School lesson: Creek catchment - video transcript

This page is a transcript of the School lesson: Creek catchment video on Brisbane City Council's YouTube channel. The video is 7 minutes and 35 seconds long.


>> CATHERINE: Hi, my name is Catherine and I am one of the Educational Officers who work here in the beautiful Raven Street Reserve in North Brisbane.  

Down below me is Downfall Creek. Downfall is one of the many creeks that cut their ways through Brisbane and like them all, it starts from the hills and ends up in Moreton Bay. Downfall Creek is actually one of the creeks in Downfall Nundah Catchment. Why am I telling you this? Because today, we are going to talk about catchments. But first, see if you can spot a water dragon, I saw them before.  

Downfall Creek, like every waterway in Brisbane, is in a catchment. When we talk about catchments, we talk about the area of land that rain falls on that flows into a creek. When rain falls on the Raven Street Reserve, we know that, that water flows down into Downfall Creek, so we can confidently say, that Raven Street is in the Downfall Creek catchment area. 

Wow! That’s heavy. Well, I have set up this highly attuned very scientific well considered experiment for you, to show you exactly how a catchment works. Now, in their simplest forms, most catchments are surrounded by hills and have a river running through the middle of them or a creek.  

Now, imagine this sucker here is a rain drop, admittedly not one you’d want to land on your head. This slide here is a hill and down the bottom is Downfall Creek. Now water likes to move downhill, so do balls, so in theory, when I let this ball go, it’s going to move down our make-believe hill and into the waterway at the bottom of the catchment. So let’s go. Nailed it. 

Well, if my really snazzy little experiment outside didn’t explain what a catchment is well enough for you, maybe this diagram will help. So, as I said outside, catchments are largely surrounded by hills and they have a waterway, running through the middle at the lowest point. Let’s have a look at this map over here. 

This is a map that shows the major waterway catchments around Brisbane. So, we’ve got Moreton Bay out here, we have the mountains over here and this blue line snaking its way all the way around through the map is the Brisbane River. You’ll notice the Brisbane River is bigger than a lot of the other rivers or creeks. That’s because it has a lot of these creeks feeding into it and it eventually ends up in Moreton Bay.  So, whatever goes into the catchment high up here will end up in Moreton Bay.  Now where is the Downfall Creek one? Ah, here we are. This is Downfall Creek, the creek we’ve been looking at. It doesn’t join the Brisbane River, but it does end up at Moreton Bay. 

There many catchments in the Brisbane area, but it’s important to know that no two catchments are the same. Water quality depends largely on where the water lands and also the natural and human elements in the landscape. So, let’s have a look at what a natural element is now. 

Natural elements in the environment are those things that occur naturally, such as, rivers, creeks, trees, plants and reserves like this. Generally, the more natural areas in the catchment, the cleaner the water and here’s why. When rain falls on natural areas like this, some of it soaks in the ground. The rest travels over the land to the nearest waterway. As it moves towards the waterway, it picks up dirt, rubbish and other pollutants. But, there’s somethings on the edge of this creek which stops these pollutant entering the water. Can you guess what it is? 

Plants such as this on the edge of waterways play a really important role in keeping our waterways clean. First, they act as buffers, so when waters flowing very quickly, they slow the water down. Secondly, their roots acts like big gloves and they hold on to the dirt really tightly, which helps stop erosion. Third, they trap a lot of the pollutants before they enter the waterway. So, natural things such as these plant play a big role in keeping our waterways clean. But do human elements do the same thing? Let’s go find out.  

Human elements are humans and things humans make such as roads, houses, schools, anything really. Now humans, we’re funny things. We like to build things with flat hard surface. This is a bit of a problem when it rains because as the rain hits it, it moves very quickly off that flat hard surface and picking up any pollutants with it that it may find in its way and heads to the nearest storm water drain, like this one here. So, where does the storm water go? I’ll show you. 

I gotta pick this plastic up first. Don’t’ want it ending up in the wrong spot.  

The rain that falls on the roofs and the roads over there, doesn’t soak into the ground because they’re concrete or smooth surfaces, instead it rushes off the road into the nearby storm water drains, which then empty straight into the creek.  

Over here, over here, excellent. This is Downfall Creek. This is the same creek that we were looking at before but it’s very different as you see. So, creeks change as they move through the catchments. This one’s been turned into a drain and you can see that there are no plants on either side of the bank. It’s very smooth and what happens is, water rushes into the drain and it rushes down the drain, pollutants and all, all the way to Moreton Bay. Because it is a drain, there is not much life living in here and because it’s shallow, it means algae can build up on the surface, again adding to the pollutants to the drain.  

Ah, yuck! I found a bit of plastic in the waterway. It’s probably washed out of somebody’s backyard, or even concrete playgrounds, a lot of these wash off from there. Now, I know that’s a plastic bag, but to a turtle or dugong, it actually looks like a jellyfish. Turtles love to eat jellyfish, so they would swallow this plastic bag and it’d get stuck in their stomach, and if they eat enough of them, they can actually die from it. But it doesn’t have to be like this. I’ll show you how we can change it.  

There are few simple steps we can take every day, that will help improve the health of the waterways and our catchments. Number one, plant a plant. Remember they are really good filters and buffers and help keep our waterways clean. Number two, pick up dog poo. Everyone loves their dogs, but they like to poo a lot. Dog poo is full of bacteria, when that washes into our waterway that create all sorts of problem. Number three, pick up three for the sea. You may have heard this catchy little slogan. It reminds us that if we can pick up three pieces of rubbish every day, we can make a really big impact on the qualities of our sea, and in turn, the waterways that runs into it. So there you go. 

Water is arguably our most precious natural resource. Without fresh water, there’d be no you, no me and definitely no batty friends here who live in the Raven Street Reserve. Water quality starts in our catchments, so it’s important that we all play our role in keeping our catchments clean and pollution free. So, remember, take three for the sea and hopefully I’ll see you out in nature again very soon.  


Last updated: 29 April 2021