What rivers are the most frequent floods. Causes of floods? What are flooding
Humanity is familiar with the floods since ancient times. We had information about the catastrophic spills on (in 2297 BC) and on the Nile River (about 3000 years ago). Previously, these natural disasters happened quite rarely, but in the last centuries their frequency and sizes of damage caused rapidly increased. If you take the period to our era, the most dangerous floods, the reasons for which will be considered below, have happened about once every 50 years (for example, in China). Now such disasters occur several times a year. In the most "yield" time, these catastrophes occur with periodicity of 2-3 days, which immediately reports to us the media. Therefore, therefore, the topic "Flood" is relevant for many people. And interest in it is constantly growing.
Water problems
It is well known that development human society Depends on the quality of many political figures and specialists are confident that the problem of water is in the first place in the list of common tasks of the last decades. "Water issues" may arise in four cases: in the absence of or insufficient quantity of livic moisture, with a mismatch of water facilities in the optimal work of ecosystems, in the mode of filing that does not meet the economic and social requirements of the population, and in excess of moisture on the oblivion of the territories suffering from For this from flooding. On a global scale, the first three problems were generated by the past century, and the fourth pursues humanity from ancient times. And although people understood what a flood was, and they were making measures to protect against him, they could not succeed in this. And with each age, the damage from this disaster continues to increase. Only for the second half of the twentieth century, damage has increased 10 times.
History
You can find out the alleged date of flooding using a hydrological forecast. It is a study directed by scientific justification The scale and nature of this catastrophe. Forecasts are divided into ultra-strength (more than 1 block), long-term (up to 3 weeks), short-term (10-12 days), territorial and local. The consequences and extent of flooding depend on their duration, the nature of the soil, the season, the terrain, the speed of the flow, the height of the water lift and other factors. Everyone heard the legend of the World Flood. Many researchers who know what a flood is believed that the traditions of the Flood are based on the catastrophe occurrence in different parts of the Earth. Ethnographers, historians, geographers and archaeologists found that in the 3rd and 4th millennium BC, these natural disasters took place in Mesopotamia. Caught areas in the Valley of Euphrates and Tiger seemed to people with a whole world. Therefore, ambitious floods with a large number of victims were associated with worldwide flood. Now archaeologists, historians and other specialists have done great work on the study of legends about the Great Flood. Based on the list of these legends, large floods occurred in almost all parts of the Earth. And this list is very impressive. It includes the legends about the flood on all continents of the planet.
The largest floods
With the growth of the population, the destruction of forests and other harmful for nature with the types of human activity, the floods began to occur much more often. At the beginning of the article, we mentioned two catastrophic floods. Now we will tell more about several.
1. Flood in Europe. Covered the territory of Germany, Great Britain and the Netherlands in 1953. With a strong storm wind, the north coast covered huge waves. This caused a sharp rise of water (3-4 meters) in the estuary of Shelda, Maas, Rhine and other rivers. More remaining countries suffered from the Netherlands. 8% of the territory was flooded. About 2000 people died.
2. Flooding in Delta Ganges. Happened in 1970. The 10th meter wave covered the sacred river and turned the course to reverse. It was flooded about 20,000 square meters. km. Hundreds of villages and dozens of cities destroyed. About 1.5 million people died. Since the flood has destroyed almost all wells, a sharp deficit was formed drinking water. Hundreds of thousands of people died from hunger and broken epidemics of typhoids and cholera.
3. Amur flood. Happened in the territory of the Russian Federation in July 2013. Common damage exceeded 3 billion rubles. Destroyed 29 bridges. Blurred almost 300 kilometers of roads. Agriculture suffered greatly. In the zone of flooding there was more than ten settlements.
Causes and types of floods
For a deeper understanding of the topic, we will give the definition of this natural disaster. After all, not everyone knows what flood is. Let's fix this omission. The simplest definition is flooding with water of essential land. Now list the reasons for this disaster.
The reasons
1. Melting of snow.
2. Waves tsunami.
3. Long rains.
4. Anthropogenic causes.
There are direct causes associated with the destruction of the dams and conducting hydrotechnical measures, and indirect - housing and industrial development, the drainage of the marshes, the formation of forests. All this changes the hydrological at the expense of the surface component of the drain. The combination of all forests will increase the maximum stock to 300%.
Now consider the main types of floods. We are confident that this topic will be very interesting to our readers.
Views
1. Forewide. It occurs with the spring melting of snow on the plains or in the mountains. It has seasonal periodicity. It is characterized by a significant rise in water level.
2. Flood. It occurs during the winter thaws due to the melting of snow or intense rains. It does not have clearly pronounced periodicity. It is characterized by a rather short-term and intense water level rise.
3. burnt and storage floods. It occur when the river bed creates a water flow resistance in separate zones. It arises due to the cluster of the ice floes in the narrowings of the bed during the ice drift (congestion) or the ice station (litters). The sparkling flood of the river is formed at the beginning of spring or at the end of winter. It has a relatively short-term high rise water level. Burnt flood occurs at the beginning of winter. It is characterized by a significant rise in the water level and a significant duration of disaster.
4. Nursing floods. Arise as a result of water in the mouths of rivers, as well as on rather windy areas of reservoirs, large lakes and the sea coast. May happen at any time of the year. Do not have frequency. The rise of the water level is significant.
5. Flooding as a result of a breakthrough of dams. With a distress, water is spilled out of a reservoir or reservoir due to a breakthrough of pressure (dams, dams, etc.) or emergency reset of water. Another reason is the natural breakthrough of dams due to natural factors.). During the disaster, a breakthrough wave is formed, flooding huge territories and damaging or destroying objects (structures, buildings, etc.), found on the way of its movement.
So, we found out the causes and types of floods, but it is not similar that these natural catastrophes are also divided into classes. The main principles of separation of these disasters is the period of repeatability and the scale of distribution.
Flood classes
1. Low. As a rule, a minor damage is applied. Enclose coastal areas of small size. Agricultural land is flooded with less than 10%. Almost do not knock the population from the current rhythm of life. Repeatability - 5-10 years.
2. High. Apply significant and material). Enclose large areas of river valleys. Complete about 10-15% of land. Violate both household and economic flow of the population. Partial evacuation of people is very likely. Periodicity - 20-25 years.
3. Outstanding. Cause a large material damage, covering river pools. Approximately 50-70% of the farmland, as well as a certain part of the settlements, is under water. Outstanding floods not only violate household lines, but also paralyzed economic activities. The evacuation of material values \u200b\u200band the population from the disaster zone and the protection of the main objects of economic significance are necessary. Repeatability - 50-100 years.
4. Catastrophic. They cause a huge material damage, extending to huge territories within one or more river systems. Lead to human victims. More than 70% of land are flooded, many settlements, engineering communications and industrial enterprises. The production and economic activity is fully paralyzed, and the household population changes. Periodicity - 100-200 years.
The effects of floods
The main features of the situation arising from such natural disasters are: the rapid increase in the strength of the striking factors, the complexity of access to the victim, the destructive nature of the situation, small figures for the survival of the victims, as well as the presence of complex weather conditions (villages, ice driving, pouring rains, etc.).
Characteristics of water flow as an affecting factor
1. The greatest water level.
2. The greatest water consumption.
3. The flow rate.
4. Square flooding.
5. The repeatability of the greatest water level.
6. Duration of flooding.
7. Water temperature.
8. Security of the greatest water level.
9. The start time of disaster.
10. Water level rise rate for all time floods.
11. Depth of flooding of the territory in the area under consideration.
Characteristics of the consequences
1. The population is in the disaster zone (victims affected by, etc.).
2. Number of objects of sectors of the economy affected by the natural element.
3. The number of settlements in the disaster area.
4. The length of the roads (iron and automotive), communication lines and power transmission in the flood zone.
5. Number of tunnels, bridges and residential buildings, damaged, destroyed and flooded as a result of disaster.
6. The number of dead animals involved earlier in agricultural industry.
7. The area of \u200b\u200bagricultural covered by the disaster and others.
Rescue work
The main goal of emergency rescue work is to find and rescue people who are in the flood zone. It is necessary to help them as soon as possible and ensure their survival in the current situation. Success during rescue work is achieved next to action.
1. Conducting advanced and systematic training of commanders, soldiers of civil defense units who know exactly what is flooding, as well as members of search and rescue services to rescue work.
2. A rapid response to the disaster that has arisen, bringing to the willingness and provision of the necessary forces and funds.
3. Organization of operational exploration and deployment of the management system.
4. Application of effective technologies for finding affected and their salvation, as well as ways to protect economic facilities and the population.
What include urgent emergency work?
1. The construction of enclosing shafts and dams.
2. Erecting drainage channels.
3. Equipment of berths for special vehicles.
4. Elimination of burdens and congestion.
5. Recovery of power supply.
6. Restoration and protection of road structures.
7. Localization of foci of secondary lesion factors.
Intelligence Objectives
1. Determination of flooding area.
2. Management of disaster development dynamics.
3. Detection of places where people and agricultural animals are located.
4. Detection of material values \u200b\u200bthat are subject to export of disaster.
5. Search and equipment equipment for landing of helicopters in the disaster area.
6. Search and selection of routes for evacuation of material values, people and animals with the help of plaels. If necessary, the equipment of berths.
Emergency and rescue work is carried out by the divisions of the army of civil defense, search and rescue services and enhanced crossing and intentional specials. To implement another urgent work, taking into account its nature, engineering and technical and road formations are appointed. When searching for victims in flooded territories, rescuers should use aviation equipment (helicopters and aircraft).
And last. Do not forget that the threat of flooding is always. Therefore, prepare in advance to meet this natural phenomenon.
The raging and destructive power of the water element is able to impose an irreparable damage to the environmental and economic industry of any state. One of the frequent, with which you have to deal with operational services is to increase the water level in local water bodies and its outlet of the coastline.
In such cases, they talk about floods, floods and floods. However, often these concepts are confused, or even at all identify them with each other. In this article, try to give precise definition These phenomena, tell me what is the difference between floods from flooding and flooding and how it follows himself, being in such a situation.
Basic concepts
Flooding, flooding, the flood is similar only in what can under certain circumstances lead to significant floods of sushi. However, the flood is a more general and widespread concept arising from a variety of reasons. Consider in more detail:
It is a short-term, but sharp rise of water in rivers and lakes. It is characteristic of his suddenness, and absolutely independent of the time of year
May arise several times a year. Causes are usually associated with external natural circumstances: long and abundant precipitation, sharp warming with rapid snowdown. Maximum duration - a few days.
Abundant types of floods, following each other or having a small temporary interval with each other, are able to lead to a flood.
This is an ordinary natural phenomenon that arises always at the same time, in the spring. It is repeated annually, and is characterized by a long and high rise in water level in water bodies. In most cases, water comes out of the river bed, but the flood can flow and without flooding of the coast area.
The level of the river during this phenomenon may rise 20-30 m. The decline can last up to 1 month. It is caused by an abundant flow of water in the reservoir due to rains, melting of glaciers and snow.
Floor types associated with excessive melting in the mountain area of \u200b\u200bsnow are characteristic of Caucasian terrain and rivers located in the Alps and Central Asia.
It is always a major natural disaster having significant sunshine floodings. Floods, and floods, and even the human factor, for example, a breakthrough can also lead to it.
Flooding carries not only the destruction of vital designs, flooding houses, but also the death of animals, harvest, causes considerable economic damage. Depending on the force of flooding, human sacrifices may be.
Floods and floods, as a rule, do not have such consequences. The term of restoration measures after flooding is quite long. Sometimes it may take several years.
Low or small
The most innocuous floods. They arise in rivers located on flat terrain. According to observations, repeated every 5-10 years. For the life of the population, there is no threat.
High or big
Characterized enough strong flooding affecting large areas of sushi. With this form, there may be a need for the evacuation of people from nearby houses. Material damage does not go beyond the average indicators, but quite notice. Often there is a destruction of fields, pastures. It rarely occur - once every 20-25 years.
Outstanding
Fixed 1 time in a century. They apply very big damage, since all agricultural activities are completely stopped. Residents of the entire settlement are evacuated to a safe place.
Catastrophic
Such floods are rarely cooled without human victims. The disaster zone covers the territory of several river systems. The human activity in the area underwent catastrophic flood is completely blocked. They are observed every 200 years.
The severity of the consequences depends on many factors: how long is the water on land, its height of the lift, the speed of the inclusive flow, the area of \u200b\u200bthe flooded territory and the density of the population.
A variety of reasons can be given to the flood. For terrain with warm soft climate A threatening factor can be protracted and strong rains, which are frequent phenomenon. On the ground, where the dry and cool climate prevails, the precipitation falls out less often, and the risk of flooding is minimal.
However, in the northern regions there is another danger - glaciers, mountain snow vertices and abundant snow cover. In cases of sharp warming or early spring, rapidly snowmage will arise, which will lead to a strong water lifting in plain rivers. A large flood can lead to a flood.
The accumulation of mineral deposits at the bottom of the river contributes to his raise. If you do not clean the bed in time, then disasters in the form of flooding, flood or flood can not be avoided.
The cause of the most catastrophic floods can be a tsunami that arise sharply and bear the terrible destruction and numerous sacrifices. They are gigantic waves that make a landing one by one by one by another, despicable everything in their path. Powerful waves on the sea can be formed due to hurricanes or strong winds. They are capable of spilling out on the coastline.
Breakthrough of the earth's crust and exit to the surface underground water Also is one of the possible causes of flooding. Sili and landslides lead to the spill of mountain rivers. They, coming out of the bed, with force and mud stream go down to the plain. This natural disaster entails serious consequences.
The human factor in the formation of flooding is improper operation or accident on hydrotechnical structures, which leads to their destruction and breakthrough of a large flow of water into settlements. Various man-made catastrophes are able to cause flooding of various scale.
In lowlands or terrain, which is within a particular river system constantly monitors water regime in local water bodies. If signs of the onset of a large flood or annual flood occurs, the public alert by special services occurs.
The main rules of behavior in flooding and floods are as follows:
- Move all valuable things and interior items on elevation (attic, 2nd floor)
- Release the attic from products. First of all, when flooding houses, water will go down.
- Everything important documents Package tight in waterproof material
- Strengthen window frames and doorways
- From the courtyard to put a building inventory or raise it above the level of land a few meters.
- Crops tightly close and remove on high shelves in the closet. A safe place to maintain food products will be a refrigerator.
- Think about domestic animals in advance. It is better to build a shelter for them higher from the ground.
- Fully de-energize the dwelling. Prepare candles, lanterns and essentials.
When an evacuation declaration, follow the instructions. Take a minimum of things and for home reception as soon as possible. Watch carefully for children and elderly and / or sick relatives.
If you did not have time to evacuate from the disaster zone, then climb the roof and serve signals. To do this, use a flashlight, phone screen. You can bind a bright tissue on some pin or stick.
You can return home only after the permission of the authorized bodies. Outside, be careful. Do not step on the torn or damaged wires, do not stand next to the strongly destroyed buildings or structures.
1. In which ocean is the Marian deep-water chute? 1) Indian 2) quiet 3) atlantic 4) Northern Icendite. 2.Kone from re
numerical seaside flows acting in the Pacific Ocean?
1) Gulf Stream 2) Brazilian 3) Guinean 4) Kurosio.
3. Casual, animal inhabiting in the natural zone:
1) steppes 2) Taiga 3) desert 4) tundra
4. However, from the main modern types of human activities in the tundra is:
1) Forest harvesting 2) mining of minerals 3) Cattle breeding 4) grain cultivation
5. The listed Flat Lake is:
1) Baikal 2) Victoria 3) Chad 4) Onega.
6. On which of the islands is the average annual precipitation as possible?
1) Iceland 2) Kalimantan 3) Madagascar 4) Tasmania.
7. What kind of minerals are confined to ancient platforms?
1) Oil 2) iron Rud. 3) copper ore 4) polymetallic ores
8.Who from the listed travelers made a great contribution to the opening and study of Africa?
1) I. Moskvitin 2) D. Cook 3) D. Livingston 4) F. Magellan
9. Moderate marine climate Characterized for:
1) Sumatra Islands 2) of the Pyrenean Peninsula 3) O.Velikobaznania 4) P-ov Yucatan
10. What out of the listed mountain systems is the longest?
1) Cordillera 2) Ural 3) Alps 4) Appalachi
11. What about the Peninsulas during the year there are monsoons?
1) Labrador 2) Alaska 3) Indochina 4) Somalia
12. For which of the listed natural zones is characterized by the greatest number of rodents?
1) Taiga 2) Tundra and Festry 3) steppe 4) semi-desert and desert
13. What of the listed rivers is a large number of thresholds?
1) Volga 2) Amazon 3) Congo 4) Mississippi
14. The sign of the sea type of climate is:
1) summer dry and hot 2) winter wet and warm 3) big amplitude temperature fluctuations
15. Oak, Mirt, Wild Masilli- Representatives of the Natural Zone:
1) Equatorial forests2) Trestle forests3) tropical deserts 4) wide forests
1) Cordillerakh 2) Andes 3) Himalayas 4) Alps.
17.And mainland is the hottest:
1) Africa 2) Australia 3) South America 4) North America
18.Kray South Point of Africa:
1) Cape needle 2) Cape of Good Hope 3) Cape Almadi 4) Cape Rasha Hafun.
19. Climate belt Africa with pronounced seasonality: dry in winter and wet summer:
1) Equatorial 2) subequatorial 3) tropical 4) subtropical.
20. The Salted Sea Sea refers to the pool:
1) Pacific Ocean 2) Atlantic Ocean 3) Pacific 4) Northern Ice
Part B.
1. Africa dispensellectric belts in order to reduce the river network thickness:
1) Equatorial 2) tropical 3) subequatorial.
2. Install the match.
Natural zone: Climate belt:
1. Wet forests a) subtropical
2. Savanna b) tropical
3. Desert c) subequatorial
d) Equatorial.
3. Distribute the southern continents as they increase their area:
1) Antarctica 2) Africa 3) South America 4) Australia.
Part S.
1. Why the highest point of Africa - Kilimanjaro volcano - is located within the platform, and not
folded area, like on other continents?
2. Are the glaciers in Africa, if so, then in which part of the mainland?
3. Why on platforms, as a rule, plains are located?
1) In which of the countries listed below most of the population professes Catholicism: Ukraine; Netherlands; Italy; Greece; Philippines;Indonesia; Sudan; Argentina?
Which of the following peoples belong to Indo-European languages: Chinese, Hinduscans, Russians, Japanese, 1. What of the listed states is Russia has a naval border? 1) Latvia 2) USA 3) Azerbaijan 4) Estonia 2. Extreme Northern Point of Russia Which of the listed rocks is by the origin of metamorphic1) pumice2) marble3) pebbles4) gypsum in wet equatorial forestsyug.Ameriki 1) There is a dry and wet season of the year 2) In the composition of vegetation, many Lianany ferns 3) are dominated by chestnut soils 4) Eucalyptus predominate in wood tier
in which of the listed countries the average population density of the highest1) Canada2) Japan3) Alger4) Brazil
in which of the listed GDP countries per capita is the highest1) Belgium2) Alger3) Morocco4) Argentina
from which of the listed countries Russia borders on the Amur River) Kyrgyzstan2) Mongolia3) Kazakhstan4) China
in which of the listed regions of Russia agroclimatic conditions are most favorable for cultivation of sugar beet and corn1) Republic of Komi2) Vologda region3) Tver region4) Voronezh region
which of the listed mineral types is mined in the Volga region1) Copper ore2) Iron Ore3) Oil4) Coal
in the supply of which of the listed types of products to the world market, Russia's share is especially large1) semiconductors2) Cars3) Marine ships4) Metal
| Origin and types of floods. Their consequences
Basics of life safety
7th grade
Lesson 16.
Origin and types of floods. Their consequences
From the history of floods
There were no four months from the day the founding of St. Petersburg, as the flood happened. On the night of August 30 to August 31, 1703, the water in the Neva rose more than 2 m and poured the camp of Russian troops. Food warehouses turned out to be flooded, part of the forest prepared for the construction of the Petropavlovsk fortress.
The head of the garrison A. I. Repnin came to Peter I: "The bearer, sovereign, we have cruel weather from the sea, and stuck in our place, where I stand with shelves, water already up to my state, night in the Preobrazhensky regiment at midnight Harchevniki many sleepy people and rhyled them poured ... "
Two years later, on the night of October 15-16, the same warehouses turned out to be flooded. Under the onslaught of fierce waves and hurricane wind, the walls of houses collapsed, the roofs fluttered, the trees pulled down with the root.
Flooding eyewitnesses, writer A. P. Bachzitsky wrote: "The Winter Palace, like a rock, standing among the stormy sea, kept on all sides of the onslaught of waves, with a roar of the striking walls and irrigated them with splashes almost to the top floor. On the Neva, the water boiled, as in the boiler, and with an incredible force, turned reversal the river back ... "
Flooding September 21, 1777. I wasted the city by the darkest autumn night. The cruel storm and the extremely fast water lift greatly aggravated the position. Due to the inorganization of the population and the unrealizancy of the authorities, the flood of 1777, despite his short-term, caused tremendous damage to the city. Many fences and fences were overturned, wearing wooden houses. The water washed off the Ostrog, who was on the seaside, together with 300 prisoners. Turned out to be destroyed fountains in Summer garden (Subsequently, they were never restored).
Catherine II in his diaries described the storm in that memorable night: "From that minute, all that, wheels, tiles, iron sheets, glasses, water, hail, snow ... on the waterfront, which is not yet completed, are piled up three thousand Merchant ships. The stock exchange changed the place ... My cellast is filled with water, and God knows that it will become with them. "
The flood of 1824 brought huge losses in the city. 208 people died (according to other data - 569 people). Neva remained restless until the middle of the winter of 1824/25, 324 houses were completely destroyed, 3257 different other structures were damaged (i.e. half of all had been). Of the 94 vessels standing in the harbor, they managed to save only 12. 3,600 livestock heads were drowned, 900 thousand poods of flour and a large number of other food were spoiled. For a long time, after this flooding in the city raged colds. Prices for food and firewood jumped sharply. For more than half a century, this flood was called "Flood".
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Origin and types of floods
Flooding is a significant flooding of water area adjacent to the river, lake, sea or a reservoir, which causes damage to the health of people or even leads to their death, and also causes material damage.
From 1900 to 2006, 2855 large floods occurred in the world. They died 7 million people.
Depending on the scale, repeatability and damage to flooding are divided into low, high, outstanding and disastrous.
Low (Small) Flood They occur mainly on plain rivers. At the same time, water floods low places (less than 10% of agricultural land). Such floods almost do not violate the rhythm of the life of the population and cause insignificant damage. They repeat once every 5-10 years.
High floods Significantly violated the well-established life of people, they cause significant material damage. In densely populated areas, the need for partial evacuation of the population often arises. Such floods occur once every 20-25 years.
Outstanding floods Covers whole river pools. They apply large material damage, flood settlements and cities. At the same time, there is a need for mass evacuation of people and material values. Take place once every 50-100 years.
Catastrophic floods Fully change the lifeline of the population and lead to huge material losses. More than 70% of agricultural land are flooded. Such floods occur no more than once every 150-200 years.
Floods occupy the world first place in the number of natural disasters created by them and the second-third place in the number of victims.
Let us turn to the history of our country. The Ipatiev chronicle recorded a terrible flood in the south of Russia in 1145, which was caused by abundant shoes ... Another chronicle (Troitskaya) said that in 1403, due to the heavy rains, the floods were celebrated from Pskov to Paris.
Depending on the causes of flooding, a few species are divided into several types.
The flood - flood caused by the spring melting of snow on the plains or melting of snow and glaciers in the mountains. Repeated annually in the same season with various intensity and duration, which depend on meteorological conditions. For the salons, a significant and long-term rise of water level is characteristic.
Floods - floods caused by rains and shoes or fast snow melting at winter thaws. It is characterized by an intense, but relatively short-term rise of water level. Unlike seating, floods happen at any time of the year.
Correct, burial floods (congestion, clouds) - floods caused by a large resistance to the water flow arising from the accumulation of ice material in narrowings or rays of the river during the ice-bearing (loss) or during the ice drift (congestion).
Cool floods Food at the end of winter or spring. They are characterized by a high and relatively short-term rise of the water level in the river.
Burnt floods Food at the beginning of winter. They are characterized by a significant, but smaller than when the water level rise and a large duration.
On medium rivers, the total length of the congestion can be from one to several kilometers. The length of the burial site may reach large rivers up to 20 km. Ice traffic police are most often on the rivers current from the south to the north. In Russia, it is Northern Dvina, Pechora, Yenisei, Ob, Lena, Irtysh, Vitim, Tom, etc. To destroy the congestion, icebreakers are used, explosive work and bombing from airplanes.
Non-naval floods are caused by wind nuclei water on the shores of large lakes, reservoirs and sea mouths large rivers. They arise on the windwater reservoir as a result of the rise of the water level under the action on the water surface of the strong wind of the cyclone. At the same time, a row wave is formed, propagating to the imaginary shore of the reservoir or up the river. For hugging floods are characterized by no periodicity and significant rise in water levels. Night wave can spread on large rivers for hundreds of kilometers, on small - ten kilometers. Flooding usually lasts from several tens of hours to several days.
Of the 200 constituents of the world, about half are located in the sea merchants of the rivers, and they are threatened with hugging floods. In Russia, the most susceptible to this phenomenon of St. Petersburg, located in Delta R. Neva on the low islands. Since the reasons (1703), it was exposed to the invasion of waves about 250 times.
Floods caused by a breakthrough of dams (hydraulic structures). They occur when the water is overflow through the crest of the dam when the reservoir is untimely conducting the prevention of the reservoir, during the destruction of the dam or the insufficient bandwidth of the water supply of dams. Damage breakthrough is also possible due to poor quality of construction work and improper operation, exposure to earthquakes and the consequences of hostilities. For such floods, the formation of a breakthrough wave, leading to the flooding of large territories and to destruction or damage to objects of objects (buildings, structures) on the way of its movement.
Floods caused by submarine earthquakes, eruptions of underwater or island volcanoes occur relatively rarely. They are on the coasts of the seas and oceans in the areas of active seismic activity.
The classification of flooding on the scale and causes of the occurrence is shown in the diagram 17.
The effects of floods
When flooding there is a rapid rise of water and flooding adjacent terrain.
Flooding - covering the surrounding area by a layer of water pouring yards, streets of settlements and lower floors of buildings.
Podopalization is the penetration of water into the basement of buildings through the sewer network (when the sewage is reported to the river), in various types of channels and trenches, as well as due to a significant groundwater subpora.
Flooding of settlements, agricultural land and natural complexes is accompanied by negative consequences: as a result of the effects of water and the rapid flow, people, agricultural and wild animals die; Buildings, structures, communications are destroyed or damaged; Lose material and cultural values; Agricultural activities are interrupted; the crop dies, fertile soils are washed or set; Landscape changes.
Secondary Flood Consequences: Reducing the strength of structures as a result of the erosion and subjo; transfer by water out of damaged storage facilities and pollution of vast territories; Complication of a sanitary and epidemic situation; Wildrocking the terrain.
Due to uneven soil drawdown during flooding, numerous breaks of sewage and water pipes, gas lines, electric, telegraph and telephone cables, building damage, roads are occurring.
The summer flood and its consequences the population transfers easier than spring, and even more so winter.
In rural areas, time (season) and the duration of flooding have crucial importance. This is primarily due to seasonality of agricultural work. But any flooding of water areas intended for the cultivation of crops leads to oss out of the soil of air. At the same time, normal gas exchange stops in the soil and carbon dioxide comes from the roots of plants, which harmors plants. This circumstance is the main reason for the fall in the yield or death of crops as a result of flooding.
The serious consequences of flooding of rare repeatability are sometimes changes to the river bed: new channels appear or the old one is deepened. In part, and sometimes the fertile top layer of the soil is completely washed or entered or entered in the floodplain, which significantly worsens land use and reduces the yield.
Flood damage reduction measures
Get rid of floods is completely almost impossibleBut in the power of people to reduce the losses from them.
To protect against most floods, the same measures are used to significantly reduce their consequences: forest protection bands are planted in river basins, strive to preserve coastal shrub vegetation, lead special treatment of slopes, build ponds and reservoirs to intercept for melting and rarewate.
On medium and large rivers, a radical tool from flooding is used - control of the flooding flow using reservoirs (this simultaneously allows you to solve the problem of electricity production). The essence of this method is that the water arriving in the reservoir is gradually spent by resetting it through the pressure hydraulic rose.
To protect against flooding along the shores of many rivers, enclosing dams are built. There is also a hide of the winding of the winding rivers, which makes it possible to increase the slope of the water surface and the water flow rate. As a result, the maximum water consumption occurs at its lower level. At the newly built-in areas, the method of subwaged territory is used.
Works on strengthening the banks of rivers reduce the danger of their erosion, and at the deepening of the bottom of the rivers allow a larger volume of water by their rivers, remove various obstacles from the bottom, to increase the flow rate.
For operational preventive measures (notification of the population about the threat of flooding; advance evacuation of the population, material values, animals from potentially sleeves, the construction of the simplest protective structures for the protection against flooding settlements and roads) is a timely and reliable hydrometeorological forecast.
Most floods can be predicted and thanks to this reduce possible losses. Residents of cities and settlements, periodically falling into flooding zones, should be informed in advance about this danger, trained and prepared for actions in the threat and during flooding.
Hydrological disasters
Floods - the most common dangerous natural phenomenaThey constitute 40% of all natural disasters of natural origin. Among the natural disasters of flooding for repeatability, the distribution area and the total average annual damage occupies the first place in a number of natural disasters. According to UNESCO, in the last century, 9 million people died from them. Floods occur in all seasons of the year and everywhere. They suffer from the inhabitants of river valleys and sea coasts, mountainous regions and even deserts. A big danger is that often they start suddenly, people do not have time to prepare them.
Flooding - various time in duration temporary flooding of water area, including settlements, industrial and agricultural facilities as a result of natural and anthropogenic causes. Floods are a consequence of the natural causes and diverse economic activities of a person, therefore, the floods represent both the phenomenon of nature and the social phenomenon. The main natural causes of flooding are hydrological phenomena: floods and floods, tightening rains and shower, features of the winter river mode, hill phenomena on rivers, as well as landslides, sat down and rods in mountain valleys, etc.
Floodcalled annually repeated in the same season to a significant increase in water content of rivers, accompanied by an increase in the water level in the river. The reason and time of the flood depends on the geographical location of the river and are associated with the influx of water into the river drill as a result of the melting of snow on the plains, melting of snow and glaciers in the mountains, loss of heavy rains during summer monsoon. River moderate belt Spilled during the Spring Snowtone on the plains. The water level on the rivers is rising by 2-20 m, the width of the flooded territory reaches many kilometers. Particularly serious consequences are flooded in the valleys of high-mountainous regions, if the period of melting of snow and ice in the mountains coincides with the melting of snow in the valleys. Spring rains can lead to a significant increase in flooding, when spring flood peak coincides with the peak spring flood. The flood can take a catastrophic character if the infiltration properties of the soil decreased due to the oversaturation of its moisture due to heavy rains, or after a very snowy winter, or deep freezing in the harsh winter.
Floodsthey call the annual short-term water lifts in the rivers caused by rains, but they can repeat several times. They are usually observed during intense and long rains. Especially severe consequences cause severe floods in the plain territories. Floods can be observed in winter time In connection with winter thaws and rains. Their frequency and intensity depend on the frequency and intensity of rains in the spring-autumn period or thaw in winter. Especially dangerous floods associated with rains of cyclone origin. The most powerful shower brings tropical cyclones, characterized by the surprise of their beginning and end, significant intensity and short-term. In our country, almost all regions suffer from rain floods. On the Far East On the Amur rivers, Ussuri, Burea and other floods caused by floods, occur almost annually. National disaster are floods for residents of China and India. The coastal flood is 1931 in the Yangtze Pool. Under the water turned out to be 300 thousand square kilometers, of which more than 5 million hectares were agricultural land. 140 thousand people died. In recent decades, severe floods on rivers are fixed. Western Europe.
Congestion- This is a multi-layered cluster of ice in line, which limits the course of the river and causing the rise of the water level at the storage area of \u200b\u200bthe river. As a result, it is spilled. The plot occurs during the ice drift and is usually formed at the end of winter and in the spring during the opening of the rivers during the destruction of the ice cover. It consists mainly of large ice floes. Powerful and frequent Ice congestion are inherent in rivers current from the south to the north, whose opening occurs on top of the course: Northern Dvina, Pechora, Lena, Yenisei, Irtysh. Iceshop on the upper, southern sections begins much earlier than in the mouth. The edge of the wrong ice plays the role of obstacles. The unevenness of freezing and opening caused by a significant length of rivers also leads to the formation of ice congestion - forehead. Water coming from still not frozen autumn or already released from ice from the spring of the spring, faces the bottoms to the bottom of the grounds, rolling on them and in conditions of negative temperatures freezes, forming huge dams from monolithic ice. When warming, the process of forming the land stops, however, ice dams are slow, and water, without having the opportunity to move down, comes out of the banks.
Burden- The phenomenon is similar to the traffic of ice. However, firstly, the burzhot consists of a cluster of loose ice (shuga, small ice floes), while the jam is a cluster of large and, to a lesser extent, small ice floes. Secondly, Ice burzhod is observed at the beginning of winter, while the jam is at the end of winter and in the spring. In winter, the movement of water in rivers occurs under the ice. The velocity of water plays a large role in the process of ice formation. The high flow rate contributes to the cooling of water throughout the depth. If the water temperature in the aqueous stream decreases at least for the hundredth fraction of the degree below zero, then in water there is an intra-wheel ice, which, popling to the surface, forms loose accumulations - Shugu. With stable frosty weather, the sampling process occurs continuously. With the advent of solid ice cover on the river, this process stops. However, the sleeper formed earlier may float under the ice cover, lingering and increasingly at the ice edge. Formed a burden that causes flooding of adjacent terrain. Such floods are observed in the autumn-winter period on the rivers of the Neva, Angara, Yenisei, etc. in the frequency of burning floods and the amount of water lifting the championship belongs to hangar and the Neva - rivers arising from the lakes.
Navage - This is the rise of the water level caused by the impact of wind on the aqueous surface. Such phenomena happen in the sea merchants of large rivers, as well as on the gentle sections of the coast of large lakes and reservoirs. The main condition of the occurrence is tides, a strong and long-lasting wind characteristic of deep cyclones. Strong winds in the passage of cyclones cause an enhanced movement of marine waters in the direction of the windward coast due to the mechanical impact of the wind on the water surface and the formation of a slope in the direction of the coast. There is a significant rise in the water level. The second condition for flooding is low and gentle coast (below sea level). In this case, the rise of the water level leads to very large floods. In the mouths of rivers having a small bias towards the sea, the hill waves apply to the flow. Noggon as it were fodding the river in the lower current, causing flooding. The highest wind harnesses on the globe occur on the coast of India.
The largest naval flood occurred in Ganges Delta in 1970. The reason for him was cyclone. A 10-meter wave persecuted with a storm wind turned over the river. Water from the banks of Ganga water flooded about 20 thousand square kilometers. Dozens of cities and hundreds of villages were demolished from the face of the Earth, the number of victims was about 1.5 million people. Hundreds of thousands of people died of hunger and flashing cholera and typhoid epidemics. In Russia, the arrivals manifest themselves on the lakes of the mound, Onega, Baikal, in the Azov and Caspian seas, in the mouths of the Daugava rivers, Northern Dvina, Neva. The most destructive hugging floods were celebrated in Leningrad. One of the most tragic was hooking in 1824, described by A.S. Pushkin in the "Copper Horseman" poem.
Flood floods They occur as a result of collaps, landslides, timelines on the slopes of mountains or hills. Educated as a result of collaps, scales or avalanche natural dams, brave the river beds. Floods may occur or as a result of limited water movement in the river bed or as a result of a breakthrough of the bounted river. Very dangerous highland lakes lidden by glaciers. Blots, isolated on ice, are very short-lived. Breakthrough such a dam is possible in a fairly short time. In Tajikistan at an altitude of about 3,500 m above sea level, there is a Sarezo lake. It was formed as a result of a mountain collapse that blown the riverbed of the Murgab River. This mountain lake hangs over the river valley, like a monstrous thunderstorm cloud. Continuous observations are underway.
Another cause of floods are tsunami. The floods generated by the tsunami are characterized by surprise, cyclical, frequency and a colossal destructive force. Due to the difficulty of determining the epicenter of the tsunami and the high speed of its movement, the tsunami is often unexpected, the population is unprepared.
Anthropogenic causes of floods are associated with human economic activities. They can be divided into direct and indirect. Indirects include those activities that are held in river basins, valleys, floodplains and ruses and can cause changes in their water mode. This is the reduction of forests, the drying of the marshes, the irregular disintegration of the slopes, the irrational development of the floodplain, industrial and civil development, etc. Direct anthropogenic causes lead directly to large floods and are associated with the conduct of various hydraulic activities and damage to dams, as well as incorrect conducting floors protection measures.
Flooding can occur as a result of a hydrodynamic accident associated with the failure (destruction) of the hydrotechnical structure or part of its part and the uncontrollable movement of large mass of water, which carry the destruction and flooding of extensive territories. The main hydraulic structures include dams, water intake and water collection facilities (gateways). The destruction of hydraulic structures occurs as a result of the action of the forces of nature (earthquakes, hurricanes) or human impact (for example, the application of shocks with nuclear or conventional weapons on hydraulic structures), as well as due to design defects or design errors.
Factor striking flooding - flooding of the territories of the water layer of various thickness, height and duration of the standing of the maximum water level; rate of level of level and water flow; washing the soil in flood zones; contamination and pollution of the area; Water carriers and postponed areas (in some areas, this phenomenon refers to positive factors).
The effects of floods. Flooding worsen the sanitary and hygienic and sanitary and epidemiological state of extensive areas. Waves formed during sudden floods and moving with huge speeds can move boulders, pull out trees, destroy buildings and bridges, break back new channels.
Low (small) floods are observed on plain rivers and repeated about once every 5-10 years. These floods are almost not disturbed by the lives of the population near the river areas.
High floods are accompanied by significant flooding, cover relatively large areas of river valleys and sometimes significantly violate the economic and household lines. Such floods are observed once every 20-25 years.
Outstanding (large) floods cover whole river basins, paralyzing economic activities, the economic and household lines are dramatically violated, large material and moral damage causes. Such floods are repeated about once every 50-100 years.
Catastrophic floods cause flooding of huge territories within one or even several river systems. Such floods happen not earlier than once every 100-200 years and are formed, as a rule, in basins, which prevail the mutual rivers prevail with the simultaneous and intense spring flood. They lead to long impairment of economic and production activities, the death of people and material values.
Flood caused damage is divided into direct and indirect damage. Direct - damage from damage and destruction of residential and industrial buildings, railways and roads, power lines and communication, livestock and harvest, destruction and damage, fuel, food, feed, and the cost of temporary evacuation of the population and material resources , Rescue and restoration costs.
The costs of purchasing and delivery to the affected areas of food, building materials and feeds for livestock usually include the costs of food, building materials and feeds for livestock, the expenditures on the development of new agricultural land in exchange, for the resettlement of people, for medical care. infectious diseases. This also includes losses from non-manufactured industrial and industrial products, from non-fulfillment of transportation, deterioration of the living conditions of the population t. P .. Direct and indirect damage are located, mostly, in a percentage ratio of 70:30. According to UNESCO for the 20th century, 9 million people died in the world from flooding, while from earthquakes and hurricanes - 2 million people. In some countries, average annual flood losses are up to 15% of gross product.
The amount of flood damage is influenced:
· Prediction service status;
· The presence and condition of hydraulic structures;
· Degree of population, industrial and agricultural development of river valleys and understand.
The main indicators of the consequences of floods are:
· The number of population in the flooding zone;
· The number of dead, wounded, remaining without people;
· The number of settlements in the flooding zone;
· The number of residential buildings and buildings of socio-cultural purposes, monuments of history and culture;
· The length of iron and roads, power lines, communications, other communications, founded in the flooding zone;
· Square flooding of agricultural land;
· The number of dead farm animals.
The trend of growth damages from floods is characteristic of both our country and for many countries of the world, since the pace of mastering the heated territories is significantly ahead of the construction pace for protection, as a whole, the amount of flooding damage on rivers exceeds the amount of effect currently achieved from construction Protective facilities.
Forecast and prevention. It is enough to simply predict the scale of flooding, but to predict the moment of its offensive, even when there is a sufficient amount of data on the costs and water levels in the river for a long period, it is quite difficult.
The accuracy of the forecasting of floods increases when obtaining reliable information about the amount and intensity of precipitation, the level of water in the river, the water intensity in the snow cover, changes in the air temperature, the state of the soil-soils in separate areas and the catchment as a whole, long-term weather forecast, etc. Folding a flood can vary from several minutes in conditions of storm sediments in the upper reaches of small rivers up to several days and more in the lower reaches of large rivers.
A modern look at preventive measures includes the use of both regulatory (softening) and preventive flood protection measures.
The first approach involves the performance of construction work aimed at adapting the aqueous stream during a flood period to the size of the bed, or to bring the channel in accordance with the force of this flow.
The second approach takes into account that in real conditions it is inevitable, it is necessary to endure the damage caused by high water, but to reduce the damage it is necessary to purposefully and skillfully use the floodplain areas.
Protection.Rescue operations In the case of dangerous floods include: alert, evacuation of people and material values, conducting emergency and repair and repair work, sanitary and hygienic and epidemiological measures, the introduction of emergency assistance to victims, etc.
In the event of a threat of flooding, flood commissions are created. Together with the management bodies, they solve the following tasks:
· Check dam and dams, various special Tools;
· Informing the public about the need to take certain measures;
· Organization of engineering work: digging of drainage channels, embrying, dam. Such works are involved in building organizations, services and formation of th, local military units.
All protective events are divided into engineering and non-venture. Under the engineering are aware of activities aimed at regulation, detention or removal of maximum runoff in order to prevent floods with artificial structures. These include: 1) accumulation of runoff in reservoirs, conducting during floods of emergency reset in them; 2) drain drain from the river to special reservoirs-drives; 30 Beresturization - construction along the shores of mounds, shafts, dam; 4) deepening, expanding or hiddening river beds in order to increase their bandwidth; 5) the creation of storm sewage systems; 6) artificial regulation of ice phenomena, etc.
Non-venture activities are to adapt to activities natural conditions In order to reduce damage, in reducing the maximum flow and elimination of anthropogenic causes leading to flood strengthening. The main role of protection is given to the regulation of land use on floodplains and reservoirs. This implies primarily the restriction or complete prohibition of the activity, as a result of which the flood enhancement is possible, which during the flooding period the greatest damage is applied. As non-ventricular measures, the creation of prevention and alarm systems, flood prediction, increasing the level of knowledge of the population about the threat of flooding are considered.
Actions in the threat and flood occur.Residents of regular flooding zone must be informed about this danger in advance, trained and prepared for actions in the threat and during flooding. With the preparation of a flood prediction, the population is notified through a network of radio and television broadcasting. In accordance with the threat of flooding, except hydrometeodata, the expected time of flooding, the boundaries of the heated territory, recommendations on the protection of the population and property of certain settlements during flooding, as well as the procedure for evacuation are indicated.
Before evacuation to protect your house (apartments) and property, everyone must fulfill the following mandatory effects:
Turn off water, gas and electricity;
Put out burning heating furnaces;
Transfer to the upper floors of buildings (attics) valuable items and things;
Remove the agricultural equipment in a safe place, bury, hide fertilizers and waste;
Help (if necessary) windows and doors of the first floors of houses by boards or plywood.
When you receive a warning about the beginning of the evacuation, you must quickly assemble and take with you:
Personal documents placed in a waterproof package;
Money and values;
Medical aid kit;
Set of outerwear and shoes for the season;
Bed linen and toiletries;
Three-day food supply. Things and products are better to put in suitcases (backpacks, bags).
All evacuated must be arrived at the timely deadline for the prefabricated evacuation point for registration and sending to a safe area. In independence from the current situation, the evacuation of the population is carried out by transport or on foot dedicated for these purposes.
With a sudden flooding, it is necessary to take the nearest safe elevated place as soon as possible and be prepared for evacuation on water, including with the help of girlfriend. In such an environment, you should not give in to panic, to lose self-control, it is necessary to take measures to allow rescuers in a timely manner to detect people cut off with water and need help. In the bright time of the day it is achieved by hanging on a high-place white or colored cloth, and at night - feeding signals.
All available plaels are used for their salvation: boats, boats, rafts, ferries with tows, amphibious all-terrain vehicles. Intelligence of the flooded area is carried out using aviation, and helicopters are also attracted to rescue people. First aid should be affected on the water. People selected on the surface of the water should be moved into dry clothes, give soothing agents, and reservoir extracted from water or from the bottom of the reservoir - to carry out artificial respiration, if they do not even have visible signs of life.
Usually, the stay of people in the flooding zone lasts until the decline of water or the arrival of rescuers, which have reliable means for evacuation in a safe area.
The self-esteem of the population on an uneplicable territory is carried out in cases of the need to provide emergency medical care to victims, the consumption or lack of food, threats of deterioration in the situation or in case of loss of confidence in obtaining assistance from the part. For self-election on the water, personal boats or boats are used, rafts from logs and other girlfriend materials.
After the decline of water, people hurry will return to their accommodation. It should be remembered about precautions. Cleaning or conductive electrical wires should be watched. Damage, as well as on the destruction of water supply, gas and sewage highways, immediately report to the relevant utilities and organizations. The products that have fallen in water are strictly prohibited to be used in food before checking by SanEpidem services and without hot processing.
Reserves of drinking water before use must be checked, and the existing wells with drinking water - Dried by pumping out polluted water from them.
Before entering the building after flooding, make sure that their designs have not undergone expressive destruction and do not pose a danger to people. Before entering the room, you need to check it within a few minutes by opening entrance doors or windows. When examining the inner rooms of the building (at home), it is not recommended to use matches or candles as a light source due to the possible presence of gas in the air. For these purposes it is better to use electric lights. Before checking by the specialists of the electrical network, it is impossible to use electricity sources.
These basic rules of behavior and the procedure for the actions of the population during flooding make it possible to significantly reduce possible material damage and preserve the lives of people living in hazardous areas and damaged by the effects of water elements.
Flood in Western Europe. In February 1962, the storm by force of 12 points raging in the North Sea, wrapped huge masses of water on the shores of West Germany. Sea water burst into the mouth of the rivers and forced them to flow back. As a result, the water of the rivers and the sea penetrated into the depths of sushi about 100 km, pouring everything in their path. Under water, the cities of Hamburg, Bremen, Kuxhafen and all the surrounding settlements were found. Water destroyed iron and highways, power lines and communication, gas pipelines, washed away and destroyed hundreds of residential buildings. Greater damage was applied industrial enterprises. More than thousands of people were left without bed, 400 people died in homes. Not having time to get out of them. Flooding caused material damage to several billion marks. In addition to the police and special divisions, 25 thousand soldiers, 100 helicopters took part in the rescue operation. The storm at the same time caused a flood in England and other seaside countries of Western Europe. In the area adjacent to the mouth of the Thames, the wave with a height of 2.5 m took over 300 human lives. In the Netherlands, avalanche of the water of four-meter height, which came from the sea. Not only turned the flow of rivers, but destroyed protective dams and devastated the southwest of the country, destroying 1800 people.
Flood in the Southern Federal District in 2002. As a result of the flood, 91 people died, including 47 in the Stavropol Territory, 31 - in Krasnodar, 6 - in Karachay-Cherkessia, 6 - in North Ossetia, 1 - in Kabardino-Balkaria. The 343 settlements were injured, in which 7,519 houses were destroyed and 45733 at home was damaged. The total number of victims of 329413 people. 101911 people were evacuated from which 38777 people returned.
The Novokubansky district of the Krasnodar Territory was most affected. The total area of \u200b\u200bflooding was more than 200 square meters. km. In the emergency zone there was more than 600 thousand people or 76% of the population. 6747 residential buildings were flooded, 18300 household buildings, 186 enterprises of agriculture, industry, construction, transport, communications, education, culture and trade, 14,800 gardens and 5678 household plots. Significantly damaged objects of housing and communal services, water supply, 8 bridges were destroyed, 186 kilometers of roads, streets and sidewalks, 63 kilometers of water supply, sewer, gas and telephone networks, 97 electric supports and radio programs, a huge amount of domestic property, livestock and animals. The total damage is about 1 billion rubles, more than 16,000 people are left without priority and livelihoods.