The health of a watershed affects the quality of our drinking water.
A sufficiently protected watershed has the capacity to supply water to its inhabitants in the long term by capturing and storing moisture/precipitation.
A healthy watershed also has the capacity to filter water and remove contaminants from various land uses within the watershed. This filtration capacity provides us with naturally clean drinking water and can reduce the economic cost of operating a water treatment plant.
For more information on the hydrological services of a healthy watershed, see Postel and Thompson (2005) Natural Resources Forum 29, 98–108.