What are the dangers of an accident at hydraulic structures? Hydrodynamic accidents in Russia: examples. Factors influencing the height of the breakthrough wave

Hydrodynamically dangerous objects are structures or natural formations that create a difference in water levels before (upstream) and after (downstream) them. These include hydraulic structures of the pressure front: dams, dams, dikes, water intakes and water intake structures, pressure basins and equalization reservoirs, waterworks, small hydroelectric power stations and structures that are part of the engineering protection of cities and agricultural land.

Accidents at hydrodynamically dangerous objects are called hydrodynamic. They are divided into the following types:

Breaks of dams (dams, locks, cofferdams, etc.) with the formation of breakthrough waves, leading to catastrophic flooding;

Breaks of dams (dams, sluices, dams, etc.), leading to the occurrence of breakthrough floods;

Breaks of dams (dams, sluices, dams, etc.), leading to the washout of fertile soils or the deposition of sediment over large areas.

The main damaging factors of hydrodynamic accidents associated with the destruction of hydraulic structures are the breakthrough wave and flooding of the area.

The consequences of accidents at hydrodynamically hazardous facilities can be difficult to predict. Being located, as a rule, within or upstream of large populated areas and being objects of increased risk, if destroyed, they can lead to catastrophic flooding of vast territories, a significant number of cities and villages, economic facilities, mass death of people, long-term cessation shipping, agricultural and fishing industries.

The consequences of catastrophic flooding can be aggravated by accidents at potentially hazardous facilities falling within its zone.

In areas of catastrophic flooding, water supply systems, sewerage systems, drainage communications, garbage collection sites and other waste may be destroyed (eroded). As a result, sewage, garbage and waste pollute flood zones and spread downstream. The risk of occurrence and spread increases infectious diseases. This is also facilitated by the accumulation of population in a limited area with a significant deterioration in material and living conditions.

The protection and safety of the population during hydrodynamic accidents is ensured by a set of organizational, engineering and other measures. The main ones of these measures: right choice locations of the dam and settlements; limiting the construction of residential buildings and economic facilities in places exposed to a possible breakthrough wave; embankment of populated areas and agricultural lands; creation of reliable drainage systems; carrying out bank protection works to prevent landslides and collapses; installation of waterproofing and special fortifications on buildings and structures; planting low-trunk forests (poplars, alders and birches) that can reduce the speed of the breakthrough wave.

In case of danger of a breakthrough of artificial dams, take the following measures: regulation of water flow; planned release of water from the reservoir during the spring flood; timely drainage of water.

If there is a danger of a natural reservoir breaking, measures are taken to strengthen the walls of the dams.

In case of catastrophic flooding or its threat, the following measures are taken to protect the population:

Notifying the population about the threat of catastrophic flooding and taking the necessary protective measures;

Independent exit of the population from the zone of possible catastrophic flooding before the breakthrough wave approaches;

Organized evacuation of the population to safe areas before the breakthrough wave approaches;

Sheltering the population in non-flooded parts of buildings and structures, as well as in elevated areas;

Carrying out emergency rescue operations;

Providing qualified and specialized assistance to the victims;

Carrying out urgent work to ensure the livelihoods of the population.

Water is one of the most dangerous and unpredictable natural phenomena. In order to protect their settlements and at the same time have the necessary supply of water, people have to build special hydraulic structures. They create differences in hydraulic levels. Before the structure there is an upper pool ( high level water), and then the lower one.

Hoover Dam

Dams are among the most common. You can also find dams and. All of them are potentially dangerous and require constant monitoring from the relevant organizations.

As a result of their destruction or breakdown, a large uncontrolled release of water occurs, resulting in an emergency situation involving the death of people, animals and numerous destructions. This is called (definition and presentation in the encyclopedia website).

What to do in such a situation, what consequences you need to be prepared for and whether it can be prevented, we will consider in this article.

Causes

The failure of a dam or dike can occur due to natural causes or due to human activity. Natural forces that can cause a breakthrough in a hydraulic structure include: earthquakes, floods, heavy and prolonged downpours, hurricanes, and landslides. Natural corrosion of concrete structures can also lead to an accident, but now soil dams are most common.

Various inaccuracies in design, errors in the construction of objects, material defects or low quality, explosions, sabotage, military operations near hydrodynamic structures are among the reasons that are associated with human activity.

If even the slightest risk of a dam break is detected, actions are taken to strengthen it and prevent a break. During spring floods, water is regularly discharged from the facility.

Streams of water

Depending on the volume and force of the released water, the following types of hydrodynamic accidents are distinguished:

• Breakthrough of a structure with the occurrence of strong waves leading to flooding of vast areas
• A dam or levee breaks, resulting in a breakthrough flood (a short-term but intense rise in the water level in a watercourse).
• An accident leading to the deposition of river sediments over a large area and the destruction of the fertile soil layer.

In most cases, the decline in water level in flooded areas occurs after 4 hours, in some cases it is necessary to wait a couple of days.

Consequences and damaging factors

As a result of a hydrodynamic accident, flooding of the area occurs, often comparable to a catastrophe. The resulting wave quickly hits the area located in the lowland.

The main damaging factors in such situations include:

• flow force;
• emerging wave;
• as well as calm waters that have a destructive effect on agricultural facilities.

The force of the wave when a structure breaks through can be compared to the shock air wave from an explosion. However, not every flood is catastrophic. To obtain the status of an emergency, its duration, depth, boundaries of the zone of possible flooding are taken into account, as well as the height of the wave and the flow speed should be maximum.

The primary consequences of hydrodynamic accidents include:

• mass death and numerous losses of animals and people;
• destruction of buildings and important public utilities;
• power outages;
• cessation of the functioning of irrigation or other water management systems (as well as pond fisheries facilities);
• destruction or flooding of populated areas and industrial enterprises;
• disruption of communications and other infrastructure elements;
• death of crops and livestock;
• removal of agricultural land from economic use;
• disruption of the life of the population and the production and economic activities of enterprises;
• loss of material, cultural and historical values;
• damage to the natural environment (including as a result of landscape changes);
• death of people.

Subsequent, secondary consequences can be called:

• and areas with substances from destroyed (flooded) storage facilities of industrial and agricultural enterprises, leading to the development of infections and epidemics among the population;
• mass diseases of people and farm animals;
• accidents on highways;
• landslides and collapses.

Frequent fires may occur in the disaster area due to broken and damaged power lines. Landslides and landslides also become a consequence of an accident as a result of severe erosion of the soil layer.

There are also residual effects breakthrough of a long-term hydraulic structure. This is a change in the landscape, ecology, and a decrease in soil fertility.

How to behave in an emergency zone

In areas with a risk of dam failure, a pre-warning system is provided in advance, and an evacuation plan is created indicating collection points. For notification, sirens, horns, loudspeakers, as well as media (radio, television) are used.

Residents living downstream should familiarize themselves in advance with the most convenient one. Most often, they are laid to the nearest elevated points in a given area. In every home, for such an emergency, a backpack with the necessary minimum set of things should be prepared; for people in uniform, such a kit is called an “emergency suitcase”, you can read about it in our article.

How should you behave if you hear a warning that a dam has broken and a flood of water is approaching?

It is necessary to adhere to the following recommendations clearly and without panic:

1. We go around the house and turn off the water supply completely, shut off the gas and electricity supplies.
2. We make (we didn’t prepare in advance) a supply of clean water and food. Pack everything in airtight packaging.
3. On the lower floors, doors and windows should be strengthened, or better yet, nailed.
4. Move all valuable items to a higher place (attic, 2nd floor)
5. Take your documents, first aid kit, and things and go to the designated collection point for your area for mass evacuation.

If a disaster takes you by surprise, then try to hide from the oncoming wave. Any elevated place (tree, top floor buildings, house roof).

Be sure to pay attention to the building itself. It must be stable and without destruction, able to withstand the impact of water. Once in the water, try to stay on the surface using floating objects. Beware of sharp, glass objects.

Signal Threat of catastrophic flooding

In a situation where your home is flooded, go up to the roof and constantly signal your presence in your home. You can hang bright fabric. IN dark time A flashlight or phone screen will do for a day.

Closely control your supplies of drinking water and food. Remember that help can only come to you after 1-2 days. Do not eat food that has been flooded. They can cause poisoning.

Actions after an accident

When you return home, you should be extremely careful and attentive. Before entering your home, inspect the outside of the walls and roof for severe damage or destruction. Open doors and windows to ventilate the room.

First of all, check the gas equipment for serviceability. Don't resort to using open fire until you are sure there is no gas leak, you can read about it in our article. All utility systems (electrical wiring, plumbing, sewerage) should also be thoroughly inspected. It is better if a specialist does this.

Water should be pumped out gradually. Don't forget about the basement and well. Before you start cleaning, the home should be dried.

In order for such accidents to occur as rarely as possible, the construction of water-retaining facilities should ensure their high quality and reliability. To this end, in 1997 it was adopted, which establishes the responsibility of authorized persons and regulates all issues regarding the safety of these structures.

The most basic preventive measure for hydrodynamic accidents is constant monitoring of the condition of the dams, as well as close cooperation with meteorological services.

Hydrodynamically dangerous objects are structures or natural formations that create a difference in water levels before (upstream) and after (downstream) them. These include hydraulic structures of the pressure front: dams, dams, dikes, water intakes and water intake structures, pressure basins and equalization reservoirs, waterworks, small hydroelectric power stations and structures that are part of the engineering protection of cities and agricultural land.

Accidents at hydrodynamically dangerous objects are called hydrodynamic. They are divided into the following types:

• 19. breaches of dams (dams, locks, dams, etc.) with the formation of breakthrough waves, leading to catastrophic flooding;
• 20. breaches of dams (dams, sluices, dams, etc.), leading to the occurrence of a breakthrough flood;
• 21. breaches of dams (dams, sluices, dams, etc.)" leading to the washout of fertile soils or the deposition of sediment over large areas.

The main damaging factors of hydrodynamic accidents associated with the destruction of hydraulic structures are the breakthrough wave and flooding of the area.

The consequences of accidents at hydrodynamically hazardous objects can be difficult to predict. Being located, as a rule, within or above the outflow of large populated areas and being objects of increased risk, if destroyed, they can lead to catastrophic flooding of vast territories, a significant number of cities and villages, economic facilities, to mass loss of life, a long-term cessation of shipping, agricultural and fishing industry

The consequences of catastrophic flooding can be aggravated by accidents at potentially hazardous facilities falling within its zone.

In areas of catastrophic flooding, water supply systems, sewerage systems, drainage communications, garbage collection sites and other waste may be destroyed (eroded). As a result, sewage, garbage and waste pollute flood zones and spread downstream. The danger of the emergence and spread of infectious diseases is increasing. This is also facilitated by the accumulation of population in a limited area with a significant deterioration in material and living conditions.

The protection and safety of the population during hydrodynamic accidents is ensured by a set of organizational, engineering and other measures. The main of these measures are: the correct choice of location for the dam and settlements; limiting the construction of residential buildings and economic facilities in places exposed to a possible breakthrough wave; embankment of populated areas and agricultural lands; creation of reliable drainage systems; carrying out bank protection works to prevent landslides and collapses; installation of waterproofing and special fortifications on buildings and structures; planting low-trunk forests (poplars, alders and birches) that can reduce the speed of the breakthrough wave.

In case of danger of a breakthrough of artificial dams, the following measures are taken: regulation of water flow; planned release of water from the reservoir during the spring flood; timely drainage of water.

If there is a danger of a natural reservoir breaking, measures are taken to strengthen the walls of the dams.

In case of catastrophic flooding or its threat, the following measures are taken to protect the population:

• 22. warning the population about the threat of catastrophic flooding and taking the necessary protective measures;
• 23. independent exit of the population from the zone of possible catastrophic flooding before the approach of the breakthrough wave;
• 24. organized evacuation of the population to safe areas before the breakthrough wave approaches;
• 25. sheltering the population on non-flooded parts of buildings and structures, as well as on elevated areas;
• 7. carrying out emergency rescue operations;
• 26. provision of qualified and specialized assistance to victims;
• 27. carrying out urgent work to ensure the livelihoods of the population.

Accidents at hydraulic structures (dam breaks)

Accidents at hydraulic structures pose a serious danger to the population, the technosphere and the natural environment. In accordance with Federal law“On the safety of hydraulic structures” such structures are: dams, hydroelectric power station buildings, spillways, drainage and water outlet structures, tunnels, canals, pumping stations, shipping locks, ship lifts; structures designed to protect against floods and destruction of the banks of reservoirs, the banks and bottom of river beds; structures (dams) enclosing liquid waste storage facilities of industrial and agricultural organizations; devices against erosion on canals, as well as other structures designed to use water resources and prevent the harmful effects of water and liquid waste.

Description of the emergency situation being considered

Accidents at hydraulic structures are diverse. The most dangerous of them are hydrodynamic accidents. A hydrodynamic accident is an accident at a hydraulic structure associated with the spread of water at high speed and creating a threat of a man-made emergency (GOST R22.05-94). The main hydraulic structures, the destruction (breakthrough) of which leads to hydrodynamic accidents, include dams and sluices.

Dams are hydraulic structures (artificial dams) or natural formations (natural dams) that create a difference in levels along the river bed. Artificial dams are hydraulic structures created by man for his own needs and include dams for hydroelectric power stations, water intakes in irrigation systems, dams, dams, dams, etc. Natural dams arise as a result of the action of natural forces, for example, as a result of landslides, mudflows , avalanches, landslides, earthquakes. In front of the dam, water accumulates up the watercourse and an artificial or natural reservoir is formed.

The section of a river between two adjacent dams on a river or the section of a canal between two locks is called a tailwater. The upstream of a dam is the part of the river above the retaining structure (dam, sluice), and the part of the river below the retaining structure is called the downstream.

Reservoirs can be long-term or short-term. A long-term artificial reservoir is, for example, the reservoir of the upper pool of a hydroelectric dam or irrigation system. A long-term natural reservoir can be formed as a result of the damming of a river after a collapse of solid rocks. Short-term artificial dams are created to temporarily change the direction of river flow during the construction of hydroelectric power stations (HPPs) or other hydraulic structures. Short-term natural dams arise as a result of blocking the river with loose soil, snow or ice.

A dam break is the initial phase of a hydrodynamic accident and represents the process of formation of a hole and the uncontrolled flow of reservoir water from the upper pool through the hole into the lower pool. A hole is a narrow channel in the body (embankment) of a dam, a spit, a sandbank, or a straightened section of a river formed as a result of the erosion of a bend during a flood.

As a result of a dam breakthrough, a breakthrough wave occurs, formed in the front of a stream of water rushing into the hole, which, as a rule, has a significant crest height and movement speed and has great destructive power. The height of the breakthrough wave and the speed of its propagation depend on the size of the breach, the difference in water levels in the upper and lower pools, the hydrological and topographic conditions of the river bed and its floodplain. The speed of advance of the breakthrough wave ranges from 3 to 25 km/h (for mountainous and foothill areas - about 100 km/h). The height of the breakthrough wave ranges from 2 to 12 m, and sometimes more.

The main consequence of a dam break during hydrodynamic accidents is catastrophic flooding of the area.

Catastrophic flooding is a hydrodynamic disaster that is the result of the destruction of an artificial or natural dam and consists of rapid flooding of the underlying area by a breakthrough wave and the occurrence of a flood. Potential catastrophic flooding is characterized by the following parameters:

The maximum possible height and speed of the breakthrough wave;

The estimated time of arrival of the crest and front of the breakthrough wave at the corresponding target;

The boundaries of the possible flood zone;

The maximum depth of flooding of a specific area of ​​the area;

Duration of flooding of the territory.

Flooding caused by a dam breakthrough initially spreads at the speed of the breakthrough wave and, some time after it, leads to the flooding of vast areas with a layer of water from 0.5 to 10 m or more. Flood zones are formed. The zone of possible flooding due to the destruction of hydraulic structures is the part of the area adjacent to the river (lake, reservoir) that is in this case flooded with water. Depending on the consequences of the impact of hydraulic flow generated during the destruction of hydraulic structures, a zone of probable catastrophic flooding should be identified in the territory of possible flooding. This zone is a zone of probable flooding, in which the death of people, farm animals or plants, damage or destruction of material assets, as well as damage to the environment is expected or possible (GOST R22.0.03-95). Zones of probable catastrophic flooding are determined in advance at the design stage of a hydraulic structure. The parameters of the zone depend on the size of the reservoir, water pressure and other characteristics of a particular hydroelectric complex, as well as on the hydrological and topographical features of the area. Zones of probable, including catastrophic, flooding and characteristics of the breakthrough wave are reflected on maps or in special atlases compiled for hydroelectric complexes and large dams.

Breaks of natural dams, for example, breaks of lakes dammed by a glacier, or breaks of moraine lakes, can also lead to catastrophic flooding of the area.

The main damaging factors of catastrophic flooding are the dynamic impact of the breakthrough wave and water flow, as well as the impact of calm waters that flooded the territory and objects. The impact of a breakthrough wave is in many ways similar to the effect of an air shock wave formed during an explosion. The significant differences between these damaging factors are the much lower speed and higher density of matter in the breakthrough wave.

As a result of major hydrodynamic accidents, the power supply may be interrupted, the functioning of irrigation or other water management systems, as well as pond fisheries facilities may cease, settlements and industrial enterprises may be destroyed or submerged, communications and other elements of infrastructure may be damaged. , crops and livestock perish, agricultural land is taken out of economic use, the livelihoods of the population and the production and economic activities of enterprises are disrupted, material, cultural and historical values ​​are lost, damage is caused to the natural environment, including as a result of changes in the landscape, people die .

Secondary consequences of hydrodynamic accidents are pollution of water and terrain with substances from destroyed (flooded) storage facilities of industrial and agricultural enterprises, mass diseases of people and non-farm animals, accidents on transport highways, landslides, and collapses.

Long-term consequences of hydrodynamic accidents are associated with residual flooding factors - sediments, pollution, changes in elements of the natural environment.

According to international classification The consequences of five types of dam accidents vary.

Note:

1. In case of destructions of types R-1 and R-2, a breakthrough wave is formed and the territory characterized by lowlands is flooded.

2. In case of accidents of types P-1, P-2 and P-3, flooding, as a rule, does not occur.

In this regard, there are three states of a hydraulic structure: no damage, damage and destruction. It should be taken into account that catastrophic flooding can only occur if a hydraulic structure is destroyed.

Hydrodynamic accidents are breaches of dams (locks, dams, dams, etc.), when breakthrough waves and catastrophic flooding are formed, when a breakthrough flood occurs, resulting in sediment deposition over large areas or the washout of fertile, useful to people soil These are accidents at hydraulic structures due to the fact that water spreads at high speed and creates the threat of an uncontrollable man-made emergency.

The most severe consequences of a hydraulic accident

The most severe consequences are necessarily accompanied by all hydrodynamic accidents - unexpected events closely related to significant destruction of a hydraulic structure (sluice, dam) and uncontrolled, without any control, movement of huge masses of water, causing flooding of large areas and damage to objects.

Flooding turns out to be catastrophic, since after the accident the surrounding area is rapidly flooded by a breakthrough wave. The scale and degree of accidents completely depend on the technical condition and parameters of the hydroelectric complex, the volume of water in the reservoir, the degree and nature of the destruction of the dam, the characteristics of the catastrophic flood and breakthrough wave, the time of day of the incident, the season, the terrain and many other factors. In such cases, evacuation of the population is widely used, as during floods and floods.

Dam break forecast

The situation is complicated by the fact that illegal construction is taking place in the periodically flooded areas of waterworks. This creates the prerequisite for the formation of emergency situations in such zones, especially when an accident occurs related to hydrodynamics or flooding. Forecasting dam failures is a thankless task; it is very difficult to predict, and most often the disaster occurs suddenly. Because of this reason, emergency, unplanned evacuations are relevant. As soon as a signal is received that hydrodynamic accidents have occurred, evacuation begins immediately. The breakthrough wave reaches 25 km/h on the plain and 100 km/h in the mountains and foothills. There is little time to leave the danger zone. Therefore, evacuation is successful if there is a local automated instant warning system.

Objects subject to safety declaration

The list of such facilities is determined in our country by the Russian Ministry of Emergency Situations and Rokhtekhnadzor. It includes industrial facilities with hazardous production facilities, all kinds of hydraulic structures, sludge reservoirs and tailings ponds where hydrodynamic accidents are possible. The Industrial Safety Law defines maximum doses hazardous substances, which are the basis for developing a declaration. It should be noted that this list is determined by Rokhtekhnadzor and the Ministry of Emergency Situations based on data received from the main departments for emergency situations and civil defense.

Hydrodynamic accidents, examples

Similar accidents happen periodically all over the world. As has already been said, it is impossible to foresee them. Let's give examples.

On 10/09/1963, such a disaster occurred at the Vajont dam in Italy. A small reservoir with a volume of only 0.169 km 3 collapsed into a mountain range with a volume of 0.24 km 3, which was marked by the overflow of more than 50 million m 3 of water through the dam. The result was a shaft of water 90 meters high. In just 15 minutes he destroyed several small settlements and two thousand people. And everything happened due to a rise in the horizon of local groundwater, which was caused by the construction of a dam.

08/07/1994 in Bashkiria, in the Beloretsk region, the dam of the Tirlyansky reservoir burst. There was an abnormal discharge of water - 8.6 million m3. Four small settlements were flooded, 85 good residential buildings were completely destroyed, 200 were partially destroyed. 29 people died, 786 were left homeless.

On August 18, 2002, due to severe flooding on the Elbe River near the city of Wittenberg, Germany, seven protective dams collapsed. A huge amount of water poured into the city, 40,000 people were urgently evacuated, 19 died, 26 disappeared.

On March 11, 2005, there were heavy downpours in southwest Pakistan, Balochistan province. Because of them, a 150-meter-long hydroelectric dam broke near the town of Pasni. Several villages were flooded, 135 people died.

On October 05, 2007, in the Thanh Hoa province of Vietnam on the Chu River, a sharp rise in water level occurred, and the dam of the Quiadat hydroelectric station under construction was broken. Five thousand houses were in the flood zone, 35 people died. These are the most famous hydrodynamic accidents, examples known to everyone.

Tragedy at the Sayano-Shushenskaya hydroelectric power station

Unfortunately, a very major disaster occurred in our country not so long ago. Hydrodynamic accidents in Russia did not end with Bashkiria.

On August 17, 2009, the world's largest accident occurred at the Sayano-Shushenskaya hydroelectric power station. It was supposed to cover a series of accidents that occurred at hydroelectric power plants when the rotors of the units come out of their shafts. A superficial, biased investigation of this disaster does not provide guarantees in this regard. After all, to establish the reasons for what happened to the hydrogenerator, it is not enough to determine why and in what way the studs securing the iron cover of its turbine were destroyed. It is necessary to find the reasons for the unit rotor coming out of its shaft. And why did the overflow and flooding of the turbine room and other underlying station premises so unexpectedly occur, which led to the death of personnel.

The only consensus is that the unit was pushed out by the water pressure at which it was operating that morning. When the hydraulic unit entered an area not recommended for operation, the studs of the turbine cover itself broke. Then the water began to affect the rotor with the turbine cover and crosspiece, and they began to move upward. That is, the unit could not be squeezed out under the influence of water pressure. The conclusion of experts is not consistent with physical laws. The calculation results confirm that the second hydraulic unit came out of the shaft independently when the impeller rotated not in turbine mode, but in motor mode, in propeller mode.

Causes of the accident

This effect, when the rotors of hydraulic units rise, was studied back in the mid-20th century. Such hydrodynamic accidents have happened many times in Russia; the accident at the Sayano-Shushenskaya hydroelectric power station is distinguished only by the death of operating personnel and its scale. The reason for all this is the very rapid filling of the station premises with water. According to the commission’s conclusion, the suction pipe from the turbine was absolutely clean at the time of the accident and further as it progressed. The cause of the disaster is hidden behind the fatigue of the metal studs. But fatigue could not accumulate. The cover is fastened in such a way that the studs are not responsible for its radial displacement relative to the turbine stator. The fitted pins are important.
Moreover, they interfere with displacement by only 8 microns, and not by 160 microns, as expected. This is not in the investigation materials. From the photographs of the broken pins, it is clear that they were torn off “with meat”, and not due to a fatigue mechanism. The consequences of hydrodynamic accidents and the causes of death of service personnel were not studied. Accidents when rotors of units come out of their shafts occurred at the following facilities: Kakhovskaya HPP, Grand Rapids HPP, Canada, Pamir-1, Sayano-Shushenskaya. The last one should have completed this list. However, now there are no guarantees of this. The causes of hydrodynamic accidents are not eliminated, so the likelihood of their recurrence remains.

What should a person do in case of an accident?

A person must know how to act in the event of an accident at hydrodynamic facilities. The main thing here is that all residents of flood zones are well trained and know possible dangers and prepared to act during flooding and its threat. When an alarm is received, the population must evacuate immediately. From home you need to take documents, essentials, valuables, a supply of clean drinking water and food for 2-3 days. In a house or apartment, it is necessary to close the doors tightly, turn off the gas and electricity, and block the ventilation holes. If sudden flooding occurs, then to save yourself from the unexpected impact of a breakthrough wave, you need to take an elevated place.
If there are no suitable buildings nearby, you need to use any obstacle that can help with moving water: large stones, road embankment, trees. Hold on to a stone, tree, or other protruding object, otherwise streams of water and air waves can drag you over various hard objects, injuring them. Hydrodynamic accidents are very dangerous, and every effort must be made to escape. When a breakout wave approaches, dive deep at the very base of the wave. And try to get to unflooded areas.

Hydrodynamic accidents - what to do after

After the water subsides, people rush to return to their apartments. There are some precautions to keep in mind. You especially need to be wary of sagging or broken electrical wires. If you notice damage to sewer, gas or water mains, you must immediately notify emergency organizations and services. Products that have been in water cannot be used as food.
Drinking water should be checked, and wells drained, contaminated water pumped out of them. You can enter a building after checking it for damage, if it does not pose a danger to people. You need to ventilate all rooms for a few minutes by opening windows and doors. Candles or matches should not be used as a light source - there may be gas in the air. It is best to use electric lights. Until specialists check the electrical network, you cannot use it.

Accident in St. Francis, California

The St. Francis Dam has gone down in the annals of engineering geology as an example of human carelessness. The reservoir began to be filled back in 1972, but the water reached its maximum on March 5, 1928. It has been leaking for a long time, but no measures have been taken. And on March 12, water broke through the entire thickness of the soil, and the dam collapsed under its pressure. Not a single witness remained alive. If you are researching hydrodynamic accidents, examples are no longer needed. Man created the disaster, which killed more than 600 people, only a few from the upper half of the valley managed to remain alive. This dam collapse is an example of how not to build hydraulic structures.

Basics of life safety

Nowadays, even in the school curriculum, a lot of time is devoted to this issue. In high school there is a subject “Life Safety”. Hydrodynamic accidents are quite well covered there. If a lot depends on causes related to human activity, then it is necessary to prevent a catastrophe. Their causes may be: structural defects, design errors, violations during operation, overflow of water over the dam, insufficient spillway, acts of sabotage, weapon attacks on hydraulic structures. The most important thing is that the owners of hydraulic structures need to organize their safe operation. This will significantly increase the reliability of these objects.