A very interesting background to the renewed drought in California is described in the article “Drought”...
Will we say goodbye to California?
From time to time we hear stories about the so-called Dust Bowl in the grain-rich US Midwest during the Great Depression of the 1930s, when strong winds and clouds of dust covered almost 75% U.S.A. Dust storms continued throughout 8 years old from 1931 to 1939. However, there is still little information, especially on national American channels, although the storms threaten to literally dry out the most populous states.
The Dust Bowl of the 1930s resulted from the widespread use of mechanized agriculture in the prairies of the Midwest. In the early 1920s, politics interest rates The Fed caused a deep recession, and in order to survive, farmers had to switch to mechanization and new tractors from the company Ford and other equipment. More than 5 million acres of previously uncultivated land were cultivated from 1925 to the 1930s. As a result, American farmers enjoyed record harvests in 1931, just as living standards began to fall as a result of the Great Depression.
The result was a large-scale overproduction and a sharp decline in market prices. The grain market was oversaturated, and consumers did not have enough money to buy it. In a desperate attempt to earn something, farmers took out loans and those who could expanded their arable fields, just as is happening today with oil fields in North Dakota and Texas for oil production. As a result, they reseeded the prairie where drought-tolerant grass grew, leaving unused land unplanted
Plowing in the Midwest resulted in the loss of topsoil, which was literally blown away by the winds, causing the soil to become hypersensitive to drought. Then the precipitation stopped. By 1932, 14 had already been recorded. dust storms, known as dust storms. In just one year their number increased to 40 , forcing millions of people to leave these regions. Precipitation began to fall again no earlier than 1939 years, bringing with it long-awaited relief
Now let's return to California, the most populous American state. The population here is 38 million, this is more than in many EU countries, the GDP level in 2012 was $2.2 trillion. If California were a separate state, it would rank 8th in the world in terms of GDP after the USA, China, Japan, Germany, France, Brazil and the UK. In general, California is important not only for the US economy, but also for the world economy as well. The centers are concentrated here high technology from Silicon Valley to the most extensive scientific laboratories and universities such as the University of Berkeley and
The state experienced severe drought for four years in a row. With each passing day, drought is depleting groundwater, lake basins and other resources. Jay Famiglietti (Jay Famiglietti) Senior Water Resources Specialist Laboratory jet engines NASA at the California Institute of Technology and a professor in the Department of Earth Sciences at the University of California, Irvine first confirmed the seriousness of the situation on the pages Los Angeles Times.
Last winter, California's normal "wet season" and "low levels of rain and snow" provided little relief from the unprecedented drought, Famiglietti said. January 2015 was the driest January in California since records began in 1895. Groundwater and level snow cover are at the lower level. Not only did we find ourselves in the water without knowing the ford, but we are also losing the water itself...” 
Famiglietti is considered the top water resource expert in the United States, if not the world. His warning sounds little like mere scare propaganda Al Gora (Al Gore). It is based on scientific facts, which can be checked. Here are some of them:
On September 30, 2014, the volume of Folsom Lake was 35% from the maximum... More than 600 docks sit empty, the harbor of Folsom Lake, one of California's largest inland harbors, bare of nothing but cracked soil.
Data from NASA satellites show that the total water storage in the Sacramento river basins (Sacramento) and San Joaquin (San Joaquin)- snow, river water and water in storage, water contained in soil and soil - was on 41 billion cubic meters less than the norm in 2014. The loss amounted to approximately 1.5 times the volume of Lake Mead, the largest reservoir in the United States.
Statewide, we have been losing more than 12 million acre-feet of water each year since 2011. Roughly speaking, two-thirds of these losses are due to groundwater pumping for irrigation in the California Valley. Farmers have no choice but to pump groundwater during drought, especially when surface water irrigation has completely stopped. Wells are also drying up. In some areas of the California Valley, the soil is sinking about a foot each year.
California is running short of water, and the problem began before today's drought. NASA data says water supplies in California have been steadily declining since satellite monitoring began in 2002.
Famiglietti warns that: “On this moment The state has only one year's worth of water in reservoirs, and our strategic backup source, groundwater, is disappearing at an extremely rapid rate. We also have no backup plan for a prolonged drought such as this (let alone a 20+ year drought) other than perhaps staying on high alert and praying for rain. Overall, we don't have a plan to overcome this crisis
California is running out of water, and this means a lack of water for economic needs, empty storage facilities and lack of water for irrigation. Despite California's image as a high-tech center, the state is one of the most important agricultural producers in the United States.
Over the course of several decades, the merger of large agribusinesses transformed the California Valley's farmlands, draining lakes and rivers to expand arable land. The environmental consequences can perhaps be compared to Kansas and Oklahoma during the 1930s, a significant factor causing the current drought, or at least exacerbating it.
Yet it is not high-tech agriculture that is thriving in the valley, but almost Slave work illegal migrants from Mexico, who are the largest source of manual labor and are in such dire need of money. According to a 2005 report by the Congressional Research Group, San Joaquin County was one of the most economically depressed regions in the United States, along with Appalachia. In total, the poverty level is 23,5% and is the highest of all states.
Eyewitness Chronicles
Joseph Reed (Joseph Reed) geologist working in the field information technologies in California, sent the author of this article his chronicle of the unfolding disaster that he has witnessed over the past several years while living in the West: “I was at Lake Oroville (Lake Oroville). It was early summer last year, and the water level in the lake was already below normal at 60 meters. According to local newspaper reports, the water level in the lake is currently 300 feet less the highest water level in the lake. You have to see it to understand. you just need to see this huge, high wall of dried clay and the puddle at the bottom of the giant lake to fully understand the scale of the problem...” Lake Oroville is the second largest reservoir in California. Here are some terrifying photos
He (Joseph) continues his story of “devastation”: “I was at Lake Shasta (Lake Shasta) near Redding (Redding), the agricultural center of Northern California - it was one and a half years ago. At that time, the water level in the lake was about 40 meters below normal. According to the weekly "Bi-Weekly Drought Briefing" from March 16th lake Shasta filled only to 58% . The lake is the largest reservoir in California and is also an important hydroelectric source. viii Here are some photos of Lake Shasta taken last summer. Reed concludes: “I also visited the lake Folsom, which is the reservoir for the city of Sacramento in the western United States. One of my co-workers has a house on a lake with a boat dock. Today the dock is dry and you will need binoculars to see the remaining water there. This is how things are with lakes. Groundwater is drying up and pollution is increasing due to fracking and toxic waste dumping (courtesy of the US Environmental Protection Agency). EPA)).
Most alarmingly, the Sierra Nevada snowpack (Sierra Nevada), which is the main source fresh water for the state during the melt season, crop yields are at their “lowest point” since 1950. Edition "The Weekly Drought Briefing" states that “electronic snow thickness sensors recorded values in 14% from the average in the north of the state, 18% in the center and 19% in the southern part."
Even after a winter with fairly heavy rainfall, water levels in storage facilities as of March 15 are still low according to data "Drought Briefing". The largest reservoirs in the state:
– Lake Castaic (Castaic Lake) – 29%
from the total volume.
– Lake Don Pedro (Don Pedro) – 43% from the total volume.
– Lake McClure (Exchequer) – 9% from the total volume.
– Folsom Lake (Folsom Lake) – 59% from the total volume.
The background to the death of California is described in the article “Drought”
The largest US reservoir is drying up
Environmentalists predict an unimaginable drought for the United States for decades
More details and a variety of information about events taking place in Russia, Ukraine and other countries of our beautiful planet can be obtained at Internet Conferences, constantly held on the website “Keys of Knowledge”. All Conferences are open and completely free. We invite everyone who wakes up and is interested...
IN DISASTER The Oroville Dam is destroyed. California is facing disaster. A general evacuation has been announced.
Original taken from vseneobichnoe c The Oroville Dam is destroyed. California is facing disaster. A general evacuation has been announced.
EVACUATION ORDER GIVEN!!! THREE ENTIRE COUNTIES IN NORTHERN CALIFORNIA FACE FLOODING DISASTER FROM IMPENDING DAM FAILURE
Residents of Oroville, California and surrounding areas have been ordered to leave their homes immediately as parts of the Oroville Dam itself high dam of all the US countries is experiencing severe structural collapse.
Damage to the main dam structure is expected within an hour. Once this structure is destroyed, over two cubic miles of water will be released. The flood will wipe out an entire area.
Oroville Reservoir is located 240 kilometers from San Francisco. The city of Oroville, located by the lake, is home to 16,000 people. The dam about which we're talking about, is the tallest in the United States, its height is 235 meters. The reservoir is also the main source of water for California, agriculture in the Central Valley and businesses in the state.
Old video clip showing what the Oroville Spillway should look like in normal operation:
This is what it looks like now:
If earlier the water extinguished its energy, smoothly flowing from a height of 770 feet, then today, after spontaneous damage to the spillway about a week ago
Due to a series of downpours that flooded the region, the lower part of the structure looks like a seething stream of water with flying blocks of reinforced concrete, eroding the surface down to the rocks.
Evacuation zone maps:
Here's what American bloggers think about the situation:
Flyingcuttlefish: Several years ago I spoke with a volunteer lifeguard from North Carolina. He secretly, fearing that someone would hear us, told me that they were conducting special exercises in case the dam upstream from a large populated area was destroyed. He even gave me an approximate date when this could happen. The rescuer’s words were not a surprise to me and only confirmed my suspicions. The fact is that in some strange coincidence it turned out that the United States Army of Engineers built more than 50% of their dams on the sites of active underground faults and in those places where large populations were gathered down the river. What if the dams were built this way on purpose - in anticipation of future events, natural Disasters? Or even disasters launched artificially, for example using devices such as HAARP. If a flood kills a lot of people, destroys the local economy - HAARP can influence not just the weather, but politics.
Jim Stone: All posts by maintenance The dams show that until recently the spillway was in excellent condition. I've analyzed hours of CCTV footage of the dam, and in some of the frames you can see chunks of the deck's concrete appear to be jumping high in the air. So I think the spillway was blown. Or is this some kind of deliberate sabotage. Obviously, I have no evidence of deliberate digging under the drain or traces of explosives, but you must agree that this is a completely rational explanation. Even engineers are terribly surprised how this happened. And that means a lot. Therefore, I have doubts that everything will end well. If the dam fails, it will be a double Niagara Falls. Or even Niagara times four.
Based on materials
A regime has been introduced in northern California emergency and an evacuation order was issued for 190 thousand people due to the threat of a dam failure near the city of Oroville, one of the largest dams in the United States. Now the water level in the Oroville Reservoir has risen to a critical level due to heavy rains, and the dam's drains are damaged, which could lead to flooding of the surrounding area at any time.
In California, the evacuation of residents of the city of Oroville and neighboring areas has been announced due to the threat of a breach of one of the largest dams in the United States. A total of 190 thousand people were ordered to evacuate. California Governor Jerry Brown declared a state of emergency in the area. According to the California Fire Department, 35 thousand people were evacuated in Butte County, where Oroville is located, 65 thousand people in Yuba County, as well as 76 thousand residents of Yuba City and 12 thousand residents of Marysville.
The dam itself is intact, but the emergency spillway, designed to quickly empty if water levels rise sharply, was destroyed on Sunday. According to authorities, the spillway may not be able to withstand the load and collapse at any time, causing water to be released from the Oroville Reservoir. The main spillway was also washed out earlier last week.
If the dam breaks, water could flood nearby towns. Water levels in the Oroville Reservoir have risen due to heavy rainfall. Precipitation levels in Northern California are 228% above average for this time of year. “A dam failure like this is a disaster. We have determined that we cannot repair the damage,” said the head of the California Department during a press conference. water resources Bill Croyle.
The Oroville Dam on the Feather River is the tallest in the United States, reaching a height of 230 m. The dam was built in the 1960s. Oroville Reservoir is the largest in California.
Doctor of Technical Sciences, Head of the Surface Water Modeling Laboratory at the Institute of Water Problems of the Russian Academy of Sciences Mikhail Bolgov: “You need to know the design of this dam and what place the emergency spillway occupies in it in order to give a full forecast. But according to preliminary data, the consequences of its breakthrough could be catastrophic; there is a very large reservoir with high pressure, so the destruction could be colossal. Typically the spillway is designed to start operating as soon as the reservoir is close to overflowing. Operational services try to never let the situation get to this point; this is an extreme measure. Why all the negative conditions accumulated there so much, why this, roughly speaking, hole began to work in emergency mode, is unclear. During construction, water conduits are specially left, which are then filled with concrete. Maybe this is one of the remaining construction water pipelines, but, as I said, they are plugging with concrete. Evacuation of people always occurs when the risks become great. This does not mean that the dam will definitely fail, but it is necessary to evacuate. It is necessary to carry out a full set of emergency measures, because it is better to resettle people than to fish out corpses later. There is only one way to reduce the level - all spillway devices are opened, all turbines, if they are in the dam, are turned on at full power, for this the thermal stations are shut down and in this beyond design mode the hydraulic structure begins to work in order to reduce the pressure on this place as much as possible where the accident occurred."
Former Director for Technical Policy of JSC RusHydro Rasim Khaziakhmetov:“Information about the condition of the Oroville Dam is contradictory, I would say too much in the media and does not allow us to accurately predict the consequences. If the media and local authorities overestimate the risks, nothing serious will happen. If the photos and video materials from the first half of the day are accurate, then the watersheds may be destroyed and, again, the consequences will not be overly catastrophic, especially since the authorities have taken serious measures to evacuate the population. It was a little annoying that in one of the helicopter shots, signs of filtration of the dam itself were visible, but this was scary. Imagine that a landslide occurs and a wave more than 200 meters high with a pressure of 20 atmospheres rushes down. Then it may turn out that it was not 180 thousand people who had to be evacuated, but much more. There was already an accident in history when in 1963 a landslide occurred in Italy and water overflowed over a dam. Given that there was almost flat desert around and the wave height was about 20 meters, several villages were washed away in 7 minutes, killing 3 thousand people. Everything seems much more dangerous here.”
Former Deputy Minister of Energy and former chairman of the Board of Directors of RAO UES of Russia Viktor Kudryavy: “Very few accurate information about the real situation with the dam, to what height it can collapse, at what speed, the characteristics of the lake itself, the volume of water accumulated in it, what the height difference is downstream, the terrain, whether there are turns that can provide overflow and smooth out the consequences. There are a lot of factors. But it is clear that the foundation of the dam is good, since they are not very afraid, and a breakthrough can only occur in the upper part. The dynamics of destruction, wave height and speed are scary. Complete destruction will lead to a catastrophe the likes of which the world has never seen. I really hope it doesn’t happen.”
Yana Rozhdestvenskaya; group "Direct Speech"
Oroville Dam is the highest in the United States. The height of its ground part reaches 235 meters. The dam is located on the Feather River (a tributary of the Sacramento River). A rock dam with a clay core forms the Oroville Reservoir, with a surface area of 10,200 square kilometers and a water volume of 4.3 cubic kilometers.
The reservoir itself is part of a complex that includes a hydroelectric power station with a capacity of 819 MW with six generators, power point Hyatt, Thermalito pump and generator station, as well as a fish factory. The main objectives of the complex are water supply to the region, flood control and electricity generation. The facility was built in 1961–1968.
The complex buildings are located with right side along the river. The object closest to the dam is an operational spillway (a tray made of reinforced concrete) for operation in normal conditions. water mode. Even further to the right is an emergency discharge in case of catastrophic floods. Until the February incident, it was not used because there were no such floods. According to statistics, large-scale floods in this region can occur no more than once every ten thousand years.
The fault looks like a hundred-meter wall with a height of 10–20 meters. The incoming water must overflow without regulation, and its layer will be tens of centimeters. Further, at the junction with the right bank of the valley, there is a blind section of the dam with a height of up to 30 meters.
Chronology of the incident
Since the beginning of 2017, water levels in the Oroville Reservoir have been rising at an exponential rate. However, the record belongs to the summer of 1983, but no emergency situations were observed then. In January 2017, the amount of precipitation in the region exceeded the norm three times. Since the beginning of February it has been extremely warm weather, even at night it did not fall below 10 degrees Celsius.
Already on February 7, a large washout was discovered in the middle part of the spillway. The karst failure, as experts from the CIS believe, occurred due to leaching of the rock base. While repairmen were inspecting the damage, water in the reservoir was rapidly accumulating. When it reached a critical point, which already threatened the safety of the dam itself, emergency crews left the failure area and directed the water through the discharge.
The consequences were not long in coming. The concrete fastening at the bottom of the structure was destroyed, after which the water began to wash away the rock underneath the drain. The destructive process began at the moment of water consumption at the level of 1.4 thousand cubic meters per second. For comparison, in 1997 the dam passed a flow of 4 thousand cubic meters per second without problems. The gap reached a size of 150 by 90 meters and a depth of 14 meters.
The engineers who identified the problem expected that the structure would collapse at any moment, so they reduced the water flow by 15%, using an emergency discharge that had not been used previously, and by February 10 it turned out that the soil foundation of the backup drain was also damaged, and the reason was the loss of integrity It was not possible to find out the object.
The flow of water carried away the debris rock into the river bed, therefore it was necessary to stop the operation of the hydroelectric power station, otherwise due to backwater it could be flooded. Meanwhile, the rupture pit on the main fault expanded, destroying its walls and eroding the adjacent slope. The situation at the emergency drainage has become critical. The decision was made to resume increased flow through the main spillway, despite the threat of loss of control of the dam due to possible failure of the flow.
Accident response and preventive measures
Since the threat of destruction of the dam infrastructure, California Governor Jerry Brown has asked President Donald Trump to send forces and resources federal level to eliminate an emergency. In his address, the official noted that assistance should also be provided to the districts where residents evacuated from possible flood zones are located.
On Monday, February 13, the Governor of California declared a state of emergency in the region, covering three counties - Yuba, Sutter and Butte. State National Guard units were put on alert. The White House reported that the president has entrusted the coordination of emergency response efforts to the Federal Emergency Management Agency of the Department of Homeland Security. In addition, the country's Ministry of Defense also joined the work. Pronedra wrote earlier that Trump also declared a state of emergency in the disaster zone.
The Russian side immediately offered its help. The Center for Development of the Water Economy Complex of the Ministry of Natural Resources of the Russian Federation stated that domestic specialists can work on solving the problem of the emergency condition of the dam, including by providing appropriate scientific advice. Such tasks are not new to Russians; Moscow has already provided assistance in similar emergencies to countries in Africa and Southeast Asia.
Large forces were put on alert in the United States - a total of about 20 thousand military personnel. 125 construction crews and four dozen heavy vehicles were sent directly to the work area. Aviation was involved, including helicopters of the National Guard, with the help of which they began to drop bags of sand and rock at the sites where the drain was washed out. Barriers made of sandbags are also being erected around the dam. Every hour, about 1.2 thousand tons of rock fragments are placed in the gullies.
The state authorities informed that the work carried out by February 15 made it possible to stop the development of the catastrophic situation, and the expected storm with precipitation was not as significant as expected. In general, the cost of priority measures was estimated at $200 million. It is still unknown how the condition of the spillways will affect further exploitation dams. Work continues. Thanks to measures taken The dam is already able to accommodate additional water inflow. Currently, the volume of discharge is 2.8 thousand cubic meters per second, while the rains do not stop and will continue for several more days.
According to RusHydro, measures are being taken to reduce the reservoir level by 2.5 meters per day in order to safely receive the upcoming precipitation. Debris is being removed in the riverbed to prevent possible flooding of hydroelectric power station structures. The launch of the station's capacity will make it possible to relieve some of the operational discharge. If the latter is subject to restoration, it will be repaired. If repair work is impossible, a new spillway will be built. It is possible that it is necessary to strengthen the emergency discharge slope with concrete and generally evaluate the possibility of its use in the future.
Evacuation, panic and looting
After information from the California Department of Water Resources appeared about the threat of an imminent dam failure (it later turned out that the forecasts were unjustifiably exaggerated), state authorities decided to evacuate the local population. By February 13, a total of 188 thousand people were removed or left on their own from the cities of Yuba City, Gridley, Olivehurst, Plumas Lake, Wheatland, Marysville and Live Oak. But along the route of the evacuees there were colossal traffic jams. Temporarily resettled citizens were placed in different areas at a distance of 32–120 kilometers from the possible flood zone.
Conflicting statements by officials, in particular the emergence of information about the possible destruction of the dam in a matter of hours, played a significant role in the emergence of panic. Already on February 15, the evacuated residents were told that they could return to their homes, although it was noted that the threat of flooding still remained and citizens might have to leave the dangerous area again. Citizens who returned to their homes faced the consequences of looting in their cities. Such reports also came from Oroville, where, in the absence of residents, mass thefts occurred in abandoned stores.
Forecast for the development of the situation in the near future
The state authorities initially took a pessimistic position in terms of forecasting developments. The California Department of Water Resources admitted that if the dam structure is damaged, the forecast could be unfavorable. According to local police, who interviewed experts in the field of hydraulic engineering, a hole in the spillway could threaten the integrity of the entire dam. However, experts emphasize that dams using concrete components are usually less susceptible to erosion processes.
However, if the structure is damaged, this can also lead to its collapse. IN Russian Institute hydraulic engineering and energy engineering believe that the dam can survive if excess water flow is released through open gates. A disaster is potentially possible if the spillway is not functioning.
The most dire forecasts appeared on February 11, when state authorities announced that the water level in the river would rise to critical levels due to a possible dam failure. Although it was announced the next day that the threat had passed, on February 13, reports of the threat of the dam collapsing again appeared. The negative scenario provides for the speed of wave propagation in flat terrain within 25 kilometers per hour, in mountainous terrain - up to 100 kilometers per hour. It is stated that the height of the breakthrough wave for small reservoirs with a water volume of up to 50 million cubic meters will be up to one meter, but in the case of Oroville, whose capacity is eight and a half times greater, the wave will reach a height of up to nine meters.
Let us remind you that in this case, six settlements with a total population of up to 200 thousand people will be in the flood zone. In turn, RusHydro noted that as of February 12, when signs of active rock erosion were noticed on the slope below the emergency discharge, a certain threat arose for residents of the region. If the overflow wall collapsed due to intense erosion, it could cause an uncontrolled discharge of a layer of about 12 meters of the reservoir in height.
There are also alternative points of view. Forecasting for the coming days is a difficult matter, according to hydraulic engineers from the CIS, interviewed by journalists. It is more likely that the dam will remain unharmed, while the spillways - both the main and the emergency ones - will be washed out to the point of complete destruction, but no noticeable damage will be caused to the population and infrastructure. The overflow through the dam will stop after some time, or the process of erosion of the spillway will take place over a long period - within one month, which will not cause sudden changes in the situation and the problem will not become more complicated.
RusHydro believes that current data gives grounds to assert that there is no threat of destruction of the dam, but the spillway structures are in disrepair. The crest of the dam is located six meters above the emergency discharge mark, therefore an emergency overflow of water is also excluded. If the drainage erosion moves to the spillways themselves, then the latter will probably be destroyed. The pit immediately near the spillway stopped actively expanding, reaching the rocky base after the weak rocks were washed away.
Meanwhile, after the accident at one dam, other “hot spots” in California were simply forgotten. Reservoir overflow due to heavy rainfall is a problem not only at the Oroville Dam, but also at most hydraulic structures in the California Valley. The situation on the Sacramento River near the city of the same name is causing concern. The river dam is showing signs of deformation after prolonged exposure to flowing water. Some water has already leaked through the dam and entered the city park, which is located near the river. In addition, a threatening situation is observed in the area of the dam on the San Joaquin River.
In addition, the water level at the Don Pedro Reservoir dam has almost reached the upper edge of the structure. If a snow storm hits the Sierra Nevada Mountains in eastern California, flooding may be inevitable. To prevent the destruction of these structures, the state authorities decided to deliberately destroy the dam on the Moklamne River, which led to the flooding of nearby agricultural land, but reduced the threat of large-scale accidents.
Possible versions of the causes of the accident
ABOUT possible problems the problem with the dam became known long before the February accident in 2006. Even then, experts discovered minor violations of the integrity of the main spillway, but the facility was declared suitable for operation. Major repair work on the dam has not been carried out for half a century - from the day it was put into operation. Last decade the dam operated under a temporary license. Probably, the reason for the uncertain status of the dam is associated with the attempt to obtain a permit for a period of 50 years by the Californian authorities and the subsequent reaction of social activists.
In 2005, a group of activists representing environmental organizations - the South Yuba Citizens League, Sierra Club and Friends of the River - demanded that officials reinforce the emergency discharge with concrete instead of an earthen foundation. The joint letter from the organizations argued that during winter rains, water will begin to overflow the main spillway, which will ultimately lead to erosion, further destruction of structures and flooding. Proposals were submitted to the Presidential Administration and the Federal Energy Regulatory Commission, but they, based on the findings of the California Department of Water Resources that such work was inappropriate, rejected the initiative. According to the authors of the letter, the authorities simply decided to save money, since strengthening the emergency spillway with concrete would have cost millions of dollars. Now the department says the cause of erosion on the drainage drains is unknown.
Like any serious threat, the situation with the risk of dam collapse has already become overgrown with rumors and exotic theories. In particular, it is assumed that a possible disaster was deliberately provoked in order to smooth out the discontent of the population of California, the majority of whom voted for Hillary Clinton in the presidential election. A great misfortune can unite a nation and eliminate political differences. In addition, it should be taken into account that California social activists are actively calling for the separation of the region from the United States.
Proponents of the conspiracy theory believe that the failure of the main spillway was controlled and was the result of sabotage - the leak arose by interfering with the work of the already worn-out infrastructure. In addition, there were statements that rescue services carried out exercises several years ago, during which they practiced actions in the event of a dam collapse. At the same time, practically exact date possible event was already specified in the maneuver scenario.
If we talk about real facts, then RusHydro, which analyzed the development of the emergency situation and possible preconditions, came to a number of conclusions. It is noted that the destruction of the operational spillway occurred suddenly, and the water flow levels were not at all maximum. Thus, we should talk about an insufficient degree of control over the condition hydraulic structure, which did not allow timely detection of damage, the company noted.
It is difficult to call the design solution itself correct, associated with the discharge of water masses onto an ordinary unequipped slope. Spillways must undergo mandatory testing. However, it must also be noted that the safety margin of the dam turned out to be sufficient, despite the fact that accidents occurred at both spillways. Thus, large hydraulic structures can generally be considered reliable structures, the company noted.
Regardless of what the results of the accident investigation turn out to be, it is obvious even to non-specialists that, if we do not take into account dubious theories of sabotage or sabotage, the unsatisfactory condition of both spillways was most likely the result of ordinary negligence of the services, which did not timely track the process of structural damage due to natural processes wear. The lack of preventive measures almost caused a large-scale tragedy, and for the happy outcome of the situation we can only thank the reliability of the dam itself, which acted as insurance against the negligence of industry services.
California authorities continue to evacuate approximately 200 thousand residents from areas in the immediate vicinity of the Oroville Reservoir dam, which is in danger of breaking due to heavy rains. And although everything is not so scary - there is a huge plain below, it is better to be overly safe than underslept.
The overflow of water over the edge of the dam washes away the soil and eats holes through which water flows increasingly uncontrollably. In the event of such a breakthrough, the reservoir's waves would flood the Feather River bed and the entire Sacramento Valley located to the east. For now, the dam, which is open to the maximum, and the emergency spillway, which is also being washed away with might and main, are coping with the limit, undermining thousands of concrete.
The head of the emergency headquarters, Kevin Lawson, says that if the problem is not solved now, a real wall of water will collapse. “It won’t be a stream from the lake, it will be a 9-meter wall of water,” notes the rescuer. Experts are trying to patch up the ravine by dropping stones from helicopters. Why the hell the rescuer lies and scares people is unclear. There will be no 9-meter wave, just look at the lowland. Even if you blow up the entire dam, it won't happen.
Maybe he has a family transport company, which the state authorities contracted to evacuate the population?
Heavy rainfall in recent days has damaged both the main and emergency spillways of the Oroville Reservoir, California's second largest. The reservoir's volume is approximately 4.3 billion cubic meters of water. At 235 meters high, the Oroville Dam is the tallest in the United States, exceeding the famous Hoover Dam by 12 meters.
A few days ago, a ravine was discovered in the main spillway of the dam, which continues to grow. To carry out repairs, the volume of water discharge through the main spillway was limited.
This, together with rains, led to an increase in the water level in the lake and the need to use an additional spillway for the first time since the construction of the reservoir in 1968, which could not withstand the load and also began to collapse. In addition, water began to overflow over the edge of the dam, reports Los Angeles Times.
Authorities have made attempts to reduce the water level in the reservoir to avoid a disaster. The discharge of water through the main spillway was, despite the need to repair the ravine, increased to 100 thousand cubic feet (2.8 thousand cubic meters) per minute.
In addition, bags of stones are dropped from helicopters onto damaged areas of spillways. Experts continue to assert that the dam itself, located away from the spillways, is not yet in danger. And it looks very much like that. that they are absolutely right.
IN last hours The water level in the reservoir began to drop, and it stopped overflowing over the edge of the dam. However, both spillways cannot yet cope with the volumes being poured out (photo and video below).
However, representatives of emergency services hope that the water level in the lake will be able to be reduced before irreparable damage is caused to the main and emergency spillway.
On the evening of February 12, mass evacuations of residents began from cities and towns in Butt County located downstream of the spillway.
In some cases, people were told the water would break within an hour and they were forced to leave their homes before they could gather their belongings, CBC News reported. As of now, state authorities report that they have the situation under control, but residents have been abandoned populated areas Cases of looting have been reported.
It all started with the need to repair these gullies. Well, then the human factor - they didn’t keep track of the reservoir level, they decided. that they will have time to dump the excess if something happens.
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