Hydraulic accidents and their consequences. Accidents at hydraulic structures and their consequences. Accidents at hydraulic structures

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.

• Municipal educational institution secondary school No. 50, Volgograd
• 2010

• Accidents
• on hydraulic engineering
• structures
• and their consequences

• Familiarize yourself with the main types of hydraulic structures, learn about hydrodynamic accidents and their consequences

• a) sun rays;
• b) nuclear power plant;
• c) atomic bombs;
• d) radon;
• e) x-ray;
• f) uranium ores.

• Match the concepts:

• natural radioactive radiation

• a) sun rays;
• d) radon;
• f) uranium ores.

• artificial radioactive radiation

• b) nuclear power plant;
• c) atomic bombs;
• d) x-ray.

• violation of technological discipline, shortcomings vocational training personnel, “human factor”;
• depressurization of the reactor primary circuit or its mechanical damage.

• Complete the phrase:
• “In case of an accident at a nuclear power plant
• necessary:
• 1) listen...; 3) carry out...;
• 2) protect...; 4) pack...

• Listen to a voice message (information) about the danger that has arisen and recommendations for action by the population.
• Protect your respiratory system using available personal protective equipment.
• Seal the room.
• Pack products and drinking water in plastic containers, bags, bottles, place them in closed cabinets, pantries, refrigerator.

• Sayano-Shushenskaya HPP
• Krasnoyarsk hydroelectric power station
• Bratsk hydroelectric power station
• Ust-Ilimskaya HPP
• Zeyskaya HPP
• Nizhegorodskaya HPP
• Zhigulevskaya HPP
• Volzhskaya HPP
• Saratov HPP

• - These are engineering or natural structures for the use of water resources and to combat the destructive effects of water.

• use of kinetic energy of water (HES);
• land reclamation;
• protection of coastal areas from floods (dams);
• for water supply to cities and irrigation of fields;
• regulation of water levels during floods;
• ensuring the activities of sea and river ports (canals, locks).

• water retaining structures (dams, dams, dams);
• dam named after K. Zubryk
• water supply structures (canals, pipelines, tunnels);
• White Sea-Baltic Canal

• water intake structures –
• are designed to take water from a river or lake to use it for water supply or field irrigation.
• Metelevsky water intake, pumping station,
• Tyumen
• spillway structures –
• are designed to discharge flood water from the reservoir, as well as pass water into the downstream of the dam.
• Spillway
• Volzhskaya HPP named after. XII Congress of the CPSU

• special structures (locks, ship lifts, etc.) –
• designed to raise or lower ships from one water level to another.
• Gateway No. 8
• White Sea-Baltic Canal
• Gateway No. 1
• Volga-Don Shipping Canal
• them. IN AND. Lenin

• - these are structures or natural formations that create a difference in water levels before (upstream) and after it (downstream), accidents on which can lead to catastrophic consequences.

• - this is an emergency situation associated with the failure (destruction) of a hydraulic structure or part of it and the uncontrolled movement of large masses of water, causing destruction and flooding of vast areas.

• Sayano-Shushenskaya HPP
• August 2009

• 1993 - Break of the dam of the Kiselevsky reservoir (Sverdlovsk region) on the river. Kakva (total damage – 63.3 million rubles)
• 1994 - Destruction of the dam of the Tirlyansky reservoir (Bashkiria) on a tributary of the river. Belaya (total damage – 52.3 million rubles)
• 2002 - Flood in Krasnodar region led to the destruction of its waterworks, killing 114 people (total damage - 15 billion rubles)
• 2009 - Accident at the Sayano-Shushenskaya hydroelectric power station on the river. Yenisei claimed the lives of 75 people. 21.6 billion rubles will be spent on restoration.

• natural phenomena or disasters;
• technogenic factors;
• Wartime emergencies and terrorist attacks.

• breakout wave:
• is formed in the lower reaches as a result of a dam breaking and the rapid fall of huge masses of water, sweeping away everything in its path.
• threat to human life and health:
• drowning, hypothermia cold water, neuropsychic stress.

• long-term destruction of the hydraulic transmission system, which entails a shortage of electricity and a decline in production;

• defeat of people, death of animals, destruction of buildings and structures, roads, bridges, power lines by a breakthrough wave;
• destruction of the water supply and sewerage systems, resulting in the danger of infectious diseases;

• flooding of large areas, populated areas, washing away of the fertile soil layer;
• sediments, damage to property by water, environmental pollution.

• Flooding

• Hydrodynamic accident

• Structures with differences in water level.

• Damaging factors of the gastrointestinal tract.

• Hydrodynamically dangerous object

• Catastrophic flood zone

• Covering the area with water.

• The formation of breakthrough waves, a threat to human life and health.

• A structure with a difference in water level.

• A flood zone within which massive losses of people, animals and plants occurred, and material assets were damaged or destroyed.

• The part of the flood zone within which the breakthrough wave propagates.

• Covering the area with water.

• - Damaging factors of the gastrointestinal tract

• - Hydrodynamically dangerous object

• - Hydrodynamic accident

• - Catastrophic flood zone

• - Flooding

• Thank you
• for your attention!

• Hydrodynamic accident

• Hydraulic structures

• Causes and consequences of hydrodynamic accidents
• Rules safe behavior in case of hydrodynamic accidents

Life Safety Teacher

Kovalev Alexander Prokofievich

Secondary school No. 2

Mozdok

Hydrodynamic accident- this is an emergency event associated with the failure (destruction) of a hydraulic structure or part of it and the uncontrolled movement of large masses of water, causing destruction and flooding of vast areas.

• On the territory of Russia there are 30,000 reservoirs, hundreds of industrial effluents and wastes;
• large reservoirs with a capacity of more than 1 billion cubic meters.

Potentially hazardous hydraulic structures:

• dams
• water intake and spillway structures and sluices.

Water intakes

and water intake structures

Small hydroelectric power stations and hydraulic structures

Pressure basins and surge tanks

Dams

Waterworks

Dams

Dams- hydraulic structures (artificial dams) or natural formations (natural dams) that limit flow, create reservoirs and differences in water levels along the river bed.

The main consequence of a dam break during hydrodynamic accidents is catastrophic flooding of the area, which consists of rapid flooding of the area below by the break wave and the occurrence of flooding.

Historical facts

Construction of the first stone dams:

• Egypt – 6,000 years ago:
• on the territory of modern Holland -

2,000 years ago;

• aqueduct of the Pont du Gard water supply in Nimes (France) - built by the Romans in the first century BC;
• Russia - since the 18th century, the Zmeevka river ( Altai region) – 1870.

Water intake structure. This is a hydraulic structure for collecting water from a power source (river, lake, underground source) in order to use it for the needs of hydropower, water supply or field irrigation.

Spillway structures. These are hydraulic structures designed to discharge excess (flood) water from the reservoir, as well as pass water into the lower pool. (Backwater - part of a reservoir, river, canal).

The upper pool is located downstream above the water pump structure (dam, sluice), the lower pool is located below the water pump structure.)

This is a network of structures for raising or lowering ships from one water level (river, canal) to another.

Hydrodynamic accidents at these structures lead to catastrophic consequences, since they are usually located higher than large populated areas.

The gateway consists of cameras, head parts (heads) and approaches. The chamber in which the vessels being raised (lowered) are located is formed by two longitudinal walls and a bottom, usually made of reinforced concrete; at the ends it is limited by metal gates (shutters) located within the corresponding head parts. There are single-chamber and multi-chamber (multi-stage) gateways.

Destruction (breakthrough) of hydraulic structures occurs as a result of the action of natural forces or human influence .

Natural causes of hydrodynamic accidents:

• earthquakes
• hurricanes,
• collapses, landslides,
• floods,

Reasons related with human activity :

• design errors;
• structural defects of hydraulic structures;
• violation of operating rules;
• insufficient spillway and overflow of water over the dam;
• acts of sabotage;
• striking hydraulic structures with nuclear or conventional weapons

Sayano-Shushenskaya HPP

• Hydrodynamic accidents can lead to catastrophic flooding vast territories, cities and villages, economic objects,

To mass death of people .

• Are common population loss can reach at night 90 %, and during the day - 60 %.
• The consequences of catastrophic flooding may be worsened accidents at potentially hazardous facilities, falling into his zone.
• In areas of catastrophic flooding, water supply, sewerage, and drainage systems may be destroyed (eroded).

communications, places for collecting garbage and other waste.

• As a result of sewage, garbage and waste pollute flood zones

and spread downstream. The risk of occurrence and spread increases infectious diseases .

In conclusion, it should be noted that major hydrodynamic accidents are not so rare. It is noted that more than 300 significant hydrodynamic accidents have occurred in the world over the past 180 years.

The consequences of accidents at hydrodynamic structures may be accompanied by side effects.

In the zone of catastrophic flooding there may be dangerous production facilities (chemical, fire and explosion hazardous), accidents at which will aggravate the situation.

In addition, in the catastrophic flood zone, the operation of water supply, sewerage, and drainage systems is disrupted.

All this creates an unfavorable sanitary and epidemiological situation and contributes to the emergence of mass infectious diseases.

Homework

§ 5.8 p.136-139

Accidents at hydraulic structures

The main hydraulic structures, the destruction of which leads to hydrodynamic accidents, include dams, dikes, dams, water intake and drainage structures (sluices). Catastrophic flooding, which is a consequence of a hydrodynamic accident, consists of rapid flooding of an area by a breakthrough wave. The scale of the consequences of hydrodynamic accidents depends on the parameters and technical condition of the hydroelectric complex, the nature and degree of destruction of the dam, the volume of water reserves in the reservoir, the characteristics of the breakthrough wave and catastrophic flood, the terrain, the season and time of day of the incident, and many other factors.

As a result of untimely and poor-quality repairs and lack of required technical supervision of the hydraulic structures, destruction and breakthroughs occurred at the Tirlyansky hydroelectric complex, Kiselyovskaya and Lena dams, which led to significant material damage.

As for the Krasnoyarsk Territory, the Yenisei ranks first in Russia in terms of water reserves, and the region’s energy system includes 6 hydroelectric power stations: Krasnoyarsk, Sayano-Shushenskaya, Manskaya, Ust-Khantayskaya, Kureyskaya and the Boguchanskaya hydroelectric power station under construction. In 1996, the Ministry of Emergency Situations Commission noted that at the Sayano-Shushenskaya HPP there is an urgent need to carry out work to eliminate water leaks in the concrete of the first pillars of the dam.

The Main Directorate for Civil Defense and Emergency Situations of the Krasnoyarsk Territory has predicted zones of possible catastrophic flooding during emergencies for the entire territory of the region, in particular:

The main damaging factors flooding during an accident at a hydraulic structure are: breakthrough wave (wave height, speed of movement) and duration of flooding.

Breakout wave(see diagram in the APPENDIX) - a wave formed in the front of a stream of water rushing into a breach, which, as a rule, has a significant crest height and speed of movement and has great destructive power.

A breakthrough wave, from a hydraulic point of view, is a wave of movement, which, unlike wind waves that arise on the surfaces of large bodies of water, has the ability to transfer significant masses of water in the direction of its movement. Therefore, a breakthrough wave should be considered as a certain mass of water moving down the river and continuously changing its shape, size and speed.

The beginning of the wave is called wave front, which, moving at high speed, moves forward. The wave front can be very steep when moving large waves in areas close to the destroyed waterworks, and relatively flat at large distances from the waterworks.

The area of ​​greatest wave height is called crest of a wave, which moves, as a rule, slower than its front. The end of the wave moves even slower - tail of the wave. Due to the difference in the speeds of these points, the wave gradually stretches along the length of the river, correspondingly reducing its height and increasing the duration of its passage.

Factors influencing dam failure:

Impact conventional means lesions;

Avalanches or mudflows (in mountainous areas);

Flood waters.

Dams are characterized pressure:

N – N b< 10 м - низконапорные;

10 m< Н – Н б < 40 м - средненапорные;

N – N b > 40 m - high-pressure;

When a dam breaks, a breakthrough wave is formed:

Factors influencing the height of the breakthrough wave:

Reservoir volume W, million tons;

-Reservoir surface area S km 2;

Reservoir depth N m;

Width of the reservoir at the hydroelectric complex In m;

- Characteristics of the dam and the nature of its destruction;

Dam height N pl.

Are being considered three degrees of destruction dams:

1)10% percent;

2)50% percent;

3)100% percent.

Characteristics in the downstream:

a) river depth (in meters);

b) river flow speed (m/s);

c) hydraulic slope of the river (%);

d) coefficient of roughness of the river bottom and floodplain (n).

To plan activities that need to be planned in areas of possible flooding, you must have:

1.Graph of the movement of the breakthrough wave.

The fundamental criterion is the chart of the movement of the breakout wave. To plot the movement of the breakthrough wave, a schematized longitudinal profile of the river is constructed.

2. Characteristics of possible flooding of the area.

The longitudinal profile of the river is divided into sections.

The waterworks site is assigned N 0;

Target No. 1 is assigned at a distance of 250-500 * N;

Target No. 2 is assigned, as a rule, 10 times further than target N1 (2500-5000 * N), counting from it.

In the area of ​​expected impact, breakthrough waves are classified according to the degree of danger: different zones flooding.

At each alignment, the height of the breakthrough wave is determined, including at alignment N 0.

Determination of breakthrough wave height:

where: H in - height of the breakthrough wave;

H is the height of the water level in the upper tail of the dam;

N b - height of the water level in the downstream of the dam;

Knowing the graph of the breakthrough wave, we can construct a time graph of the passage of the breakthrough wave for carrying out evacuation measures (if necessary).

Time chart for the passage of a breakthrough wave.

Indicators of a possible situation are:

Flood zone parameters;

The number of people in the flood zone;

The number of farm animals caught in the flood zone;

The area of ​​agricultural land affected by the flood zone;

Length of destroyed (flooded) roads;

Number of destroyed (flooded) buildings and hydraulic structures.

Flood zones should be characterized by:

Zone A - extremely dangerous flooding (dangerous for the population);

Zone B is a zone of dangerous flooding (zone of destruction of economic facilities and hydraulic structures).

Knowing the speed of movement of the breakthrough wave, it is possible to determine the travel time of the breakthrough wave for planning evacuation measures.

The territory within which flooding is possible in the event of destruction or damage to the structures of the pressure front of a waterworks is called possible flood zone.

Depending on the consequences of the impact of a breakthrough wave, the area of ​​possible flooding is allocated catastrophic flood zone, the parameters of which at the zone boundaries are:

Height at the crest H = 4 m; - movement speed V > 2.5 m/sec.

It poses a mortal danger to the unprotected population and has a tremendous destructive effect on buildings and structures.

The section of the catastrophic flooding zone through which the breakthrough wave will pass within 1 hour from the moment of its formation is called the site is extremely dangerous flooding, where the greatest population losses and severe destruction of objects occur. The parameters of the breakthrough wave at the boundaries of the site are:

Height at the crest H in > 1.5 m; - movement speed V max = 2.5 m/sec.

Plot possible flooding characterized by terrain marks that are wetted by the breakthrough wave. Population losses and destruction of facilities on it are unlikely.

The critical parameters that determine the destruction of ground-based buildings by a breakthrough wave, depending on the greatest depth of flow (H ZAT) and the highest flow velocity (V MAX) are presented in the table:

Protection of the population in areas of possible catastrophic flooding

The population from settlements located in the zone of possible flooding and located within the 4-hour zone of reaching the breakthrough wave is evacuated after receiving an order to carry out evacuation measures.

The population from settlements located in the zone of possible flooding beyond the 4-hour zone of reaching the breakthrough wave is evacuated only after the destruction of the dam and upon receipt of the appropriate order.

The largest working shift of economic facilities located in the zone of possible flooding takes shelter in special shelters (increased sealing and a towering emergency vertical exit, with 3 ventilation modes), built in places with a possible flood depth of up to 10 meters and having a collection radius of up to 1000 meters .

To protect the population evacuated from settlements located in the flood zone, PRUs are built in advance at the places of their evacuation.

To protect the population living in the flooded areas of uncategorized cities and towns, it is planned to build a PRU in the non-flooded areas of these settlements. The working shift of economic facilities located in uncategorized cities in the flood zone takes shelter in PRUs built outside these zones.

Sheltering the population in protective structures in a number of cases is the only and most reliable method of protection, which can be used both in peacetime emergencies and in war time.

APPLICATION

Longitudinal section of a formed breakthrough wave.

h - household water level in the river; Hv - wave height;

H - flow height

Accidents at hydraulic structures and their consequences

Subject: life safety.

The date of the:

Compiled by: teacher-organizer of life safety Musagitov R.T.

Goal: to get acquainted with the main causes of accidents at hydraulic structures and their possible consequences.

During the classes

Repetition of covered material.

What factors determine the preservation high degree the likelihood of an emergency at explosion- and fire-hazardous facilities?

Under what conditions is it necessary to develop an industrial safety declaration at an explosion- and fire-hazardous facility?

What created the conditions for the emergence of the State Fire and Rescue Service in the country?

State the topic and purpose of the lesson.

The topic of the lesson is “Accidents at hydraulic structures and their consequences.”

Purpose of the lesson: to get acquainted with the main causes of accidents at hydraulic structures and their possible consequences.

Presentation of program material.

Hydraulic structures are designed to use water resources for human needs, as well as to combat the destructive effects of water on human life. According to their purpose, hydraulic structures are divided into water supply (dams, dams, etc.), water supply (canals, pipelines, tunnels, etc.), regulatory (half-dams, enclosing shafts, etc.), water intake, spillway and special ( buildings of hydroelectric power stations (HPP), locks, ship lifts, etc.).

Currently on site Russian Federation More than 30 thousand reservoirs and several hundred storage tanks for industrial wastewater and waste are in operation. There are about 60 large reservoirs with a capacity of more than 1 billion m 3 .

The main potentially dangerous hydraulic structures include dams, water intake and spillway structures and sluices.

A water intake structure is a hydraulic structure for collecting water from a power source (river, lake, underground source) in order to use it for the needs of hydropower, water supply or field irrigation.

Spillway structures are hydraulic structures designed to discharge excess (flood) water from a reservoir, as well as pass water into the downstream. (The pool is a part of a reservoir, river, canal. The upper pool is located downstream above the water pump structure (dam, sluice), the lower pool is located below the water pump structure.)

A lock is a network of structures for raising or lowering ships from one water level (river, canal) to another. The largest locks are over 30 m wide and up to several hundred meters long.

Hydrodynamic accidents at these structures can lead to catastrophic consequences, since all these hydraulic structures are located, as a rule, within or above large populated areas and are objects of increased risk. The occurrence of a hydrodynamic accident at such a facility can lead to catastrophic flooding of vast areas and the formation of a catastrophic flooding zone.

Remember!

A hydrodynamic accident is an emergency situation associated with the failure (destruction) of a hydraulic structure or part of it and the uncontrolled movement of large masses of water, causing destruction and flooding of vast areas.

A catastrophic flood zone is a flood zone that arose as a result of a hydrodynamic accident that occurred at a hydraulic structure, within which massive losses of people, farm animals and plants occurred, buildings and various structures were significantly damaged or destroyed.

Hydrodynamic accidents at hydraulic structures can occur as a result of natural forces (earthquakes, hurricanes, spills, destruction of a dam by flood waters) or human influence (strikes). modern means damage to hydraulic structures and acts of sabotage), as well as due to design defects or errors in the design and operation of hydraulic structures.

Everyone should know this

The main consequences of major hydrodynamic accidents are:

damage and destruction of hydraulic structures, short-term or long-term cessation of their functions;

defeat of people and destruction of structures by a breakthrough wave formed as a result of the destruction of a hydraulic structure and having a height of 2 to 12 m and a speed of 3 to 25 km/h (in mountainous areas it can reach up to 100 km/h);

catastrophic flooding of vast territories and a significant number of cities and villages, economic facilities, long-term cessation shipping, agricultural and fishing production.

Statistics

Currently, hydraulic structures at 200 reservoirs and 56 waste storage ponds have been in operation without significant reconstruction for more than 50 years, and this increases the likelihood of hydrodynamic accidents occurring there.

According to the Russian Ministry of Emergency Situations

History knows several examples of the catastrophic consequences of accidents at hydraulic structures due to the destruction of a dam.

If a dam collapses, water rushes down the river with high speed and pressure. A so-called breakthrough wave is formed, which is the main damaging factor of a hydrodynamic accident.

HISTORICAL FACTS

Such an accident occurred on March 12, 1928 at the St. Francis Dam in California (USA). The dam was built 70 km from Los Angeles in the San Francisco Canyon to store water for its subsequent distribution through the Los Angeles water supply (water intake hydraulic structure). The reservoir began to be filled with water in 1927; the water reached its maximum level on March 5, 1928. At this time, water had already begun to seep through the dam, but no protective measures were taken. As a result, on March 12, 1928, the dam was breached by water and collapsed. The water rushed along the canyon in a wall reaching a height of up to 40 m, and hit a power plant located 25 km downstream. The water flooded the valley for 80 km; not many people who found themselves in the path of the water survived. About 600 people died. The cause of this accident was errors in technology during the construction of the dam and failure to take timely measures when water was found to be leaking through the dam.

In June 1993, in our country there was a breakthrough of the Kiselyovsky reservoir dam on the Kakva River (located in the Serovsky district Sverdlovsk region 17 km from the city of Serov). The dam was 2 km long and 17 m high. The reservoir was filled with water in 1979. The volume of the reservoir at a normal retaining water level was 32 million m 3 . The volume at the formed retaining level (which could only be allowed for a short time) reached 37 million m 3 .

The emergency situation arose as a result of severe flooding resulting from the superposition of rain flows during the final phase of the spring flood. In connection with this, an increase in discharge flows from the reservoir was made, but the influx of water into the reservoir continuously increased. The normal retaining level was noted on June 12. On June 13, the bottom outlets and all dam gates were completely opened at the dam, but the discharge flow did not compensate for the increasing volume of water in the reservoir. The calculated forced level was reached by the morning of June 14, the water rose to the crest of the dam, and it began to overflow over the dam along the front of about 1900 m, then the dam broke, followed by the dam overflowing to its entire height. The accident led to a sharp rise in water in the Kakwa River below the dam, resulting in flooding of 69 km 2 the floodplain of the river, residential areas of the city of Serov and a number of settlements. The flood affected 6.5 thousand people, 12 people died. 1,772 houses fell into the flood zone, of which 1,250 became uninhabitable. The railway and 5 road bridges were destroyed, 500 m of the main railway track were washed away.

In conclusion, it should be noted that major hydrodynamic accidents do not happen very rarely. It is noted that more than 300 significant hydrodynamic accidents have occurred in the world over the past 180 years.

The consequences of accidents at hydrodynamic structures may be accompanied by side effects. In the zone of catastrophic flooding there may be dangerous production facilities (chemical, fire and explosion hazardous), accidents at which will aggravate the situation. In addition, in the catastrophic flood zone, the operation of the water supply, sewerage, and drainage systems is disrupted. All this creates an unfavorable sanitary and epidemiological situation and contributes to the emergence of mass infectious diseases.

IV. Lesson summary

Questions for self-control:

What structures are considered hydrodynamic? Name their main purpose.

Which hydrodynamic structures Are they classified as potentially dangerous structures?

What are the causes of a hydrodynamic accident?

What damaging factors arise during a hydrodynamic accident?

List the main consequences of a hydrodynamic accident.

Homework

Find several examples of hydrodynamic accidents that have occurred in the world from various sources (books, magazines, etc.). Analyze the causes of their occurrence and consequences for the life of the population in the emergency zone. Select from the messages the activities that contributed to reducing the negative consequences of the accident.