What is Sustainability really?

It’s an in-depth consideration of whatever you’re doing; developing land, building a house, planting a garden…, and then proceeding so you can do it again and again without impacting the Earth. Many modern processes externalize effects and costs, moving them to other places and to the future.

Starting with a place to think this through
A place is an intersection of people, plants and geography plus time – past, present, future. To be sustainable we have to fit in there and ensure others can follow. We also need to protect a place’s past, so we and future people can learn from all our pasts. Here I’ll use stormwater to look at sustainability

storm lawnRunoff Wanaka21Jul17rs
Storm water running off a public lawn (a hard compacted surface), Stormwater always has an origin although politicians love to speak of non-point source pollution – but really you just need to look harder

One of the most costly aspects of land development (both financially and to nature) is stormwater construction (25-35% of total development cost). A new approach is SUDS (Sustainable Urban Drainage Systems). SUDS handles water pollution locally, reducing downstream flooding and has cost savings of 15-80% compared with a piped system (US EPA 2007 and NZ Auckland City Council 2008 – both links are small .pdf files). With ‘Conventional’ piped stormwater rainfall is a waste to be ‘dealt with’ i.e. exported to other places and times.

By contrast SUDS

  • Keeps water local and reduces flooding
  • Removes pollutants from water
  • Reduces development costs
  • Lowers carbon and site footprints
  • Is easily understood – you can see it working
  • Makes it harder for contractors to make ‘short cuts’
  • Maintainable by locals in an emergency
  • Utilises local skills and,
  • local materials; these are not solutions that come in boxes from afar
    … so local money stays local
OLYMPUS DIGITAL CAMERA
A stormwater detention basin in its dry state, the basin has to fill up to the weir at left before any water is lost and most rain events never reach this point
OLYMPUS DIGITAL CAMERA
This is the same basin from a different angle after a storm, the water is brown from sediment and this will settle out. The base of the pool is porous so water drains into groundwater

How to make SUDS
Before a site is developed its permeability (ability to absorb stormwater) will probably be at a maximum so you need to preserve this:

1 Find where water is flowing and design to live within it
2 Find impermeable areas and make them permeable
3 Design where roads, paths, drives, houses etc. go so they don’t impact the network
4 Restrict contractor movement to areas in point 3
5 Construct a network of channels, pools and other devices e.g. ‘rain gardens’ to slow water down and cleanse and filter it
6 Enable water to percolate into ground and soils, evaporate, and be taken up by plants

OLYMPUS DIGITAL CAMERA
Stormwater detention basin with weir to restrict and slow water release. This pond is grass-lined, with a porous base and planted (native flaxes – Phormium species) to increase water loss to atmosphere. SUDS design is partly about lots of small actions leading to a large effect and about designing redundancy into infrastructure to enable storms to be handled
grassed swale suds kci2017897rs.jpg
Grass-lined swale – these are constructed with porous gravel bases to connect the swale to groundwater. The grass slows the flow; increases atmospheric loss of water via transpiration; and helps water enter the soil via roots.

Maintenance
As the plants grow their roots increase soil permeability and soil carbon levels so the soil can handle more water more quickly. Fully engineered systems degrade from the day they’re built, eventually becoming irreparable and require replacement.

In upcoming posts, among other things, I’ll explore the topics outlined above among other aspects of land planning and Earth-care in general

Links:
(1) Reducing Stormwater Costs through Low Impact Development (US EPA, 2007)

(2) lmpact Design vs Conventional Development – Literature Review of Developer-related Costs and Profit Margins (NZ, AKL, 2008)

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3 thoughts on “What is Sustainability really?

Add yours

  1. Sustainability is a key issue for our world right now, I hope you get a wide audience for your thoughtful ideas. I like the term ‘Earth-care’ and look forward to hearing more about that.

    1. Thanks Helen, one of my aims with this blog is to unearth other people and companies who are interested in Earth care and repair – we will all have to learn to maintain our home as her systems are failing…

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