Abstract |
The Gwynns Falls watershed aquatic health scores, consisting of the Benthic Index of Biotic Integrity (BIBI) and Fish Index of Biotic Integrity (FIBI), indicate that the biological metrics for the watershed exhibit a significant negative deviation from reference conditions based on Marylands biocriteria listing methodology. The biocriteria listing methodology assesses the overall condition of Marylands 8-digit (MD 8-digit) watersheds that have multiple sites with failing biological metrics by measuring the percentage of stream miles that are degraded, based on the BIBI and FIBI scores at these sites, and then calculating whether the percentage of degraded stream miles differs significantly from reference conditions (i.e., unimpaired watershed <10% stream miles degraded) (Roth et al. 2005; MDE 2008). The objective of the TMDL established herein is to ensure that there will be no sediment impacts affecting aquatic health, thereby establishing a sediment load that supports the Use I/III/IV designations for the Gwynns Falls watershed. |