A water shed is all of the land that drains its water into the same area or body of water. It collects all of the water in a specific area and drains it in the nearest body of water, like a funnel. Where you work or go to school, or even your house is apart of a watershed. Watersheds can be affected by building roads, changing the natural surface of the Earth, pollution of the air, and the removal of plants that prevent runoff.
The hydrologic cycle is the movement of water throughout the atmosphere, geosphere, biosphere, and the hydrosphere. For example, the atmosphere is full of water molecules (water vapor) which becomes a cloud. The cloud then forms more and more until it starts to rain. -> After it rains, the ground stares a large amount of rain -> Through vents in the ocean, water from deep in the ground makes its way to the hydrosphere -> After that, plants take in the water to survive -> Finally, plants release the water through a process called transpiration, which releases the latter into the atmosphere.
The Flint Michigan water crisis occurred because of lead from aging pipes. Michigan had switched it's water source to the Flint River to save money, but the water was not properly treated and cured. This lead to lead polluting the water and turning the water brown, therefore making it unsafe and dangerous to drink. The situation could have been prevented if the water was cured and if everyone working on changing the water source paid more attention to what they were doing.