Nature-Based Pollution Solutions Coming to Northwood!

TTF Admin
Apr 12, 2023


As part of the twenty-five-year Green City Clean Waters program, the Philadelphia Water Department (PWD) is installing Green Stormwater Infrastructure (GSI) projects across the city to combat pollution from stormwater runoff and the resulting combined sewer overflows into our waterways, including the Tacony Frankford Creek. 

We’re excited when GSI projects come to our watershed because of the many benefits they bring along with them! Projects coming to Northwood include 30 tree trenches, a subsurface storage trench, six bumpouts, and two rain gardens. 

What’s runoff? Runoff is one of the biggest challenges to the health of the TTF Watershed. Runoff is rainwater that flows off of roofs and roads, carrying pollutants and dirt into our creeks and rivers.

A system of thirty tree trenches between Oxford and Castor Avenues and Overington Street will be connected to an underground infiltration structure, designed to manage incoming runoff. Infiltration is the process of water entering soil.

A subsurface storage trench will be installed in Overington Park on the corner of Orthodox and Leiper Streets. This subsurface storage area is designed to slow the flow of excess stormwater into the system; stormwater will enter the trench through an inlet, fill the storage area, then seep to the bottom of the trench and soak into the soil below. Any excess water that does not seep into the soil will be released into the combined sewer system at a controlled rate.

There are 6 bumpouts around Frankford High School and Philadelphia Charter School for the Arts. These bumpouts are designed to direct runoff water under the bumpout to be stored, infiltrated, and absorbed by plants such as grasses and shrubs.

The piece of the plan is the installation of rain gardens —  one at Oxford Avenue and Oakland Street, and two in Northwood Park at each end of Northwood Street. Rain gardens are planted with native plants that thrive in wet and dry weather. Rain gardens collect runoff from impervious — or hard — surfaces like roofs, walkways, and parking lots. 

PWD wants to hear from you with any comments or ideas! Contact Jackie Ng, GSI District 4 Outreach Specialist at

You can find more information about the Northwood plan here.

You can find information and a map of TTF projects across our watershed here.

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