Wissahickon Creek

Philadelphia Water Department | Philadelphia County, PA

The United States Environmental Protection Agency developed a sediment Total Maximum Daily Load (TMDL) for Wissahickon Creek in 2003 to address the stream’s listing on the Clean Water Act’s 303(d) list of impaired waters. AEG assisted the Philadelphia Water Department in their documentation of sediment load reductions in the Wissahickon Creek. To achieve a target sediment load reduction of over one million pounds per year, the PWD implemented numerous stream stabilization and stormwater retrofit projects throughout the Wissahickon Creek watershed. The multi-year monitoring effort for this project includes the re-establishment of the 11 Bells Mill Run cross-sections disturbed during the recent reconstruction effort; photo monitoring of the three stormwater wetland sites (52 photo locations); and photo monitoring of the seven stream restoration sites (98 cross-section photo locations); video monitoring and structure condition scoring of the stream restoration efforts; and re-survey of all 98 stream cross-sections. RiverMorph was used to facilitate the comparison of cross- sections over multiple years to calculate erosion and deposition changes to estimate yearly sediment inputs. SWWM was used to estimate the effectiveness of constructed stormwater wetlands at trapping sediment and reducing the sediment load carried in Wissahickon Creek. The results of the photo monitoring, video monitoring and scoring, cross-section comparison and SWWM modeling were summarized in a report to satisfy the TMDL monitoring requirement.