* Why do some rivers have deltas and others not? Hint: Rivers that have steep gradients with deep channels as they near their end do not form deltas.

* Do you know where your nearest river delta is? How is it like the Okavango?

* Can you find a small-scale delta in your yard or neighborhood?

* How would you make your own delta? Hint: You will need to slow down the flow of the water, by making a flat piece of land near the end of the river so that the water piles up and meanders across the land. For example, the Nile delta forms over a wide coastal plain where the river and sea waters mix.