Tag Archives: Sustainability

Green vs. gray – two sides of the same coin

DC Water's Blue Plains waste water treatment facility. CC image from erin m.

While perusing Twitter (hat tip to Jeff Wood), I came across this Guardian article about urban uses of natural processes to do the dirty work of urban pollution mitigation.  The piece discusses all types of green infrastructure and the natural processes they emulate, such as bio-filtration. I’ve taken note of local examples before, but the phrasing of their summary of the concept caught my eye:

Gray infrastructure is the system of pipes and ditches that channel storm water. Green infrastructure is the harnessing of the natural processes of trees and other vegetation — so-called ecosystem services — to carry out the functions of the built systems. Green infrastructure often intercepts the water before it can run into streets and become polluted and stores the water for gradual release through percolation or evapotranspiration. Trees also clean dirty water through natural filtering functions.

While drawing the contrast between green and gray infrastructures, the idea of “harnessing… natural processes” sparked a memory of this extensive summary from Mammoth of DC’s Blue Plains wastewater treatment facility – gray infrastructure on a massive scale.  In describing what goes on at Blue Plains, they note “the process of waste water treatment mimics — in an accelerated fashion — the natural cleaning processes of waterbodies.” The accompanying footnote:

Scott Huler explains this in his fascinating On the Grid, quoting a Raleigh wastewater treatment superintendent T.J. Lynch:

“All we’re doing is what a river would do… what happens in our plant  is the exact same thing that happens in a stream. That’s exactly where the process came from. We’ve just concentrated it. It might take the river a couple hundred miles to accomplish what we’d do in a couple days.”

Figuring out where any given piece of green infrastructure might fall in the spectrum from a naturally occurring ecology to a engineered technology is an interesting mental exercise. Rhetoric about sustainability aside, the same physical process is occurring using mostly similar mechanisms.

Low impact development near the Navy Yard

Near the soon to be opened and fantastic Park at the Yards, there’s a lot of new low-impact development infrastructure.  These bioretention areas should be a great example of the new kind of both urban and environmentally sustainable infrastructure can be.

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These are not ordinary tree boxes.  Instead of draining into a standard storm sewer, these gutters drain into the tree boxes, where stormwater then naturally drains into the ground instead of into a storm sewer.  This reduces the amount of water entering the combined storm and sanitary sewer, and thus can help reduce the number of combined sewer overflow (CSO) events.  Since the combined sewer system mixes storm water and regular sewage, substantial rainfall will force the system to overflow into area rivers, dumping raw sewage mixed with stormwater directly into the Anacostia and Potomac.

From the street side:

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Storm water will slowly absorb into the ground, aided by the various plants soils that can capture pollutants though the process of biofiltration.  Look at other rain gardens and tree boxes under construction – note the drainage layers of soil and gravel to be added.

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In this completed rain garden/tree box, note the grade of the soil in the box, below the grade of the curb:

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Cross-posted at Greater Greater Washington

Things that matter

Museo Guggenheim Bilbao - from La Tête Krançien

Museo Guggenheim Bilbao - from La Tête Krançien

Mammoth directs our attention to this post from LA Times architecture critic Christopher Hawthorne, talking about the systemic flaws of lists of the best buildings (and architecture criticism in general):

When Vanity Fair magazine recently released the results of a survey ranking the most significant pieces of architecture of the last 30 years — with Frank Gehry’s Guggenheim Museum in Bilbao, Spain, topping the list — the poll was met with more than a little grumbling. Some people griped about the many architects, including Richard Meier and Daniel Libeskind, who voted for their own work (talk about a vanity fair!); others noted that the average age of those polled, a group including architects, critics and academics, seemed to be pushing 70.

Mammoth also notes the tendency for architects to nominate their own buildings to the list – particularly the ones that don’t show up on any other lists.  Another criticism was the list’s complete whiff on any green architecture, spurring an alternative contest with an emphasis on sustainability.  Hawthorne delves into the more fundamental issue:

Asking voters to submit a list of single buildings necessarily produces results that give a skewed view of the way architecture — and more important, the way we think and write about it — has evolved in recent years.Among critics and architects alike, there has been a growing understanding that architecture is not just about stand-alone icons but is tied inextricably to real-estate speculation, urban planning, capital flows, ecology and various kinds of networks. Similarly, ambitious architecture criticism now means a good deal more than than simply writing about impressive new landmarks, green or not, produced by the world’s best-known firms […]

Maybe, in other words, the most important achievement in green architecture over the last 10 or 30 years is not a single building at all. Maybe it’s a collection of schools or linked parks or the group of advisors brought together by a young mayor somewhere. Maybe it’s a new kind of solar panel, a tax credit or a zoning change. Maybe it’s tough to hang a plaque on — or photograph for a magazine spread.

Emphasis is mine.  The same logic applies to the environmental benefits of urban density and city living, as opposed to just adding LEED certified buildings.   How about hanging that green award on a carbon tax or the elimination of parking minimums.