This indicator measures the area of each watershed that has been logged in the past 20 years. Logging activities are associated with road building, which leads to greater public access, as well as the potential for increased erosion and sedimentation, all of which could lead to degraded drinking water quality. The measure only looks at the past 20 years because young forests have a different impact on the hydrology of an area than older forest. A watershed that has had more extensive recent logging will tend to have greater potential for more rapid runoff which may lead to more erosion and flooding.