A flyover of the American River.

Here is a 5 minute video of a flyover of the American River:
https://www.youtube.com/watch?v=3E0_jIn3GTE

Here is a link to an 11 minute video discussing various aspects of the American River:
https://www.youtube.com/watch?v=LWOPUTBJKnc&feature=emb_imp_woyt

Watch both videos.

Think of a pattern you have seen (or go outside and explore a little and find one near you) in nature. You need to find a natural area near you or you can search videos, etc.

Develop an explanation of that pattern (it must be testable). How can it be tested in a meaningful way?