The Adventure Begins
This whole mystery took place among the mountains, rivers, and lakes of Napa Valley, California. This is a region extremely popular for its breathtaking panoramic views of the valleys of the Mayacamas Mountains. It is also home to the Robert Louis Stevenson State Park, which is particularly famous among hikers, given that it offers a five-mile hike to the summit of the famous Mount St. Helena. Last but not least, Napa Valley is famous for its beautiful vineyards. So why would anyone not want to go there?
For all of these reasons, David B, a resident of this area, set out to explore Napa Valley's wildlife in February 2017. A huge hiking fan, his first aim was to hike the nearly five-mile Blue Ridge Trailhead, located near the town of Winters. The trail also features a lake, which is one of its main attractions. For that purpose, David brought his drone with him, in order to capture and film the astonishing landscape.
Filming With The Drone
While hiking the first mile of the Blue Ridge Trailhead, Bobby was already amazed by the views of the surrounding Sacramento Valley. Equally as beautiful were the wildflowers that he came across along the way. Thus, after the first thousand feet of the trail, he decided it was already time to launch his drone and record the scenery.
So David prepared his device and started flying it through the air. It managed to stream the live feed to David's smartphone, thus making it possible for David to watch the footage from his smartphone. It's amazing how much technology advances year by year, isn't it? I bet many of you didn't know connecting the drone to your cellphone was even possible!
The Famous Lake
One of Blue Ridge Trailhead's landmarks is Lake Berryessa. Surrounded by tree-filled hills, this lake is known to be the seventh largest artificial lake in California. So yes, as hard as it is to believe, the lake you see in the picture has been all man-made. Quite impressive!
David headed towards the lake, hoping to record its beauty with his drone as well. He was probably surprised just as you all are by how weird the name of the lake is. Interesting fact: the name Berryessa actually comes from the first European settlers in the Berryessa Valley, José Jesús and Sexto "Sixto" Berryessa. So the history of this place truly does go a long way!
First View Of The Lake
The lake covers a total of 20,000 acres. Besides, it measures 15.5 miles long and 3 miles wide, not to mention the 165 miles of shoreline surrounding it. If you're having trouble picturing the true dimensions of these waters, take a look at the picture. Yes, I know: it looks even more beautiful than what it sounds like.
Just before reaching the lake, David came across some woods: when you encounter the woods, it means you're nearly there. So when flying the drone, he could already catch a glimpse of the lake. Both the day and the weather were perfect, so he managed to obtain a crystal-clear view of the lake's waters. When he first started flying the drone, there wasn't anything odd about the footage. At least not until now.
It's The Valley's Fault!
The Lake happens to have certain abnormalities. Basically, the active Green Valley Fault runs parallel to the Berryessa Lake, bordering nothing less than to the Concord Fault. The Concord Fault is a high-stress fault, also prone to earthquakes. If you got lost by all the technicalities, just take a look at the map below.
So basically, hiking the lake is only for the braves. However, David had done his studying, so he was already familiar with all these geographical facts. He really knew where he was going. Despite this, he went on with his footage, since all of this was not much of his concern. At least, not yet.
First Drone Experience
When deciding to hike the Blue Ridge Trailhead, David never even doubted of bringing along his drone with him. However, this wasn't the first time that he decided to try out his drone on a hiking trip. The first time he gave it a try was also on a hiking trail, near the Putah Creek State Park Wildlife Area.
The Putah Creek Park isn't too big, but the greenbelt trail alongside the creek leading to it is quite beautiful. You can appreciate the trail's beautiful landscape in the picture above. But it had never occurred to David that on his following trip, he would end up recording such unexpecting sights on the footage.
An Inexplicable Hole
After going through the woods, David came across road 128, exactly the one which borders Lake Berryessa. But just as he reached the road, he noticed something rather odd in the water. He still wasn't sure what it was: after all, he was only able to see it on his smartphone, thanks to the drone's live feed. At first glance, there seemed to be an enormous hole right there in the middle of the lake! Could that be true? Was it physically possible?
Awestruck, David zoomed in the image on his phone, and to his surprise, he confirmed his initial suspicion. There was, in fact, a hole in the middle of the giant mass of water. He stood still in disbelief, and couldn't stop asking himself how the hole had originated.
Water Vacuum
As he drove the drone nearer and nearer, he was able to appreciate it with further details. It appeared to be that the water not only flooded into the hole, but it also looked like something from the inside was vacuuming it. The hole resembled a huge crater into which the water crashed. Basically, it pretty much looked like a sinkhole.
Was it some sort of geographic phenomena? Was there some sort of man-made machinery beneath the water? Neither option seemed to convince him. Luckily, his drone allowed him both to film and to take pictures. So David was able to collect plenty of evidence of the yet unraveled mystery.
Not The Only Soul
At first, David had the impression that he was alone. At least he couldn't manage to spot anyone else with the naked eye. But when taking a close look at his footage, he realized that he was not alone: there were other hikers on the trail, only that they were at a distance.
Therefore, David walked some more, until he encountered the first hiker. He kindly asked him to take a look at his smartphone. He wanted to see if the two had similar interpretations of what was seen in the picture: basically, he wanted to know if he was nuts, or if the other hiker also spotted a giant hole in the middle of the lake. Oh, and if you were wondering: the photo shown above is real! It is, in fact, Lake Berryessa, and this is exactly what David could see in the footage.
Getting Closer And Closer
The other hiker reacted just the same way that he had done: he laid in plain disbelief. He stated that he had never seen anything like that before. Luckily for David, this was actually good news: he now knew he was not insane!
After that, both David and his new companion decided to fly the drone closer to the hole, until the point where it was right over it. They wanted to know what would happen if they neared the drone just a couple of meters over the hole. What if it got sucked by the hole?
Drone Goes Crazy
Bad luck for David! Unfortunately, his drone suddenly lost control after bringing it too close to the sinkhole. According to their account, it suddenly became very unstable, and it crashed onto the side before they could get a clearer image of the sinkhole. Tough luck!
After a few moments, David managed to gain control of the drone again, and this time he steered it just a little bit further from the hole. Both of them realized that if they brought the drone too close to the cavity once again, it would suck it down. It seemed just like a whirlwind, which sucks down everything that crosses its path. But whirlwinds don't just form in lakes. So if it wasn't that, what could it be?
The Truth Unfolds
Despite analyzing the footage for several more minutes, they never managed to find out the real truth. Little did they know that the strange hole wasn't really as weird as it seemed. It is actually called "The Glory Hole", and was constructed between 1953 and 1957 as a spillway for the adjoining Monticello Dam. But this doesn't end here! It also seems that the dam, which creates Lake Berryessa, is responsible for impounding the Putah Creek. Curious, isn't it?
But not only is this lake a tourist landmark. Apart from that, the water from the reservoir is supplied to farms in Sacramento Valley for agriculture. However, this spillway operates only when there is an excess of water in the reservoir. If the level of water is not as elevated, then the cemented spillway can be clearly seen. So apparently, the day David went to visit the lake, the level of water was so high that the water-covered spillway did indeed look like some sort of a whirlwind.
Tragedy In The Lake
Now we know that what lies in the lake isn't any kind of natural phenomenon: instead, it is a fine piece of human engineering. However, this doesn't mean that it is safe to get near it. As you can imagine, swimming inside the lake is strictly prohibited.
In spite of this, in 1997, a woman named Emily Schwalek decided not to abide by the rules and went for a swim anyway. She kept getting closer to the hole, wanting to examine it. However, her quest ended tragically, as she got sucked by the sinkhole and drowned. It is said that she actually managed to hand on for almost 20 minutes before going down the hole. Unluckily, help didn't arrive on time.
Grabbing On The Edge
After reading about Emily Schwalek's story, one may wonder: how on earth did she manage to hold on for 20 minutes before drowning? Well, she managed to hold onto the edge of the sinkhole's lip. Of course, the current was much too strong, so her efforts were fruitless.
Of course, when David went to the lake, the edge was completely covered by water due to the excess of water. But if you take a look at this photograph, you can see that the hole's edge is clearly in sight. Sure, holding on to it doesn't seem as hard when there's no water!
The Hole's Size
The glory hole measures around 72 feet in diameter at its very surface. As to its depth, the pipe has a straight drop of almost 200 feet. Towards the bottom, the diameter shrinks down to up to 28 feet. Lastly, the hole has a maximum capacity of 48,000 cubic feet per second. That sounds like an awful amount of water!
We've already seen pictures of the hole covered by water. However, you're probably wondering how the glory hole looks like at times of drought. If you're curious, then don't miss the next picture, because you'll be surely surprised!
At Times Of Drought
Spotting the hole when the level of water is high, just like David did, must be quite thrilling. But visiting the lake at times of drought is just as impressive. Just take a look at the photograph below: this is what the glory hole looks like when the volume of water of the dam goes down, and when no water is spilling over its edges. There is actually a layer of rock beneath and surrounding the hole's surface. It's amazing how the volume of the lake's water can make such a difference!
In 2017, the water level of Lake Berryessa suddenly rocketed. Apparently, the lake had been rather dry and empty for almost a decade. But on February 16th of 2017, water began spilling over the dam once again. The lake's water level rose 35.5 inches after heavy rainfall and a couple of storms. As you may imagine, this was the exact day that David visited the lake. But you're probably wondering: what is the mechanism behind the working of this spillway? Keep on reading if you want to know the answer.
How It Really Works
Let's talk about how this whole mechanism really works. Lake Berryessa extends for 1,602,000-acre-feet, and it also features a reservoir elevation of 440 feet above sea level. Therefore, when the water level is full to the brim, water will start pouring over the lip of the Glory Hole. Check out the map shown in the photo to have a clearer picture.
However, ever since David went hiking on that afternoon of February 17th, water hasn't spilled over the Glory Hole again. So now, the question is: after how long does the reservoir become full, just as David saw it? Check out the following slide!
A Bit Of History
Building the Glory Hole sure took a lot of effort. But once the construction was completed, it took a total of five years for the reservoir to fill it. The first time this happened was on April 18th, in the year of 1963. So the people who went for a hike on that day of mid-April were probably just as bewildered as David was half a century later.
On that day of 1963, the reservoir covered the Monticello dam completely and flooded 20,700 acres of the surrounding Berryessa Valley. But did you know that a very similar spillway is found in Japan? Check out the following picture if you're curious.
Hole At Nekogahara
So it turns out that there are several spillways very similar to the one at Lake Berryessa. These include the ones found at Nekogahara Pond in Japan, at Shing Mun Reservoir in China and at the Ladybower Reservoir in Great Britain. The picture shown below offers a clear image of the one found in Japan.
Last but not least, Covão dos Conchos, found in Portugal, has a spillway extremely similar to the ones mentioned above, although its spillway looks more natural. If you're wondering how these sinkholes look like, then don't miss the next pictures!
Portuguese Glory Hole
The sinkhole of Covão dos Conchos is quite different from the one in Lake Berryessa. It is located in the mountains of Serra da Estrela in Portugal. As you can see in the picture below, it truly looks like a natural wonder, given that bright green bushes have grown on its sides. The tunnel was built way back in time in 1955, to ensure the water diversion from Ribeira das Neves to the lake named Lagoa Comprida.
The hole is way bigger than the one in California: its 1519 meters deep! Fortunately, the sinkhole can be visited by tourists. You can access it by foot on a dirt road that starts off on the left side of Lagoa Comprida. It's a 4 or 5-kilometer walk from the entrance to the site of the sinkhole. It's not a very well-known place, so hardly any tourists go there... but you still shouldn't miss it if you ever have the chance!
The Famous 2017 Rainfalls
As I have mentioned, the very heavy rainfalls of February 2017 caused Lake Berryessa's water level to rapidly increase. The mass of water that spilled from the Monticello Dam caused the sinkhole to be filled with water. However, this wasn't the only dam in the region that was affected by the amount of rainfall. The nearby Oroville Dam, located east of Sacramento Valley in the Sierra Nevada Mountains, also suffered serious consequences. Let us highlight the fact that Oroville Dam is nothing less than the tallest dam of the USA.
As a result of the February rainfalls, the Oroville Dam suffered a frightening breach. The rainfall damaged the dam, forcing the emergency spillway open. Fearing a collapse, this accident forced the evacuation of all the people who lived in the surrounding areas. Nearly 180,000 people were evacuated! Take a look at the next slide to learn about the storm's effects.
Facing The Storm
The storm greatly damaged the dam's spillway, thus reducing the capacity of the dam to release water. It also caused the dam to release a great deal of debris, which made the water quite turbid and dirty, causing damage to the Feather River Fish Hatchery. As a result of the amount of debris, state workers had to evacuate fish and eggs from the hatchery. So not only the people were forced to evacuate: as a matter of fact, a total of nine million fish were evacuated downstream!
All these measures were taken as a means of precaution. But fortunately, the collapse never happened, and residents were allowed to go back to their homes shortly after. So even though this accident almost ended in a tragedy, not a single person ended up wounded. Phew!
Tourist Landmarks
When people come across a spillway like the one at Lake Berryessa or the one near the Oroville dam, they usually regard them as complex pieces of architecture that are one of a kind and nowhere else to be seen. They are not so far from the truth: the building of a dam and its spillways requires some extremely delicate architectural and engineering work.
The marvelous architectural complexity of dams can explain why people from all over the world visit some of USA's biggest dams, as well as the spillways that were built in them. But after learning about David's story at Lake Berryessa, we now know why the lake's spillway is particularly worth seeing. So if you have the chance of visiting it, don't spoil it!