Wednesday, June 1, 2011

The 3 R's of Sustainable Site Design

I think just about everyone knows the 3 R's - "Reduce, Reuse, Recycle".  My 6 yr old has been known to recite it on occasion, and to his credit he understands at least the basics of it.  Recycling certainly gets the most air time and for the most part I think everyone associates the 3 R's with trash.  Reducing often requires some sacrifice which most of us don't like and in our expendable society reuse is more often than not ignored.  Recycling our trash is admirable and we should all do our best to do this very simple green task.  But I believe that the 3 R's have merit beyond just our consumables.  As a civil engineer and site designer I started thinking about how Reduce, Reuse, Recycle could be applied to what I do the most - site design.  Here is what I came up with - the 3 R's of Sustainable Site Design.

Reduce is probably the most impactful of the 3 R's - after all it is listed first.  The more we can reduce (consumption, development, etc) the less we will need to reuse and recycle.  This applies to development and construction projects as well.  If we first reduce, then we spend less time, money and energy trying to reuse, recycle, control etc.  In the early phases of our site designs we, as design professionals need to be thinking about how we can reduce:

  • Impervious area - Almost always when we develop a previous undeveloped site (more on that below) we increase the impervious surface area.  By replacing pervious areas (grass, forest, brush etc) with impervious area (asphalt, concrete, roofs etc) we increase stormwater runoff, reduce groundwater recharge, increase surface temperatures and create a host of other problems.  If we first focus on REDUCING impervious area we can reduce the amount of work it takes to counteract these effects.
  • Disturbance - Land disturbance damages the soil ecosystems, destroys vegetation, alters stormwater patterns and pollutes runoff.  Some of these affects can be remedied or counteracted, but if we first REDUCE the area disturbed we can reduce the impact as well. 
  • Runoff - Both of the items listed above contribute to increased stormwater runoff, so the first line of defense it to reduce impervious area and land disturbance.  But you can only reduce those so much and still develop and build, but you can still focus additional attention on reducing runoff.  Many stormwater ordinances and practitioners still focus solely on flow rate reduction and not volume reduction.  To reduce the impact on groundwater resources, erosion and the hydrologic cycle we need to also REDUCE runoff volumes to at or below pre-development levels. 
If we are to assume that reduce has the most impact judging by its place in the 3 R's then we can also assume that reuse has the second greatest opportunity for impact - which I believe is true.  In many ways reuse and recycle are interchangeable, but here we are going to consider that reuse does not require re-manufacturing, processing etc.  Can we apply this to site design?  I think so and here's how we can - reuse:
  • Development sites - REUSING previously developed sites is one of the best ways to limit the environmental degradation caused by the development process.  In addition to preserving a green field site that would be used for your project you are also able to take advantage of existing infrastructure and hopefully limit the impact associated with transportation to a more remote site.
  • Natural features - The natural features of a site; topography, water features, vegetation, etc have been refined over time in a way that is difficult or impossible to replicate.  Rather than working against these natural features we should concentrate on REUSING them for the benefit of the site.  This could include improving and reusing an existing wetland for stormwater management or using existing tree canopy to shade buildings and hardscapes. 
  • Artificial features - As with natural features its often possible and beneficial to REUSE any existing artificial features on the site.  If there is an existing farm pond, road or parking lot on site, try to REUSE those features rather than demolishing them and starting over.  Doing this eliminates demolition waste and saves on raw materials and labor associated with rebuilding them.
Last and maybe least (depending on your viewpoint!) of the 3 R's is recycle.  Recycling is certainly important, it can reduce raw material consumption, energy use and landfill space among other benefits.  It's also one of the easiest and most visible green things that you can do.  There are a lot of things you can do as a designer that the general public won't understand or appreciate but people can relate to recycling and that can propel more people to act sustainably.  So beyond our trash, what can we as site designers recycle?
  • Stormwater - Traditional/conventional civil engineering wisdom was/is to get stormwater off site as quickly and efficiently as possible.  But why not RECYCLE it?  Stormwater can be captured and RECYCLED for gray water in buildings, irrigation, fire protection or habitat creation and restoration.  
  • Materials - There are a myriad of opportunities for RECYCLED materials use in site development.  Recycled asphalt pavement, fly ash replacement in concrete and recycled rubber and plastic appurtenances are just a few of the products that can be specified and used in the site development process. By doing this we are encouraging recycling of materials and reducing raw material extraction and energy.
  • Waste - Almost all site development projects require some sort of demolition or clearing.  Rather than hauling off this waste we should consider the opportunities for RECYCLING that waste on site.  For example, demolished concrete can be used as aggregate base for paved surfaces, cleared trees can be chipped/mulched on site and used for erosion control or landscaping and demolished asphalt can be RECYCLED into new asphalt surfaces.
I am sure that are points that I missed here so please send your ideas my way if you have any thing to add.  Ultimately, I think that the 3 R's are a good example that going green and creating more sustainable spaces doesn't have to be complicated.  In engineering school the most important thing that they teach you is how to break down a problem into simple parts - and that's what the Reduce, Reuse, Recycle mantra helps us do.  And if you're not a civil engineer or site design professional hopefully you can use the 3 R's to make your life and work more sustainable.