Runoff (noun)

1. The action or process of flowing or running off.
2. Water, especially rainwater, that runs off from a surface.
3. An additional election held to decide the winner of a contest in which no candidate receives a majority of the vote.

Origin:

Late 19th century: from run off in the sense "flow away".

Examples:

1. The heavy rain caused a lot of runoff in the streets.
2. The runoff from the melting snow caused the river to rise.
3. The runoff election will be held next month.
4. The runoff from the farm was contaminating the drinking water.
5. The runoff from the industrial park was polluting the river.