How is an oasis formed?

Related questions

1. What even is a Wonderwall?
2. When was Oasis last gig?
3. Why did Oasis call themselves oasis?
4. What are oasis named after?

Tags

1. #enough
2. #underground
3. #water
4. #pressure
5. #surface
6. #naturally
7. #river
8. #creates
9. #sources
10. #oasis
11. #formed
12. #their
13. #forming
14. #spring
15. #places
16. #aquifer
17. #oases