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May Gabat
May Gabat is a river of northern Ethiopia. Rising in the mountains of Enderta (woreda), Inderta (2233 metres above sea level), it flows westward to Giba River which empties finally in the Tekezé River. The Gereb Segen (May Gabat), Gereb Segen reservoir has been built on this river in 2016, mainly for providing Mekelle with potable water. Hydrography It is a confined river, locally meandering in its narrow alluvial plain, with a slope gradient of 15 metres per kilometre. With its tributaries, the river has cut a deep gorge. Tributaries Main tributary is Kalamino River which drains a large part of Mekelle; it joins May Gabat downstream from the Gereb Segen (May Gabat), Gereb Segen reservoir. Hydrology Hydrological characteristics The runoff footprint or annual total runoff volume is 58 million m³. Hydrograph#Terminology, Peak discharges up to 190 m³ per second occur in the second part of the rainy season (month of August) when there are strong rains and the soils are water ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Giba River
Giba is a river of northern Ethiopia. It starts at the confluence of Genfel and Sulluh (which rises in the mountains of Mugulat) (3298 metres above sea level) and flows westward to the Tekezé River. Future Lake Giba will occupy the plain where Sulluh, Genfel and Agula'i Rivers meet, and hence be the future source of Giba River. Hydrography It is a confined river, locally meandering in its narrow alluvial plain, with a slope gradient of 7 metres per kilometre. With its tributaries, the river has cut a deep gorge. Tributaries Main tributaries, from downstream to upstream, are * Tanqwa ** Tsech'i River ** May Qoqah ** Arwadito ** Adawro River * May Selelo * Zikuli River * Gra Adiam River, also called Bitchoqo River * Zeyi River * Inda Sillasie River ** May Zegzeg *** May Harena *** May Sho'ate ** May Be'ati River * Addi Keshofo River * May Gabat * Inda Anbesa * Ruba Bich'i River * Hurura ** Afedena River *** May Ayni ** Shimbula * Ilala River * Qarano River * Agula'i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stormwater
Stormwater, also spelled storm water, is water that originates from precipitation (storm), including heavy rain and meltwater from hail and snow. Stormwater can soak into the soil ( infiltrate) and become groundwater, be stored on depressed land surface in ponds and puddles, evaporate back into the atmosphere, or contribute to surface runoff. Most runoff is conveyed directly as surface water to nearby streams, rivers or other large water bodies (wetlands, lakes and oceans) without treatment. In natural landscapes, such as forests, soil absorbs much of the stormwater. Plants also reduce stormwater by improving infiltration, intercepting precipitation as it falls, and by taking up water through their roots. In developed environments, such as cities, unmanaged stormwater can create two major issues: one related to the volume and timing of runoff (flooding) and the other related to potential contaminants the water is carrying (water pollution). In addition to the pollutants carr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Upper Gabat
Upper may refer to: * Shoe upper or ''vamp'', the part of a shoe on the top of the foot * Stimulant, drugs which induce temporary improvements in either mental or physical function or both * ''Upper'', the original film title for the 2013 found footage film '' The Upper Footage'' See also {{Disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Check Dam
A steel check dam A check dam is a small, sometimes temporary, dam constructed across a swale, drainage ditch, or waterway to counteract erosion by reducing water flow velocity. Check dams themselves are not a type of new technology; rather, they are an ancient technique dating from the second century A.D. Check dams are typically, though not always, implemented in a system of several dams situated at regular intervals across the area of interest. Function A check dam placed in the ditch, swale, or channel interrupts the flow of water and flattens the gradient of the channel, thereby reducing the velocity. In turn, this obstruction induces infiltration and reduces eroding. They can be used not only to slow flow velocity but also to distribute flows across a swale to avoid preferential paths and guide flows toward vegetation. Although some sedimentation may result behind the dam, check dams do not primarily function as sediment-trapping devices. For instance, on the Graliwdo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Terrace (earthworks)
In agriculture, a terrace is a piece of sloped plane that has been cut into a series of successively receding flat surfaces or platforms, which resemble steps, for the purposes of more effective farming. This type of landscaping is therefore called terracing. Graduated terrace steps are commonly used to farm on hilly or mountainous terrain. Terraced fields decrease both erosion and surface runoff, and may be used to support growing crops that require irrigation, such as rice. The Rice Terraces of the Philippine Cordilleras have been designated as a UNESCO World Heritage Site because of the significance of this technique. Uses Terraced paddy fields are used widely in rice, wheat and barley farming in east, south, southwest, and southeast Asia, as well as the Mediterranean Basin, Africa, and South America. Drier-climate terrace farming is common throughout the Mediterranean Basin, where they are used for vineyards, olive trees, cork oak, and other crops. Ancient history ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Infiltration (hydrology)
Infiltration is the process by which water on the ground surface enters the soil. It is commonly used in both hydrology and soil sciences. The infiltration capacity is defined as the maximum rate of infiltration. It is most often measured in meters per day but can also be measured in other units of distance over time if necessary. The infiltration capacity decreases as the soil moisture content of soils surface layers increases. If the precipitation rate exceeds the infiltration rate, runoff will usually occur unless there is some physical barrier. Infiltrometers, permeameters and rainfall simulators are all devices that can be used to measure infiltration rates. Infiltration is caused by multiple factors including; gravity, capillary forces, adsorption and osmosis. Many soil characteristics can also play a role in determining the rate at which infiltration occurs. Factors that affect infiltration Precipitation Precipitation can impact infiltration in many ways. The am ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exclosure
An exclosure, in an area being used extensively for grazing, is a limited area from which unwanted browsing animals, such as domestic cattle or wildlife such as deer, are excluded by fencing or other means. Environmental protection Most commonly, exclosures are areas that are set aside for regreening. Wood harvesting and livestock range are not allowed there. Effects on environment The establishment of an exclosure has positive effects on: * biodiversity * water infiltration * protection from flooding * sediment deposition * carbon sequestration Economic benefits In developing countries, people commonly have economic benefits from these exclosures through grass harvesting, beekeeping and other non-timber forest products. The local inhabitants also consider it as “land set aside for future generations”. Carbon credits Exclosures have as an additional benefit that the surrounding communities may receive carbon credits for the sequestered CO2, as part of a carbon offs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aerial Reconnaissance In World War II
A transformational growth in aerial reconnaissance occurred in the years 1939–45, especially in Britain and then in the United States. It was an expansion determined mostly by trial and error, represented mostly by new tactics, new procedures, and new technology, though rarely by specialized aircraft types. The mission type branched out into many sub-types, including new electronic forms of reconnaissance. In sharp contrast with the case during the pre-war years, by 1945 air reconnaissance was widely recognized as a vital, indispensable component of air power. Pre-war situation In the interwar years, reconnaissance languished as a mission type and tended to be overshadowed by routine aerial mapping. This was despite the growth (in the United States and Britain) of a doctrine of strategic bombardment as the decisive weapon of war. Experience would soon prove that bombing was completely ineffective unless accompanied by intensive aerial reconnaissance. In the 1930s, gradual technic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
May Gabat Downstream From Gereb Segen
May is the fifth month of the year in the Julian and Gregorian calendars and is the third of seven months to have a length of 31 days. May is a month of spring in the Northern Hemisphere, and autumn in the Southern Hemisphere. Therefore, May in the Southern Hemisphere is the seasonal equivalent of November in the Northern Hemisphere and vice versa. Late May typically marks the start of the summer vacation season in the United States (Memorial Day) and Canada (Victoria Day) that ends on Labor Day, the first Monday of September. May (in Latin, '' Maius'') was named for the Greek goddess Maia, who was identified with the Roman era goddess of fertility, Bona Dea, whose festival was held in May. Conversely, the Roman poet Ovid provides a second etymology, in which he says that the month of May is named for the ''maiores,'' Latin for "elders," and that the following month (June) is named for the ''iuniores,'' or "young people" (''Fasti VI.88''). Eta Aquariids meteor shower ... [...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] |
Flash Floods
A flash flood is a rapid flooding of low-lying areas: washes, rivers, dry lakes and depressions. It may be caused by heavy rain associated with a severe thunderstorm, hurricane, or tropical storm, or by meltwater from ice or snow flowing over ice sheets or snowfields. Flash floods may also occur after the collapse of a natural ice or debris dam, or a human structure such as a man-made dam, as occurred before the Johnstown Flood of 1889. Flash floods are distinguished from regular floods by having a timescale of fewer than six hours between rainfall and the onset of flooding. Flash floods are a significant hazard, causing more fatalities in the U.S. in an average year than lightning, tornadoes, or hurricanes. Flash floods can also deposit large quantities of sediments on floodplains and can be destructive of vegetation cover not adapted to frequent flood conditions. Causes Flash floods most often occur in dry areas that have recently received precipitation, but they may ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sediment Yield
Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sand and silt can be carried in suspension in river water and on reaching the sea bed deposited by sedimentation; if buried, they may eventually become sandstone and siltstone (sedimentary rocks) through lithification. Sediments are most often transported by water (fluvial processes), but also wind (aeolian processes) and glaciers. Beach sands and river channel deposits are examples of fluvial transport and deposition, though sediment also often settles out of slow-moving or standing water in lakes and oceans. Desert sand dunes and loess are examples of aeolian transport and deposition. Glacial moraine deposits and till are ice-transported sediments. Classification Sediment can be classified based on its grain size, grain shape, and comp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
