(Al-Kahf) 18 : 41
أَوْ يُصْبِحَ مَاؤُهَا غَوْرًا فَلَنْ تَسْتَطِيعَ لَهُ طَلَبًا
“Or its water will become sunken so that you would never be able to seek it".
See explanation 13: 2-4, 17-18, and 15: 22-23.