Nature Days outdoor learning resources – Build a river.
With a lot of rain falling over night my challenge for you is to build yourself a river.

Watch my video to see how.

What you will need:
Tray
Sand
Stones of different sizes
Moss
Twigs
Lego
Watering can or plastic bottle with holes in
Water

How to do it:
You can build your river in a tray or if you have an area on a slope you could build it there.
Start by building the landscape of the river. Rivers start in the mountains or hills. So start by building a hill out of sand, soil or using a rock. If you have a slope then you can place your tray on the slope so that one end is higher than the other and represents the hills.
Use the soil or sand to create the land either side of the river leaving a gap for the river channel. Think about the shape that rivers take. Usually there are more meandering, bendy, especially close to the mouth end.
Then populate the river catchment, the area around the river which catches the rain that enters your river. You could add vegetation by foresting an area adding twigs, or moss. Build some houses along the river banks out of lego. Next place some river sediment, stones or small pebbles inside the river channel. Spread them out some near the source, the start of the river and all the way along the river’s course towards the mouth.
Once you are happy with your river model you need to add the water.
Before you do take a before photo of your river.
Then you are going to simulate a light rain. Take a watering can, or make some small holes in a plastic bottle. Very gently poor some water into the tops of the river starting at the source on the top of the mountain.
If you can you could film what happens.
Once the water has all been poured look at the river model.
What has changed? Look at the photo you took and play spot the distance. What has moved? Have the small stones or big stones moved? What about the houses? HAs the river channel changed size or shape?
Take another photo of the river.
Next rebuild the river so it looks like it did before you added water.
Now you are going to simulate a storm!
Build some extra houses and place them at different distances form the river and different heights above the river level.
Then take the watering can and removed the spray rose or take the lid off the bottle.
Pour the water straight into the top of the river channel close to the sources all in one go without stopping.
What happened to your catchment area? How did the changes compare to the slight rain?
You can fill in the worksheet below and draw a picture to see what moved and to where. All you can take another photo and play spot the difference again.

You can play with your model as much as you like changing the volume and intensity of the rainfall. Seeing if you can locate the houses in the best places to save then from flooding. Seeing if dredging of the river sediment helps reduce flooding. You could try to build flood defences along your river course and see what protects the banks of the river.

I would love to see your models and the impact of the storm on them so please share photos on Twitter #Naturedays @DawnNaturedays or on the Nature Days Facebook page.