Green infrastructure: For stadiums, your city and everywhere in between

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January 4, 2013
By: David Motzenbecker
David Motzenbecker

We are at a point in the evolution of cities — with more people moving back to downtowns across the country — where we have an opportunity to change the way we approach the treatment of stormwater. This old, yet very new look at stormwater infrastructure has the capacity to enhance livability for all.  It's called Green Infrastructure.  Let's look at how...

According to an EPA Report to Congress, as of 2008 the total water infrastructure needs of the United States were $298.1 billion.  Of that, $42.3 billion was allocated to stormwater management,  a very conservative estimate, as only 22 percent of municipal stormwater systems were included in that report.  These costs are capital costs associated with new infrastructure, repairs to aging infrastructure, and higher water quality standards demanding better systems.

So if the other 78 percent of systems were included, would the cost eclipse $100 billion for just stormwater? Possibly. Most of this infrastructure is invisible until it backs up or crumbles into oblivion after a century of use.  This type of infrastructure is well-understood, it’s comfortable to many, it has a useful life, and always needs to be replaced. It  provides the single benefit of keeping our cities, businesses, and homes free from the deluges of a hundred-year storm, but can you think of any other benefits it provides? Does a grey concrete pipe encourage habitat for birds and butterflies? Does a catch basin allow you to stroll through it while it filters out the nasty particulates? Not last time I checked.

We are on the verge of re-creating nearly 40-acres of downtown Minneapolis with a new 1.5 million square foot Vikings Stadium as the anchor. This presents the City, the team, all the policy makers, and most importantly the people — since this is being touted as “The People’s Stadium” — with a choice to look at this as more than just an object and see it as a rare chance to re-make a long neglected corner of the city. Can we gather our collective sense of what's best?  Then we must stop focusing on the  bottom line of dollars and expand our focus to the triple-bottom line (TBL) elements of social responsibility, ecological responsibility, as well as economic responsibility.

The stadium legislation (473J.11, Section 15, subd.3) requires 2,000 parking spaces within one block of the stadium and 500 spaces within two blocks (with a dedicated walkway on game days).  The legislation also includes language about stadium infrastructure, defined as “…plazas, parking structures, rights of way, connectors, skyways and tunnels, and other such property, facilities and improvements…to facilitate use and development of the stadium.”  The recently released Scoping EAW has an interesting statement on page six in that it identifies two acres of the current 39 as “landscaped islands or green space” and then  statesthe amount of green space is anticipated to remain the same and  cover types are not anticipated to change materially and that “no further evaluation is requiredcover types will not be addressed in the EIS.”

Current annual water use at the Metrodome is 18 million gallons — this could increase by as much as 66 percent (11.9 million gallons).  Could any of this be re-used to irrigate?  According to City staff,  the stormwater infrastructure that will serve the stadium and its surrounds does not have adequate capacity for the current flows.  What happens when the size of the stadium increases by 66 percent?  Current stormwater flows into a variety of shallow and deep tunnels and then heads over to the Mississippi.  It is unclear whether there are any elements between the inlets and the outlets that help clean the runoff.  With 2,500+ parking spots, vehicle emissions on event days will be prevalent.  Could a forest of urban trees sprouting from “pixelated parking” lots or “parking gardens” help clean the water we love and air we all breathe?

 What could happen is that — as anticipated by the EAW — most of the land cover types stay the same, meaning mostly impervious.  Small steps are taken to investigate different ways to filter, retain, and detain the stormwater, some lipstick is placed on the pig — but most options outlined are mechanical .  Mechanical choices must be maintained, repaired, and replaced at the end of their useful life – all at an economic cost.  Choices are implemented to improve  what exists, but not to the standard needed  for future generations. 

I proposed  that the People’s Stadium is surrounded by a People’s District.  This will integrate an extensive green connective network of trails, paths, trees, tailgating areas, parking gardens, and enriched habitat.  The primary purpose of  this green space will be to serve as the desperately needed stormwater infrastructure for the stadium district.  But that's only the beginning of what's possible.  It will also clean the air and water, not dirty it.  It will provide multiple opportunities for recreation – on game days and beyond.  It will improve our health — by allowing us green connections via which we can move across the city and connect to the Gateway Park, the Grand Rounds, the Mississippi and more.  It will increase property values and aesthetics.  It will reduce the urban heat island effect, increase seasonal ozone, increase electricity and natural gas savings due to the cooling effect of trees.  Over time, it will take less fuel (for construction, operations, and maintenance vehicles) than traditional gray infrastructure.  It would reduce carbon dioxide and improve oxygen counts.  That’s twelve distinct, measurable improvements — and I’m sure you could name twelve more.  How many benefits does traditional infrastructure have again? 

Where is this happening?  New York City has identified nearly $3 billion dollars that could be saved by switching from gray to green infrastructure with Mayor Bloomberg's latest PlaNYC.  They can also reduce sewer overflow volumes by nearly 2 billion gallons over an all gray approach.  Philadelphia has been practicing a green model —  and continually improving it since 1999.  Their “triple-bottom line” review resulted in an understanding that making their city's stormwater infrastructure 50 percent green would result in exponentially more benefits across the board than a 30 foot tunnel ever could.  Cory Buckwalter Berkooz, a planner in Ann Arbor, Mich., stated that Detroit could, by adding green infrastructure, reduce their annual costs from $192 million to $33 million.  I’d say the R.O.I. is looking pretty good for green infrastructure.

Please make your voice heard that the People’s Stadium has only one opportunity to think beyond the present and into a green, urban future.