Watershed liming is a type of way to get rid of Acid Mine
Drainage (AMD). It is when you take ground agricultural limestone
and spread it over all or part of a watershed. The limestone
neutralizes the water that leaves the watershed so it will not
infect other bodies of water. Rain, snow, etc. types of water react
with limestone and move through soil, in result making it less
acidic. The less acidic water will not leach aluminum from soil
into close streams and will not make cases of acidic runoff. It
also makes forest productivity and health better. : )
Source: Freshman Earth and Space Science class