Maldives has no hills and is rarely higher than 1.5m above sealeve. Consequently, it has no rivers.

Freshwater floats in a layer, or "lens," above the seawater that permeates the limestone and coral sands of the islands. These lenses are shrinking rapidly on Male and on many islands where there are resorts catering to foreign tourists. Mango trees already have been reported dying on Male because of salt penetration. Most residents of the atolls depend on groundwater or rainwater for drinking purposes. Concerns over global warming and a possible long-term rise in sea level as a result of the melting of polar ice are important issues to the fragile balance between the people and the environment of Maldives in the 1990s.