Did you know? How PWSA is evaluating wetlands and streams in Four Mile Run.

Image of Panther Hollow Run in Schenley Park showing stream erosion.

Four Mile Run Wetlands and Streams

The Four Mile Run (4MR) project area includes several historic streams that have been and will continue to be evaluated as part of this project. These streams include Phipps Run, Panther Hollow Run, and Junction Hollow, along with Panther Hollow Lake. During site visits, CEC staff delineated wetlands and streams, identified benthic macroinvertebrate communities, and measured various stream channel characteristics including width, depth, and bank erosion potential. Twenty-five stream channels were delineated in the study area, totaling 12,633 linear feet. Eleven wetlands were delineated in the study area, totaling 0.865 acres, not including Panther Hollow Lake, a more than 2-acre open water wetland.

Streams were listed as perennial (flowing year round), intermittent (flowing most of the year except during dry months), and ephemeral (flowing only during storm events, with dry channels for the remainder of the time). The wetlands delineated include Palustrine Emergent (PEM) wetlands (including mainly grassy and cattail plant species) and Palustrine Shrub-Shrub (PSS) wetlands (including plants such as willows, spicebush, and sugar maple and red oak saplings).

Fluvial Geomorphic Processes

CEC is also investigating the abovementioned stream channels to mitigate current stream issues. One such issue is increased sediment and silt supply into Panther Hollow Lake, the removal of which requires maintenance. Mitigation of the issues will then be categorized as “green infrastructure improvements” for 4MR.

Restoration of the 4MR watershed for the betterment of the ecologic and social communities requires adjustments to the natural “fluvial geomorphic processes” that shape the stream network. Restoration of these “processes” will create more stable channels, which will help preserve trails and bridges of cultural and historical significance, as well as reduce maintenance efforts required to remove sediments from Panther Hollow Lake. When restored to a more stable configuration, the stream network will benefit stream ecology by increasing substrate (silt and rock) availability for macroinvertebrate colonization and increasing dissolved oxygen. While restoration efforts in the stream network will improve conditions primarily by decreasing sediment supply, work within the watershed will continue to focus on reducing flashy stream discharge into Panther Hollow Lake and flood flow to the nearby communities.