wherever they're built dams are pretty critical pieces of infrastructure but if they go wrong they can go really really wrong in Russia a dam collapse has forced thousands to leave their homes now rescue efforts are continuing in Brazil water from the old kajo Dam washed away houses in KFA major road this is the story of a Dam built just 19 years ago that has already been declared doomed and completely unfixable now the government is in a race to build a second Dam Downstream before It suffers a catastrophic collapse this is Paradise Dam built in 2005 at a cost of$ 240 million Australian dollar it spans 600 M across the Bernett River in Queensland some 60,000 people live Downstream from it it's a vital source of water for the farms in the region and it was supposed to stand for more than a century only it won't it's now been deemed one of Australia's largest ever infrastructure failures and will have to be entirely rebuilt a few meters Downstream so how did it come to this once a source of riches the burnard river played host to Prospectors who traveled here to A Town Called Paradise to pan for gold and make their fortune in the late 1800s but by 2003 when construction of the dam began Paradise had become a ghost town so it was decided it would be sacrificed and submerged beneath a new man-made lake that would be created behind the dam the new dam was then named after the old town but it wasn't long before problems started to emerge the structure was severely damaged during record shattering floods in 2013 23 million Australian dollars was spent to repair the damn wall and it was declared safe but despite that concerns remained and an independent investigation found an additional 10 million Australian dollars worth of sa work had to be carried out to address these concerns the wall of the dam was lowered by 5. 8 m in 2020 that reduced the Dam's capacity to just 40% of what it should be holding but it meant there was less risk of catastrophic failure that in turn sparked protest from the farmers who depended on the dam as their source of water with less water there's less they can grow it also puts them at the mercy of Australia's dry climate you see dams are especially important for places like austral Australia a country that's prone to long and devastating droughts water is extremely precious in 2023 work began on repairing the wall to return it to its original height that was supposed to be done by raising the height of the existing structure and reinforcing it by butting the wall with additional concrete the state and federal governments committed 1. 2 billion Australian dollars to the projects far more than the initial $240 million to build the the dam in the first place but these Works were eventually scrapped when experts on the site investigating the wall declared it couldn't be mended or reinforced they discovered Concrete in the dam was losing its strength over time now some of the issues with the concrete in the dam were already known and had been known for years that was related to the bond between the layers of roller compacted concrete within the structure the foundations under the secondary Spillway and the risk of erosion immediately Downstream of the damn wall paradig dam was actually the first roller compacted Dam built in the country it's a more cost-effective way of building a dam and it's done safely throughout the world but it does use less cement but while investigating the dam experts found even more issues with the concrete because of a poor concrete mix used in the original Dam which combined a large amount of clay with a small amount of cement content the dam wall became prone to swelling and Contracting with moisture the Porous concrete also caused the cement to leech out leading to structural weaknesses when they discovered this the team of international experts put samples of the concrete through a range of tests including artificial aging and compressive and stiffness tests they found the concrete degraded far more quickly than was expected now clearly a huge project like this is expensive and balancing the budget is no easy feat to keep track of a multi-million dollar operation you're going to need to make sure that you're confident with money if you're Keen to brush up on your numeracy skills you might be interested in today's video sponsor brilliant whether you're looking to learn the basics of mathematics or ready to conquer more advanced topics brilliant has courses for every skill level welcoming users from 13 to 113 but it's not just mathematics with over 70 courses brilliant is a real reservoir of information covering everything from programming with python to understanding the physics of the everyday there really is something for everyone and with brilliant's Daily Progress goals you can keep the information flowing whatever time of the day works for you to try everything brilliant has to offer for free for a full 30 days visit brilliant.
org theeb 1M or click the link in the description you'll also get 20% off an annual premium subscription now let's get back to the damn video so after spending millions of dollars to build and then repair the dam and then committing 1. 2 billion to fix the issue it was finally decided they would abandon the thing alog together they determined the only solution now was to rebuild the dam 70 M further Downstream and then partially demolish the original Dam structure queensland's troubled Paradise Dam will have to be rebuilt with thousands of residents Downstream told it has too many issues to be repaired needless to say the farmers were not impressed nor were the 60,000 people who live further down the river now to reassure everyone experts say the dam is not in any immediate danger of collapse and may last many more years without any incident those experts just don't believe it's going to last the 100 years it's supposed to In fact when measured against the more than 900 other publicly recorded roller compacted concrete dams Paradise Dam ranks among the very lowest in terms of cement content which isn't good prior to the wall being lowered the dam was at risk of failure in a 1 in2 200 year event which is what the 20133 flood was but because of climate change extreme weather events like these are becoming an increasingly more likely occurrence in Queensland a state which has seen more than its fair share of record floods and severe storms in recent years Paradise Dam has the capacity to hold 300,000 megal of water but now that water level will be reduced to 42% because the wall has been lowered and there's now less water in the reservoir behind it it's now at risk of failure in a 1 in 5000 year event but that still isn't safe enough and the dam isn't operating as it should nor is it storing nearly enough water and that's going to be a problem in the long summer months ahead plans are currently being drawn up and a business case put forward for the second Dam most likely the existing Dam will stay in place for now and be used as a coffer Dam to create a dry and safe working environment during construction meaning it'll hold back the river while the work Begins the new dam will then be built pretty much in the same way that the original one was only this time we assume with a lot more cement now strangely enough there is actually a precedent for this and it's one we've covered in depth before the span Dam in Switzerland which was once one of the tallest in the world is having a second Dam built directly in front of it because of a crack that makes it Beyond repair only the Swiss dam is nearly a century old and the cost of building its replacement is just 140 million us quite a lot lower than the price tag of $787 million us already pledged to repair Paradise Dam it's been a turbulent Journey for this Australian dam named after the sunken Ghost Town it submerged unfortunately it too seems destined for a watery grave the hope now is that the second Paradise dam is going to be built in a way that can withstand as many one in 5,000 Year events as the Queensland weather can throw at it [Music] this video was sponsored by Brilliance you can learn more about that at the link below don't forget that we're inspiring the next generation of Builders through our investment into brick borrow a fantastic Lego subscription service you can learn more and get started today over at brick.
