This graph illustrates the
impervious cover percentages for each subwatershed within the Youngs
Creek Watershed for 1992 (historical), 2001 (current), and zoned
(potential future) land uses.
Stream research indicates that
certain zones of stream quality exist. Subwatersheds below 10 %
impervious cover are likely to have sensitive streams that are
of high quality, good habitat structure and diverse fish
communities. As a subwatershed exceeds 10 % impervious cover,
streams are more likely to be impacted and show signs of
degradation. Physical stream characteristics as well as habitats
decline due to increasing stream flow. Once a subwatershed
exceeds 25 % impervious cover, streams are likely to be non-supporting
and water quality is often degraded. (Center for Watershed Protection,
http://www.cwp.org)
