Wadi (Arabic: ?????? ?, translit.Ã, w? d? ; Hebrew: ???? ? v? D? ), or w? d (Arabic: ???? ?), is the Arabic and Hebrew term traditionally referring to a valley. In some cases, this may refer to a dry riverbed (ephemeral) that contains water only during heavy rains.
Video Wadi
Etimologi
The term w? D? is very much found in Arabic toponyms. Some Spanish toponyms come from the Andalusian language where w? D? used to interpret permanent rivers, for example: Guadalcanal of w? D? al-qan? l (Arabic: ?????? ???????????? ?, "stream refresh kiosk "), Guadalajara from w? d? al-? ij? rah (Arabic: ?????? ????????????? ?, "rock river "), or Guadalquivir, of al-w? d? al-kab? r (Arabic: ?????????????????????? ? , "the great river").
Maps Wadi
Morphology and general processes
Wadis is located on a sloping and almost flat slope; usually they start from distal fans and extend to sabkhas or inland playas. In the topography of the basin and range, the wadi trend along the axle basin is at the end of the fan. The permanent channel does not exist, due to the lack of sustainable water flow. Wadi shows a braid flow pattern due to lack of water and the amount of sediment. Water seeping into the bottom of the river causes sudden energy loss and produces enormous precipitation. Wadis can develop a sedimentary dam that produces changes in the flow pattern of the next banjir bandang.
Wind also plays its role in deposition. When the wadi sediment is under water or moist, the wind sediments are deposited on top of them. Thus the wadi sediment contains wind and water sediments.
Sediment and sedimentary structure
Wadi sediments may contain the entire range from gravel to mud. There are also various sedimentary structures. Thus, most diagnostic wad sediments from all other desert environments.
Flash floods represent severe energy conditions and produce a variety of sedimentary structures, including ripples and common beds. Common pebbles of screen lubrication, Mud curtains show desiccation cracks. The wind activity also produces its own sedimentary structure, large-scale cross-stratification and cross-set wedge forms present. The typical wadi sequence consists of alternating units of wind and water sediments; each unit ranges from 10-30 cm (3.9-11.8 inches). Water sediments show up order. Gravel shows imbrication. The sediment winds are cross-linked and covered with mud deposits. Some horizontal Loess can also be present.
Hydrological action
The use of modern English distinguishes wadi from other canyons or washes with action and water prevalence. Wadis, as drainage courses, are formed by water, but are distinguished from river basins or trenches on alternating or short surface waters. Wadis are generally dry throughout the year, except after rain. Desert environment is characterized by sudden but rare rains, often resulting in flash floods. Crossing the wadis at certain times of the year can be dangerous as a result.
Wadis tend to be associated with human population centers because subsurface water is sometimes available in them. The nomadic and pastoral desert people will rely on the seasonal vegetation found in wadi, even in areas of Sahara fuses, as they travel on complex transhumation routes.
The centrality of wadi for water - and human life - in the desert environment gave rise to different sub-fields of hydraulic wadi in the 1990s.
Deposit
Deposition in wadi fast due to loss of flow velocity and seepage of water into porous sediments. Wadi deposits thus usually have gravel and poorly laid sand. These sediments are often reworked by the eolian process.
Over time, wadi deposits can be "Inverted Legacy" where presence at one time underground water causes vegetation and sediment to fill eroded wadi channels, to the point that the previous washing appears as a mountain that flows through the desert region.
Gallery
See also
References
Bibliography
- Summary: Drainage Program, Wadis. United States Army Engineer Corps. The Desert Working Group; Knowledge Sciences, Inc. (n.d), taken 2008-08-26.
- Summary: Summary: Drainage Program, Wadis - Reversed. United States Army Engineer Corps. The Desert Working Group; Knowledge Sciences, Inc. (n.d), take 2008-08-2onments
- Gelennie, K. W., 1970 Get rid of sedimentary environments. Development in Sedimentology, v.14. Elsevier, Amsterdam, 222p.
External links
- IHP REGIONAL WADI HYDROLOGY NETWORK, International Hydrology Program, UNESCO.
- Arabic Center for the Study of Arid and Dry Zones (ACSAD): The water resources division.
Source of the article : Wikipedia
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