Anyone ever been to the Salton Sea or the Algodones sand dunes east of San Diego? People should read the fascinating history of how the Sea was made by a flood and the sand dunes were unable to be crossed until Ed Fletcher built a wooden road so people could drive to Phoenix for the first time. Here are some links:

https://en.wikipedia.org/wiki/Algodones_Dunes

https://en.wikipedia.org/wiki/Salton_Sea

Also Google them and use the Google satelitte map to look down on them.

Here is a pic of the waterways that created the Salton Sea: