We need a picture in order to answer the question.
The Volga River is the main water way in western Europe. Glad to help :)
Answer:
Either communism/socialism
Explanation:
Creation of the Soviet Union from the strains of the Russian Empire within WW1.
Heavy Sediment deposits affect waterways because it can fill in drains, lakes, rivers, and sewage blockage. Sediment loss affects land and soil quality because it can mean a loss in nutrients that the land may need for vegetation. It can also cause flooding, which can carry toxins into water ways.
Where, I'm unsure, but when, I think I know. There is a theory that the first asteroid to hit Earth was actually a comet. It wiped out the dinosaurs.
