NTM Engineering quantified the Functional Credit Gain (FCG) associated with project study areas using Pennsylvania’s Function-Based Aquatic Resource Compensation Protocol (Compensation Protocol) for the Cathedral Run and Wises Mill Run stormwater management projects and the Wises Mill Run and Gorgas Run stream restoration projects, in Philadelphia, Pennsylvania.
NTM created GIS-based stream assessment reach (SAR) and wetland assessment area (AA) map figures for inclusion in the final evaluation report. An overall AA or SAR map was prepared for each of the four project sites. Additionally, NTM created a sub-reach scale SAR map for each of the five Gorgas Run and eight Wises Mill Run sub-reaches. Each SAR and AA map depicted the following information:
- Existing and proposed SAR and AA boundaries, as applicable to each site;
- Riparian vegetation zones, defined as the area between the stream channel and the 100-year FEMA flood zone boundary, at stream restoration project sites;
- Riparian Zones of Influence (RZOI), defined as the area between the 100-year flood boundary and a line offset 100 feet from the 100-year flood boundary, at stream restoration project sites;
- Inner Wetland Zones of Influence (Inner WZOI), defined as the area between the AA boundary and a line offset 100 feet from the AA boundary, at stormwater wetland project sites; and
- Outer Wetland Zones of Influence (Outer WZOI), defined as the area between the Inner WZOI boundary and a line offset 200 feet from the Inner WZOI boundary, at stormwater wetland project sites.
The total area of each of the following function-based aquatic resource groups was also shown on each overall and sub-reach scale SAR map and each AA map:
- Hydrologic (HYD1), Biogeochemical (BGC1), Habitat (HAB1), and Recreation or Resources Support (REC1 or RS) function group zones for stream restoration project sites; and
- Hydrologic (HYD2), Biogeochemical (BGC2), and Habitat (HAB2) function group zones for stormwater wetland project sites.