Any construction or alteration upon any lot that results in an increase
of impervious surface on such lot equal to or greater than 200 square
feet must include facilities for on-site retention and discharge of
stormwater runoff from the added area of impervious surface. If the
added impervious surface is constructed in separate locations, such
that connecting those separate areas of increased impervious surface
to a single retention system is impractical, then facilities for the
on-site retention and discharge of the additional stormwater may be
connected to existing areas of impervious surface, rather than to
the newly constructed portions.
Any construction or alteration project subject to site plan review pursuant to Article XIIIC of this chapter must include facilities for the on-site retention and discharge of all stormwater runoff from all impervious surfaces, both existing and proposed; provided, however, that the Planning Board, in connection with its site plan review, may grant relief from the provisions hereof, in its discretion.
Facilities required hereunder shall be designed for the on-site retention
and discharge of 100% of runoff calculated on the basis of three inches
of rainfall over a one-hour period.