How Does an Oasis Form in a Desert?
How does something as lush as an oasis form in a place like a desert? At first glance it may not make sense, but knowing a few simple principles can go a long way in helping you know where to place an oasis on your fantasy maps. It’s little pieces of information on how geology works in the real world that can add a whole new layer of depth and realism to your worldbuilding.
Limited Rainfall
A region can be classified as a “desert” if it receives less than 10 in. (20 cm.) of annual rainfall. But, many deserts such as the Mojave, Sahara, or the Atacama don’t even receive half that much! This isn’t a lot rain, especially in a warm environment where evaporation can happen rapidly.
It All Adds Up
But, even 10 in. of rainfall can quickly add up spread over a large area. All this water has to go somewhere! While some of the rain quickly evaporates, thousands of gallons also seep into the ground and create underground aquifers that flow toward low points in the landscape.
Cartographer’s Liner Brush Field Kit
$29 | For Procreate, Photoshop, & Clip Studio Paint
Want the brushes I am using for this Map Tip? The Cartographer’s Liner Brush Field Kit contains 21x unique liner brushes designed to give an analog quality to your digital work.
Low Points
Oases are found at low points in the terrain where the underground aquifers emerge above the surface. This happens when the water table is forced higher, due to an impenetrable layer of bedrock below the sands.
If You Were Wondering…
Singular - Oasis
Plural - Oases
Islands of Life
Oases become important islands in a sea of sand. But here, life can thrive for centuries and sometimes thousands of years! Oases don’t have to be a single small pool either. The largest oasis in the world, Al-Hasa, in Saudi Arabia spans more than 30,000 acres with around 280, 1.5 million palm trees, and over 600,000 inhabitants.
I hope you found this little Map Tip helpful and it aids you in your map-making journey. If you want to support Map Effects and help other map makers be sure to share this with someone who will find it helpful and pin it to save for later!
Happy Mapping!
Josh
