Intro Quiz: How can rivers be managed using hard engineering strategies?

Video: How can rivers be managed using hard engineering strategies?

﻿Hi everyone, it's Miss Dubas here, and welcome to lesson 11 of the rivers unit. This is all about hard engineering as a strategy for flood management. Please make sure that you've got a pen, a pencil, a ruler, a piece of paper, and a different colour pen to mark with, and make sure that you're working somewhere nice and quiet and free of distraction, so that you can focus on your learning. And when you're ready, we can get started. So, the title of this lesson is "How can rivers be managed "using hard engineering strategies?" So we will learn about four different hard engineering strategies today, and we're going to evaluate them. So, what is positive about the strategy and what is negative about the strategy? But, let's let's first consider what hard engineering actually means. So, what is hard engineering? It's using artificial structures to defend against natural processes. The aim is to control the flow of rivers and reduce flooding and its impacts. And as you can see from the photograph, the impacts of flooding or the effects of flooding can be really significant for people, for the economy of an area, and for the environment. Now, each strategy has its costs and benefits. And when we talk about costs, we mean anything negative about the strategy. When we talk about benefits, we mean anything positive about the strategy. And costs and benefits can be social, economic, and environmental. So, what we're going to do is review each of the four hard engineering strategy together, and in order to do that, you need to now make a copy of this table, ensuring that the boxes are quite large, because what we're going to do is to complete the table together. So please pause the video at this point to create a copy of the table, and then when you're ready to continue with the lesson, please resume the video. So, let's begin with our first hard engineering strategy, dams and reservoirs. Please don't write anything into your table just yet, I'll let you know when you need to add some information to it. So, a dam is a concrete barrier built across a river channel. A reservoir is an artificial lake behind the dam. River discharge is released from the reservoir in a controlled way, reducing the flood risk, and the diagram at the bottom of the screen shows this. The reservoir is created by flooding land behind the dam. Water is stored here, and can be released in a controlled way. So if the river discharge in a channel is too high, less water will be released and this reduces the flood risk because it means that the river will not reach its bankfull capacity and flood. The photograph is of the Three Gorges Dam in China, and this is one of the largest dams in the world. So, let's consider the benefits and costs of dams and reservoirs. We will use the Kielder Dam and Reservoir in Northumberland as an example, and you can see it in the photograph. Any case study facts are in bold in the table. So, let us review the benefits first. So, hydroelectric power can be generated as water is released through the dam. The Kielder Dam and Reservoir powers 11,000 homes this way, it's a renewable energy. Tourism also is popular to reservoirs. People may choose to visit the beautiful scenery. At the Kielder Dam and Reservoir, this generates six million pounds a year. Forestry provides jobs and new habitats, as trees are planted in the area. Over 200 jobs have been created at the Kielder Dam and Reservoir through forestry. There are, however, costs to dams and reservoirs. So firstly, they are very expensive to build. The Kielder Dam and Reservoir cost 167 million pounds. To create the reservoir, settlements and land had to be flooded. This displaced 58 families in the construction of the Kielder Dam and Reservoir. Farmland is also less fertile downstream of dams and reservoirs, because rivers are less likely to flood, which means they're less likely to deposit their fertile silt onto farmers' fields. So, we're now ready to fill in the first part of our table. So, what I would like you to do is to complete this activity by pausing the video and then resuming the video when you are finished. So, you need to complete the table to show the benefits and the costs of dams and reservoirs from memory. So, what do you remember about what you've just been told about the benefits and costs? Don't worry if you don't remember everything, because in a moment you will be able to mark your work and add in anything that you're missing. So pause the video, write into your table what you do remember, and then resume the video when you are ready to mark your work. So, we're now ready to mark our work. So what I would like you to do is to make sure that you've got a different colour pen. Anything that you've included that is in the table, tick; and anything you are missing, I would like you to add into your table. So please pause the video at this point to complete your marking, and then when you are ready, you can resume the video and we'll look at our next strategy. So, the next hard engineering strategy that we will look at is channel straightening. Remember, do not add any notes to your table at this stage. So, channel straightening is where meanders are removed from the channel and the channel is made wider, deeper, and straighter. This allows river discharge to flow away from the area more quickly, reducing the risk of a flood, and you can see an example of this in the photograph. In order to make the channel wider, deeper, and straighter, concrete needs to be added to the channel in order to hold it in place. The first diagram shows that by removing meanders, the channel becomes straighter and river discharge can flow faster because there's less chance that it will back up and flood within the meanders. The second diagram shows that if a river is widened and deepened, the capacity of the river increases. This means the river can hold more water or more river discharge, which means that it's less likely to reach its bank full capacity and flood. So, let's now consider the benefits and costs of channel straightening. Remember, don't add any notes to your table at this stage. So, the example you can see in the photo is the River Valency in Boscastle, which is in Cornwall. This river was made wider, deeper, and straighter as part of a 10-million-pound management plan. So, let's review the benefits of channel straightening. So, new habitats can be created to make the channel look natural, and we can see this in the photo. There can also be a reduction in insurance costs for nearby houses and businesses because this strategy reduces the chance of flood damage. And the last benefit here is that navigation can improve in rivers that have been straightened. This is because boats can navigate the river more easily. So, let's consider the costs or the negatives. So, flooding and erosion may happen downstream because the river discharge will flow faster into those areas. This causes a backup of water, which can lead to a flood. Also, as we've seen, this can be an expensive strategy. And in order to create the new channel, habitats are damaged, particularly when concrete is added to the channel. So, we're now going to pause the video to complete the table for channel straightening. So, I would like you to pause the video at this point and complete your table to show the benefits and the costs of channel straightening from what you can remember. Now remember that you don't need to worry if you can't remember everything, because when you resume the video I'm going to show you the benefits and costs again, and then you can add in anything that you're missing. So please pause the video at this point, complete what you remember, and then resume the video when you are ready to mark your work. So, we are now ready to mark our work, so please make sure that you have a different colour pen. If you have included something that's in the table, please make sure you give it a big tick; and if you need to add in anything extra, that is also absolutely fine, and you may want to pause the video in order to undertake this. So, please pause the video to mark your work, and then when you're ready to look at the next strategy, please resume the video. So, the name of the next hard engineering strategy is embankments. So, what are embankments? So, embankments are artificially raised river banks. They deepen the channel so that the capacity of the river increases, and this reduces the flood risk. The diagram shows how the embankments will raise the banks of the river. If the water level rises, the embankments contain the water within the channel, preventing a flood, and an example can be seen in York in the photograph. So, let's consider the benefits and costs of embankments. Remember, please don't add any notes to your table at this stage. So, in terms of benefits, let's think about each of these in turn. So, foot and cycle paths can be added to embankments, and this can create an area for people to enjoy recreational activities, and this has been undertaken in York. This strategy is cheaper, and therefore, compared to the other options, this could be more attractive. Also, some embankments are more natural looking and include vegetation, which increases the habitats in the area. However, the maintenance costs are high, meaning that once they are built, they need funding to ensure they can continue to work safely. Some people will view them as being quite unattractive. Also, if they break or breach when the river is in flood, a more severe flood may occur. So, it is now time to complete the table with what you can recall about the benefits and costs of embankments. So, please pause the video at this stage to complete the table, and then when you are ready, resume the video so that we can mark your work and check that you've included all of the key ideas that you need. So, we're now ready to mark our work. So, make sure that you've got a different colour pen to do this, and if you've got something in the table in your own work, make sure you give it a tick; and if you need to add in any additional notes, that is absolutely fine. So, you might want to pause the video at this point to mark your work, to check that you have everything, and then resume the video when you're ready to look at our final strategy. So, the final hard engineering strategy we will review are flood relief channels. So, flood relief channels are artificial channels which divert river discharge away from risk areas, a bit like a bypass. They can also be used to divert excess river discharge during periods of high rainfall, in order to prevent the river reaching its bankfull capacity and flooding. So, the diagram shows the main river channel with an attached flood relief channel. If this river channel is experiencing high levels of river discharge, the flood relief channel can be opened to remove some of the excess river discharge. This reduces the chance that the river would reach its bankfull capacity and flood. And you can see an example of a flood relief channel in the photograph. So, let's now review the benefits and costs for flood relief channels. Remember not to add anything to your table at this stage. So in the photograph, you can see an example of a flood relief channel on the River Exe in Exeter. So, the first benefit is that gates on the flood relief channels allow the controlled release of river discharge. This means the flood risk can be managed. Also, lower insurance costs will be available to local homes and businesses because the flood risk has been reduced. The flood relief channels on the River Exe protect over 3,000 properties. Some flood relief channels also contain new habitats. However, there are some costs. For example, when discharge is released, it could cause a flood if it's not being managed properly. Also, this is expensive. The flood relief channels on the River Exe cost eight million pounds. And lastly, in order to build flood relief channels, it takes up a lot of land, and it can be very unattractive at low flow. So, it's now time to complete your table. So, you need to ensure that you add to your table what you can remember about the benefits and costs of flood relief channels. So, please pause the video at this point to complete that activity, and then resume the video when you're ready to check your work. So, we're now ready to check and mark our work. So, please make sure you've got a different colour pen to do this. So, if you have got something in your table which is on this table, make sure you give it a big tick; but if you need to add any in any other additional information, that is absolutely fine. You might want to pause the video at this point to add in any of those additional details before you continue on with the lesson. So, now we've completed a table of the benefits and costs of the four hard engineering strategies, we are now going to consider which strategy is the best. So, is it dams and reservoirs, channel straightening, embankments, or flood relief channels? You now need to decide. So, we have considered the costs and benefits of each, and you've added these to your table. So, you need to decide which strategy has enough benefits to outweigh the costs, and this is called a cost-benefit analysis. So, you now need to summarise which of the four hard engineering strategies you think is the best option, and you need to justify your decision. So, tell me why you've come to that conclusion. So, please pause the video, complete your summary, and then resume the video when you're ready to mark your work. So, we're now ready to mark our work. So, make sure that you have a different pen in order to do this. So, the example I'm giving you here is just an example. You may have chosen a different strategy as your best strategy, and that is absolutely fine, there's no right or wrong answer. What matters is, have you fully justified your answer and your decision? So, let's have a look at an example. So, the best hard engineering strategy would be embankments. Embankments are not as expensive as the other strategies, and have less impact on the environment. They also create social opportunities for people through the creation of foot and cycle paths. So, just ensure that your answer is fully developed and that you've given several reasons for your decision. So, we're now going to ensure that we understand how hard engineering strategies reduce the flood risk. So, we will apply our knowledge to a question. So, your final task is to answer this question. Explain how hard engineering can be used to reduce river flooding, six marks. So, you will need to choose two of our hard engineering strategies to write about. You cannot choose dams and reservoirs, however, because I've used it here to show you a model answer. You can write about channel straightening, embankments, and flood relief channels. In my answer, which I will show you when we come to mark our work, I have written about embankments and flood relief channels, but it's entirely up to you if you want to choose those two. So, let's have a look at the model paragraph. So, a dam is a concrete barrier built across a river channel. A reservoir is an artificial lake behind the dam. Dams and reservoirs reduce flooding by storing excess river discharge at times of high rainfall, one mark. This excess river discharge is then released downstream in a controlled way, one mark. This means that the river levels can be managed to reduce the chance of rivers reaching their bankfull capacity and flooding, one mark. So, you can see how I've fully developed the idea to show how this particular strategy reduces the risk of a flood. So, please pause the video at this point to write your answer, and then resume the video when you are ready to mark your work. So, we're now ready to mark our work. So, please make sure that you have a different colour pen to do this. So, I'm going to show you here, my answer that I've written about embankments and flood relief channels. So, embankments are artificially raised river banks which reduce flooding. Embankments help to create an artificially deeper river channel, one mark. This means that the river channel has increased capacity to hold excess river discharge at times of high rainfall, one mark. This means that the excess river discharge is contained within the river, rather than flooding the surrounding areas, one mark. Flood relief channels are artificial channels which divert river discharge away from risk areas like a bypass. They can also be used to divert excess river discharge during periods of high rainfall, one mark. This means that levels of river discharge within a river channel can be controlled at times of high rainfall, one mark. This prevents the river reaching its bankfull capacity and flooding, one mark. So, please ensure that you have developed your ideas fully. If you would like to redraft any of your answer, that is also absolutely fine. So, that brings us to the end of our lesson today about how rivers can be managed using hard engineering strategies. Thank you so much for all your hard work. Please make sure that you complete the exit quiz so that you can ensure that you've understood everything from today, and you might decide to summarise three key ideas from the lesson, just to make sure that you've consolidated your learning. Thank you very much, and it'll be great to see you again, soon.

Exit Quiz: How can rivers be managed using hard engineering strategies?

Completed: How can rivers be managed using hard engineering strategies?

In this lesson, we will learn about four types of hard engineering strategies that can be used to manage river flooding. We will also evaluate these strategies.

Geography

How can rivers be managed using hard engineering strategies?

Introductory Quiz

Video

Final Quiz

Lesson Complete