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Definition
| A weak acid (H2CO3) that forms from the reaction of water and carbon dioxide. Most rain water is a very weak carbonic acid solution formed by the reaction of rain with small amounts of carbon dioxide in the atmosphere |
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chemical weathering [image] |
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Definition
The breaking down of surface rock material by solution or chemical alteration. Common alteration processes are oxidation and hydrolysis. |
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| Soil creep is a very, very slow form of mass wasting. It's just a slow adjustment of soil and rocks that is so hard to notice unless you can see the effects of the movement. These effects would be things like fenceposts shifted out of alignment, or telephone poles tipping downslope. Another effect is the way a grass covered slope seems to ooze downhill forming little bulges in the soil. This heaving of the soil occurs in regions subjected to freeze-thaw conditions. The freeze lifts particles of soil and rocks and when there is a thaw, the particles are set back down, but not in the same place as before. |
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| A general term applied to the wearing away and movement of earth materials by gravity, wind, water and ice. |
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| A physical weathering process in which concentric layers of rock are removed from an outcrop. |
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A chemical reaction involving water that results in the breakdown of mineral material. |
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When water infiltrates fractures in rock and freezes, the force of expansion is great enough to break
the rock into smaller pieces. |
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| A downslope movement of rock and soil over a failure surface and under the influence of gravity. Slumps, earthflows, debris flows and debris slides are examples. |
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| A general term used for any downslope movement of rock, soil, snow or ice under the influence of gravity. Includes: landslides, creep, rock falls and avalanches. |
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mechanical weathering [image] |
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| A general term applied to a variety of weathering processes that result in the particle size reduction of rock materials with no change in composition. Frost action, salt crystal growth and pressure relief fracturing are examples. Also known as physical weathering. |
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| A type of mass movement composed mainly of clay-size materials with a high enough water content that it flows readily. |
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| A chemical reaction in which substances combine with oxygen. For example, the combination of iron with oxygen to form an iron oxide. |
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| in soil science, means the underlying geological material (generally bedrock or a superficial or drift deposit) in which soil horizons form. Soils typically get a great deal of structure and minerals from their parent material. Parent materials are made up of consolidated or unconsolidated mineral material that has undergone some degree of physical or chemical weathering. |
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| is a fraction obtained from petroleum distillation, either as a distillate or a residue. Broadly speaking, fuel oil is any liquid petroleum product that is burned in a furnace or boiler for the generation of heat or used in an engine for the generation of power, except oils having a flash point of approximately 40 ℃ (104 ℉) and oils burned in cotton or wool-wick burners. In this sense, diesel is a type of fuel oil. Fuel oil is made of long hydrocarbon chains, particularly alkanes, cycloalkanes and aromatics. The term fuel oil is also used in a stricter sense to refer only to the heaviest commercial fuel that can be obtained from crude oil, heavier than gasoline and naphtha. |
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Soil is the naturally occurring, unconsolidated or loose covering on the Earth's surface. Soil is made up of broken rock particles that have been altered by chemical and environmental conditions, affected by processes such as weathering and erosion. Soil is different from its parent rock(s) source(s), altered by interactions between the lithosphere, hydrosphere, atmosphere, and the biosphere.[1] It is a mixture of mineral and organic constituents that are in solid, gaseous and aqueous states.[2][3] Soil particles pack loosely, forming a soil structure filled with pore spaces. These pores contain sol solution (liquid) and air (gas).[4] Accordingly, soils are often treated as a three state system.[5] Most soils have a density between 1 and 2, and weigh between 60 and 120 pounds per cubic foot. [6] Soil is also known as earth: it is the substance from which our planet takes its name. |
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Erosion is the carrying away or displacement of solids (sediment, soil, rock and other particles) usually by the agents of currents such as, wind, water, or ice by downward or down-slope movement in response to gravity or by living organisms (in the case of bioerosion). |
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| A soil horizon is a specific layer in the soil which measures parallel to the soil surface and possesses physical characteristics which differ from the layers above and beneath. Horizon formation is a function of a range of geological, chemical, and biological processes and occurs over long time periods. Soils vary in the degree to which horizons are expressed. Relatively new deposits of soil parent material, such as alluvium, sand dunes, or volcanic ash, may have no horizon formation, or only the distinct layers of deposition. As age increases, horizons generally are more easily observed. The exception occurs in some older soils, with few horizons expressed in deeply weathered soils, such as the oxisols in tropical areas with high annual precipitation. |
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Subsoil (also called substrata) is the layer of soil under the topsoil on the surface of the ground. The subsoil may include substances such as clay and has only been partially broken down by air, sunlight, water etc., to produce true soil. Below the subsoil is the substratum, which can be residual bedrock, sediments, or aeolian deposits, largely unaffected by soil-forming factors active in the subsoil. It contains partially weathered particles. |
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| Topsoil is the upper, outermost layer of soil, usually the top 2 to 8 inches. It has the highest concentration of organic matter and microorganisms and is where most of the Earth's biological soil activity occurs. Plants generally concentrate their roots in and obtain most of their nutrients from this layer. The actual depth of the topsoil layer can be measured as the depth from the surface to the first densely packed soil layer known as subsoil. |
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Weathering is the decomposition of earth rocks, soils and their minerals through direct contact with the planet's atmosphere[1]. Weathering occurs in situ, or "with no movement", and thus should not to be confused with erosion, which involves the movement of rocks and minerals by agents such as water, ice, wind, and gravity. |
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| An aquifer is an underground layer of water-bearing permeable rock or unconsolidated materials (gravel, sand, silt, or clay) from which groundwater can be usefully extracted using a water well. The study of water flow in aquifers and the characterization of aquifers is called hydrogeology. Related terms include: an aquitard, which is an impermeable layer along an aquifer, and an aquiclude (or aquifuge), which is a solid, impermeable area beneath an aquifer. The surface of saturated material in an aquifer is known as the water table. |
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artesian formation [image] |
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evapotranspiration [image] |
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Definition
| Evapotranspiration (ET) is a term used to describe the sum of evaporation and plant transpiration from the earth's land surface to atmosphere. Evaporation accounts for the movement of water to the air from sources such as the soil, canopy interception, and waterbodies. Transpiration accounts for the movement of water within a plant and the subsequent loss of water as vapor through stomata in its leaves. Evapotranspiration is an important part of the water cycle. An element (such as a tree) that contributes to evapotranspiration can be called an evapotranspirator.[1] |
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| A hot spring that intermittently erupts a spray of steam and hot water. Caused by the heating of ground water within a confined opening in hot rock. |
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the water on or surrounding the surface of the globe, including the water of the oceans and the water in the atmosphere. |
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| not permeable; impassable. |
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| the property or state of being permeable. |
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| Geology, Engineering. the ratio, expressed as a percentage, of the volume of the pores or interstices of a substance, as a rock or rock stratum, to the total volume of the mass. |
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to charge again with electricity. |
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| something that remains above what is used or needed. |
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| the planar, underground surface beneath which earth materials, as soil or rock, are saturated with water. |
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| a scraped spot or area; the result of rubbing or abrading: abrasions on his leg caused by falling on the gravel. |
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| a fan-shaped alluvial deposit formed by a stream where its velocity is abruptly decreased, as at the mouth of a ravine or at the foot of a mountain. |
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the lowest level to which running water can erode the land. |
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| the sand, gravel, boulders, or other debris transported by rolling or sliding along the bottom of a stream. |
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| An engine powered hand-held power tool and engine lubrication method is provided, the power tool being intended to be carried by an operator during use. |
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| a nearly flat plain of alluvial deposit between diverging branches of the mouth of a river, often, though not necessarily, triangular: the Nile delta. |
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| to relieve of a charge or load; unload: to discharge a ship. |
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| to separate into parts, groups, sections, etc. |
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| the ridge or crest line dividing two drainage areas; water parting; divide. |
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Definition
| a sudden and destructive rush of water down a narrow gully or over a sloping surface, caused by heavy rainfall. |
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Definition
| a nearly flat plain along the course of a stream or river that is naturally subject to flooding. |
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| a small valley or ravine originally worn away by running water and serving as a drainageway after prolonged heavy rains. |
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Definition
| Headward erosion is a fluvial process of erosion that lengthens a stream, a valley or a gully at its head and also enlarges its drainage basin. The stream erodes away at the rock and soil at its headwaters in the opposite direction that it flows. Once a stream has begun to cut back, the erosion is sped up by the steep gradient the water is flowing down. As water erodes a path from its headwaters to its mouth at a standing body of water, it tries to cut an ever-shallower path. This leads to increased erosion at the steepest parts, which is headward erosion. If headward erosion continues long enough, it can cause a stream to break through into a neighboring watershed and capture drainage that previously flowed to another stream. |
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Definition
| A levee, levée, dike (or dyke), embankment, floodbank or stopbank is a natural or artificial slope or wall to prevent flooding of the land behind it. It is usually earthen and often parallel to the course of a river or the coast.[ |
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| A meander in general is a bend in a sinuous watercourse, also known as an oxbow loop, or simply an oxbow. A meander is formed when the moving water in a river erodes the outer banks and widens its valley creating a meander. A stream of any volume may assume a meandering course, alternatively eroding sediments from the outside of a bend and depositing them on the inside. The result is a snaking pattern as the stream meanders back and forth across its down-valley axis. When a meander gets cut off from the main stream, an oxbow lake is formed. Over time meanders migrate downstream, sometimes in such a short time as to create civil engineering problems for local municipalities attempting to maintain stable roads and bridges. |
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| An oxbow lake is a U-shaped lake water body formed when a wide meander from the mainstem of a river is cut off to create a lake. This landform is called an oxbow lake for the distinctive curved shape that results from this process. In Australia, an oxbow lake is called a billabong. By itself, the word oxbow can also mean a U-shaped bend in a river or stream, whether or not it is cut off from the mainstream.[ |
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| A pothole (sometimes called kettle and known in parts of the Western United States as a chuckhole) is a type of disruption in the surface of a roadway where a portion of the road material has broken away, leaving a hole. Most potholes are formed due to fatigue of the pavement surface. As fatigue cracks develop they typically interlock in a pattern known as "alligator cracking". The chunks of pavement between fatigue cracks are worked loose and may eventually be picked out of the surface by continued wheel loads, thus forming a pothole. The formation of potholes is exacerbated by cold temperatures, as water expands when it freezes and puts more stress on cracked pavement. Once a pothole forms, it grows through continued removal of broken chunks of pavement. If a pothole fills with water the growth may be accelerated, as the water 'washes away' loose particles of road surface as vehicles pass. In temperate climates, potholes tend to form most often during spring months when the subgrade is weak due to high moisture content. However, potholes are a frequent occurrence anywhere in the world, including in the tropics. |
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| In chemistry, a solution is a homogeneous mixture composed of two or more substances. In such a mixture, a solute is dissolved in another substance, known as a solvent. A common example is a solid, such as salt or sugar, dissolved in water, a liquid. Gases may dissolve in liquids, for example, carbon dioxide or oxygen in water. Liquids may dissolve in other liquids. Gases can combine with other gases to form mixtures, rather than solutions.[1] All solutions are characterized by interactions between the solvent phase and solute molecules or ions that result in a net decrease in free energy. Under such a definition, gases typically cannot function as solvents, since in the gas phase interactions between molecules are minimal due to the large distances between the molecules. This lack of interaction is the reason gases can expand freely and the presence of these interactions is the reason liquids do not expand. |
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| Stream capture, river capture, or stream piracy is a geomorphological phenomenon occurring when a stream or river drainage system or watershed is diverted from its own bed, and flows instead down the bed of a neighbouring stream. |
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| a mixture of two chemicals with the character that one does not rapidly settle out |
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| A water gap is an opening or notch which flowing water has carved through a mountain range. Water gaps often offer a practical route for roads and railroads to cross a mountain ridge |
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