it takes about 34 days
A Marsh
In short, certain areas have radioactivity, which can contaminate ground water, even long after surface water has regenerated itself. Even floods, sink holes-all kinds of things, can cause water to become contaminated. Surface water can be contaminated easily, by farmers' chemicals, oil from vehicles, including watercraft. Anything that contaminates can get to surface water.
Marsh
A marsh
As long as the water entered above the ground surface level.
days
It's simply a long pipe that is bored into the ground in order to reach an aquifer. The water is then pumped into a surface reservoir.
As long as you like just be careful that no ground water gets under it as this will be able to float the pool upwards out of the ground and then it will probably become a jack hammer job
days
It remains as water vapor, or somewhere else in the water cycle. Some water has probably been stuck as ice in Glaciers for a long, long time, or perhaps stuck as water in the ocean for a long time, but it all still has the potential to evaporate and then become precipitation.
A creature of the water's surface is the water strider. It uses the surface tension of the water and its long legs to actually walk on the surface.
Rhizomes.