Question

Identify two cost effective methods society can use to preserve the quality of our water

Answer 1

this is obviously the most economical way to preserve our water by preserving the natural purification sources such as wetlands and swamps ... this also provides a area for many animals and fish to live ..

wetland preservation also provides a buffer for floods when river banks overflow they generally fill the swamp first and that causes less damage to the living areas where humans habitate..

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you could also use desalination processes to take water from the oceans and make it drinkable. these are less economical as they cost money for the energy but they are necessary in some areas on the coastal areas where the population dense and the sources of water are limited.

desalination in its simplest form would be evaporation or distillation of the water. when the water evaporates it leaves the salt behind and the evaporated water then drips into a separate container that holds the fresh drinkable water...