N the semi arid regions of China, the country's inhabitants have practiced water harvesting for generations. Water harvesting is the process of collecting rainfall and/or runoff for later use. How does this water conservation method help the environment?
A) Water harvesting causes drought-like conditions the rest of the year.
B) Keeping the water for later use leads to over farming and land degredation.
C) Water harvesting causes the area to become uninhabitable the rest of the year.
D) By collecting runoff during the rainy season much of the land degredation caused by water erosion is prevented.