Environmental Chemistry

Part of the precipitation goes back to the atmosphere
through vaporization after reaching the ground while
the rest seeps into the soil.
Overland runoff (地表径流) comes into being when
precipitation overtakes the infiltration capacity of soil
and water accumulates on the land surface.
Water seeping into the soil can enlarge the reservation of
water between the pores and gaps in soil while at the
same time flows slowly into deeper soil.
The root system of plants absorb water from soil and
leave the surplus water which further seep to the
underground and serve as new supply for
underground water source. The whole process is
called water circulation.