What Happens When You Remove a Dam

dams are some of the world's most impressive Feats of Engineering in the us alone there are more than 90 000 of them generating electricity controlling flooding and supplying water to their surrounding communities like these four dams here sitting on the Klamath River stretching across the Oregon California border but there's a big damn problem these structures aren't so great for the river's fish or water quality it's kind of like arteries if you block an artery you're going to have so many different problems throughout the entire body after more than a decade of debate over money ecology and salmon officials called for a drastic move the demolition of all four dams and this is the largest river restoration and dam removal project that's ever been undertaken now if you thought that building a dam was tough wait until you hear about how to take one down thank you the Klamath river is known for its stunning scenery and Wildlife it flows to more than 400 kilometers through parts of Oregon and California and drains a basin covering 31 000 square kilometers at one stage the river was home to the third largest salmon population on the west coasts providing a vital resource to local indigenous groups but that all changed when these hydroelectric dams were built in the early 1900s from around 1895 to 1915 breakthroughs in hydroelectric design led to the construction of many new dams and power plants like these ones here in Klamath today the dams produce enough energy to power 70 000 Homes at their Peak although they aren't usually operating at full capacity because of low water levels and some other issues and like almost any major infrastructure projects there's always a trade-off while these structures have stopped potential flooding provided tax revenue and created great spaces for having fun they've also blocked the fish from reaching their sporting habitats Upstream because of that the salmon population has dwindled to less than 10 percent of its original volume and that's not the only impact of the dams during the warmer months the waters are frequently played with toxic blue-green algae blooms which occur when nutrient-rich water gets trapped in the shallow reservoirs environmentalists and local tribal groups have long fought to find a solution while some homeowners worried that removing the dam will cost them in tax money and lost property values in the end pacificorp the energy supplier itself said that removal would be cheaper than the alternative of building fish ladders and that the electricity the dam generated could easily be replaced then in 2022 the Federal Energy Regulatory Commission officially authorized the 450 million dollar removal of four major dams Copco dams one and two JC boil Dam and the Iron Gate Dam no Dam product of this size has ever been torn down before and it's going to take meticulous planning and construction work to get it right and of course it'll be costly with operating expenses factored in it would cost an estimated 20 million US dollars per year to maintain the dams and address the water quality impacts in their current condition so removing them saves money longer term that's important because the US government is already facing a debt crisis its citizens are a collective 17 trillion US Dollars which is why leading money managers and professional investors are scrambling for Safe Haven assets that's where today's video sponsor Masterworks comes in not only does Masterworks give you access to Contemporary Arts one of the most exclusive assets on the market they've done all the legwork for you Masterworks has sold over 45 million dollars worth of art so far and distributed net proceeds to investors in fact each of their sales to date has delivered positive returns Masterworks is unveiling new offerings on a regular basis to meet demand so there may be a way to join the platform's more than seven hundred thousand members but the big one M subscribers can skip the wait lists by clicking the link in the description now let's get back to the Klamath River so as it turns out there are two methods to remove a dam instantaneous or staged instantaneous removal happens quickly think hours or days we know not exactly instantaneous but pretty quick here a reservoir drawdown takes place which is a process that involves releasing the water and built up sediment stored behind the dams Downstream now most dams have an emergency drainage system in case the water level needs to be lowered quickly that usually takes the form of either a low-level conduits which is basically a channel that can be opened to water to flow through or a stop lock which is essentially a stack of logs or beams that can be raised to let water through once the water is released Downstream the dam itself is demolished with explosives that's the instantaneous bit and the rubble is removed from the sights that's the bit that takes a bit longer conversely staged removal happens over a longer period of time usually months or even years this method is reserved for taller dams with larger amounts of built up sediments that would pose environmental risks If released too quickly in a stage demolition rivers are pumped or diverted away from the construction site through tunnels or channels allowing for more control during the reservoir drawdown and sediment release once the rivers are diverted and the Basin is dry the dam is demolished using tools like excavators or explosives depending on the material it's this longer staged method that's being used as the basis for the Klamath Dam removals albeit with some slight variations depending on the size and materials in each Dam ultimately this project will return the river to its free-flowing condition starting in 2023 Copco number two the smallest of the four dams is going to be the first to be demolished we will actually get underway with the drilling of a brand new 10 foot diameter tunnel through the base of the dam from the downstream end toward the Upstream face of the dam will stop about 10 to 12 feet short of the Upstream face of the dam in the fall of this year there are a series of box culverts underneath the the concrete Spillway that have stop logs thin concrete stop logs at the Upstream end of the dam and when we're ready to initiate the drawdown at Boyle we'll simply blast out those stop logs now unlike the others Copco number two has no real reservoirs so drawdown isn't going to be necessary but that is going to have to take place at the other three in early 2024 crews are going to open up low-level outlets for the rest of the dams to slowly initiate drawdown of water and sediments at a rate of around 1.5 meters a day the three remaining drawdowns will take place at the same time taking advantage of the water power to help mobilize and push water and sediment through the river will then be diverted through new or existing diversion tunnels from the original construction of the dams that'll cause the channel to dry up so demolition can take place safely now dam removal itself is only part of the equation following drawdown a 2200 acre footprint is going to remain behind the dams and that's going to be in need of restoration through native vegetation and the enhancements of habitats before the salmon can return the scale of this dam removal is unprecedented and it hasn't come without controversy there's no doubt the complexities of the Demolition and restoration require a huge effort but while it may be the largest effort in U.S history it doesn't Mark the first stem removal in fact the Project's actually part of a much larger removal Trends happening right across the country in 2022 alone 20 States tore down 65 dams in an effort to reconnect streams and rivers now to be very clear we're of course not saying that every Dam needs to be torn down there are many that still provide their intended purpose but as the decades go by environmental standards change and unexpected impacts can emerge and then it's right to reevaluate the benefits of these structures what's happening on the Klamath River shows the power of both construction and deconstruction and how infrastructure can impact millions of people's lives it'll be some time before we see the impact of this dam removal but this project shows how construction is continually evolving to our ever-changing world this video was sponsored by Masterworks you can skip their Queue at the link in the description there's also the chance to dive deeper on this and the other topics on our Channel over on the world's best construction podcasts available now wherever you get your podcasts and as always guys if you enjoyed this video and you want to get more from the definitive video channel for construction hit that subscribe button [Music] foreign

Channel: The B1M

Views: 1,081,015

Keywords: B1M, TheB1M, Construction, architecture, engineering, The B1M, Fred Mills, building, infrastructure, dam, demolition, deconstruction, klamath river, oregon, california, salmon, west coast, hydroelectric, salmon habitat, wildlife, Federal Energy Regulatory Commission, copco dam no. 1, copco dam no. 2, JC Boyle Dam, Iron Gate Dam, dam removal, dam restoration, klamath dams, reservoir

Id: zcUrUE6-ZCw

Length: 9min 45sec (585 seconds)

Published: Wed Jun 07 2023