rivers. These characteristics also encourage invertebrate species with broad temperature tolerances and greater tolerances to low oxygen levels and ecologies revolving around fine sediments or alternative habitats such as submerged woody debris ("snags") or submergent macrophytes ("water weed"). Lowland alluvial plains form when there
108-595: Is deposition of sediment over a long period of time by one or more rivers coming from highland regions, and then are deposited in lowland regions for long periods of time. Examples include American Bottom , a flood plain of the Mississippi River in Southern Illinois, Bois Brule Bottom , and Bottomland hardwood forest a deciduous hardwood forest found in broad lowland floodplains of the United States. River bed A streambed or stream bed
126-438: Is different from Wikidata All article disambiguation pages All disambiguation pages Lowland Upland and lowland are portions of a plain that are conditionally categorized by their elevation above the sea level . Lowlands are usually no higher than 200 m (660 ft), while uplands are somewhere around 200 m (660 ft) to 500 m (1,600 ft). On unusual occasions, certain lowlands such as
144-453: Is frequently colored by sediment and organic matter. These classifications overlap with the geological definitions of "upland" and "lowland". In geology an "upland" is generally considered to be land that is at a higher elevation than the alluvial plain or stream terrace , which are considered to be "lowlands". The term "bottomland" refers to low-lying alluvial land near a river. Much freshwater fish and invertebrate communities around
162-433: Is not the sole determinant of whether a river is upland or lowland. Arguably the most important determinants are those of stream power and stream gradient . Rivers with a course that drops rapidly in elevation will have faster water flow and higher stream power or "force of water". This in turn produces the other characteristics of an upland river—an incised course , a river bed dominated by bedrock and coarse sediments,
180-473: Is the bottom of a stream or river ( bathymetry ) and is confined within a channel , or the banks of the waterway. Usually, the bed does not contain terrestrial (land) vegetation and instead supports different types of aquatic vegetation ( aquatic plant ), depending on the type of streambed material and water velocity. Streambeds are what would be left once a stream is no longer in existence. The beds are usually well preserved even if they get buried because
198-574: The Caspian Depression lie below sea level. Uplands areas tend to spike into valleys and mountains , forming mountain ranges while lowland areas tend to be uniformly flat, although both can vary such as the Mongolian Plateau . Upland habitats are cold, clear and rocky whose rivers are fast-flowing in mountainous areas; lowland habitats are warm with slow-flowing rivers found in relatively flat lowland areas, with water that
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#1732764755059216-412: The banks and canyons made by the stream are typically hard, although soft sand and debris often fill the bed. Dry, buried streambeds can actually be underground water pockets. During times of rain, sandy streambeds can soak up and retain water, even during dry seasons, keeping the water table close enough to the surface to be obtainable by local people. The nature of any streambed is always a function of
234-666: The flow dynamics and the local geologic materials. The climate of an area will determine the amount of precipitation a stream receives and therefore the amount of water flowing over the streambed. A streambed is usually a mix of particle sizes which depends on the water velocity and the materials introduced from upstream and from the watershed. Particle sizes can range from very fine silts and clays to large cobbles and boulders ( grain size ). In general, sands move most easily, and particles become more difficult to move as they increase in size. Silts and clays, although smaller than sands, can sometimes stick together, making them harder to move along
252-429: The same term This disambiguation page lists articles about distinct geographical locations with the same name. If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=Low_Country&oldid=1154522209 " Category : Place name disambiguation pages Hidden categories: Short description
270-422: The stream meanders downhill. Pools can also form as water rushes over or around obstructions in the waterway. Under certain conditions a river can branch from one streambed to multiple streambeds. For example, an anabranch may form when a section of stream or river goes around a small island and then rejoins the main channel. The buildup of sediment on a streambed may cause a channel to be abandoned in favor of
288-399: The streambed. Deposition usually occurs on the inside of curves, where water velocity slows, and erosion occurs on the outside of stream curves, where velocity is higher. This continued erosion and deposition of sediment tends to create meanders of the stream. In streams with a low to moderate grade, deeper, slower water pools ( stream pools ) and faster shallow water riffles often form as
306-424: The streambed. In streams with a gravel bed, the larger grain sizes are usually on the bed surface with finer grain sizes below. This is called armoring of the streambed. The streambed is very complex in terms of erosion and deposition. As the water flows downstream, different sized particles get sorted to different parts of a streambed as water velocity changes and sediment is transported, eroded and deposited on
324-531: The world show a pattern of specialization into upland or lowland river habitats. Classifying rivers and streams as upland or lowland is important in freshwater ecology , as the two types of river habitat are very different, and usually support very different populations of fish and invertebrate species. In freshwater ecology, upland rivers and streams are the fast-flowing rivers and streams that drain elevated or mountainous country, often onto broad alluvial plains (where they become lowland rivers). However, elevation
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