Introduction

1. Causes of flooding

2. Effects of floods

3. Flood prevention measures, rescue work

Conclusion

Bibliography

Introduction

It is well known that the state and development of both the biosphere and human society is directly dependent on the state of water resources. IN recent decades All more experts and politicians among the problems facing mankind, at number 1 call the problem of water. Water problems arise in four cases: when there is no or insufficient water, when the quality of water does not meet social, environmental and economic requirements, when the regime of water bodies does not correspond to the optimal functioning of ecosystems, and the regime of its supply to consumers does not meet the social and economic requirements of the population, and, finally, when the habitable territories suffer from floods from excess water.

In the global aspect, the first three problems were the product of the outgoing century, and the fourth has been accompanying human society since ancient times. And paradoxically, for many centuries, humanity, making incredible efforts to protect against floods, cannot succeed in this event. On the contrary, with every century the damage from floods continues to grow. Especially strong, about 10 times, it has increased over the second half of the past century. According to our calculations, the area of ​​flood-prone areas on the globe is about 3 million square meters. km, which is home to about 1 billion people.

1.Causes of the flood

Flooding - temporary flooding of a significant part of the land with water as a result of the action natural forces. Depending on the causing causes, they can be divided into groups.

Floods caused by heavy rainfall or heavy melting of snow, glaciers. This leads to a sharp rise in the level of rivers, lakes, and the formation of congestion. The breakthrough of congestion and dams can lead to the formation of a breakthrough wave, characterized by the rapid movement of huge masses of water and a significant height. The flood in August 1989 in Primorye demolished a significant number of bridges and buildings, killing a huge number of livestock, damaging power lines, communications, roads destroyed, and thousands of people were left homeless.

Floods caused by surge winds. They are typical for coastal regions where there are mouths major rivers flowing into the sea. The surging wind delays the movement of water into the sea, which sharply raises the water level in the river. Under the constant threat of such a flood are the coasts of the Baltic, Caspian and Seas of Azov. So, St. Petersburg has experienced more than 240 such floods during its existence. At the same time, cases of the appearance of heavy ships were observed on the streets, which caused the destruction of urban buildings. In November 1824, the water level in the Neva rose 4 m above the norm; in 1924 - by 3.69 m, when water flooded half of the city; in December 1973 - by 2.29 m; January 1984 - by 2.25 m. And as a result of the floods - huge material losses and victims.

Flooding caused by underwater earthquakes. They are characterized by the appearance of giant waves of great length - tsunamis (in Japanese - "big wave in the harbor"). Tsunami propagation speed up to 1000 km/h. The height of the wave in the area of ​​its origin does not exceed 5 m. But when approaching the shore, the steepness of the tsunami increases sharply, and the waves crash on the coast with great force. At flat coasts, the wave height does not exceed 6 m, and in narrow bays it reaches 50 m (tunnel effect). The duration of the tsunami up to 3 hours, and affected by them coastline reaches a length of 1000 km. In 1952, the waves almost washed away Yuzhno-Kurilsk.

natural causes floods are well known to readers, and therefore we will only mention them. In most areas globe floods are caused by prolonged, intense rain and downpours resulting from the passage of cyclones. Floods on the rivers of the Northern Hemisphere also occur due to the rapid melting of snow, ice jams, ice jams. Foothills and high-mountain valleys are exposed to floods associated with outbursts of intraglacial and dammed lakes. In coastal areas, surge floods are not uncommon during strong winds, and during underwater earthquakes and volcanic eruptions, floods caused by tsunami waves.

In recent centuries, especially in the 20th century, anthropogenic factors have played an increasing role in increasing the frequency and destructive power of floods. Among them, first of all, we should mention deforestation (the maximum surface runoff increases by 250-300%), irrational management Agriculture(as a result of a decrease in the infiltration properties of soils, according to some calculations, in the central regions of Russia from the 9th to the 20th century, surface runoff increased 4 times and the intensity of floods increased sharply). A significant contribution to the increase in the intensity of floods and floods was made by: longitudinal plowing of slopes, overconsolidation of fields when using heavy equipment, overwatering as a result of violation of irrigation norms. The average flood discharge in urban areas has approximately tripled due to the growth of impermeable coatings and development. A significant increase in the maximum runoff is associated with economic development 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 a breach of embankment dams, destruction of artificial dams, emergency drawdown of reservoirs, etc.

2. Effects of floods

The structure of sanitary losses during floods is dominated by injuries (fractures, damage to the joints, spine, soft tissues). Cases of diseases as a result of hypothermia (pneumonia, acute respiratory infections, rheumatism, worsening of the course of chronic diseases), the appearance of victims from burns (due to flammable liquids spilled and ignited on the surface of the water) have been recorded.

In the structure of sanitary losses, children occupy a significant place, and the most common consequences among the population are psychoneuroses, intestinal infections, malaria, and yellow fever. Human casualties are especially high on the coasts during hurricanes and tsunamis, as well as during the destruction of dams and dams (more than 93% drowned). As an example, the consequences of the 1970 flood in Bangladesh can be cited: on most of the coastal islands, the entire population died; out of 72 thousand fishermen in coastal waters, 46 thousand died. More than half of the dead were children under 10 years old, although they accounted for only 30% of the population of the disaster zone. Mortality among the population older than 50 years, among women and patients was also high.

Frequent companions of floods are large-scale poisoning. Due to the destruction of treatment facilities, warehouses with hazardous chemicals and other harmful substances, drinking water sources are poisoned. The development of extensive fires is not ruled out when flammable liquids spill over the surface of the water (gasoline and other combustible liquids are lighter than water).

3. Flood prevention measures, rescue work.

Floods are successfully predicted, and the relevant services give warnings to dangerous areas, which reduces damage. In places of floods, dams, dams, hydraulic structures are built to regulate the flow of water. In the winding places of the rivers, work is carried out to expand and straighten their channels. During the threatened period, duty and maintenance of readiness of civil defense formations are organized. Early evacuation of the population, cattle theft, and removal of equipment are being carried out.

Rescue work in flooded areas often takes place in difficult weather conditions (rain showers, fogs, squally winds). Work to save people begins with reconnaissance, using boats and helicopters equipped with communications equipment.

Places of congestion of people are established, and funds are sent there to ensure their salvation. Work on hydraulic structures is carried out by the formation of engineering and emergency technical services of the Civil Defense and Emergency Service: this is the strengthening of dams, dams, embankments or their construction.

In case of floods, the following are involved in rescue operations: rescue teams, teams and groups, as well as departmental specialized teams and subunits equipped with watercraft, sanitary teams and posts, hydrometeorological posts, reconnaissance teams and units, combined teams (teams) for mechanization of work, formation of construction, repair and construction organizations, protection of public order.

Rescue operations during floods are aimed at searching for people in a flooded area (landing them on boats, rafts, barges or helicopters) and evacuating them to safe places.

Reconnaissance groups and units operating on high-speed watercraft and helicopters determine the places where people gather in the flooded area, their condition and periodically give sound and light signals. Based on the intelligence data received, the head of the civil defense specifies the tasks for the formations and puts them forward to the objects of rescue operations.

Small groups of people in the water are thrown out with lifebuoys, rubber balls, boards, poles, or other floating objects, taking into account the flow of water, wind direction, they are taken to floating craft and evacuated to safe areas. For rescue and removal from the flooded area a large number people use motor ships, barges, launches, boats and other watercraft. Landing people on them is carried out directly from the shore. In this case, they choose and designate places convenient for ships to approach the shore, or equip berths.

When rescuing people who are in a break in the ice, they give the end of the rope, boards, ladders, any other object and pull it out to a safe place. Approaching people in the polynya should be crawling with outstretched arms and legs, leaning on boards or other objects.

To remove people from semi-flooded buildings, structures, trees and local objects or rescue them from the water, all watercraft used to perform rescue operations must be equipped with the necessary equipment and devices.

Medical assistance is provided by rescue units or sanitary teams directly in the flood zone (the first health care) and after delivery to the berth (first medical aid).

The situation in the area of ​​flooding can be sharply complicated as a result of the destruction of hydraulic structures. Work in this case is carried out in order to increase the stability of the protective properties of existing dams, dams and embankments; prevention or elimination of water washing of earthworks and increasing their height. The fight against flooding during the period of ice drift is carried out by eliminating congestion and ice jams that form on the rivers.

Carrying out rescue and urgent emergency and restoration work in flood control causes a certain danger to the life of the personnel of the formations. Therefore, the personnel of the formations must be trained in the rules of behavior on the water, methods of rescuing people and using rescue equipment. When carrying out work, it is forbidden to use faulty equipment, overload watercraft, carry out explosive work near power lines, underwater communications, industrial and other facilities without prior approval from the relevant organizations.

Flood prevention measures:

1. In the economic development of flood-prone territories, both in river valleys and on sea coasts, detailed economic and environmental studies should be carried out. Their goal is to identify ways to obtain the maximum possible economic effect from the development of these territories and at the same time minimizing the possible damage from floods.

2. When developing flood control measures in river valleys, the entire watershed should be considered, and not its individual sections, since local flood control measures that do not take into account the entire flood situation in the river valley can not only not give an economic effect, but also significantly worsen the situation as a whole. and result in more flood damage.

3. It is necessary to skillfully combine engineering protection methods with non-engineering ones. First of all, these include: restriction or complete prohibition of such types of economic activity, as a result of which floods may increase (forest harvesting, etc.), as well as the expansion of measures aimed at creating conditions leading to a decrease in runoff. In addition, in flood-prone areas, only such types of economic activity should be carried out, which, if flooded, will cause the least damage.

4. Engineering structures for the protection of lands and economic facilities must be reliable, and their implementation must be associated with minimal disturbance to the natural environment.

5. A clear zoning and mapping of floodplains should be carried out with drawing the boundaries of floods of various probability. Taking into account the type of economic use of the territory, it is recommended to allocate zones with 20% flood security (for agricultural land), 5% security (for buildings in countryside), 1% security for urban areas and 0.3% security for railways. It goes without saying that in different natural zones and ecological regions the number of zones and the principles of their allocation may change to some extent.

6. The country should have a well-functioning system for forecasting floods and for notifying the population about the time of the onset of the flood, about the maximum possible levels of its level and duration. Forecasting floods and floods should be carried out on the basis of the development of a wide, well-equipped with modern instruments service for observing the hydrometeorological situation.

7. Great importance should be given to informing the public in advance about the possibility of flooding, explaining its likely consequences and measures to be taken in case of flooding of buildings and structures. To this end, television, radio and other media should be widely used. Flood knowledge should be widely promoted in flood-prone areas. All state structures, as well as each resident, must clearly understand what they should do before, during and after the flood.

8. It is very important to develop and further improve methods for calculating both direct and indirect damage from floods.

9. Regulation of the use of flood-prone areas should be the prerogative of the republics, territories, regions, districts and cities. The state can direct and stimulate their activities only by adopting certain laws on the regulation of land use.

10. The system of flood protection measures should include both state and public organizations, as well as private individuals. The successful operation of such a system should be coordinated and directed by a central authority at the federal level.

11. The best tool for regulating land use in flood prone areas may be a flexible flood insurance program that combines both compulsory and voluntary insurance. The main principle of this program should be as follows: in case of adopting a rational type of use of the territory from the standpoint of flood protection, the insured is paid a significantly larger sum insured than if he ignores the relevant recommendations and norms.

12. A set of measures in flood-prone areas, including forecasting, planning and implementation of work, should be carried out before the onset of a flood, during its passage and after the end of a natural disaster.

A detailed development of the above provisions of the concept is an urgent task for a number of research and design institutes, a number of ministries, and primarily the Ministry of Emergency Situations.

Conclusion

An analysis of floods over the past century, carried out by us in many countries, showed that all over the world, including Russia, there is a tendency for a significant increase in flood damage caused by irrational management in river valleys and increased economic development of flood-prone areas.

It is necessary to study the factors leading to an increase in floods, especially catastrophic ones, in the 21st century: climate change (increased precipitation, melting ice and rising ocean levels, etc.), further growth in the economic development of river valleys due to an increase in population. Special problems should be studied in the valleys of those rivers whose channels are protected by dams and whose bottom sometimes rises many meters above the floodplains and terraces above the floodplains (Huang He, Yangtze, etc.).

Further clarification of the concept of flood protection is needed, taking into account a wide range of environmental, social, technical, cultural, educational and health measures to be implemented in flood-prone areas before, during and after the end of floods.

Among the priorities in the field of flood research should also include: the development of a methodology for accounting for damage caused by changes in natural environment: valley morphology, soil cover, vegetation, wildlife, water quality, as well as methods for accounting for damage to human health during and after floods.

List of used literature:

1. http://intra.rfbr.ru/pub/vestnik/V4 01/3 1.htm

2. Floods // Fundamentals of life safety. - 1999. - N: 3. - S. 60.

3. Avakyan, Artur Borisovich. Floods / Artur B. Avakyan, Alexey A. Polyushkin,. - M.: Knowledge, 1989. - 46 p.

4. Osipov V.I. Natural disasters at the turn of the 21st century / V.I. Osipov // Vestn. RAN. - 2001. - N: 4 - S. 291-302

5. Avakyan A. Natural and anthropogenic causes of floods. / Avakyan A. // Fundamentals of Life Safety. - 2001. - N 9. - S. 22-27.

5.1. Flood - this is a temporary flooding of a vast territory as a result of a rise in the water level in a river, lake, or sea. Floods occur as a result of intense melting of snow (glaciers), heavy rainfall, traffic jams and ice dams, destruction of hydraulic structures, and tsunamis.

Congestion- this is the accumulation of ice in the riverbed, limiting its flow, as a result, the water rises and spills. The jam is formed during ice drift and consists of large and small ice floes.

Zazhor- this is the clogging of the riverbed with internal ice under a fixed ice cover and the formation of an ice plug. Ice dams form in rivers during the formation of the ice cover.

high water- a relatively long-term increase in the flow of rivers, which is repeated annually in the same season, accompanied by an increase in the water level. May cause flooding.

high water- relatively short-term and non-periodic water level rise. Floods following one after another can lead to floods.

Surge floods arise under the influence of powerful cyclones, when the wind reaches high speed and creates a huge surge wave that blocks the flow of rivers and the natural discharge of water into the sea. Encountering such an obstacle, the water in the river rises sharply and can flood a significant area of ​​the adjacent territory. Surge floods often occur in St. Petersburg, Holland, England.

Flooding is the most common natural hazard, the damage from which annually amounts to hundreds of millions of rubles in Russia.

Today, most floods are predictable, which allows timely preparatory work. The main methods of flood control are the construction of enclosing dams and reservoirs, the diversion of water into the channels of other rivers and reservoirs, and the carrying out of bank and dredging works.

Those who live in areas prone to frequent flooding should:

build houses on high foundations;

have a floating facility (boat, raft);

store in an accessible and secure place papers, valuables;

stock up on food and medicine.

Actions during a flood:

Before leaving the house, everything that water can spoil should be transferred to the upper floors or other non-flooded places; turn off gas and electricity. Then, taking with you the documents, the most necessary things, a small supply of food and water, arrive at the collection point.

Evacuation is carried out in large settlements outside the flood zones.

About the sudden onset of flooding, for example, during the destruction of a hydraulic structure, the population is warned by all available technical means. You should go up to the upper floors, and if the house is one-story, take the attic or go to the roof. The evacuation of the population in this case will be carried out on boats, boats, rafts and other floating facilities. During landing on them, strict discipline must be observed. One should go down into the boat one at a time, stepping on the middle of the flooring, and sit down only at the direction of the elder. During the movement of the boat, you can not change places, get on board; The bow of the boat should be kept perpendicular to the wave. After mooring, one of the passengers must go ashore and hold the boat until all people are on land.

If the flood caught you in a field, in a forest, take the most elevated place: climb a tree, etc.

Remember: the search for people in the flooded area is organized immediately. A drowning person is approached in a boat against the current, and lifted from the stern.

Actions after the flood:

° After the water subsides, keep away from torn and sagging electrical wires, damaged gas lines.

Before entering the house, make sure it is secure. Then dry it: pump out water from cellars and cellars; open all windows and doors. Heavily damaged houses are being demolished.

You can use gas, electricity, sewerage only after obtaining permission from the utilities. It is better not to touch electrical wires and sockets until they are completely dry.

Organize the cleaning of wells from the applied dirt and remove water from them. Strictly observe the rules of hygiene in order to prevent outbreaks of epidemics associated with the mass death and decomposition of animals. Do not eat food that has been in contact with water.

5.2. Tsunami- these are giant sea waves resulting from the upward or downward displacement of extended sections of the bottom during strong underwater and coastal earthquakes, less often volcanic eruptions (Fig. 2.2).

The height of the waves in the area of ​​their occurrence is 0.1-5 m, near the coast - up to 40 m, in wedge-shaped bays and river valleys - over 50 m. Tsunamis can spread inland up to 3 km. The main area where tsunamis appear is the coasts of the Pacific and Atlantic oceans (80% of cases), less often the Mediterranean Sea.

Possessing great energy, tsunamis lead to flooding of the area, destruction of buildings and structures, power transmission and communication lines, roads, bridges, as well as to the death of people and animals. An air shock wave propagates in front of the water shaft, which acts similarly to a blast wave, destroying buildings and structures.

A natural tsunami warning signal is an earthquake. Before the start of the tsunami, the water recedes far from the coast, exposing sea ​​bottom hundreds of meters or even several kilometers. Low tide can last from a few minutes to half an hour. The movement of the waves is accompanied by thunderous sounds (they are heard before the approach of the tsunami waves). Before the tsunami, the behavior of animals also changes.

Actions during a tsunami:

Leave the room immediately, after turning off the electricity and gas.

In the shortest way, move to an elevated place 30-40 m above sea level or at a distance of 2-3 km from the coast.

If you are driving, drive in a safe direction, picking up running people along the way.

Once in the water, get rid of shoes and wet clothes, try to catch on floating objects (be careful - the wave can carry large objects and their fragments with it).

Before entering the house after the tsunami, check its strength, the safety of the doors, the condition of the electric lighting, and the absence of gas leaks in the room.

There is no reliable protection against a tsunami. Important for the protection of the population from tsunamis are warning services about the approach of waves, based on the advance registration of earthquakes by coastal seismographs. Tsunamis are not dangerous for ships on the high seas.

FLOODING is a significant flooding of the area as a result of a rise in the water level in a river, lake or sea during the period of snowmelt, heavy rains, wind surges of water, during traffic jams, blockages, etc.

Floods caused by wind surge of water in the mouths of rivers are of a special type. Floods lead to the destruction of bridges, roads, buildings, structures, cause significant material damage, and at high water speeds (more than 4 m/s) and high water rise (more than 2 m) cause death of people and animals. The main cause of destruction is the impact on buildings and structures of hydraulic shocks of water masses, ice floes floating at high speed, various debris, watercraft, etc. Floods can occur suddenly and last from a few hours to 2-3 weeks.

Types of flood

Depending on the cause of the flood, they are divided into 5 types:

• high water - flooding resulting from the melting of snow and the release of a reservoir from its natural banks
• flood - flooding associated with heavy rains
• floods caused by large accumulations of ice that clog the riverbed and prevent water from flowing downstream
• surge floods , occurring due to strong winds that drive water in one direction, most often against the current
• floods resulting from dam break or reservoirs.

high water	high water	Congestion	Zazhor	wind surge
recurring, rather prolonged rise in the water level in rivers, usually caused by spring snowmelt on the plains or rainfall. Floods low terrain.	an intensive relatively short-term rise in the water level in the river, caused by heavy rains, downpours, and sometimes rapid snowmelt during thaws. Unlike floods, floods can occur several times a year. A particular threat is the so-called flash floods associated with short-term, but very intense downpours, which also occur in winter due to thaws.	clogging of the channel by a motionless ice cover and heaping of ice floes during the spring ice drift in the narrowings and on the bends of the river channel, restricting the flow and causing a rise in the water level in the place of ice accumulation and above it. Jam floods are formed in late winter or early spring, and occur due to the non-simultaneous opening of large rivers flowing from south to north. Opened southern sections of the river in its course spring up accumulation of ice in the northern regions, which often causes a significant increase in water levels. Jam floods are characterized by a high and relatively short-term rise in the water level in the river.	ice plug, accumulation of in-water, loose ice during winter freezing in narrowings and on the bends of the channel, causing the rise of water in some areas above the level of the main river channel. Jag floods form at the beginning of winter and are characterized by a significant, but less than during a jam, rise in the water level and a longer duration of the flood.	rise in the water level in the sea mouths of large rivers and in windy areas of the coast of the seas, large lakes, reservoirs caused by the impact of strong winds on the water surface. They are characterized by the absence of periodicity, rarity and a significant rise in the water level, as well as, as a rule, short duration. Floods of this type have been observed in Leningrad (1824, 1924), the Netherlands (1953).
periodically for a long time	fast briefly	ice is standing, piling up water can't get out high level briefly	ice plug loose ice low level for a long time	wind from the sea into the riverbed water can't get out high level brevity

Causes of floods:

1. Long rains
2. snowmelt
3. tsunami wave
4. bottom profile
5. Dam failure
6. Other natural and man-made causes

Flood classification:

1. storm (rain);
2. floods and floods (associated with the melting of snow and glaciers);
3. jamming and jamming (associated with ice phenomena);
4. overwhelming and breakthrough;
5. surge (wind on the coasts of the seas);
6. tsunamigenic (on the coasts from underwater earthquakes, eruptions and large coastal landslides).

River floods are divided into the following types:
1. low (small or floodplain) - a low floodplain is flooded;
2. medium - high floodplains are flooded, sometimes inhabited or technogenically processed (arable land, meadows, vegetable gardens, etc.);
3. strong - terraces with buildings located on them, communications, etc. are flooded, evacuation of the population is often required, at least partial;
4. catastrophic - vast areas are significantly flooded, including cities and towns; emergency rescue operations and mass evacuation of the population are required.

According to the scale of manifestation, there are 6 categories of floods:
1. global flood;
2. continental;
3. national;
4. regional;
5. district;
6. local.

Anthropogenic causes of floods:

Direct causes - are associated with the implementation of various hydraulic engineering measures and the destruction of dams.
Indirect - deforestation, drainage of swamps (draining of swamps - natural runoff accumulators increases runoff up to 130 - 160%), industrial and housing development, this leads to a change in the hydrological regime of rivers due to an increase in the surface component of runoff. The infiltrating capacity of soils decreases and the intensity of their washout increases. The total evaporation is reduced due to the cessation of precipitation interception by forest litter and tree crowns. If all forests are reduced, then the maximum runoff can increase up to 300%.
There is a decrease in infiltration due to the growth of waterproof coatings and buildings. The growth of water-resistant coatings in an urbanized area increases floods by 3 times.

Human activities leading to floods:
1. Restriction of the free section of the flow along the channel roads, dams, bridge crossings, which reduces the capacity of the channel and raises the water level.
2. Violation of the natural regime of discharges and water levels, as occurs on the lower Volga as a result of seasonal regulation of the flow by overlying reservoirs: the need for winter energy forced a 2-3-fold increase in water discharges in winter, which, in the presence of ice cover, is accompanied by an increase in water level (winter floods), often higher than in high water.
3. Development of territories in the downstream pools of reservoirs of long-term flow regulation. The economic development of the floodplains increases the maximum runoff.

flood classes

1. Low. They usually do minor damage. They cover small coastal areas. Agricultural lands are flooded by less than 10%. Almost do not knock out the population from the current rhythm of life. Repeatability - 5-10 years.

2. High. Cause significant damage (moral and material). They cover large areas of river valleys. They flood about 10-15% of the land. Violate both household and economic way of life of the population. Partial evacuation of people is very likely. Periodicity - 20-25 years.

3. Outstanding. They cause great material damage, covering river basins. Approximately 50-70% of agricultural land, as well as a certain part of settlements, is under water. Outstanding floods not only disrupt the way of life, but also paralyze economic activity. Evacuation required material assets and the population from the disaster zone and the protection of the main objects of economic importance. Repeatability - 50-100 years.

4. Catastrophic. They cause huge material damage, spreading over vast territories within one or more river systems. Lead to human casualties. More than 70% of the land is flooded, many settlements, utilities and industrial enterprises. Completely paralyzed production and economic activity, as well as changing the way of life of the population. Periodicity - 100-200 years.

Danger factors:

1. height of water level change;
2. the rate of its change;
3. the duration of the rise period;
4. accompanying phenomena (wind, landslides, soil erosion, turbulent streams, destruction of agricultural products, livestock, death of people, etc.).

The flow of water as a damaging factor

Characteristics of the water flow as a damaging factor:

1. The highest water level.

2. The highest water consumption.

3. The speed of the current.

4. Area of ​​flooding.

5. Repeatability of the value of the highest water level.

6. Duration of flooding.

7. Water temperature.

8. Security of the highest water level.

9. Time of start of the disaster.

10. The rate of rise in the water level during the entire time of the flood.

11. The depth of flooding of the territory in the area under consideration.

Damaging factors:

The combined effect of waves, wind, rainfall causes flooding of the area. This is accompanied by a significant erosion of the coast, leading to the destruction of buildings and structures, erosion of railways and roads, accidents on utility networks, destruction of crops and other vegetation, casualties among the population and the death of domestic animals and natural ecosystems. After the water falls, buildings and land sag, landslides and landslides begin.

Flood consequences:

The main features of the situation that arises during such natural disasters are: the rapid increase in the strength of damaging factors, the difficulty of access to the victims, the destructive nature of the situation, the low survival rates of the victims, as well as the presence of difficult weather conditions (mudflows, ice drift, heavy rains, etc.). ).

The amount of damage depends on:
1. - lifting heights;
2. - speed of water level rise;
3. - areas of flooding;
4. - timeliness of the forecast;
5. - availability and condition of protective structures;
6. - the degree of population and agricultural development of the river valley;
7. - the duration of standing flood waters;
8. - the frequency of floods (with repeated rises in the water level, the damage is less than with the initial one).

The passage of floods (flooding of agricultural land) after harvesting leads to less damage than before harvesting.
The severity of emergencies during channel floods depends not so much on the absolute value of the rise in the water level, but on its value relative to the altitude of settlements.

How to prepare for a flood?

If your area often suffers from floods, study and remember the boundaries of possible flooding, as well as elevated, rarely flooded places located in close proximity to 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 areas for boats, rafts and building materials for their manufacture. Prepare in advance a list of documents, property and medicines taken out during the evacuation. Put valuables, necessary warm clothes, a supply of food, water and medicines in a special suitcase or backpack.

HOW TO PROCEED DURING A FLOOD

At the warning signal of the threat of flooding and evacuation, immediately, in accordance with the established procedure, leave (leave) the danger zone of possible catastrophic flooding to the designated safe area or to elevated areas of the area, taking with you documents, valuables, necessary things and a two-day supply of non-perishable food. Register at the final evacuation point.

Before leaving the house, turn off the electricity and gas, put out the fire in the heating stoves, secure all floating objects that are outside the buildings, or place them in utility rooms. If time permits, move valuable household items to the upper floors or to the attic of a residential building. Close the windows and doors, if necessary and have time, board the windows and doors of the first floors from the outside with boards (shields). In the absence of an organized evacuation, stay on the upper floors and roofs of buildings, on trees or other towering objects until help arrives or the water subsides. At the same time, constantly give a distress signal: during the day - by hanging or waving a clearly visible panel lined with a pole, and in the dark - by a light signal and periodically by voice. When the rescuers approach, calmly, without panic and fuss, in compliance with the precautionary measures, go to the swimming facility. At the same time, strictly follow the requirements of the rescuers, do not overload the boats. During the movement, do not leave the assigned places, do not board the sides, strictly follow the requirements of the crew. It is recommended to get out of the flooded area on your own only if there are such serious reasons as the need to provide medical assistance to the victims, the 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 facility and know the direction of movement. During self-advance, do not stop giving a distress signal.

Help people who are swimming in the water and drowning.

IF A MAN DROWNS

Throw a floating object to a drowning person, encourage him, call for help. When reaching the victim by swimming, consider the course 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.

HOW TO ACT AFTER A FLOOD

Before entering a building, check to see if it is in danger of collapsing or falling.

Ventilate the building (to remove accumulated gases). Do not turn on electric lighting, do not use open flames, do not light matches until the room is completely ventilated and the gas supply system is checked for proper operation. Check the serviceability of the electrical wiring, gas supply pipelines, water supply and sewerage. Do not use them until you have verified that they are working properly with the help of specialists. To dry the premises, open all doors and windows, remove dirt from the floor and walls, pump out water from the basements. Do not eat food that has been in contact with water. Organize the cleaning of wells from the applied dirt and remove water from them.

Distinguish between such concepts as high water, high water and flood.

high water called a relatively long-term increase in the flow of rivers, which is repeated annually in the same season, accompanied by an increase in the water level.

high water- a relatively short-term and non-periodic rise in the water level. Following one after another pickups can form high water, and the last flood.

Significant flooding of the area adjacent to a river, lake or reservoir, which causes material damage, damages the health of the population or leads to death of people, is called flood.

Causes of floods are heavy rainfall, intense snowmelt or underwater earthquakes, which result in giant waves -. greatest danger represent sudden floods during the destruction of hydraulic structures. Floods are often accompanied by loss of life and significant material damage. If flooding is not accompanied by damage, it is a flood of rivers, lakes, reservoirs.

River floods in Russia

Floods to a greater or lesser extent are periodically observed on most of the rivers of Russia. In terms of frequency, distribution area and total average annual material damage, they rank first among natural disasters. In terms of the number of human casualties and material damage, floods are second only to earthquakes. Neither in the present nor in the near future to prevent them entirely is not possible. Floods can only be weakened or localized.

Numerous rivers of the country differ from each other in different conditions for the formation of water flow, and this to a large extent determines the conditions for the occurrence of floods.

Based on this, the rivers of Russia, according to the conditions for the occurrence of floods, are divided into four types:

• rivers with maximum flow caused by melting snow on the plains. It includes most of the rivers of the European part and Western Siberia.
• rivers with the maximum flow that occurs when melting mountain snows and glaciers. Floods here can be observed several times during the year. These are mainly the rivers of the North Caucasus.
• rivers with the maximum runoff due to heavy rainfall. Rivers of this type are Far East and Siberia.
• rivers with maximum flows generated from joint effects of snowmelt and precipitation. Their regime is characterized by spring floods from melting snow, increased summer and winter runoff due to abundant groundwater, and significant autumn precipitation. The presence of this type of rivers is typical for the northwestern regions of Russia.

Rice. 1. The consequences of the flood

Particularly dangerous floods are observed on the rivers of rain and glacier feeding or a combination of these two factors.

Flood characteristic for rivers of the first type, often call high water. This is a significant and rather long rise in the water level on the river, repeated annually in the same season. Usually floods are caused by spring melting of snow and on the plains or by rainfall.

Flood characteristic for rivers of the third type, usually called flood. This is an intense, relatively short-term rise in the water level. It is formed by heavy rains, sometimes by melting snow during winter thaws.

In addition to these sources, floods can occur as a result of other hydrometeorological phenomena, such as traffic jams, surges and dam breaks.

Flood characteristics and factors

The most important main features are maximum level and maximum water flow during the flood. The area, layer and duration of flooding are associated with the maximum level. One of the main characteristics is the rate of rise of the water level.

To make a flood forecast, it is also necessary to know such a characteristic as flow rate, which is expressed in meters per second.

The factors that determine the values ​​of the maximum level and maximum water discharge for the case of spring floods include the following:

• water reserve in the snow cover before the start of spring thaw;
• atmospheric precipitation during the period of snow thawing and floods;
• autumn-winter soil moisture by the beginning of spring snowmelt; soil freezing depth; ice crust on the ground;
• snowmelt intensity.

It should be taken into account that in the European part of Russia, after the snow melts, the amount of precipitation is 1.5-2 times more than during the period of snowmelt itself. To determine the intensity of snowmelt, the method of measuring the so-called melting coefficient is widely used - a layer of melt water per one degree of the average daily air temperature. The coefficients of snow melting are given in Table. 1.

Table 1. Dependence of snow melt on natural area

Behavior of a person in a flood zone

Hydrologists divided all floods into four types: low, high, outstanding, catastrophic.

Low- are observed on flat rivers and occur once every 5-10 years. They practically do not break the rhythm of life with some preparation.

high floods they flood quite large sections of river valleys and sometimes significantly disrupt the usual life, even require evacuation and occur once every 20-25 years.

outstanding floods(once every 50-100 years) flood at least 50 percent of agricultural land and require mass evacuation of the population. The flooding of cities and towns begins.

catastrophic floods occur once every 100-200 years: several river systems are flooded, the way of life is completely changed. They say this is what the Flood looked like.

When there is a threat of flooding, preventive measures are taken. First of all, this is informing people about the emergence of a threat, strengthening monitoring of the water level, alerting forces and means to combat the elements and to evacuate the population. The condition of dams, dams, bridges is checked and the identified shortcomings are eliminated. Additional embankments are being erected, drainage ditches are being dug, and hydraulic structures are being prepared.

Enterprises introduce a regime of emergency measures, the protection of food, the removal of livestock, the export of equipment and inventory begins.

When the threat of flooding increases, the work of enterprises, organizations and institutions stops, people are sent home or evacuated to safe areas. First of all, children, children's institutions and hospitals are evacuated.

In the event of flash floods, the warning of the population is carried out by all available technical means notifications, including with the help of loud-speaking mobile installations.

The evacuation of people is carried out using watercraft: boats, boats, ferries, etc. When evacuating, it is necessary to observe safety measures: enter the boat, boat one at a time, during their movement do not board, do not change places and do not push.

Evacuation is carried out to the nearest settlements located outside the flood zones. The resettlement of evacuees is carried out in public buildings, on the living area of ​​local residents or in tent camps.

What to do with a flood forecast?

Hydrologists usually warn in advance about high water - the rise of water from the spring snowmelt (water rises for a long time). It is more difficult to predict flooding - a brief rise in water due to downpours or winter thaws. Even more difficult is the rise in the level in the rivers due to the surge of water from the sea or reservoir, and even more so - the flood due to the breakthrough of dams or.

However, most floods can be predicted and losses reduced: flood commissions are created to check the condition of dams and dams, various special equipment, inform the population and, if necessary, start engineering work. For example, drainage ditches are being dug and embankments are being erected, for which, in addition to construction organizations and civil defense services, local military units are involved.

Typically, a flood forecast contains information about the expected evacuation order. If your home falls into a declared flood region, you need to: turn off gas, water and electricity; put out the fire in the furnaces; move valuable items and things to the upper floors and attics; close windows and doors, if necessary, upholster the windows and doors of the first floors with boards or plywood.

If an evacuation warning is received: prepare warm comfortable clothes, boots, blankets, money and valuables; collect a three-day supply of food; prepare a first aid kit and medicines that you usually use; wrap your passport and other documents in a waterproof bag; bring toiletries and bed linen.

The weight of things and products is best placed in a backpack, suitcase or bag. It will be announced where and how ( special transport or on foot) must be directed from the danger zone. At the end of the evacuation you need to register. After that, people are placed on temporary residence. First of all, children, children's institutions and hospitals are evacuated. Enterprises introduce a regime of emergency measures, the protection of food begins, the withdrawal of livestock, equipment and inventory.

High water, even in the floodplain of a small river, usually lasts seven days. For medium-sized rivers, this period is from two weeks to a month. However, there are torrential floods that literally fall for 2-3 hours.

This happened in the center of Moscow on July 29, 1924: a real river rushed along Tverskaya to the Kremlin and newsstands floated in it. The zoo's ponds overflowed their banks and merged into a lake with neighboring streets. The most remarkable thing is that not a single drop of rain fell on the outskirts of the city that day. Also, a sudden July downpour in 1948 in Chisinau turned some streets into ravines 5-6 m deep. Flash floods can also last longer.

What to do if the water rises sharply?

First, take measures to protect the house (they are described above) and prepare for the evacuation. Secondly, get to a safe elevated place as soon as possible and stock up on any items that can help in the event of a so-called self-evacuation.

Simply put, in addition to boats or rafts, barrels, logs, shields, doors, fragments of wooden fences, poles and car cameras can be prepared for forced navigation. There is a recommendation even to fill a shirt or trousers with plastic closed bottles and balls, if there was nothing else at hand that could support you in the water.

Until help arrives or the water subsides, you need to stay on the upper floors and roofs, on trees or other elevations. In order for rescuers to find victims more quickly, it is necessary to hang a white or colored canvas on a high place during daylight hours, and to give light signals in the dark.

When the rescuers approached, it is necessary to go to the boat or boat, but only one, not arranging a panic and stopping it by all means for others. During the movement, it is not allowed to change places, walk on a watercraft, or sit on board. You can get out of the flooded area on your own only in hopeless situations - when one of the victims needs medical help, when the water is rising and there is no hope for rescuers. Lack of food (even for a long time) cannot be considered a valid reason for the risk of self-evacuation. The decision to get out on your own should be made deliberately and well prepared: watercraft, protection from the cold, route and consideration of the situation (current, rise or fall of water, no signs of rescue activity, etc.). Jumping into the water with an improvised means is possible only in the most extreme case, when there is no hope of salvation and the hill is completely flooded. Wade into elevated places only with insurance and checking every step ahead, because the familiar path can be blurred. If you have to leave the car, then you can not throw it on the road.

Experts note two ways in which water destroys settlements. Direct flooding, when streets, courtyards and the first floors of buildings are flooded, and flooding - when water enters the basements through sewers, through various ditches and the groundwater level rises sharply. In both cases, the foundations of houses suffer, rough lines, gas, electricity and communications are torn.

Therefore, after the water has receded, it is necessary to enter buildings with caution, after making sure that the structures were not damaged. Before lingering in the room, it must be ventilated by opening all windows and doors, and in any case, do not light a fire, do not turn on the electricity - a gas leak is possible. To dry the house, you need to leave the windows open, take out all the wet things, if possible, collect water and wet garbage. You can use electricity, gas, water supply and sewerage only after permission from specialists.

As with other natural disasters, secondary risks must be kept in mind: industrial accidents, spills chemical substances, the danger of various damage to pipes and breakage of electrical wires. However, there is also a specificity: you can’t use products that have fallen into the water, and flooded wells must be drained and then pumped out until the water becomes drinkable. If you see a carcass of an animal, inform the local authorities. It is up to sanitation workers to decide when to take drinking water and use sodden food supplies.

What to do if a person is drowning in front of your eyes?

First of all, give yourself a second to think. Does Her have a rescue facility nearby? It can be anything that will increase the buoyancy of a person and that you are able to throw it to him. The lifebuoy can be thrown at 20-25 meters, the end of Alexandrov - a little further (from the ship, due to the height - much further). Is there a boat? Is it possible to call someone else for help? Having encouraged the victim with a cry, you go to the rescue.

If you get to a drowning swimmer, you must take into account as much as possible the flow of water, the wind, the distance to the coast, etc. When approaching, try to calm and encourage the swimmer who is exhausted. If this is successful and he can control his actions, the swimmer should hold on to the shoulders of the rescuer. If not, it must be handled harshly and unceremoniously. Some instructions even recommend stunning a drowning person in order to save him and his life.

Short rescue technique looks like this. Having swum up to a drowning man, you need to dive under him and, taking one of the capture methods from behind (classic - by the hair), transport him to the shore. If the drowning man managed to grab your arms, neck or legs, free yourself and dive immediately - the instinct of self-preservation will make the victim let you go.

If a person has already plunged into the water, do not give up trying to find him in the depths, and then bring him back to life. This can be done if the drowned person has been in the water for about 6 minutes. Having pulled ashore, examine the victim: the mouth and nose can be clogged with mud or sand, they must be immediately cleaned (with your fingers, turning the person’s head to one side). Then put the victim on your knee with your stomach (head hanging face down) and, pressing hard, throw out the water from the stomach and respiratory tract. All this must be done quickly and just as quickly put the victim on his back, unfasten his belt and top buttons and start artificial respiration.

Kneel on the left, tilt the head of the drowned man as much as possible (this is very important!) And, having shifted the jaw down, open his mouth. Take a deep breath, put your lips to the victim's lips (recommended through a handkerchief or gauze) and forcefully exhale the air. The nostrils of the victim must be clamped with a hand. Exhalation will happen on its own.

If the victim's heart does not beat, artificial respiration should be combined with chest compressions. To do this, place one palm across the lower part of the sternum (but not on the ribs!), The other palm - on top of the first crosswise. Press on the sternum with your wrists so that it bends 3-5 centimeters, and release. You need to bend strongly, with a push, using the weight of your body. Through each inhalation of air, do 4-5 rhythmic pressures.

It's good to have two help. Then one does artificial respiration, the other then - a heart massage. Do not stop resuscitation until the ambulance arrives: thanks to your actions, the body can still live.

Of course, the techniques of resuscitation and rescue are not at all easy to apply without practice, and one should learn such things in advance. But even if you have no preparation, act! We must use every chance.

And by the way, finally, let's return to the first echelon of human protection: not to end up in extreme situation. There are also purely social methods, for example, to equip the beach, clean the bottom, organize a departmental or public OSVOD rescue post. True, here it is also easy to notice the obligatory condition of protection already known to us - act.

Introduction

1. Causes of flooding

2. Effects of floods

3. Flood prevention measures, rescue work

Conclusion

Bibliography

Introduction

It is well known that the state and development of both the biosphere and human society is directly dependent on the state of water resources. In recent decades, an increasing number of specialists and politicians among the problems facing humanity, number 1 call the problem of water. Water problems arise in four cases: when there is no or insufficient water, when the quality of water does not meet social, environmental and economic requirements, when the regime of water bodies does not correspond to the optimal functioning of ecosystems, and the regime of its supply to consumers does not meet the social and economic requirements of the population, and, finally, when the habitable territories suffer from floods from excess water.

In the global aspect, the first three problems were the product of the outgoing century, and the fourth has been accompanying human society since ancient times. And paradoxically, for many centuries, humanity, making incredible efforts to protect against floods, cannot succeed in this event. On the contrary, with every century the damage from floods continues to grow. Especially strong, about 10 times, it has increased over the second half of the past century. According to our calculations, the area of ​​flood-prone areas on the globe is about 3 million square meters. km, which is home to about 1 billion people.

1.Causes of the flood

Flooding - temporary flooding of a significant part of the land with water as a result of the action of natural forces. Depending on the causing causes, they can be divided into groups.

Floods caused by heavy rainfall or heavy melting of snow, glaciers. This leads to a sharp rise in the level of rivers, lakes, and the formation of congestion. The breakthrough of congestion and dams can lead to the formation of a breakthrough wave, characterized by the rapid movement of huge masses of water and a significant height. The flood in August 1989 in Primorye demolished a significant number of bridges and buildings, killing a huge number of livestock, damaging power lines, communications, roads destroyed, and thousands of people were left homeless.

Floods caused by surge winds. They are typical for coastal regions, where there are mouths of large rivers flowing into the sea. The surging wind delays the movement of water into the sea, which sharply raises the water level in the river. The coasts of the Baltic, Caspian and Azov seas are under constant threat of such flooding. So, St. Petersburg has experienced more than 240 such floods during its existence. At the same time, cases of the appearance of heavy ships were observed on the streets, which caused the destruction of urban buildings. In November 1824, the water level in the Neva rose 4 m above the norm; in 1924 - by 3.69 m, when water flooded half of the city; in December 1973 - by 2.29 m; January 1984 - by 2.25 m. And as a result of the floods - huge material losses and victims.

Flooding caused by underwater earthquakes. They are characterized by the appearance of giant waves of great length - tsunamis (in Japanese - "big wave in the harbor"). Tsunami propagation speed up to 1000 km/h. The height of the wave in the area of ​​its origin does not exceed 5 m. But when approaching the shore, the steepness of the tsunami increases sharply, and the waves crash on the coast with great force. At flat coasts, the wave height does not exceed 6 m, and in narrow bays it reaches 50 m (tunnel effect). The duration of a tsunami is up to 3 hours, and the coastline affected by them reaches a length of 1000 km. In 1952, the waves almost washed away Yuzhno-Kurilsk.

The natural causes of floods are well known to readers, and therefore we will only mention them. In most parts of the world, floods are caused by prolonged, intense rain and downpours resulting from the passage of cyclones. Floods on the rivers of the Northern Hemisphere also occur due to the rapid melting of snow, ice jams, ice jams. Foothills and high-mountain valleys are exposed to floods associated with outbursts of intraglacial and dammed lakes. In coastal areas, surge floods are not uncommon during strong winds, and during underwater earthquakes and volcanic eruptions, floods caused by tsunami waves.

In recent centuries, especially in the 20th century, anthropogenic factors have played an increasing role in increasing the frequency and destructive power of floods. Among them, first of all, it is necessary to name deforestation (the maximum surface runoff increases by 250-300%), irrational agriculture (as a result of a decrease in the infiltration properties of soils, according to some calculations, in the central regions of Russia from the 9th to the 20th century, the surface runoff increased by 4 times and the intensity of floods increased sharply). A significant contribution to the increase in the intensity of floods and floods was made by: longitudinal plowing of slopes, overconsolidation of fields when using heavy equipment, overwatering as a result of violation of irrigation norms. The average flood discharge in urban areas has approximately tripled due to the growth of impermeable coatings and development. A significant increase in the 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 a breach of embankment dams, destruction of artificial dams, emergency drawdown of reservoirs, etc.

2. Effects of floods

The structure of sanitary losses during floods is dominated by injuries (fractures, damage to the joints, spine, soft tissues). Cases of diseases as a result of hypothermia (pneumonia, acute respiratory infections, rheumatism, worsening of the course of chronic diseases), the appearance of victims from burns (due to flammable liquids spilled and ignited on the surface of the water) have been recorded.

In the structure of sanitary losses, children occupy a significant place, and the most common consequences among the population are psychoneuroses, intestinal infections, malaria, and yellow fever. Human casualties are especially high on the coasts during hurricanes and tsunamis, as well as during the destruction of dams and dams (more than 93% drowned). As an example, the consequences of the 1970 flood in Bangladesh can be cited: on most of the coastal islands, the entire population died; out of 72 thousand fishermen in coastal waters, 46 thousand died. More than half of the dead were children under 10 years old, although they accounted for only 30% of the population of the disaster zone. Mortality among the population older than 50 years, among women and patients was also high.

Frequent companions of floods are large-scale poisoning. Due to the destruction of treatment facilities, warehouses with hazardous chemicals and other harmful substances, drinking water sources are poisoned. The development of extensive fires is not ruled out when flammable liquids spill over the surface of the water (gasoline and other combustible liquids are lighter than water).

3. Flood prevention measures, rescue work.

Floods are successfully predicted, and the relevant services give warnings to dangerous areas, which reduces damage. In places of floods, dams, dams, hydraulic structures are built to regulate the flow of water. In the winding places of the rivers, work is carried out to expand and straighten their channels. During the threatened period, duty and maintenance of readiness of civil defense formations are organized. Early evacuation of the population, cattle theft, and removal of equipment are being carried out.

Rescue work in flooded areas often takes place in difficult weather conditions (rain showers, fogs, squally winds). Work to save people begins with reconnaissance, using boats and helicopters equipped with communications equipment.

Places of congestion of people are established, and funds are sent there to ensure their salvation. Work on hydraulic structures is carried out by the formation of engineering and emergency technical services of the Civil Defense and Emergency Service: this is the strengthening of dams, dams, embankments or their construction.

In case of floods, the following are involved in rescue operations: rescue teams, teams and groups, as well as departmental specialized teams and subunits equipped with watercraft, sanitary teams and posts, hydrometeorological posts, reconnaissance teams and units, combined teams (teams) for mechanization of work, formation of construction, repair and construction organizations, protection of public order.

Rescue operations during floods are aimed at searching for people in a flooded area (landing them on boats, rafts, barges or helicopters) and evacuating them to safe places.

Reconnaissance groups and units operating on high-speed watercraft and helicopters determine the places where people gather in the flooded area, their condition and periodically give sound and light signals. Based on the intelligence data received, the head of the civil defense specifies the tasks for the formations and puts them forward to the objects of rescue operations.

Small groups of people in the water are thrown out with lifebuoys, rubber balls, boards, poles, or other floating objects, taking into account the flow of water, wind direction, they are taken to floating craft and evacuated to safe areas. Motor ships, barges, launches, boats and other watercraft are used to rescue and transport a large number of people from the flooded area. Landing people on them is carried out directly from the shore. In this case, they choose and designate places convenient for ships to approach the shore, or equip berths.

When rescuing people who are in a break in the ice, they give the end of the rope, boards, ladders, any other object and pull it out to a safe place. Approaching people in the polynya should be crawling with outstretched arms and legs, leaning on boards or other objects.