We’ve been talking a lot about our city’s watersheds and water management on this blog lately — both the problems and the progress. Yesterday, some 300 residents of the East End turned out for a meeting initiated by Councilman Bill Peduto on the the problem of chronic flooding in the East End of Pittsburgh. As we all know, an August flash flood also led to the tragic deaths of two women and two girls on Washington Boulevard in Highland Park. What you may not know is that most major cities have departments specifically charged with stormwater management. Pittsburgh does not. Urbanization presents specific challenges to managing stormwater as concrete and steel do not soak up water. Moreover, older cities like Pittsburgh have a patchwork of infrastructure systems including a combined sewer system (one that combines stormwater and sewage). As 3 Rivers Wet Weather notes:
Over time, a network of 83 municipal combined and separate sanitary systems, which flow into each other before reaching the ALCOSAN sewage treatment plant, has evolved in the region surrounding Pittsburgh. Much of the system today is deteriorated and overloaded during wet weather, which results in frequent and illegal sewage overflows into our waterways, streets and homes.
Furthermore, an EPA evaluation of Pennsylvania’s draft Watershed Implementation Plan found serious deficiencies. As regards urban areas, they described the strategies for strong stormwater as having “questionable enforceability and accountability.” Pittsburgh City Council has addressed the issue of the combined sewer system, but there is much more that can be done and must be done to better manage stormwater and we don’t have to look very far. From The Dirt:
Now, Philadelphia Water Department’s Office of Watersheds may be leading the next generation of innovation in water infrastructure with its plans to roll-out an ambitious $1.6 billion green infrastructure plan, which would use rain gardens, green roofs, pervious pavements, and trees to recycle and reuse rainwater. According to one study, “one inch of rain water hitting one acre of asphalt means 27,000 gallons of water” is going into the sewer. For a city like Philadelphia, that means billions of gallons are flooding its now aged water management system.
The green infrastructure proposal would turn 1/3 of the city’s impervious asphalt surface, or 4,000 acres, into absorptive green spaces. The goal is to move from grey to green infrastructure. Grey infrastructure includes “man-made single purpose systems.” Green infrastructure is defined as “man-made structures that mimic natural systems.” As an example, networks of man-made wetlands, restored flood plains, or infiltration basins would all qualify as green infrastructure. The benefits of such systems include: evaporation, transpiration, enhanced water quality, reduced erosion / sedimentation, and restoration. Some grey / green infrastructure feature integrated systems that create hybrid detention ponds or holding tanks, which are designed to slow water’s release into stormwater management systems.
As Councilman Peduto has remarked:
It is imperative that Pittsburgh develops comprehensive planning, rather than try to rely on spot fixes. We live in a complex watershed and we must look at it as a whole system, not focus on a few streets in a few neighborhoods. The lack of a comprehensive plan means we are unintentionally creating new problems down the road as we try to “fix” old ones.
With determination and leadership, a smart, comprehensive stormwater management plan is not out of reach. The Nine Mile Run Watershed Restoration is a great example of what is possible. It’s a partnership between federal government, city, community, and nonprofits which uses principles of natural systems to inform man-made systems. We need a plan like this for the entire region, starting with the City of Pittsburgh.