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Rill
In hillslope geomorphology, a rill is a shallow channel (no more than a few inches/decimeters deep) cut into soil by the erosive action of flowing surface water. Similar but smaller incised channels are known as microrills; larger incised channels are known as gullies. Artificial rills are channels constructed to carry a water supply from a distant water source. In landscape or garden design, constructed rills are an aesthetic water feature. Rills created by erosion Rills are narrow and shallow channels which are eroded into unprotected soil by hillslope runoff. Since soil is regularly left bare during agricultural operations, rills may form on farmland during these vulnerable periods. Rills may also form when bare soil is left exposed following deforestation, or during construction activities. Rills are fairly easily visible when first incised, so they are often the first indication of an ongoing erosion problem. Unless soil conservation measures are put into place, ri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rill Network From Tyrone, Ireland
In hillslope geomorphology, a rill is a shallow channel (no more than a few inches/decimeters deep) cut into soil by the erosive action of flowing surface water. Similar but smaller incised channels are known as microrills; larger incised channels are known as gullies. Artificial rills are channels constructed to carry a water supply from a distant water source. In landscape or garden design, constructed rills are an aesthetic water feature. Rills created by erosion Rills are narrow and shallow channels which are eroded into unprotected soil by hillslope runoff. Since soil is regularly left bare during agricultural operations, rills may form on farmland during these vulnerable periods. Rills may also form when bare soil is left exposed following deforestation, or during construction activities. Rills are fairly easily visible when first incised, so they are often the first indication of an ongoing erosion problem. Unless soil conservation measures are put into place, ri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rill Initiation, Finger Pointing At A Newly-developed Headcut
In hillslope geomorphology, a rill is a shallow channel (no more than a few inches/decimeters deep) cut into soil by the erosive action of flowing surface water. Similar but smaller incised channels are known as microrills; larger incised channels are known as gullies. Artificial rills are channels constructed to carry a water supply from a distant water source. In landscape or garden design, constructed rills are an aesthetic water feature. Rills created by erosion Rills are narrow and shallow channels which are eroded into unprotected soil by hillslope runoff. Since soil is regularly left bare during agricultural operations, rills may form on farmland during these vulnerable periods. Rills may also form when bare soil is left exposed following deforestation, or during construction activities. Rills are fairly easily visible when first incised, so they are often the first indication of an ongoing erosion problem. Unless soil conservation measures are put into place, ri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rill Close-up From Tyrone, Ireland
In hillslope geomorphology, a rill is a shallow channel (no more than a few inches/decimeters deep) cut into soil by the erosive action of flowing surface water. Similar but smaller incised channels are known as microrills; larger incised channels are known as gullies. Artificial rills are channels constructed to carry a water supply from a distant water source. In landscape or garden design, constructed rills are an aesthetic water feature. Rills created by erosion Rills are narrow and shallow channels which are eroded into unprotected soil by hillslope runoff. Since soil is regularly left bare during agricultural operations, rills may form on farmland during these vulnerable periods. Rills may also form when bare soil is left exposed following deforestation, or during construction activities. Rills are fairly easily visible when first incised, so they are often the first indication of an ongoing erosion problem. Unless soil conservation measures are put into place, ri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aqueduct (water Supply)
An aqueduct is a watercourse constructed to carry water from a source to a distribution point far away. In modern engineering, the term ''aqueduct'' is used for any system of pipes, ditches, canals, tunnels, and other structures used for this purpose. The term ''aqueduct'' also often refers specifically to a bridge carrying an artificial watercourse. Aqueducts were used in ancient Greece, ancient Egypt, and ancient Rome. The simplest aqueducts are small ditches cut into the earth. Much larger channels may be used in modern aqueducts. Aqueducts sometimes run for some or all of their path through tunnels constructed underground. Modern aqueducts may also use pipelines. Historically, agricultural societies have constructed aqueducts to irrigate crops and supply large cities with drinking water. Etymology The word ''aqueduct'' is derived from the Latin words (''water'') and (''led'' or ''guided''). Ancient aqueducts Although particularly associated with the Romans, aqueducts we ... [...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] |
Water Feature
In landscape architecture and garden design, a water feature is one or more items from a range of fountains, jeux d'eau, pools, ponds, rills, artificial waterfalls, and streams. Before the 18th century they were usually powered by gravity, though the famous Hanging Gardens of Babylon are described by Strabo as supplied by an Archimedean screw and other examples were supplied with water using hydraulic rams. Ancient water features were powered using gravitational forces, human power or animals to pump in the water. Since the 18th century, the majority of water features have been powered by pumps. In the past, the power source was sometimes a steam engine, but in modern features it is almost always powered by electricity. There is an increasing range of innovative designs as the market becomes more established and people become more aware of alternate installation methods, such as solar power. The advantages of using solar power include environmental benefits, no electrical lin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gully
A gully is a landform created by running water, mass movement, or commonly a combination of both eroding sharply into soil or other relatively erodible material, typically on a hillside or in river floodplains or terraces. Gullies resemble large ditches or small valleys, but are metres to tens of metres in depth and width and are characterised by a distinct 'headscarp' or 'headwall' and progress by headward (i.e. upstream) erosion. Gullies are commonly related to intermittent or ephemeral water flow usually associated with localised intense or protracted rainfall events, or snowmelt. Gullies can be formed and accelerated by cultivation practices on hillslopes (often gentle gradient) in farmland, and they can develop rapidly in rangelands from existing natural erosion forms subject to vegetative cover removal and livestock activity. Etymology The earliest known usage of the term is from 1657. It originates from the French word ''goulet'', a diminutive form of ''goule'' which m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Semi-arid
A semi-arid climate, semi-desert climate, or steppe climate is a dry climate sub-type. It is located on regions that receive precipitation below potential evapotranspiration, but not as low as a desert climate. There are different kinds of semi-arid climates, depending on variables such as temperature, and they give rise to different biomes. Defining attributes of semi-arid climates A more precise definition is given by the Köppen climate classification, which treats steppe climates (''BSk'' and ''BSh'') as intermediates between desert climates (BW) and humid climates (A, C, D) in ecological characteristics and agricultural potential. Semi-arid climates tend to support short, thorny or scrubby vegetation and are usually dominated by either grasses or shrubs as it usually can't support forests. To determine if a location has a semi-arid climate, the precipitation threshold must first be determined. The method used to find the precipitation threshold (in millimeters): *multiply by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Badlands
Badlands are a type of dry terrain where softer sedimentary rocks and clay-rich soils have been extensively eroded."Badlands" in ''Chambers's Encyclopædia''. London: George Newnes, 1961, Vol. 2, p. 47. They are characterized by steep slopes, minimal vegetation, lack of a substantial regolith, and high drainage density.A.J. Parsons and A.D. Abrahams, Editors (2009) ''Geomorphology of Desert Environments'' (2nd ed.) Springer Science & Business Media Ravines, gullies, buttes, hoodoos and other such geologic forms are common in badlands. Badlands are found on every continent except Antarctica, being most common where there are unconsolidated sediments. They are often difficult to navigate by foot, and are unsuitable for agriculture. Most are a result of natural processes, but destruction of vegetation by overgrazing or pollution can produce anthropogenic badlands. Badlands topography Badlands are characterized by a distinctive badlands topography. This is terrain in which w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Topsoil
Topsoil is the upper layer of soil. It has the highest concentration of organic matter and microorganisms and is where most of the Earth's biological soil activity occurs. Description Topsoil is composed of mineral particles and organic matter and usually extends to a depth of 5-10 inches (13–25 cm). Together these make a substrate capable of holding water and air which encourages biological activity. There are generally a high concentration of roots in topsoil since this is where plants obtain most of their vital nutrients. It also plays host to significant bacterial, fungal and entomological activity without which soil quality would degrade and become less suitable for plants. Bacteria and fungi can be essential in facilitating nutrient exchange with plants and in breaking down organic matter into a form that roots can absorb. Insects also play important roles in breaking down material and aerating and rotating the soil. Many species directly contribute to the health ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shear Velocity
Shear velocity, also called friction velocity, is a form by which a shear stress may be re-written in units of velocity. It is useful as a method in fluid mechanics to compare true velocities, such as the velocity of a flow in a stream, to a velocity that relates shear between layers of flow. Shear velocity is used to describe shear-related motion in moving fluids. It is used to describe: * Diffusion and dispersion of particles, tracers, and contaminants in fluid flows * The velocity profile near the boundary of a flow (see Law of the wall) * Transport of sediment in a channel Shear velocity also helps in thinking about the rate of shear and dispersion in a flow. Shear velocity scales well to rates of dispersion and bedload sediment transport. A general rule is that the shear velocity is between 5% to 10% of the mean flow velocity. For river base case, the shear velocity can be calculated by Manning's equation. :u^*=\langle u\rangle\frac(gR_h^)^ * ''n'' is the Gauckler–Manning ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Construction
Construction is a general term meaning the art and science to form objects, systems, or organizations,"Construction" def. 1.a. 1.b. and 1.c. ''Oxford English Dictionary'' Second Edition on CD-ROM (v. 4.0) Oxford University Press 2009 and comes from Latin ''constructio'' (from ''com-'' "together" and ''struere'' "to pile up") and Old French ''construction''. To construct is the verb: the act of building, and the noun is construction: how something is built, the nature of its structure. In its most widely used context, construction covers the processes involved in delivering buildings, infrastructure, industrial facilities and associated activities through to the end of their life. It typically starts with planning, financing, and design, and continues until the asset is built and ready for use; construction also covers repairs and maintenance work, any works to expand, extend and improve the asset, and its eventual demolition, dismantling or decommissioning. The constructio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
