Section 303(d) of the federal Clean Water Act (CWA) and the United States Environmental Protection Agencys (USEPA) implementing regulations direct each state to identify and list waters, known as water quality limited segments (WQLSs), in which current required controls of a specified substance are inadequate to achieve water quality standards. For each WQLS listed on the Integrated Report of Surface Water Quality in Maryland (Integrated Report), the State is to either establish a Total Maximum Daily Load (TMDL) of the specified substance that the waterbody can receive without violating water quality standards, or demonstrate via a Water Quality Analysis (WQA) that water quality standards are being met. Gwynns Falls, located in Baltimore County and Baltimore City was identified in Marylands Integrated Report as impaired by nutrients, sediments (1996 listings), bacteria (fecal coliform) , and combination benthic/fishes bio-assessment (2002 listings) (MDE 2008). All impairments are listed for non-tidal streams. The 1996 nutrient listing was refined in the 2008 Integrated Report and phosphorus was identified as the specific impairing substance. Similarly, the 1996 sediments listing was refined in the 2008 Integrated Report to a listing for total suspended solids. A TMDL addressing the 2002 bacteria impairment was approved by the USEPA in 2008. In 2002, the State began listing biological impairments on the Integrated Report. The current Maryland Department of Environment (MDE) biological assessment methodology assesses and lists only at the Maryland 8-digit watershed scale, which maintains consistency with how other listings on the Integrated Report are made, how TMDLs are developed, and how implementation is targeted. The listing methodology assesses the condition of Maryland 8-digit watersheds with multiple impacted sites by measuring the percentage of stream miles that have an Index of Biotic Integrity (IBI) score less than 3, and calculating whether this is significant from a reference condition watershed (i.e., healthy stream, <10% stream miles degraded).