Maps

Short Term Trend: Over the past 10 years, 63 percent of the monitoring stations show little or no change in flow-adjusted phosphorus concentrations. Between 2003 and 2012: - 9 out of 43 sites show improving flow-adjusted trends for phosphorus concentrations, - 7 site shows degrading trends, and - 27 sites show small changes that are not statistically significant.

Short Term Trend: Over the past 10 years, 54 percent of the monitoring stations show improving flow-adjusted nitrogen concentrations. Only one site showed degrading nitrogen conditions. Between 2003 and 2012: - 25 out of 46 sites show improving flow-adjusted trends for nitrogen concentrations, - 1 site shows degrading trends, and - 20 sites show small changes that are not statistically significant.

Long Term Trend: Forty-four percent of long-term stream monitoring sites in the Chesapeake Bay Watershed show little change in flow-adjusted concentrations of sediment. The remaining sites were evenly split between improving and degrading conditions. Between 1985 and 2012: - 8 out of 29 sites show improving flow-adjusted trends for sediment concentrations, - 8 sites show degrading trends, and - 13 sites show small changes that are not statistically significant.

Long Term Trend: Seventy-three percent of long-term stream monitoring sites in the Chesapeake Bay Watershed show improving flow-adjusted concentrations of phosphorus. Between 1985 and 2012: - 22 out of 30 sites show improving flow-adjusted trends for phosphorus concentrations, - 4 sites show degrading trends, and - 4 sites show small changes that are not statistically significant.

Long Term Trend: Seventy percent of long-term stream monitoring sites in the Chesapeake Bay Watershed have improving flow-adjusted concentrations of nitrogen. Between 1985 and 2012: - 21 out of 30 sites show improving flow-adjusted trends for nitrogen concentrations, - 3 sites show degrading trends, and - 6 sites show small changes that are not statistically significant.

Non- tidal watersheds, under regulatory anti-degradation protection, that exceed minimum applicable water quality criteria and standards. Currently, Tier II streams are identified according to fish and benthic indices of biotic integrity.

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.

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.

Water quality criteria are used to protect designated water uses, such as fish and aquatic life, recreation, and water supply. Designated uses establish the reason for protection and the water quality criteria define the criteria required to protect that benchmark. Use designations and water quality criteria together, constitute Pennsylvania Water Quality Standards as defined in Title 25 Environmental Protection, Department of Environmental Protection, Chapter 93. 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.

The Waterbody Inventory/Priority Waterbodies List (WI/PWL) is an inventory of the state's surface water quality. The dataset provides a summary of general water quality conditions, tracks the degree to which a water body supports its designated uses, and monitors progress toward the identification and resolution of water quality problems, pollutants, and sources. The category of No Known Impact represents 'segments where monitoring data and information indicate that there are no use restrictions or other water quality impacts/issues.'