BiG TeA PaRtY Member Volunteers
at Local Park Cleanup & Plant Tending Day
(and learns about sustainable approaches to storm water management)
by Valerie Keller
|Here I am with some of the organizers standing in the ‘retention basin’ – I’m 2nd from right|
I live near a few city parks, but this one is something special.
Last year this public playground was transformed from what had been a cement playground with outdated equipment, very little grass or other vegetation, and a traditional cement basketball court in the Pennsport section of South Philadelphia.
The old playground and pool was converted to a state-of-the-art green project, now called Herron Playground, that is a model site to demonstrate the broader plans for the greening of Philadelphia. It employs porous paving for sidewalks and basketball court, recycled material as playground surface, drainage beds and pipes to carry excess water into a retention basin full of native plant species, and islands of vegetation for retaining water and slowing runoff.
Herron Playground is a fantastic example of trying to mimic nature’s methods of dealing with excessive storm water in an urban environment where for generations most land has been paved over with impervious surfaces (cement or asphalt or other paving materials which water cannot penetrate), causing major problems when there is a heavy rainfall and water has nowhere to go, so it just sheets off into the street and rushes into the nearest storm drain, overloading the city’s sewer system often just from the first inch of rain of a typical rainstorm.
This can cause flooding of city streets and of the river itself, but also this leads directly to polluting the waterways – also the source of drinking water in Philadelphia – since a lot of that water flows over dirty streets and sidewalks and parking lots, picking up dirt and trash and car fluids along the way and then traveling straight to the rivers taking all that gunk with it.
The old way of thinking would be that we should just install bigger pipes, but that would be a huge construction project, digging up streets and city lots, and creating traffic, parking and quality of life issues for years to come (including air pollution and water pollution just from the construction itself!). Not to mention it would be very expensive.
Luckily there are a host of organizations dedicated to a happier, healthier approach to Philly’s storm water runoff issues that, if enacted all over the city, could make Philly a new paragon of sustainable green infrastructure.
Herron Playground is a prime example of using a combination of methods to deal rainwater as it falls. The main goal is to slow the water down and absorb as much of it as possible on-site, leaving very little overflow to enter the storm drainage system.
Herron Park boasts porous pavements that water filters through and then that water is both dispersed into the soil and held in underground natural basins. The playground surfaces are made from recycled materials that look like wood chips and also absorb water, and there are islands of vegetation throughout, since trees and flowers help hold drops of rainwater and thus slow the water down in its path to the ground, and they also absorb water with their roots, as well as providing shade and beauty for people who use the park.
|Here I am trimming last year’s flowers to make room for new growth|
Herron Playground also has a porous asphalt basketball court, which not only was built with storm water management in mind, but is also has the added perk of being quieter than a traditional asphalt court because it is less of a hard, solid surface and thus absorbs the sound of running feet and dribbling balls.
The basketball court was specially designed with a water filtration and retention system built underneath, so the water that works its way through the porous surface moves between rocks and fills a basin under the ground. Then if there is a heavy rainfall with more water than that underground storage system can hold, the court has a drainage system around the perimeter so excess water is channeled into a retention basin, which is a planted area that is a little bit lower than the rest of the park, forming a sort of shallow valley that is filled with native vegetation, specially selected for its ability to handle extremes of dryness or excessive moisture [see photo at the top of this article].
Because of all these storm water management systems, it’s estimated that this park takes care of 80-85% of its rainfall, so only the remaining 15-20% ends up in the city storm drains, some of which feed straight to the Delaware River. Not only that, but the overflow that does make its way into the river has been cleaned because it has been filtered through earth, rocks, and other porous materials, so less pollution is winding up in the river.
Although it is sad that we have so disrupted nature’s perfect plan to deal with rainstorms, projects like Herron Playground prove that if we look to nature for clues, we can construct smarter surfaces and restore some of the missing plant life to help return our most paved-over areas back to a state of sustainable storm water management.
For more info on the greening of Philadelphia:
Philadelphia Horticultural Society’s Philadelphia Green project,
For more info on Herron Park:
phillyplaygrounds blog article “Waves of happy kids: Herron Park sprayground“
cenews.com article “Sustainable, urban stormwater management“