A giant wall of water and by an ocean
The water cycle starts with ground water. As it is heated up by the sun it evaporates, (or transpiration happens on plants and trees) and then condensation occurs as the new clouds form. Hope this helps!
Human activity has a great impact on waterways. Decreased amounts of vegetation leads to erosion of water banks. Increased fertilizer and nutrients levels in water from agriculture, sewage, and industry lead to the formation of algal blooms and subsequent decrease in other aquatic organisms.
Degrades the quality of water for drinking, wildlife, and the land surrounding streams