Existing Use establishes protection for a waterbody on or after November 28, 1975 whether or not that use is included in the water quality standards (25 Pa. Code §93.1 and 40 CFR §131.3(e)). Existing Use is different from a Designated Use; Designated Use is defined for each waterbody or segment whether or not the use is being attained. Existing Use is the actual use the waterbody is attaining at the time of an evaluation. The Department maintains a publicly accessible list of surface water segments where data has been evaluated which indicates an existing use classification of a waterbody that is more protective than the designated use (including those segments which are HQ or EV). Only an existing use which is more stringent than the designated use in §§ 93.9a - 93.9z for a particular waterbody is placed on the existing use list. This GIS watershed layer (which is not part of the Water Quality Standards) is offered to provide a spatial representation of the Aquatic Life Use Tiers contained in the portion of the Pennsylvania Code referenced above. These spatial representations are intended to supplement the Water Quality Standards but should not be substituted for the official version of the standards found in the Pennsylvania Code.
Author: Chesapeake Bay Program
Date created: Feb 27 2013 / Download ( 668.24 KB )