Beneath the desert sands of the Sahara lie ancient rivers and watersheds. Hydrologists–using LIDAR (Light Detection and Ranging)–are gaining a rapidly growing understanding of these ancient waterways that have laid hidden for centuries, if not millennia.
Paleorivers, as they are commonly called, are the sub-surface water channels that have been lost to time, and only recently discoverable through ground-penetrating laser measurement that has begun to reveal their secrets in recent years.
Climate Change is dramatically evident in these case studies, as entire continents show the effect of desertification or adaptation over time. Here are a few examples of how landform and water channels & delivery changed over the millennia: