Water that flows downhill along the earth’s surface is
called runoff. Runoff or also called as surface water runoff or overland flows
is the flow of water when there’s excess water caused by ice melted, rain or
storm. These occur because maybe the rain or the storm pours so hard and quick
that the soil can’t absorb it fastly. If runoff water flows on the ground and
reached a channel, it is called as nonpoint source. One example of nonpoint
source are the canals full of leaves, the water can’t continue flowing because
the leaves stops it.