Maps

The 2012 Dissolved Oxygen Indicator showing Percent of Goal Achieved using the three year analysis method.

An effective way to measure the health of freshwater streams and rivers is to study the many tiny critters that live in these waters, called “benthic macro-invertebrates.” The abundance and diversity of snails, mussels, insects and other bottom-dwelling organisms are good indicators of the health of streams because they can’t move very far and they respond to pollution and environmental stresses. Benthic macroinvertebrates are generally harmed by direct and indirect effects of pollutants such as metals, acidity, sediment, pesticides, nitrogen and phosphorus. These pollutants come from sources such as mining, agriculture, urban and suburban runoff, automobile and power plant exhaust, and wastewater treatment facilities. Health of streams was evaluated by the Chesapeake Bay Basin-wide Benthic Index of Biotic Integrity (or “Chessie B-IBI”), which was developed from benthic macroinvertebrate data collected across the entire Chesapeake Bay watershed from over 20 federal, state, local, and river basin commission monitoring programs throughout the Chesapeake Bay basin. Each sampling event is scored on a standardized quantitative scale that allows scoring across jurisdictional boundaries. B-IBI scores were averaged for each site over all years of sampling (2000-2010) and then qualitatively categorized in one of the following categories – very poor, poor, fair, good or excellent for a total of 15,112 scored sites. An analysis was conducted on a subset of the 15,112 sites to investigate regional variation in the B-IBI scores. The subset of sites (8,871) were chosen where a random sampling design was used. By using only randomly selected sites, BIBI scores can be averaged across the smallest feasible watershed size without introducing bias associated with sampling designs that target areas with known degraded or high quality waters. For more information see: Buchanan, C., K. Foreman, J. Johnson, and A. Griggs. 2011. Development of a Basin-wide Benthic Index of Biotic Integrity for Non-Tidal Streams and Wadeable Rivers in the Chesapeake Bay Watershed: Final Report to the Chesapeake Bay Program Non- Tidal Water Quality Workgroup. ICPRB Report 11-1. Report prepared for the US Environmental Protection Agency, Chesapeake Bay Program.

The Phytoplankton (Index of Biological Integrity) map shows the percent of the goal achieved by CBP Monitoring Segment.

The map shows the average Index of Biological Integrity Score for phytoplankton by monitoring station.

This map shows the 2012 indicator status of the Benthic Index of Biological Integrity by station.

This map shows the percent of the Index of Biological Integrity indicator goal achieved by segment.

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.