Water erosion and the terrain:
Water erosion of conduct:
1. Impact (impcut)
On steep slopes to turbulence, flow strong, born of kinetic energy will have an impact force, the riverbed at the bottom or at the side of soft rock song, or more cracks in the rock bedding face, joints and so on, due to the impact of the role of fragments formed by flowing water Jiang forward to taking the lower reaches of the accumulation. This effect occurred in the upper reaches of the river.
II. Abrasion role (corrasion)
Taking gravel or rock flow times, and as a tool for its abrasion bed rock foundation, the occurrence of erosion is the most effective and most powerful way of erosion. Gravel friction between themselves or with the bed grinding collision, resulting in sharp particles Polyhedrosis Gradient into a round gravel, handling the longer distance, the more increase in its roundness. Therefore, removal of gravel rivers are mostly gravel round.
III. Excavation role, (gurrying)
Taking water into the gravel or stones in the riverbed rock fissure terrified and immediately out collisions friction growing fissures and finally collapse of the role of the phenomenon known as the excavation.
IV. Dissolution (solution)
River dissolution of soluble minerals, so that the riverbed was corrosion and damage, such a role in the region and other soluble limestone rock by the river area into a more common, more along the rock joints and other surfaces generated.
Water erosion and the development of the valley:
Usually the terrain of a river valley development by the following three types of erosion affected by:
1. To enhance the role of (deeping)
General of the upper reaches of the river bed or a tributary of the nascent, fast-flowing steep slope, under the power cut, so that the riverbed erosion down low phenomenon, known as the role under the cut (downcutting), making the valley into a V-shaped multi-terrain.
II. Broadbanding role (widening)
Due to increased traffic flow of river water erosion will occur side (lateral erosion). Water side corrosion can widen the two sides back, it is also called the lateral erosion "broad role"
III. Lengthened role (valley lengthning)
In the development of the upper reaches of the river, a tributary of the new collection of the most significant, it is very likely the first rock and steep valley, rock collapse of earth and rock slide, with the result that the source of upward stretching the length of the upper reaches of the increase, it referred to as "extended role." This phenomenon is known as to the source of erosion (headward erosion), referred to as the "source of corrosion."
River erosion terrain
Day-to-day most likely to see the erosion of the terrain are the following:
1. Rapids and waterfalls (rapids or waterfalls)
Riverbed profile radical dumping, rugged, or the strength of different rock resist force, Kennedy protruding rocks obstructing cross the river, or down the steep cliff, a large gap between upper and lower can be into the rapids or waterfalls, such as between China's Shaanxi Yellow River , there are rapids and Hukou Waterfall Longmen. Qara mud between the United States and Canada Falls, drop up to 60 meters, hydraulic highly.
2. Tam Hang or pothole (potholes)
In falls below water are under the influence of gravel, hit the bottom, resulting in low-lying point, stagnant water into the lake, known as "Tan pit", body of water that often swirl, gravel with water rotation, percussive Wall, in the lake surface generate Wall groove will enable the expansion of Lake pit. Great Falls under the water before the formation of a deep circular pit teams, known as "diving pool." Northern Taiwan, the upper reaches of the Keelung River Valley pothole terrain is developed.
III. Meandering stream (meander)
Water is fluid, even when flows are resistance, then to the lateral flow away from the phenomenon. When towards the right bank of the river, the wharf by water erosion, thus gradually become a concave bank; the other hand on the left bank of the relative velocity due to slow momentum reduction is Health deposition was into convex shore. Bump synthesis of cross-strait Riverbend back songs like Snake rivers, is to "meandering", also known as the "Snake River."
Meandering stream will be formed during the development of all-terrain following:
(1) etching meandering stream (incised mannder)
The upper reaches of mountains and rivers staggered back to peak to valley, the river bypass become a meandering stream,flow due to acute and severe water cut etching, so that deep valley, on both sides of the steep such as V-shaped, then the river known as the "moment meandering stream erosion. "
(2) freedom of meandering stream (free mannder)
Once the river into the plain, the river bed gradient to reduce the water slowly, to both sides of the swing, both sides of the well-the result of erosion, widening the valley (more than deepen the Valley), was wide into the bottom level, flow into S-shaped "free meandering stream."
(3) cutting slope (undercut slope)
Qu stream erosion by flowing backward concave bank, high and steep river bank, known as the "cut slope," because the rock base of the very significant erosion, it is also called the "eclipse-based slope."
(4) slippery slope away (slip-off slope)
The prevalence of the opposite concave bank deposits, low-shore spread gently flowing water, coastal, referred to as the "slippery slope away."
(5) meandering stream neck (meander neck)
If the radius of meandering stream gradually expanded so that resettlement outside the meandering stream, the meandering stream into a meandering stream and between the ground has been gradually reduced by the fact that the narrow watershed said, "meandering stream neck."
(6) oxbow lake (oxbow lake)
As the meandering stream on a narrow neck, if it was pierced, the bends of the river cut through the meandering stream shortcut (neck cutoff), trip into the new river channel, was to abandon the old Road, the meandering stream water into a lake, called the "oxbow Lake ", also known as the Horseshoe Lake (horseshoe-shaped lake), meandering stream meandering stream that marks relics (mander scerrs).
IV river (river terrace)
Rivers above the river, up and down like a row, such as band-like platform, known as the "river." The formation of river bluffs of the following factors:
(1.) Sudden increase in river flow
(2.) Sand content dropped
(3.) Site uplift
(4.) Reduce erosion datum
The impact of the factors mentioned above is to cut down water erosion force from weak to strong, and erosion of the resurrection, so that the original alluvial plain rivers will no longer be cut, a part of being corroded to produce V-shaped valley, the two sides of the left part of the plains to become a high tableland of the river; similar situations such as intermittent times, while the formation of ladder-shaped platform, said Riverside platform that river. Depending on the nature of river can be divided into river
(1.) River bed rock (bedrock terrace)
Water into the bedrock, deep valley to make the bed rock surface formed by the Ministry of valley mesa (starth terrace) that the river bed rock. Although inter-impermeable rock, but also weathered, anti-hard lasting.
(2.) Alluvial river (alluvial terrace)
Rivers in the alluvial or flood plain re-cut after the two sides over the river erosion will be higher than the alluvial river into a band-like, named. Alluvial river bluffs, the hard rock, if the emergence of resistance to water erosion forward, so that the protection of river (protected terrace).
V. river capture
Pro-phase difference between two rivers due to erosion, low water level in the river to the high water level upstream of the river, or to grab some water phenomenon has been called the "river capture."
(A), the causes of river capture
1) rock resist the strength of different forces
In rainfall or less the same climatic conditions, such as rivers, as more soft rock, poor corrosion resistance is lower places valley, well the source of corrosion and corrosion-side result of the watershed has been pierced, penetrated the high-water level of the B River, then B River became a tributary of the river or on the new source, so a river called the river capture. B upper reaches of the river called the River B looted River attack cut away to become the first river.
2) slope and rainfall due to the different
In the watershed on both sides, different slope, climate also vary, and run counter to the flow of two rivers, such as a river slope more rainfall, and its erosion, relatively strong compared to the source of erosion will speed, such as river slope smaller B , traffic little less erosion, river erosion of a more moderate upward source. Two Rivers watershed is therefore a must for crossing the river by the invasive B River, so that B A River water into the river. B River became a tributary of the river. Such as Northeast China Nenjiang was the upper reaches of the Liaohe, Songhua river erosion as a result of strong Nenjiang speed was seized for a tributary of the East China, Nenjiang became the Liaohe River divert become truncated River.
(B), river capture terrain
1) capture bending
Attack away down the river in the transition to capture injected into a river by bending branches, namely the so-called capture bends, such as the Jinsha River in Yunnan Province near the east of Shek Kwu Department is of folding.
2) river bluffs and canyon
Capture river flow due to the sudden increase, erosion enhanced, re-cut, have a river valley along the river or canyon.
The role of water removal
The river water flow along the river bed slope, the velocity and flow will produce kinetic energy, can be from water erosion of soil, gravel and handling, this erosion of the river to carry the material to the role of its role as the removal. These substances known as the river load, carrying the weight of the material because of transportation and the removal force size, have the following three ways
I suspended the role of
Fine mud lighter can be suspended in the water, drift down for transportation, these substances known as the "suspended load."
II jumps role
Larger because of the weight of sand and gravel, and by boosting the water a short distance ahead jump phenomenon.
III rolling or shifting the role of
Sand or gravel by flowing water forces, rolling along the river bed or pan phenomenon. This removal of material called bed load 』. And some substances dissolved in the water with the water and the next, known as the "dissolved load."
(1) etching meandering stream (incised mannder)
The upper reaches of mountains and rivers staggered back to peak to valley, the river bypass become a meandering stream,flow due to acute and severe water cut etching, so that deep valley, on both sides of the steep such as V-shaped, then the river known as the "moment meandering stream erosion. "
(2) freedom of meandering stream (free mannder)
Once the river into the plain, the river bed gradient to reduce the water slowly, to both sides of the swing, both sides of the well-the result of erosion, widening the valley (more than deepen the Valley), was wide into the bottom level, flow into S-shaped "free meandering stream."
(3) cutting slope (undercut slope)
Qu stream erosion by flowing backward concave bank, high and steep river bank, known as the "cut slope," because the rock base of the very significant erosion, it is also called the "eclipse-based slope."
(4) slippery slope away (slip-off slope)
The prevalence of the opposite concave bank deposits, low-shore spread gently flowing water, coastal, referred to as the "slippery slope away."
(5) meandering stream neck (meander neck)
If the radius of meandering stream gradually expanded so that resettlement outside the meandering stream, the meandering stream into a meandering stream and between the ground has been gradually reduced by the fact that the narrow watershed said, "meandering stream neck."
(6) oxbow lake (oxbow lake)
As the meandering stream on a narrow neck, if it was pierced, the bends of the river cut through the meandering stream shortcut (neck cutoff), trip into the new river channel, was to abandon the old Road, the meandering stream water into a lake, called the "oxbow Lake ", also known as the Horseshoe Lake (horseshoe-shaped lake), meandering stream meandering stream that marks relics (mander scerrs).
IV river (river terrace)
Rivers above the river, up and down like a row, such as band-like platform, known as the "river." The formation of river bluffs of the following factors:
(1.) Sudden increase in river flow
(2.) Sand content dropped
(3.) Site uplift
(4.) Reduce erosion datum
The impact of the factors mentioned above is to cut down water erosion force from weak to strong, and erosion of the resurrection, so that the original alluvial plain rivers will no longer be cut, a part of being corroded to produce V-shaped valley, the two sides of the left part of the plains to become a high tableland of the river; similar situations such as intermittent times, while the formation of ladder-shaped platform, said Riverside platform that river. Depending on the nature of river can be divided into river
(1.) River bed rock (bedrock terrace)
Water into the bedrock, deep valley to make the bed rock surface formed by the Ministry of valley mesa (starth terrace) that the river bed rock. Although inter-impermeable rock, but also weathered, anti-hard lasting.
(2.) Alluvial river (alluvial terrace)
Rivers in the alluvial or flood plain re-cut after the two sides over the river erosion will be higher than the alluvial river into a band-like, named. Alluvial river bluffs, the hard rock, if the emergence of resistance to water erosion forward, so that the protection of river (protected terrace).
V. river capture
Pro-phase difference between two rivers due to erosion, low water level in the river to the high water level upstream of the river, or to grab some water phenomenon has been called the "river capture."
(A), the causes of river capture
1) rock resist the strength of different forces
In rainfall or less the same climatic conditions, such as rivers, as more soft rock, poor corrosion resistance is lower places valley, well the source of corrosion and corrosion-side result of the watershed has been pierced, penetrated the high-water level of the B River, then B River became a tributary of the river or on the new source, so a river called the river capture. B upper reaches of the river called the River B looted River attack cut away to become the first river.
2) slope and rainfall due to the different
In the watershed on both sides, different slope, climate also vary, and run counter to the flow of two rivers, such as a river slope more rainfall, and its erosion, relatively strong compared to the source of erosion will speed, such as river slope smaller B , traffic little less erosion, river erosion of a more moderate upward source. Two Rivers watershed is therefore a must for crossing the river by the invasive B River, so that B A River water into the river. B River became a tributary of the river. Such as Northeast China Nenjiang was the upper reaches of the Liaohe, Songhua river erosion as a result of strong Nenjiang speed was seized for a tributary of the East China, Nenjiang became the Liaohe River divert become truncated River.
(B), river capture terrain
1) capture bending
Attack away down the river in the transition to capture injected into a river by bending branches, namely the so-called capture bends, such as the Jinsha River in Yunnan Province near the east of Shek Kwu Department is of folding.
2) river bluffs and canyon
Capture river flow due to the sudden increase, erosion enhanced, re-cut, have a river valley along the river or canyon.
The role of water removal
The river water flow along the river bed slope, the velocity and flow will produce kinetic energy, can be from water erosion of soil, gravel and handling, this erosion of the river to carry the material to the role of its role as the removal. These substances known as the river load, carrying the weight of the material because of transportation and the removal force size, have the following three ways
I suspended the role of
Fine mud lighter can be suspended in the water, drift down for transportation, these substances known as the "suspended load."
II jumps role
Larger because of the weight of sand and gravel, and by boosting the water a short distance ahead jump phenomenon.
III rolling or shifting the role of
Sand or gravel by flowing water forces, rolling along the river bed or pan phenomenon. This removal of material called bed load 』. And some substances dissolved in the water with the water and the next, known as the "dissolved load."
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