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Ambuliyar River
The Ambuliyar or Ambuli River is a non-perennial river in the Pudukkottai and Thanjavur districts of Tamil Nadu, India, that flows southeast into the Palk Strait. Course The Ambuliyar begins as the outflow of a retention basin east of the town of Alangudi in the Alangudi taluk of Pudukkottai district. From its source the river flows southeast, passing the towns of Vadakadu and Keeramangalam. South of Peravurani, the Ambuliyar is joined on its right bank by the Maruthankudiyar River, its largest tributary, which flows into the Ambuliyar from the west. Almost immediately past this confluence, the Ambuliyar is joined on its left bank by the Punakkuttiyar River, which flows into it from the north. After this confluence, the Ambuliyar flows east until it empties into the Palk Strait south of Kodivayal, forming a small estuary in the Peravurani taluk of Thanjavur district. The river runs for a total length of . Tributaries The three main tributaries of the Ambuliyar are the Marutha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
States And Union Territories Of India
India is a federal union comprising 28 states and 8 union territories, with a total of 36 entities. The states and union territories are further subdivided into districts and smaller administrative divisions. History Pre-independence The Indian subcontinent has been ruled by many different ethnic groups throughout its history, each instituting their own policies of administrative division in the region. The British Raj mostly retained the administrative structure of the preceding Mughal Empire. India was divided into provinces (also called Presidencies), directly governed by the British, and princely states, which were nominally controlled by a local prince or raja loyal to the British Empire, which held ''de facto'' sovereignty ( suzerainty) over the princely states. 1947–1950 Between 1947 and 1950 the territories of the princely states were politically integrated into the Indian union. Most were merged into existing provinces; others were organised into ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vertisol
A vertisol, or vertosol, is a soil type in which there is a high content of expansive clay minerals, many of them known as montmorillonite, that form deep cracks in drier seasons or years. In a phenomenon known as argillipedoturbation, alternate shrinking and swelling causes ''self-ploughing'', where the soil material consistently mixes itself, causing some vertisols to have an extremely deep A horizon and no B horizon. (A soil with no B horizon is called an ''A/C soil''). This heaving of the underlying material to the surface often creates a microrelief known as ''gilgai''. Vertisols typically form from highly basic rocks, such as basalt, in climates that are seasonally humid or subject to erratic droughts and floods, or that impeded drainage. Depending on the parent material and the climate, they can range from grey or red to the more familiar deep black (known as "black earths" in Australia, "black gumbo" in East Texas, "black cotton" soils in East Africa, and "vlei soils" ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alfisol
Alfisols are a soil order in USDA soil taxonomy. Alfisols form in semi-arid to humid areas, typically under a hardwood forest cover. They have a clay-enriched subsoil and relatively high native fertility. "Alf" refers to aluminium (Al) and iron (Fe). Because of their productivity and abundance, Alfisols represent one of the more important soil orders for food and fiber production. They are widely used both in agriculture and forestry, and are generally easier to keep fertile than other humid-climate soils, though those in Australia and Africa are still very deficient in nitrogen and available phosphorus. Those in monsoonal tropical regions, however, have a tendency to acidify when heavily cultivated, especially when nitrogenous fertilizers are used. In the World Reference Base for Soil Resources (WRB), most Alfisols are classified as Luvisols or Lixisols, but some are classed as Retisols or Nitisols. Aqualfs are mainly Stagnosols or Planosols. Alfisols with a natric horizon are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mudflat
Mudflats or mud flats, also known as tidal flats or, in Ireland, slob or slobs, are coastal wetlands that form in intertidal areas where sediments have been deposited by tides or rivers. A global analysis published in 2019 suggested that tidal flat ecosystems are as extensive globally as mangroves, covering at least of the Earth's surface. / They are found in sheltered areas such as bays, bayous, lagoons, and estuaries; they are also seen in freshwater lakes and salty lakes (or inland seas) alike, wherein many rivers and creeks end. Mudflats may be viewed geologically as exposed layers of bay mud, resulting from deposition of estuarine silts, clays and aquatic animal detritus. Most of the sediment within a mudflat is within the intertidal zone, and thus the flat is submerged and exposed approximately twice daily. A recent global remote sensing analysis estimated that approximately 50% of the global extent of tidal flats occurs within eight countries (Indonesia, China, Austral ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Floodplain
A floodplain or flood plain or bottomlands is an area of land adjacent to a river which stretches from the banks of its channel to the base of the enclosing valley walls, and which experiences flooding during periods of high discharge.Goudie, A. S., 2004, ''Encyclopedia of Geomorphology'', vol. 1. Routledge, New York. The soils usually consist of clays, silts, sands, and gravels deposited during floods. Because the regular flooding of floodplains can deposit nutrients and water, floodplains frequently have high soil fertility; some important agricultural regions, such as the Mississippi river basin and the Nile, rely heavily on the flood plains. Agricultural regions as well as urban areas have developed near or on floodplains to take advantage of the rich soil and fresh water. However, the risk of flooding has led to increasing efforts to control flooding. Formation Most floodplains are formed by deposition on the inside of river meanders and by overbank flow. Whereve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pediment (geology)
A pediment, also known as a concave slope or waning slope, is a very gently sloping (0.5°-7°) inclined bedrock surface. It is typically a concave surface sloping down from the base of a steeper retreating desert cliff, escarpment, or surrounding a monadnock or inselberg, but may persist after the higher terrain has eroded away. Pediments are erosional surfaces. A pediment develops when sheets of running water (sheet floods) wash over it in intense rainfall events. It may be thinly covered with fluvial gravel that has washed over it from the foot of mountains produced by cliff retreat erosion. A pediment is not to be confused with a bajada, which is a merged group of alluvial fans. Bajadas also slope gently from an escarpment, but are composed of material eroded from canyons in the escarpment and redeposited on the bajada, rather than of bedrock with a thin veneer of gravel. Description Pediments were originally recognized as the upper part of smoothly sloping (0.5°-7°) co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluvial Processes
In geography and geology, fluvial processes are associated with rivers and streams and the Deposition (geology), deposits and landforms created by them. When the stream or rivers are associated with glaciers, ice sheets, or ice caps, the term glaciofluvial or fluvioglacial is used. Fluvial processes Fluvial processes include the sediment transport, motion of sediment and erosion or deposition (geology), deposition on the river bed. The movement of water across the stream bed exerts a shear stress directly onto the bed. If the Cohesion (geology), cohesive strength of the substrate is lower than the shear exerted, or the bed is composed of loose sediment which can be mobilized by such stresses, then the bed will be lowered purely by clearwater flow. In addition, if the river carries significant quantities of sediment, this material can act as tools to enhance wear of the bed (abrasion (geology), abrasion). At the same time the fragments themselves are ground down, becoming smaller ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Denudation
Denudation is the geological processes in which moving water, ice, wind, and waves erode the Earth's surface, leading to a reduction in elevation and in relief of landforms and landscapes. Although the terms erosion and denudation are used interchangeably, erosion is the transport of soil and rocks from one location to another, and denudation is the sum of processes, including erosion, that result in the lowering of Earth's surface. Endogenous processes such as volcanoes, earthquakes, and tectonic uplift can expose continental crust to the exogenous processes of weathering, erosion, and mass wasting. The effects of denudation have been recorded for millennia but the mechanics behind it have been debated for the past 200 years and have only begun to be understood in the past few decades. Description Denudation incorporates the mechanical, biological, and chemical processes of erosion, weathering, and mass wasting. Denudation can involve the removal of both solid particles and diss ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sandstone
Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates) because they are the most resistant minerals to weathering processes at the Earth's surface. Like uncemented sand, sandstone may be any color due to impurities within the minerals, but the most common colors are tan, brown, yellow, red, grey, pink, white, and black. Since sandstone beds often form highly visible cliffs and other topographic features, certain colors of sandstone have been strongly identified with certain regions. Rock formations that are primarily composed of sandstone usually allow the percolation of water and other fluids and are porous enough to store large quantities, making them valuable aquifers and petroleum reservoirs. Quartz-bearing sandstone can be changed into quartzite through metamorphism, usually related to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alluvium
Alluvium (from Latin ''alluvius'', from ''alluere'' 'to wash against') is loose clay, silt, sand, or gravel that has been deposited by running water in a stream bed, on a floodplain, in an alluvial fan or beach, or in similar settings. Alluvium is also sometimes called alluvial deposit. Alluvium is typically geologically young and is not consolidated into solid rock. Sediments deposited underwater, in seas, estuaries, lakes, or ponds, are not described as alluvium. Floodplain alluvium can be highly fertile, and supported some of the earliest human civilizations. Definitions The present consensus is that "alluvium" refers to loose sediments of all types deposited by running water in floodplains or in alluvial fans or related landforms. However, the meaning of the term has varied considerably since it was first defined in the French dictionary of Antoine Furetière, posthumously published in 1690. Drawing upon concepts from Roman law, Furetière defined ''alluvion'' (the F ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Agniyar River
The Agniyar River is a non-perennial river in the Indian state of Tamil Nadu that flows southeast into the Bay of Bengal. Course The river begins as a small stream south of Keeranur, proceeding south and east, passing Karambakkudi. Southeast of Karambakkudi, the Grand Anicut canal connects to it. The river continues eastward past Sendakkottai, until it is joined by the Maharajasamundram River south of Pattukkottai and west of Adirampattinam. After this confluence, the river flows south for a short distance, until it empties into the Palk Strait south of the village of Rajamadam, in the Pattukkottai taluk of Thanjavur district.http://nwm.gov.in/sites/default/files/Agniyar_Report.pdf Watershed The Agniyar River is located with the greater Agniyar basin, which includes the Agniyar's drainage basin, along with the watersheds of the neighboring Ambuliyar and Vellar rivers. This basin is situated to the north of the Pambar basin, and to the south and east of the Kaveri basi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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