Answer:
waterway has its own particular characteristics related to water flow, velocity, and quantity.
Altered water ways or hydrology defines the variation in such characteristics including water flow. Water flow naturally depends on the climate and landscape ( valleys, mountains and flood plains).
There are several examples of people changing the way water flows such as construction of a dam or weir and the addition of a culvert or pipe. Dams are use to control the flow of water and through culvert or pipe, the flow or direction can be changed.
Changes in vegetation and landscape by people also affects the flow of water as well.