Surface runoff happens when, usually a liquid, flows from a high point to a low point because of a driving force in pressure difference as evident in the difference in elevation. In other words, liquid will runoff from the mountains to the plains. Since a low, flat plain has no difference in elevation, it will not cause the fluid to flow. Thus, it is impossible for surface runoff to happen within a low, flat plain.
Modern art includes artistic work produced during the period extending roughly from the 1860s to the 1970s, and denotes the styles and philosophy of the art produced during that era. The term is usually associated with art in which the traditions of the past have been thrown aside in a spirit of experimentation.
