All about floods. Do not use electrical appliances until specialists check the condition of the electrical network. Flooding - covering the surrounding area with a layer of water, flooding courtyards, streets of populated areas and the lower floors of buildings

Flooding is a significant inundation of an area as a result of a rise in the water level in a river, lake or sea during the period of snowmelt, rainfall, wind surges of water, congestion, ice jams, etc. A special type includes floods caused by wind surges of water into river mouths. Floods lead to the destruction of bridges, roads, buildings, structures, cause significant material damage, and at high speeds of water movement (more than 4 m/s) and high heights of water rise (more than 2 m), they cause the death of people and animals.

The main cause of destruction is the impact on buildings and structures of hydraulic shocks from the mass of water floating with high speed ice floes, various debris, watercraft, etc. Floods can occur suddenly and last from a few hours to 2-3 weeks.

How to prepare for a flood

If your area experiences frequent flooding, learn and remember flood boundaries and high, rarely flooded areas located in close proximity from places of residence, the shortest routes to them. Familiarize family members with the rules of conduct during organized and individual evacuations, as well as in the event of a sudden and rapidly developing flood. Remember the storage locations for boats, rafts and building materials for their manufacture.

Make a list of documents, property and medicines to be removed during evacuation in advance. Place valuables, necessary warm clothes, food supplies, water and medicines in a special suitcase or backpack.

What to do during a flood

If there is a warning signal about the threat of flooding and evacuation, immediately, in the prescribed manner, leave (leave) from danger zone possible catastrophic flooding to a designated safe area or to elevated areas, areas, taking with you documents, valuables, necessary items and a two-day supply of non-perishable food. At the final evacuation point, register.

Before leaving home, turn off the electricity and gas, turn off the fire in heating stoves, secure all floating objects located outside the building or place them in utility rooms. If time permits, move valuable household items to the upper floors or attic of a residential building. Close the windows and doors, if necessary and if there is time, board the windows and doors of the first floors from the outside with boards (shields).

In the absence of organized evacuation, until help arrives or the water subsides, stay on the upper floors and roofs of buildings, on trees or other elevated objects. At the same time, constantly give a distress signal: during the day - by hanging or waving a clearly visible banner, tacked to the staff, and in dark time- with a light signal and periodically with a voice.

When rescuers approach, calmly, without panic or fuss, and taking precautions, get into the swimming craft. At the same time, strictly follow the requirements of rescuers and do not overload the watercraft. While driving, do not leave the designated places, do not board the aircraft, and strictly follow the requirements of the crew.

It is recommended to get out of a flooded area on your own only if there are such serious reasons as the need for assistance medical care victims, a continuing rise in the water level, with the threat of flooding of the upper floors (attic). In this case, it is necessary to have a reliable swimming device and know the direction of movement. During your independent deployment, do not stop sending the distress signal. Provide assistance to people floating in water and drowning.

If a person is drowning

Throw a floating object to a drowning person, encourage him, call for help. When getting to the victim by swimming, take into account the current of the river. If the drowning person does not control his actions, swim up to him from behind and, grabbing him by the hair, tow him to the shore.

What to do after a flood

Before entering a building, check whether it is in danger of collapsing or falling of any object. Ventilate the building (to remove accumulated gases). Do not turn on electric lighting, do not use open flame sources, and do not light matches until the room is completely ventilated and the gas supply system is checked to ensure that it is working properly. Check the serviceability of electrical wiring, gas supply pipelines, water supply and sewerage. Do not use them until you have verified that they are in good working order with the help of a professional. To dry the premises, open all doors and windows, remove dirt from the floor and walls, and pump out water from the basements. Do not eat food that has been in contact with water. Organize the cleaning of wells from applied dirt and remove water from them.

Report on the topic:

"Flood"

performed by: Armina Sargsyan

Faculty: State Medical University 10th group

Flood- this is a significant flooding of an area as a result of a rise in the water level in a river, lake or sea during snowmelt, rainfall, wind surges, congestion, floods, etc. A special type includes floods caused by wind surges of water into river mouths. Floods lead to the destruction of bridges, roads, buildings, structures, cause significant material damage, and at high speeds of water movement (more than 4 m/s) and high heights of water rise (more than 2 m), they cause the death of people and animals.

The main cause of destruction is the impact on buildings and structures of hydraulic shocks from a mass of water, ice floes floating at high speed, various debris, watercraft, etc. Floods can occur suddenly and last from a few hours to 2-3 weeks.

There are also reasons caused by human activity. In recent centuries, especially in the twentieth century, anthropogenic factors have played an increasingly important role in increasing the frequency and destructive power of floods. Among them, first of all, deforestation should be mentioned (maximum surface runoff increases by 250-300%), irrational management Agriculture. A significant contribution to the increased intensity of floods and high waters was made by: longitudinal plowing of slopes, over-compaction of fields when using heavy equipment, and over-watering as a result of violation of irrigation standards. Average flood flows in urbanized areas have approximately tripled due to the growth of impervious covers and development. A significant increase in maximum flow is associated with the economic development of floodplains, which are natural flow regulators. In addition to the above, several reasons should be mentioned that directly lead to the formation of floods: improper implementation of flood protection measures leading to the breaking of embankment dams, destruction of artificial dams, emergency operation of reservoirs and others.

Types of floods

High water - a periodically repeated rather long rise in water levels in rivers, usually caused by spring melting of snow on the plains or rainfall. Floods low-lying areas. A flood can become catastrophic if the infiltration properties of the soil have significantly decreased due to its oversaturation with moisture in the fall and deep freezing in the harsh winter. Spring rains can also lead to increased flooding, when its peak coincides with the peak of the flood.

Flood - an intense, relatively short-term rise in the water level in the river, caused by heavy rains, downpours, and sometimes rapid melting of snow during thaws. Unlike floods, floods can occur several times a year. A particular threat is posed by the so-called flash floods associated with short-term but very intense downpours, which also occur in winter due to thaws.

Congestion - clogging of the riverbed by a stationary ice cover and accumulation of ice floes during the spring ice drift in narrowings and bends of the river bed, restricting the flow and causing a rise in the water level in the place of ice accumulation and above it. Jam floods form at the end of winter or early spring, and arise due to the non-simultaneous opening of large rivers flowing from south to north. The exposed southern sections of the river in its flow are dammed by the accumulation of ice in the northern regions, which often causes a significant increase in the water level. Jam floods are characterized by a high and relatively short-term rise in the water level in the river.

Zazhor - ice plug, accumulation of in-water, loose ice during winter freeze-up in narrowings and bends of the riverbed, causing water to rise in some areas above the level of the main riverbed. Jam floods form at the beginning of winter and are characterized by a significant, but less than jam, rise in the water level and a longer duration of the flood.

Wind surge is a rise in water level in the sea mouths of large rivers and on windy areas of the coast of seas, large lakes, and reservoirs, caused by the impact of strong winds on the water surface. They are characterized by a lack of periodicity, rarity and significant rise in water level, and, as a rule, short duration. Floods of this type were observed in Leningrad (1824, 1924), the Netherlands (1953). However, this type of flood is very short-lived.

Classification of floods by scale.

Low (small) - they are observed on lowland rivers. Covers small coastal areas. Less than 10% of agricultural land is flooded. They hardly disturb the rhythm of life of the population. The frequency of recurrence is 5-10 years, causing minor damage.

Dangerous - cause significant material and moral damage, covering relatively large land river valleys, flood approximately 10-20% of agricultural land. They significantly disrupt the economic and everyday life of the population. Lead to partial evacuation of people. Repeatability 20-25 years.

Particularly dangerous - cause great material damage, covering entire river basins. Approximately 50-70% of agricultural land and some populated areas are flooded. Paralyze economic activity and sharply disrupt the everyday life of the population. They lead to the need for mass evacuation of the population and material assets from the flood zone and the protection of the most important economic facilities. Repeatability 50-100 years. A striking example of this is the flood in Tomsk in 1947.

Catastrophic - lead to loss of life, irreparable environmental damage, and cause material damage, covering vast territories within one or more water systems. More than 70% of agricultural land, many settlements, industrial enterprises and utilities are flooded. At the same time, economic and production activities are completely paralyzed, and the lifestyle of the population is temporarily changed. The evacuation of hundreds of thousands of people, an inevitable humanitarian catastrophe requires the participation of the entire world community, the problem of one country becomes a problem of the whole world. If the city is located close to a river experiencing flooding, it is not very high place, as a rule, floods it too.

Flood protection measures

1) reducing the maximum water flow by redistributing the flow over time;

2) regulation of flood flow using reservoirs;

3) straightening the river bed:

4) construction of enclosing dams (shafts);

5) carrying out bank protection and dredging works, filling low places;

6) plowing land across slopes and planting shelterbelts in river basins;

7) terracing slopes, preserving tree and shrub vegetation.

Prompt preventive measures include:

1) warning the population about the threat of flooding;

2) early evacuation of the population, farm animals, material and cultural assets from potentially flooded areas;

3) partial restriction or cessation of the functioning of enterprises, organizations, institutions located in areas of possible flooding, protection of material assets.

Before evacuating, to protect their home (apartment) and property, everyone must take the following mandatory actions:

1) turn off water, gas and electricity;

2) extinguish burning heating stoves;

3) move valuable items and belongings to the upper floors of buildings (attics);

4) cover (if necessary) the windows and doors of the first floors of houses with boards or plywood.

When receiving an evacuation warning, you must quickly gather and take with you:

1) personal documents placed in a waterproof bag;

2) money and valuables;

3) medical first aid kit;

4) a set of outerwear and shoes for the season;

5) bed linen and toiletries;

6) three-day supply of food. It is better to put things and food in suitcases (backpacks, bags).

All evacuees must arrive at the evacuation assembly point by a specified time to be registered and sent to a safe area.

Target: Upon completion of the topic, students should:

Rules for safe behavior in the event of hydrodynamic accidents;

Methods for reporting accidents at hydrodynamically hazardous facilities;

Basic measures to reduce the consequences of accidents at hydrodynamically hazardous facilities;

b) have the skills to carry out measures to protect against damaging factors of accidents at hydrodynamically hazardous objects;

c) have an understanding of the consequences of accidents at hydrodynamically hazardous facilities and measures taken to protect the population.

Methods: story, conversation, explanation.

Location: classroom.

Time spending: 45 min.

Plan:

1.Introductory part:

• org. moment;
• survey

2.Main part:

• learning new material

3.Conclusion:

• repetition;

Flood call the flooding of a large area with water as a result of a rise in the water level in a river, reservoir, lake or sea, caused by an abundant influx of water during snowmelt or rainstorms, “wind” surges, during congestion, jams, and dam breaks.
There are six main types of floods based on their causes.
High water- periodically repeating relatively long-term rise in water level in rivers, usually caused by spring melting of snow on the plains or rainfall, as well as spring-summer melting of snow in the mountains; its consequence is the flooding of low-lying areas.
Flood- an intense periodic, relatively short-term rise in the water level in the river, caused by heavy rains, downpours, and sometimes rapid melting of snow during winter thaws. Congestion- accumulation of ice floes during the spring ice drift in the narrowings and bends of the river bed, restricting the flow and causing a rise in the water level in the place where the ice accumulates and in some areas above it.
Zazhor- accumulation of loose ice material during freeze-up (at the beginning of winter) in narrowings and bends of the river bed, causing a rise in the water level in some areas above it.
Wind surge- a rise in water level caused by the influence of wind on the water surface, usually occurring at the mouths of large rivers, as well as on the windward shore of large lakes, reservoirs and seas.

The main damaging factor flood is a flow of water characterized by high levels, and in case of dam breaks and floods - also at significant flow speeds. Additional damaging factors jams result in the accumulation of large masses of ice and their pressure on coastal structures, as well as low water temperatures.
Based on frequency, size (scale) and total damage caused, floods are divided into four groups - low, high, outstanding and catastrophic. Low (small) floods are observed mainly on lowland rivers and have a frequency of approximately once every 5-10 years; when they occur, agricultural lands located in floodplains are flooded. These floods cause relatively little material damage and hardly disrupt the rhythm of life of the population.
High floods are accompanied by significant flooding of territories and cover large areas of river valleys and lowlands. They significantly disrupt the economic and everyday life of the population, necessitate the partial evacuation of people and animals, and cause significant material damage. Occurs once every 20-25 years.
Major floods cover entire river basins, paralyze economic activity and disrupt the everyday life of the population over large areas, causing great material damage. They usually lead to the need for mass evacuation of population and material assets from the flood zone and the implementation of special measures to protect the most important economic facilities. Occurs once every 50-100 years.
During catastrophic floods, large areas within one or more river systems are inundated. In the flood zone, economic and production activities of the population are completely paralyzed. Such floods lead to loss of life and enormous material losses. They occur once every 100-200 years.
One of the greatest known floods is recorded in the Book of Genesis. Here, apparently, events that occurred 3000 BC are reflected in hyperbolic form. At that time, the Euphrates River flooded a vast area, including the city of Ur, located in southern Mesopotamia. The destruction caused by the river was so severe that the memory of it was passed down from generation to generation and was included in one of the books of the Bible.
The rise in water level in rivers, lakes or reservoirs depends on the conditions for the formation of water flow when it moves along the surface of the land or underground in the process of the water cycle in nature.

HOW TO ACTION IN THE THREAT OF A HYDRODYNAMIC ACCIDENT

When receiving information about the threat of flooding and evacuation, immediately, in the prescribed manner, leave the danger zone to a designated safe area or to elevated areas. Take with you documents, valuables, essentials and food supplies for 2-3 days. Some of the property that needs to be preserved from flooding, but cannot be taken with you, should be moved to the attic, upper floors of the building, trees, etc.
Before leaving home, turn off the electricity and gas, and tightly close windows, doors, ventilation and other openings.

HOW TO ACT IN FLOODING CONDITIONS IN HYDRODYNAMIC ACCIDENTS

In case of sudden flooding, to escape from the impact of a breakthrough wave, urgently take the nearest elevated place, climb a large tree or the top floor of a stable building. If you are in the water, when a breakout wave approaches, dive into the depths at the base of the wave.

Once in the water, swim or use improvised means to get out dry place, it is best to take a road or dam along which you can get to a non-flooded area. If your house is flooded, turn off its power supply, signal that there are people in the house (apartment) by hanging a flag made of bright fabric from the window during the day, and a lantern at night. To receive information, use a self-powered radio. Move your most valuable possessions to the upper floors and attics. Organize the accounting of food and drinking water, their protection from the effects of rising water and their economical use. In preparation for a possible evacuation by water, take documents, essential items, clothes and shoes with water-repellent properties, improvised life-saving equipment(inflatable mattresses, pillows).
Do not attempt to evacuate on your own. This is possible only if there is visibility of a non-flooded area, the threat of worsening the situation, the need to receive medical care, the consumption of food and the lack of prospects for receiving outside help.

1. Flooding of territories, dwellings, economic facilities, agricultural land.
2. Coastal erosion.
3. Destruction and damage to engineering structures (bridges, tunnels, gas pipelines, oil pipelines, automobile and railways and so on.).
4. Destruction of hydraulic structures and communications (dams, dams, city communications, etc.).
5. Destruction of buildings and structures, reduction of their capital value (wood is damaged by rot, plaster falls off, due to liquefaction and erosion of the soil under the foundation, uneven settlement of the building occurs, etc.);
6. Damage and damage to enterprise equipment.
7. Damage to forested areas of cities (during major floods and when a breakthrough wave moves, the flow of water uproots trees...)
8. Fires due to breaks and short circuits of electrical cables and wires;
9. Occurrence of secondary natural hazards:

1. landslides, landslides, mudflows, subsidence of forest species, etc.
2. biological damage to the lithosphere, hydrosphere, atmosphere as a result of chemical and radioactive contamination of the territory
3. infectious diseases of humans and animals
4. Removal of the most fertile soil layers from agricultural fields (soil erosion), etc.

Main characteristics of flood consequences.

1. The number of people in the flood-prone area (number of victims; number of injured; number of people left homeless, etc.).
2. Quantity settlements caught in the flooded area.
3. The number of objects of various economic sectors that found themselves in the flood zone.
4. Number of flooded, destroyed and damaged bridges and tunnels.
5.Agricultural land flooding area.
6. The number of dead animals, as well as such general characteristics as the amount of damage to various sectors of the economy.

A distinction is made between direct and indirect damage from flooding.
Direct damage includes:

1. damage and destruction of residential and industrial buildings, iron and highways, power lines, communications, etc.;
2. loss of livestock and crops;
3. destruction and damage to raw materials, fuel, food, feed, fertilizers, etc.;
4. costs of temporary evacuation of population and material assets;
5. washing away the fertile soil layer and filling the soil with sand and silt

Indirect damage includes:

1. costs of purchasing and delivering food, construction materials, and livestock feed to the affected areas;
2. reduction in production output and slowdown in the rate of development of economic sectors;
3. deterioration of living conditions of the population;
4. impossibility of rational use of the territory;
5. increase in depreciation costs for maintaining buildings in good condition.

Direct and indirect damage are usually in the ratio of 70 and 30%.

Floods

Hydrological dangerous phenomena include; high water levels (floods), rain floods, congestion and fire, the effect of surge winds, etc.

Flood- temporary flooding of a significant part of the land with water as a result of rising water levels in a river, lake or sea.

Depending on the causes, natural floods are divided into:

Floods caused by heavy precipitation or intense melting of snow (glaciers) in its river basin.

Floods resulting from a combination of flood waters and ice drift. Ice drift is often accompanied by jams (a pile of ice in the river bed) or jams (accumulation of inland water ice that forms an ice plug), causing additional rise of water and flooding of new territories. If water breaks through an obstacle, a stormy wave can form, creating a risk of flooding in the area downstream. Jams most often form on rivers that flow from south to north, since the southern sections of the river are freed from ice earlier than the northern ones, and the ice flow, which has begun, encounters an obstacle in its path in the form of freeze-up. Zazheri are formed in the pre-frost period and, in the presence of non-freezing sections of the river, during the winter.

Floods caused by wind surges. They are observed on sea coasts and at the mouths of rivers flowing into the sea. The air surge traps water at the mouth, causing its level in the river to rise. Floods of this type were observed in the Neva delta, Holland, England, Germany and other regions of the globe. A classic example of this type of flood is the floods in St. Petersburg (there were more than 300 of them during the existence of the city). The largest floods on the Neva were recorded in 1824 and 1924. In terms of their consequences, they were close to the largest floods and tsunamis.

Flooding. The causes of flooding are rising groundwater levels due to heavy rainfall and faulty drainage systems. One of the reasons for land flooding is hydraulic engineering construction, which can lead to redistribution of river flow and blocking of natural groundwater drainage routes.

Hydrological disaster, caused by a tsunami, is also considered a type of flood, although it has tectonic causes.

Experts believe that people are in danger when the water layer reaches 1 m and the flow speed exceeds 1 m/s. A rise of water of 3 m leads to the destruction of buildings and structures.

In Ukraine, floods are the most common natural disaster.

Catastrophic floods with large material losses, as well as human casualties in last years occur in Transcarpathia, their cause is not only natural factors, but also ill-considered human activities, primarily deforestation.

During a flood, there are four flood zones:

First zone- catastrophic flooding - adjacent directly to hydraulic structures or flood sources. It can reach from 6 to 12 km, and the height of the waves reaches several meters, their speed of propagation is 30 km/h or more. The time it takes for a wave to pass through the zone is up to 30 minutes.

Second zone- fast current zone. The length of the zone is up to 15-20 km, the current speed is 15-20 km/h. Wave travel time -

Third zone- middle flow zone. The length of the zone is 30-50 km. Current speed is 10-15 km/h. The wave travel time is 2-3 hours.

Fourth zone- zone of weak current (spill). Its length depends on the terrain and can be 36-70 km from the hydraulic structure or the starting point natural phenomenon. Current speed is 6-10 km/h.

Floods on rivers based on the height of the water rise, the area of ​​flooding and the amount of damage caused are divided into 4 categories: low (small), high (medium), significant (large) and catastrophic. Low floods repeat after 5-10 years, high - after 20-25 years, significant - after 50-100 years and catastrophic - no more than once every 100-200 years.

In Ukraine, floods of the 1st and 2nd categories (low and high) are possible. In total, there are 22.4 thousand rivers on the territory of Ukraine with a total length of 130 thousand km. The rivers of the Carpathians and Crimea are mountainous, fast-flowing, and predominantly rain-fed. Floods and inundations occur there, of course, during the summer rainy season. Other rivers are of the flat type, predominantly snow-fed. Floods and floods are most often a consequence of spring melting of snow.

Gum- a typical lowland river with high spring floods and low summer and winter low water. The food is mainly snow. Spring runoff is more than 50% of the annual flow. The flood begins in mid-April and reaches its maximum in mid-May. In some rainy years there are autumn floods.

Dnieper-characterized by great unevenness of flow both from year to year (change in annual flow from 24 to 73 billion m3) and within one year. During the spring flood, 60-70%, and in some years - up to 80% of the total annual water flow, passes through. In autumn, the water reserves of the Dnieper can increase several times, so in winter, during the thaw period, floods are observed.

In order to regulate the flow of the Dnieper, reduce the risk of floods and provide water to the Dnieper region, Donbass, Krivoy Rog and Crimea, a scheme for the water and energy use of the Dnieper was developed, which included the construction of six large hydroelectric power stations and reservoirs.

Dniester- the water regime is characterized by a clearly defined spring flood and big amount floods that throughout the year (except for one to three winter months) alternate with short periods of low levels. Floods occur in the spring as a result of melting snow, in the summer - due to heavy rains, in the winter - during thaws.

Southern Bug has fluctuations in water levels from 1.64 m to 9.4 m. The river is fed by snow, rain and underground runoff. Many dams have been built in the upper and middle reaches. In the area of ​​the mouth, flooding is possible due to the impact of surge winds. Runoff is characterized by significant variability. Spring runoff is 61% of the annual flow, summer - 9%, autumn - 12%, winter - 18%.

Pripyat- the right tributary of the Dnieper, it is characterized by long (more than 4 months) spring floods and low water levels in late summer and early autumn. During spring floods, the river overflows its banks, flooding numerous areas.

Seversky Donets- the largest tributary of the Don is right. The average annual flow is 160 m3 per 1 s. Powered by snow and rain. In Ukraine it flows through the territory of the largest industrial regions (Kharkov, Donbass) and is the main source of their water supply. To provide water to Donbass, the Seversky Donets-Donbass canal was built. To improve water supply in Kharkov, a reservoir with a volume of 400 million m 3 was built.

A significant part of the year is regulated by dams, the destruction of which can lead to catastrophic flooding.

Probable zones of possible floods in Ukraine:

- in the northern region- basins of the Pripyat and Desna rivers and their tributaries. Flood area only in the river basin. Pripyat can reach 600-800 thousand hectares;

- in the western region- basins of the upper Dniester (area can reach 100-130 thousand hectares), Tisa, Prut, Western Bug (area possible flooding 20 - 25 thousand hectares) and their tributaries;

- in the eastern region- basins of the Seversky Donets with its tributaries, the rivers Psla, Vorskla, Sula and other tributaries of the Dnieper;

- in the southern and southwestern regions- basins of tributaries of the Lower Danube, the Southern Bug River and its tributaries.

The duration of floods (flooding) can reach 7-20 days or more. In this case, it is possible to flood not only 10-70% of agricultural land, but also a large number of man-made hazardous objects.

Floods were often accompanied mudflows and landslides, destruction of residential buildings, protective dams, bridges, roads and human casualties.

Protecting people in flood conditions includes warning, evacuation of people and other measures in accordance with flood control and population protection plans.

In order to prevent floods, reservoirs are created to regulate river flow, and special protective structures (dams) are built. Thus, a network of reservoirs has been created on the Dnieper River, which makes it possible to systematically regulate river flow and significantly reduce the scale of floods. For example, in Russia, in the Neva delta, a protective complex more than 25 km long is being built, which will close the water area and become a protection against floods.

To ensure protection during floods, civil defense forces and the population are trained.

Personal safety. When you hear a warning about the threat of flooding, turn off the gas and electricity and immediately go to a safe place - to increase. If the flood spreads slowly and you have time, take measures to save property and material assets: move them to a safe place, and occupy the upper floors (attics) and roofs of buildings. Stock up on food and drinking water. Use existing flotation devices or make them from logs, boards, inner tubes and other items.

Once in the water, take off your heavy clothes (woolen clothes can retain heat in water, so it is not recommended to take them off in cold water) and shoes, use objects floating nearby or raised above the water and wait for help.

Actions during floods in enterprises. When there is a threat of flooding, enterprises, if necessary, stop the work of some units, workshops, departments, and in some cases the entire enterprise. IN educational institutions and children's institutions are suspending classes. In departments that have temporarily stopped working, electricity is cut off and the supply of steam, gas, and water is stopped.

24-hour duty of responsible officials and emergency technical service specialists is organized at the facilities.

To protect populated areas, utility buildings, and industrial premises from flooding, the simplest protective hydraulic structures are built: earthen embankments, dams, and dams. In addition, it is necessary to organize surveillance of such structures. Near them, in case of water leakage, emergency materials are placed to close breaks and to build up dams.

The size of human and material losses during a flood depends on the nature and scale of the flood, the population density in the flooded area, the distance of populated areas from the source of the flood, the nature of the development, the cost of material assets located in the flooded area, the presence of protective structures, environmentally hazardous objects, and the seasons. and days, etc.

Important conditions for effective rescue work during a flood are forecasting the possible time of occurrence and scale of floods, timely notification of the population and its evacuation, organizing a search for people in the flooded area, the accuracy of rescue operations, the number of rescue teams, their provision with special means and equipment and preparedness personnel of these formations, the timeliness and quality of medical care to victims, the organization of clear interaction between health authorities, rescue and other formations involved in the liquidation of the consequences of the flood and the provision of first medical aid to victims.

In conditions big city in the event of a catastrophic flood, the proportion of the affected population that needs emergency medical care (as a percentage of the population) will fluctuate during the warm period of the year during the day from 0.02% to 2.7%, at night - from 0.06% to 4 ,5%; in the cold season - from 0.04% to 4.3% during the day and up to 0.08% -5.7% at night.

In the event of an immediate threat of flooding, by decision of the head of the civil defense district (facility), the control point is put on alert, where responsible officials are organized and the tasks of the headquarters, services and civil defense formations are clarified.

If there is a threat of flooding, an urgent evacuation of the population and material assets is organized. The population is informed of the locations of the deployment of prefabricated evacuation points, the timing of arrival at the points, and evacuation routes.

The search for people in the flooded area and evacuation are carried out by civil defense units, the population and, if possible, military units. For this purpose, all watercraft are used (bots, barges, boats, boats), etc., you can use improvised means (logs, boards, barrels) and build rafts; it is also allowed to transport people in a designated ford with a depth of no more than 1 m.

After the water has subsided, they begin to eliminate the consequences of flooding. These works include: draining water from flooded areas and draining them; filling up and cleaning dilapidated structures that cannot be restored; pumping water from basements and other premises; repair of water-damaged buildings, utility networks, roads, bridges and other structures; cleaning of flooded areas, agricultural lands, lands, areas of livestock farms, rural streets, courtyards, etc.

Engineering flood protection provides for the construction of small and large reservoirs, which makes it possible to regulate river flow and thus reduce the risk of floods during flood periods.

The problem of flood control requires a long-term forecast.