Hydrologic Cycle and Floods Theory

Sunday, January 23, 2011

Hydrologic Cycle and Floods Theory

Hydrologic cycle water circulation, which never stops from the atmosphere to the Earth and back into the atmosphere by condensation, precipitation, evaporation and transpiration.

The hydrologic cycle is a phenomenon that occurs primarily in the atmosphere and is managed by the heat from the Sun, which evaporates water from the oceans and land surface. A pair of water rises in the atmosphere, then go with the flow of air. On the road with airflow, some condensation of water vapour is then experience rainfall or snow and get back into the ocean or land.

Precipitation that falls to the ground to flow into the river, soak into the soil, or evaporates back into the air to move back in cycles. Most of the water in the soil are absorbed by plants, and then return the water to the atmosphere through the leaves with the transpiration process. Snow can remain in soil for a season or two and may take longer to melt and flow of water leaving the snow.


The Ocean by solar water heating is the key process in the hydrological cycle can be run continuously. Water will evaporate, then they fall in the form of precipitation in the form of rain, snow, hail, sleet and snow (hail), light rain or fog.


Hydrology Cycle



On the way to land some rainfall can evaporate back up or down, which is then intercepted the plant before it reaches the Earth. After reaching the Earth's hydrologic cycle continues to move continuously in three different ways:

  • Evaporation/transpiration of water from the sea, on land, in rivers, plants, etc. then evaporate into the air (atmosphere), and a cloud. In a saturated water vapour state (cloud) will go to the spots, which in turn decreases the water (precipitation) as rain, snow and ice.
  • Infiltration / percolation into the soil - water moves into the soil through cracks and pores of soil and rock into groundwater. Water can move due to capillary action or water can move vertically or horizontally below the soil surface until the water re-entering the surface water system.
  • Surface Water - Water moving across the ground surface close to main stream and lake; more sloping land and fewer and fewer of the pores of the soil, the greater the surface flow. The flow of the soil surface can be seen usually in urban areas. The rivers join each other and form a major river that carries all the water surface around the watershed to the sea.

Surface waters, either flowing or stagnation (Lakes, reservoirs, wetlands) and partly under the water surface will be collected and thread forming rivers and ended in the sea. Process water traveling inland in the hydrological cycle components that make up the watershed system (DAS). The amount of water on Earth as a whole is relatively fixed, change the shape and location.

As can be seen from the picture and a brief explanation of the hydrologic cycle over, catch basin precipitation is the output of the joint action of all these processes. Runoff appears on a very complex system after crossing through several stages of rainfall storage and transfer. increase the complexity of this with regional diversity of vegetation, geological formations, soil conditions and in addition also the time diversity-diversity climate factors.


Precipitation in all its forms (snow, hail, rain, etc.), fell into the vegetation, bare rock, surface soil, surface water and river channel (channel deposition). Water that falls on vegetation can be stopped (which later berevaporasi and / or achieve the same ground with drip and stem flow) during the time of or immediately fell on the ground (water penetration through the fall =) especially in terms of rainfall with high intensity and length. berevaporasi during the trip from the atmosphere and partly on the ground Most precipitation. Most of the wet rainfall infiltration into the soil surface and move down as percolation into the zone (zone) below the ground saturated. This water slowly moves through the aquifer into the river channel. Some of the moving water seeping into the bottom of the river without reaching the soil as subsurface flow. Infiltration of water also gives life to vegetation soil moisture. Some of the moisture captured by vegetation and leaf transpiration lasted from stomata.

After the first deposition of wet and infiltrate into the soil surface, a thin membrane formed on the surface of water called the detention of surface soil (water layer). Furthermore, the detention of the surface becomes thicker (deeper) and the flow of water began in the form of laminar. With increasing flow velocity, water flow becomes turbulent (rapids). Water flow is called runoff. During the journey toward the bottom of the river, part of the surface flow is stored on the surface of depression and depression is called backup. Finally, the flow reaches the surface of the river channel and river discharge increases.

The flow of the river evaporate directly into the atmosphere or flowing back into the sea . Then, this water appear on the surface of the earth as rain. As can be seen from the picture and a brief explanation of the hydrologic cycle over, catch basin precipitation is the output of the joint action of all these processes. Runoff appears on a very complex system after crossing through several stages of rainfall storage and transfer. increase the complexity of this with regional diversity of vegetation, geological formations, soil conditions and in addition also the time diversity of climate factors.

Hydrologic cycle disorder caused by floods and drought because rain water tincture in ground water surface should be .The burden that must be accepted or downstream river channel becomes larger. The disorder can be viewed on the characteristics of river flow fluctuations that have a large enough.


During the rainy season the river water discharge is very large even too large, but the level of dry season river water flow is very small even completely dry. Ideally fluctuations in river flow is not too big or nearly uniform. Flow of water in the River during the dry season comes from the water in the soil, which came out of the spring. " the greatest contribution in dry river flow season in fact since the spring. Flooding allegedly caused by falls or river channel capacity due to sedimentation processes, waste disposal or structures that impede water flow.


Floods that occurred in the rainy season, because most of the rainwater that falls to the ground running as a "water larian" is wasted into the sea. The advantages that cause a decrease in water soak into the ground which means that the water stored in the soil will also decrease. Although the water savings that contribute to water flow in springs and rivers in the dry season.


Floods and droughts which frequently occur almost every year, especially in Central Java, has demonstrated the existence of environmental damage on a large scale. Flood and oysters along with the pollution in some parts of the river is a picture of the water crisis that is being and will be facing in the future. Efforts to overcome the problem of flooding and drought are increasing the amount of water infiltration into the ground, among others, could do with a forest preserve and inhibit the rate of "surface water" through absorption wells.


Before entering the channel , Rain will be run into recharge well in order to the opportunity for water to seep into the soil increase.

According to the hydrological cycle, water content in the earth is still and continues to travel the earth in the form of cycles. Although the hydrologic cycle continues, but the circulation of this water is not evenly distributed (influenced by time). Floods caused by the interruption of water circulation in the form of excessive water circulation. If there are more circulation (floods), it must be held flood control efforts to reduce their impact on society. Hydrological analysis of flood problem is one method that is widely used in analyzing the flood. Hydrological analysis methods used are: comparison discharge hydrographs, flood search, rational methods, empirical methods, statistical methods, and mathematical models.

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