[0:00]So we're going to start taking a look at our freshwater resources. And although it says freshwater resources, we'll look at salt water and fresh water, but freshwater kind of has a more intimate relationship with human use and we affect our freshwater resources more. This isn't to say that we don't affect our salt water resources. We definitely do. But as you'll learn, you know, we really, really, really depend on freshwater, and due to this dependency, that's why we run into a lot of issues surrounding this topic. So if you recall, we looked at this quite a while ago. There is really not that much fresh water in the world. If you look at this graph on the left, you know, 97 and a half percent of our water on Earth is sailing. It's salt water. We can't drink salt water. There are operations that can turn salt water into fresh water, but they're expensive and it's on a very, very small scale. So only two and a half percent of the water on Earth is fresh water or drinkable. And of that fresh water, a lot of that's trapped in snow and ice. And then you have a lot trapped in the ground and only half a percent of that 2.5% is accessible in lakes and rivers. So the fact that we rely so much on fresh water, but in actuality, there's not that much of it, can definitely pose some problems. So why even protect it in the first place? I keep talking about humans this and humans that, but what did we actually get out of it? Well, the first thing you're probably thinking of is drinking water. This could be drinking water, or it can be shower water, or your dishwasher, or laundry machine. But the water that you are drinking that we literally rely on for sustenance, can't drink salt water. If you were to drink salt water, you would die. So you can't ingest it. Our body has to have fresh water. Now, although this is, of course, incredibly important. This is actually not the number one way that we as humans use it. We actually use it a lot for agriculture. But that should make sense to you. We can't use salt water on our crops either. Just like plants and just like humans, we all need fresh water. So a lot of our fresh water resources are cleaned and filtered and not only go to our tap, but are also going to farms, which is used for our agriculture. So these are the two main ways when it comes to humans, why we care about fresh water. And because of these two reasons, that's why we really care about keeping our fresh water clean. You don't want to be drinking pollution. Our food shouldn't be polluted. But also, I mean, this is an environmental class and we do care about the environment. There are organisms that live in those water bodies. So, not only do we want to protect it for ourselves as humans because we use that resource, but we also want to protect it for all of the organisms that are living in those water bodies as well.
[3:07]So, what we're going to focus on for the next couple of topics is the water cycle. And by the water cycle, I'm really not talking about this part here. I mean, yes, there's that water cycle, water evaporates and then it makes clouds and then it condenses and precipitates and evaporates. Yes, that's the water cycle. But what we're really going to focus on is the human water cycle. You know, how do we kind of interrupt it or change it or influence it. Not so much how do we influence evaporation, but more of where do we fit in to this whole picture? So we'll talk about these more in depth, but for example, you know, we take water out in order to fuel our homes. So here it's showing a drinking water plant, that's drinking, filtering it and delivering it to our homes. You know, we create waste water that gets cleaned and returned. We have storm water that gets returned to the ocean. So we as humans kind of cycle our water as well. We're getting water from the environment, we use it, we clean it and return it to the environment.
[4:20]So first thing we're going to focus on is our drinking water. And by drinking water, although this does mean, yes, the water you are literally drinking, this is actually we're referring to any water that's coming into your home. All the water in your home, whether it comes from the tap or whether it goes into your dishwasher, is the same exact water. The water in your toilet is also the same exact water. Not to suggest to drink your toilet water, but technically just as clean as all the other water in your household. So although I'm going to keep referring to it as drinking water, what I'm really referring to is just water going into your house. But we refer to that as drinking water is because we have a whole bunch of standards that meet the standard of people are going to drink this.
[5:10]Right? We don't have a separate line of water that goes to the toilet and water that's meant for drinking. It's much easier to make sure it's clean enough for you to drink and then just have one line going into your house to supply that drinking water. So of our drinking water, 60% of it comes from surface water. So if you remember back to that original graph, 0.4% of our water, of our fresh water. Again, fresh water was really small. 0.4% with surface water. Of that water, we get drinking water from it, and a majority of our drinking water is from it. So these are things like lakes and reservoirs and rivers and streams. These are things that you can literally go outside and look at and be like, hey, look, there's water on the surface. So majority, but not an overwhelming majority, but a majority of our water is coming from surface water. The other 40% is coming from ground water. And ground water is literally as it sounds. This is water that is in the ground. Now, this isn't like some river flowing underneath of us, but instead, it's water that is filling up the cracks in between rocks. So this picture is showing you or diagramming for you what ground water looks like. Now, this is showing a water body. In this case, it's showing some sort of lake or maybe a cross section of a stream. Here we have our land and it's showing you with these blue arrows, like where the water is going. So it rains on the surface, it goes down through the soil and then it kind of starts pooling somewhere. That water starts pooling. And in this diagram, on both sides, you can see here's like the soil and bed rock up above, and then as you go a little bit further down, you have water that's in between these rocks. It's not dry anymore. Water's getting stuck there. Even with these smaller rocks, it's the same thing. So again, it's not a river flowing underneath of us, but really just water that exists between the rocks. And so when I say, well, we get we get drinking water from this, how does that exactly work? It's small little droplets of water in between rocks. Well, you may have actually experienced this before. So if you dig a hole, depending on where you are, uh for example, the beach. If you go to the beach and you dig a hole, if you dig down far enough, it's going to start filling with water. Not because the waves are crashing in, but because you have hit ground water. You have hit the point where there's a lot of water in those surrounding rocks and you just dug a hole for all of that water to seep into. For wild like wildlife survival, or if you want to, you know, go backpacking and like do it super roughing it, you can do the same thing. Literally start digging a hole and if you're lucky, the ground water is not too far from the surface. Now, that's going to be different everywhere around the world. You know, some places don't have ground water. The water never pulls anywhere. Some places that ground water is only a couple of inches below the soil. So that's what this image is showing is kind of digging that hole and water is just accumulating there. Because that water was actually with all of this stuff and it's just seeping in. You also know ground water as well water. If someone says their house is on well water, that's what it is. They're just getting their water from a ground water source. Typically, they have to do some sort of cleaning about it, but we'll talk about that more when we get to that part. So as a summary, our fresh water is a very, very small proportion of the water resources that we'll be talking about. And because it's such a small portion and we rely so much on it for drinking, for showering, for our food, and not just our crops, but also the food that lives in those fresh water resources. They're incredibly important. When we look at our drinking water, the stuff that you and I directly rely on, a lot of it's coming from the surface water like you see in this picture, and a small part of it is coming from our ground water.
