麻烦翻译这段英语
The total amount of water that is received in the form of rainfall over an area is called the rainwater endowment of that area.
The actual amount of rainwater that can be effectively harvested
from the rainwater endowment is called the rainwater harvesting
potential.18 Rainwater yields vary with the size and texture of
the catchment area. A maximum of 90 percent of a rainfall can
be effectively captured through rooftop rainwater harvesting.
The quality of the captured rainwater depends, in part, upon
catchment texture: the best water quality comes from the smoother, more impervious catchment or roofing materials.