当前位置 :| Home>Water and culture>

System of of all kinds water

来源: 作者:Stand originally 时间:2009-01-04 Tag: 点击:

The water that flows in the earth's surface forms brook and river, collect ocean finally. Whole this one course makes shed a route, the character of current differs along with what shed a route and change.

Upper reaches sorts source that is in a river. Rainwater ooze forms groundwater into earth, the blame that groundwater collects in claypan and so on appears water layer over. When this cultivate land enters the water to pour out of the earth's surface from a sloping field, spring spew and piece, form a brooklet. As new rainwater and the affiliation of around spring, the water quantity of brooklet increases, make the stream with larger flow. Be in lime cliff area, water is easy infiltration underground, because this appears,bigger spring perhaps happens answer shed a phenomenon. These large springs or answer flow, it is subterranean river sheds the phenomenon that stems from the earth's surface suddenly actually.

Be in a mountainous area, the hillside makes brook is become can move the driving race of clastic rock. Race gives the gorge of cliff type in the quarter corrode in rock gradually. Go to again lower part, current is erosive a V form valley. Reduce to Campagna from country as riverbed, v form valley gradually spreading.

In race reach, vegetation is exiguous, because powerful current makes,the plant cannot grow in cross-strait take root. This also is why over there outside dividing trout and salmon, have piscine reason rarely.

Brook and race collect a river. When the river enters Campagna, velocity of flow begins to decelerate. The whole range of a river and its affluent forms a drainage area. The area of catchment can differ very big. Area of region of river of accept of a place of strategic importance is 79000 square kilometre, the Zaire river of continent of and rather than (call Congo river before) drainage area amounts to 3800000 square kilometre.

The likelihood drifting a route of a river is very bumpy. For example, the river may flow via a few grand chute. Fluvial affluent introduces different water amount, can change the discharge of trunk stream consequently, and after heavy rain passes or the likelihood when a mountainous area snows melts causes the flood. When sending the flood, the river has overflowed it at ordinary times riverbed, invade the flush Campagna all round.

In burning hot or dry season, moisture evaporates, the water quantity of supply river decreases, consequently fall after a rise goes to the river of its common, lower even riverbed. At this moment water level is called the lowest water level.

When the river sheds coastal waters ocean, because the ground becomes flatter, fluvial velocity of flow slows, surface spreading, and often form meander. Because velocity of flow slows, the silt happening that fluvial place carries is deposit, form alluvium. Vegetation grows in great quantities, especially the two sides of edge river, vegetation is more dense.

最新评论共有 0 位网友发表了评论
用户名: 密码: