We have already noted that in the process of the water cycle in nature, dangerous phenomena hydrological nature. The most common and frequently recurring of these are floods.

According to the Ministry of Emergency Situations of Russia, floods in terms of frequency, distribution area, and total average annual damage rank first in Russia among known natural disasters. In terms of the number of human casualties, they rank second after earthquakes.

In Russia, floods threaten almost 40 cities and several thousand others settlements. The frequency of floods on average ranges from once every 5-10 years to once every 15-20 years. But there are cities where floods are observed once every 2-3 years (Ufa, Orsk, Kursk and a number of others).

What is a flood?

Flood- this is a significant flooding of the area as a result of a rise in the water level in a river, lake, reservoir or sea, causing material damage to the economy, social sphere And natural environment. Floods occur due to abundant and concentrated inflow of water during the melting of snow and glaciers, prolonged intense rainfall in river basins, blockage of river channels by melting ice (jamming) or clogging of river channels by internal, newly formed ice (jamming), water surge by wind in sea mouths of rivers .

One of the many floods in St. Petersburg

Flooding of the area with water, which is not accompanied by damage environment, is called the bottling of a river, lake or reservoir.

Types of floods

Floods can be caused by various reasons related to the characteristics of the river runoff and its changes at different times of the year. The flow of water in the rivers is influenced by the melting of snow and ice, heavy rainfall and surge winds in the mouths of the rivers. Depending on these reasons, there are several types of floods.

  1. Floods associated with water runoff during high water.

    high water- this is an annual increase in the volume of water in the same season, which is accompanied by the release of its waters from the banks and flooding of the river floodplain. High water of lowland rivers in places with temperate climate caused by spring snowmelt (spring flood). High water on rivers originating high in the mountains is caused by the melting of snow and glaciers in summer time(summer flood). This type of flood is characterized by a significant and rather long rise in the water level in the river.

  2. Flooding caused by floods.

    high water- this is a rapid, short-term and non-periodic rise in the water level, resulting from the rapid melting of snow, glaciers, and heavy rains. Significant flooding can cause flooding. This type of flood is characterized by an intense, relatively short-term rise in the water level.

  3. Floods caused by great resistance that the water flow meets in the riverbed. They occur during traffic jams and ice jams in the river.

    Congestion An accumulation of ice in a river bed that limits its flow. Traffic jams usually form at the end of winter and in spring when rivers open up. Most often, traffic jams form on rivers flowing from south to north (Northern Dvina, Pechora, Lena, Yenisei, Irtysh).

    Zazhor- This is a phenomenon similar to ice jam, but it is observed on the rivers at the beginning of winter. Zazhors are formed on the rivers during the formation of the ice cover. A blockage occurs due to the accumulation of loose ice and small ice floes in the riverbed and its involvement under the edge of the formed ice cover, which prevents the free flow of water and causes a rise in the water level in the river upstream. The Angara and Neva rivers are noted in terms of the frequency of floods and the magnitude of the rise in water.

  4. Floods associated with wind surge on the banks large lakes and in sea estuaries major rivers. Such floods occur on the windward shore of a reservoir, when, under the influence on the water surface strong wind the water level rises.

All of the above types of floods, depending on their scale and material damage, are divided into low, high, outstanding and catastrophic.

Low (small) floods are observed mainly in lowland rivers. The frequency of their repetition is approximately once every 5-10 years. These floods cause minor material damage and almost no disruption to the lives of the population.

High (large) floods are accompanied by significant flooding, cover large areas of river valleys and disrupt the livelihoods of the population. In densely populated areas, floods often lead to the need for partial evacuation of people and cause significant material damage. The frequency of recurrence of large floods is approximately once every 20-25 years.

outstanding floods cause flooding of vast territories, paralyze the economic activity of the population, and cause great material damage. In this case, there is a need for mass evacuation of the population from the flood zone. Such floods occur approximately once every 50-100 years.

catastrophic floods cause flooding of vast areas within one or more river systems. In the flood zone, human life is completely paralyzed. Such floods lead to huge material losses and loss of life. They are celebrated approximately once every 100-200 years.

The scale of the consequences of a flood depends on the height and duration of dangerous water levels, the speed of the water flow, the area of ​​flooding, the time of year and the population density in the flooded area.

History knows many examples of catastrophic floods.

The picture of the oldest of them was restored according to archaeological research.

It was found that the Black Sea 12,000 years ago was a freshwater lake, and 7500 years ago, due to global warming on Earth, the melting of glaciers and the rise in the water level in the oceans, it was filled with water mediterranean sea and turned into the salty Black Sea.

Modern American geologists V. Pitman and V. Ryan, having brought together all known to science facts about the breakthrough of oceanic waters 7.5 thousand years ago, managed to reproduce the picture of a hydrological catastrophe.

The waters of the Mediterranean Sea rushed into the passage between Asia and Europe. For about a year in this place, water rushed down from a height of 120 m. The lake, turned into the Black Sea, overflowed its banks and flooded almost one hundred thousand square kilometers of land, mainly the northwestern coast. Near the Black Sea, a new one, the Sea of ​​\u200b\u200bAzov, was formed. In the east the waters came to the foot Caucasian ridge. For at least three hundred days, the waters rushed through the valley, where the Bosphorus Strait is now located, connecting the Black and Marmara Seas. Every day, 50 cubic kilometers of water flowed through it, and the level of the Black Sea rose by 15 centimeters every day.

On the north and west coasts The Black Sea catastrophe took on a tragic character. For every day, the water here advanced by 400 m. A large area of ​​​​land was flooded here.

Global flood. The death of all living things. Engraving by Gustave Doré

Mortal danger forced people to quickly leave their homes, thereby causing a powerful movement of the human masses. The people who escaped the stream remembered forever terrible days and nights of flight from the water rushing after them.

This catastrophe may have been identified later with the Flood described in the Bible.

Test yourself

  1. Define the natural phenomenon flood.
  2. List the main types of floods.
  3. What natural phenomena of hydrological origin can cause floods?

After lessons

In the safety diary, give examples of floods in Russian Federation that occurred for various reasons (high water, high water, surge winds). Specify their consequences and actions for protection of the population. Examples can be collected using the Internet and the media.

The raging and destructive power of the water element is capable of causing irreparable damage to the ecological and economic sectors of any state. One of the frequent cases that operational services have to deal with is an increase in the water level in local reservoirs and its overflowing the coastline.

In such cases, they speak of floods, floods and floods. However, these concepts are often confused, or even completely identified with each other. In this article, we will try to give precise definition to these phenomena, we will tell you how the flood differs from floods and floods and how you should behave when you find yourself in a similar situation.

Basic concepts

Flooding, high water, high water are similar only in that they can, under certain circumstances, lead to significant land flooding. However, flooding is a more general and broad concept that arises for a variety of reasons. Let's consider in more detail:

It is a short-term, but sharp rise in water in rivers and lakes. It is characterized by its suddenness, and is completely independent of the time of year.

May occur several times a year. The reasons are usually associated with external natural circumstances: prolonged and heavy rainfall, a sharp warming with rapid snowmelt. The maximum duration is several days.

Abundant types of floods, following one after another or having a short time interval between them, can lead to flooding.

This is a common natural phenomenon that always occurs at the same time of the year, in spring. It repeats annually, and is characterized by a long and high rise in the water level in reservoirs. In most cases, water comes out of the riverbed, but floods can occur without flooding the coastal area.

The level of the river during this phenomenon can rise by 20-30 m. The decline can last up to 1 month. It is caused by an abundant influx of water into the reservoir due to rain, melting glaciers and snow.

Flood types associated with excessive melting in highlands snows are characteristic of the Caucasian terrain and rivers located in the Alps and Central Asia.

This is always a major natural disaster, with significant land flooding. Floods, floods, and even a human factor, for example, a breakthrough, can lead to it.

Flooding brings not only destruction to vital important structures, flooding of houses, but also the death of animals, crops, causing significant economic damage. Depending on the strength of the flood, there may be human casualties.

Floods and floods, as a rule, do not have such consequences. The period of restoration measures after the flood is quite long. Sometimes this can take several years.

low or small

The most harmless floods. They occur in rivers located on flat terrain. It has been observed to recur every 5-10 years. They pose no threat to the life of the population.

tall or big

They are characterized by fairly severe flooding, affecting large areas of land. With this view, it may be necessary to evacuate people from nearby houses. The material damage does not go beyond the average, but is very noticeable. Fields and pastures are often destroyed. Occur rarely - once every 20-25 years.

Outstanding

They are fixed once a century. They cause very great damage, as all agricultural activities are completely stopped. Residents of the entire settlement are evacuated to a safe place.

catastrophic

Such floods rarely do without loss of life. The disaster zone covers the territory of several river systems. The vital activity of a person in an area that has undergone a catastrophic flood is completely blocked. They are observed once every 200 years.

The severity of the consequences depends on many factors: how long the water stays on land, its height of rise, the speed of the falling stream, the area of ​​the flooded territory and population density.

Flooding can be caused by a variety of reasons. For areas with a warm, mild climate, protracted and heavy rains, which are a frequent occurrence there. In areas where the climate is dry and cool, precipitation is less frequent and the risk of flooding is minimal.

However, in the northern regions there is another danger - glaciers, mountain snow peaks and abundant snow cover. In the event of a sharp warming or early spring, rapid snowmelt will occur, which will lead to a strong rise in water in the lowland rivers. A major flood can lead to flooding.

The accumulation of mineral deposits at the bottom of the river contributes to its uplift. If the channel is not cleaned in time, then disasters in the form of floods, floods or floods cannot be avoided.

The cause of the most catastrophic floods can be tsunamis, which occur abruptly, and bring terrible destruction and numerous victims. They are gigantic waves that crash onto the land one after another, sweeping away everything in their path. Powerful sea waves can form due to hurricanes or strong winds. They are able to splash out on the coastline with force.

Breakthrough earth's crust and access to the surface of groundwater is also one of the possible causes floods. Mudflows and landslides lead to spills mountain rivers. They, leaving the channel, with force and a mud stream descend to the plain. This natural disaster has serious consequences.

The human factor in the formation of floods is the improper operation or failure of hydraulic structures, which leads to their destruction and the breakthrough of a large flow of water to settlements. Various man-made disasters capable of causing floods of various sizes.

In lowlands or areas that are within a particular river system, monitoring is constantly carried out water regime in local waterways. When signs of a major flood or annual flood are detected, the population is notified in advance by special services.

The basic rules of conduct during floods and floods are as follows:

  1. Move all valuables and interior items to higher ground (attic, 2nd floor)
  2. Clear the attic of groceries. First of all, when flooding houses, the water will go down.
  3. Pack all important documents tightly in waterproof material.
  4. Strengthen window frames and doorways
  5. Bring construction equipment from the yard or raise it several meters above ground level.
  6. Close the cereal tightly and put it on high shelves in the closet. A refrigerator is a safe place to keep food out of water.
  7. Think about pets first. It is better to build a shelter for them higher from the ground.
  8. Completely de-energize your home. Prepare candles, a lantern, and essentials.

When an evacuation is declared, follow the instructions. Take a minimum of things and arrive at the check-in point as quickly as possible. Keep a close eye on children and elderly and/or sick relatives.

If you did not have time to evacuate from the disaster area, then climb onto the roof and give signals. To do this, use a flashlight, phone screen. You can tie a bright fabric to some kind of pin or stick.

You can return home only after the permission of the authorized bodies. Be careful on the street. Do not step on broken or damaged wires, do not stand near heavily damaged buildings or structures.

Tasks 4. Geoecological problems

Global climate change can lead to the melting of sheet glaciers and, as a result, an increase in the level of the World Ocean. Which of the listed cities in Russia could suffer the most in the event of such a development of events?

1) Kemerovo

2) Kaliningrad

3) Novosibirsk

Such adverse climatic events as droughts, hot winds and dust storms, make it very difficult economic use territory. For which of the following territories of Russia are they most typical?

1) Kirov region

2) Kamchatka Territory

3) Astrakhan region

4) Komi Republic

Permafrost has an impact on human economic activities: mining, construction of roads and buildings. In which of the following regions of Russia is it necessary to take into account the consequences of permafrost thawing?

1) Samara Region

2) Krasnoyarsk region

3) Rostov region

4) Chuvash Republic

4. Global climate change can lead to the melting of sheet glaciers and, as a result, an increase in the level of the World Ocean. Which of the listed cities in Russia could suffer the most in the event of such a development of events?

1) Smolensk

2) Yekaterinburg

3) Arkhangelsk

4) Novosibirsk

Seismicity and underwater volcanism are closely related to the danger of huge sea waves - tsunamis, which threaten the territories of coastal cities and towns. Which of the following territories of Russia needs the work of special services to warn the population about the tsunami?

1) Chukotka Peninsula

2) Kola Peninsula

3) Kuril Islands

4) Novaya Zemlya archipelago

For the safety of people in earthquake-prone areas, a special construction technology is used. In which of the following regions is it necessary to conduct earthquake-resistant construction?

1) Tula region

2) Smolensk region

3) Leningrad region

4) Sakhalin region

Such unfavorable climatic phenomena as droughts, dry winds and dust storms significantly complicate the economic use of the territory. Which of the following areas are the most typical?

1) Republic of Kalmykia

2) Perm region

3) Khabarovsk region

4) Republic of Karelia

For many countries, monitoring of volcanic activity and the work of services to alert the population about upcoming volcanic eruptions are relevant. For which of the following countries is it important to constantly monitor volcanic activity?

1) Finland

2) Iceland

4) Australia

Mud flow - mud or mud-stone flow, characterized by destructive power, suddenness of occurrence. In which of the following regions of Russia is the occurrence of mudflows most likely?

1) Kabardino-Balkarian Republic

2) Smolensk region

3) Republic of Kalmykia

4) Kaliningrad region

Earthquakes - natural disasters from which people often suffer. Timely notification of the population by special services can prevent catastrophic consequences of earthquakes. Which of the following countries requires special services?

1) Australia

2) Mexico

3) Ireland

4) Netherlands

Seismicity and underwater volcanism are closely related to the danger of huge sea waves - tsunamis, which threaten the territories of coastal cities and towns. In which of the listed regions of Russia is the work of special services necessary to warn the population about the approaching tsunami?

1) Transbaikal region

2) Yamalo-Nenets Autonomous Okrug

3) Primorsky Krai

4) Arkhangelsk region

Seismicity and underwater volcanism are closely related to the danger of huge sea waves - tsunamis, under the threat of which are the territories of coastal cities and towns. Which of the following countries requires the work of special services to warn the population about the approaching tsunami?

2) Bulgaria

3) Turkmenistan

4) Philippines

13. Snow avalanches are one of the most formidable and dangerous natural phenomena. In which of the following regions of Russia do snow avalanches pose the greatest danger?

1) Chuvash Republic

2) Kaliningrad region

3) Arkhangelsk region

4) Republic of North Ossetia - Alania

Floods are natural disasters that affect people living on the banks of rivers. On which of the following rivers floods most often occur in the summer?

Earthquakes are natural disasters that often affect people. Timely notification of the population by special services can prevent catastrophic consequences. Which of the following countries requires such special services?

1) Finland

3) Netherlands

1. What ocean is the Mariana Trench in? 1) Indian 2) Pacific 3) Atlantic 4) Arctic. 2.Which of the

numerical sea currents operates in the Pacific Ocean?

1) Gulf Stream 2) Brazilian 3) Guinean 4) Kuroshio.

3. Sable is an animal that lives in a natural area:

1) steppes 2) taiga 3) deserts 4) tundra

4.One of the main modern species economic activity man in the tundra is:

1) logging 2) mining 3) raising livestock 4) growing grain

5. Among the listed endorheic lakes is:

1) Baikal 2) Victoria 3) Chad 4) Onega.

6. Which of the islands has the highest average annual rainfall?

1) Iceland 2) Kalimantan 3) Madagascar 4) Tasmania.

7. Which mineral deposits are confined to ancient platforms?

1) oil 2) iron ore 3) copper ores 4) polymetallic ores

8. Which of the listed travelers made a great contribution to the discovery and study of Africa?

1) I. Moskvitin 2) D. Cook 3) D. Livingston 4) F. Magellan

9. Moderate maritime climate is typical for:

1) Sumatra Islands 2) Iberian Peninsula 3) Great Britain 4) Yucatan Peninsula

10. Which of the following mountain systems the longest?

1) Cordillera 2) Ural 3) Alps 4) Appalachians

11. Which of the peninsulas has monsoons during the year?

1) Labrador 2) Alaska 3) Indochina 4) Somalia

12. Which of the listed natural zones is characterized by the largest number rodents?

1) taiga 2) tundra and forest-tundra 3) steppes 4) semi-deserts and deserts

13. On which of the listed rivers does a large number of thresholds?

1) Volga 2) Amazon 3) Congo 4) Mississippi

14. Sign marine type climate is:

1) summer is dry and hot 2) winter is wet and warm 3) large amplitude of temperature fluctuations

15. Oak, myrtle, wild olive - representatives of the natural zone:

1) equatorial forests2) hardwood forests3) tropical deserts 4) deciduous forests

1) Cordillera 2) Andes 3) Himalayas 4) Alps.

17. Which continent is the hottest:

1) Africa 2) Australia 3) South America 4) North America

18. The extreme southern point of Africa:

1) Cape Agulhas 2) Cape of Good Hope 3) Cape Almadi 4) Cape Ras Hafun.

19. climate zone Africa with pronounced seasonality: dry winters and wet summers:

1) equatorial 2) subequatorial 3) tropical 4) subtropical.

20. The most salty sea belongs to the pool:

1) Pacific Ocean 2) Atlantic Ocean 3) Pacific Ocean 4) Arctic Ocean

Part B

1. Distribute the climatic zones of Africa in order of decreasing density of the river network:

1) equatorial 2) tropical 3) subequatorial.

2. Match.

natural area: Climate zone:

1. wet forests a) subtropical

2. Savanna b) tropical

3. Desert c) subequatorial

d) equatorial.

3.Distribute southern continents as their area increases:

1) Antarctica 2) Africa 3) South America 4) Australia.

Part C

1. Why is the highest point in Africa - Mount Kilimanjaro - located within the platform, and not

folded area, as on other continents?

2. Are there glaciers in Africa, if so, in what part of the mainland?

3. Why do platforms tend to have plains?

1) In which of the following countries do most of the population profess Catholicism: Ukraine; Netherlands; Italy; Greece; Philippines;

Indonesia; Sudan; Argentina?

Which of the following peoples belong to the Indo-European family of languages: Chinese, Hindustanis, Russians, Japanese, 1. With which of the listed states does Russia have a maritime border? 1) Latvia 2) USA 3) Azerbaijan 4) Estonia 2. The extreme northern point of Russia which of the following rocks is metamorphic in origin 1) pumice 2) marble 3) pebbles 4) gypsum in humid equatorial forests

South America 1) there is a dry and wet season of the year 2) there are a lot of fern vines in the vegetation 3) chestnut soils predominate 4) eucalyptus trees predominate in the tree layer

Which of the following countries has the highest average population density 1) Canada 2) Japan 3) Algeria 4) Brazil

in which of the following GDP countries per capita highest1) Belgium2) Algeria3) Morocco4) Argentina

Which of the following countries does Russia border on the Amur River 1) Kyrgyzstan 2) Mongolia 3) Kazakhstan 4) China

in which of the following regions of Russia are the agro-climatic conditions most favorable for growing sugar beet and corn

which of the following types of minerals is mined in the Volga region 1) copper ores 2) iron ores 3) oil 4) coal

in the supply of which of the following types of products to the world market, the share of Russia is especially large 1) semiconductors 2) cars 3) ships 4) metals