How do plants help water?

Answer 1

Imagine a city that has not grass. Its all just cement and buildings. When it rains where will all the water go? Of course it will go to storm drains but it also goes into plants and grass. When there is grass water gets soaked up into it helping to prevent flooding. The same idea applies on mountainsides. If they are covered in trees the soil is held together, water soaks in and is released slowly to feed the rivers on the plains below. If the trees are cut down the soil is quickly washed away and further rain runs straight off, resulting in flash floods interspersed with periods of drought.

Answer 2

Plants do not always help water. Shallow wells (12-25 ft) that are surrounded by vegetation, especially plants and trees with deep roots can be badly affected. The roots encourage iron bacteria and other contaminants