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Sunday, March 3, 2013

Stormwater Runoff - The Good, The Bad, The Ugly

OK, with a title like that, you might think I would actually quote that classic spaghetti western.  But no.  I'll open with a quote from a different classic flick.


“Someday a real rain will come and wash all this scum off the streets.”  That’s what Travis Bickle, the Taxi Driver, said in the 1976 Martin Scorsese movie of the same name. Bickle, played by Robert DeNiro, was referring to vigilante justice as the rain and some of New York City’s shadiest characters as the scum that would be washed away.

photo by the author
But this post isn’t about violence or criminals.  It’s about the inanimate scum that gets washed from streets, sidewalks, and everywhere by actual rain storms.  You can call it stormwater, runoff, or the more technical “overland flow.”  But the effect is the same.  Trash, sediment, and chemicals get washed from the land’s surface into the nearest body of surface water.  Even in the absence of trash and chemicals, many streams become degraded by sediment washing off of sparsely vegetated areas and by stormwater that gets heated up by washing over hot asphalt surfaces during summer thunderstorms (trout cannot tolerate warm water).

I read a post this weekend on the American Rivers blog about some big strides that the city of Atlanta is taking to make their stormwater infrastructure greener and thereby easing the effects of urban runoff on the rivers and streams that receive their stormwater.  Atlanta recently updated their stormwater ordinances to encourage implementing green infrastructure, recognizing that,

“The use of green infrastructure and runoff reduction practices improves water quality in our streams and reduces the magnitude and frequency of flooding and combined sewer overflow events through the infiltration, evapotranspiration, and reuse of stormwater runoff…”

The City of Philadelphia has been proactive with its stormwater management for a number of years.  The Philadelphia Water Department is in charge of managing the stormwater runoff and has a system in place to charge property owners based on the volume of stormwater they discharge to the city’s storm sewer system.  Philadelphia is approaching the runoff problem the right way by getting property owners to pay for their stormwater runoff in proportion to the volume they discharge.  Therefore, a 30-year old big-box store surrounded by a sea of asphalt does not get away with discharging their stormwater, untreated, to the city stormwater system.  They pay.  So they have an incentive to treat as much of their stormwater on-site as they can.

Little Lehigh Creek. Sedimentation and elevated temperatures are the most significant stressors in this segment of this spring-fed stream (photo by the author).
Ironically, many U.S. cities understand the big picture of stormwater management better than some medium-sized municipalities that still have delusions of being a semi-rural bedroom communities as opposed to the suburban wastelands they are allowing  themselves to become. With increasing suburbanization and urbanization, the stormwater runoff problems become more acute.  EPA regulations governing Municipal Separate Storm Sewer Systems (abbreviated as MS4) are requiring municipalities to take responsibility for the stormwater that their storm sewer systems discharge into surface water bodies.  And here in Pennsylvania, our Department of Environmental Protection’s newer stormwater regulations are requiring new construction projects to manage their stormwater on site using either old-fashioned, ugly retention basins or, preferably, naturalized stormwaterbasins, pervious pavement, or other green infrastructure.

photo credit: LowerMacungiePatch.com
In my township, however, we still have voluminous problems with the stormwater runoff from all of the recklessly approved new construction from the early 1990s up through the middle of the last decade.  We have serious, recurring flooding problems because of the stormwater runoff entering the stream that runs the length of our township – stormwater coming from a Walmart shopping center with inadequate on-site stormwater management facilities, and stormwater coming from hundreds upon hundreds of acres of warehouse facilities built in a neighboring township.

photo credit: LowerMacungiePatch.com
I’m sure my local stormwater runoff problem is also happening in many other municipalities that have experienced unchecked suburbanization in the past 20-30 years.  This problem cannot be solved by simply requiring all future development to manage its stormwater on-site. It’s time to make all property owners pay for the burden of their stormwater on the public.  Stormwater runoff should be managed by a municipal authority in the same manner that sanitary sewer services are managed.  Pennsylvania’s municipal code allows for creation of a municipal authority to manage a utility, and stormwater management is a utility that has been ignored for too long in many areas.  Unlike sanitary sewer service, which can be apportioned based on political subdivision boundaries, however, stormwater management authorities would function more practically if they are based on watershed boundaries.  All dischargers should pay their fair share to manage their runoff so that it does not exacerbate flooding or impair water quality in the receiving streams.

There should be no free lunch when it comes to discharging large volumes of stormwater that can cause localized flooding and seriously impair high-quality streams.

2 comments:

  1. Also, inlet filter for curbs can help reduce the flow of sediment.

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