Sustainability calculator

A sustainability calculator is built into gCADPlus. It provides a mechanism for applying a structured approach to assessing landscape designs with regard to sustainability and runs in its own window ‘floating’ on top of the gCADPlus design.

gCADPlus to SketchUp Reviewing the gCADPlus sustainability calculator.

As it runs, the tool poses a number of questions. Each asks for your assessment of how well a particular ‘sustainable‘ characteristic has been dealt with in the underlying gCADPlus design. Your response to each question is rated with a score ranging between 1 and 10. As a question is answered, a tick appears in a checkbox. and the calculator adds the total and calculates a sustainability index. The figure below shows the calculator in action.


The first question.

Here you are asked to make an assessment of the proportion of the landscape area that is open to the penetration of rainfall, i.e. it wants an estimate of the percentage of permeable surfaces in the design. A site in which there is a high proportion of permeable surfaces will score highly on a scale of 1-10.

Sustainability row 1
The second question is shown below. Here you are asked about the species chosen and their reliance on extra watering. If all species chosen in the planting plan will survive on natural rainfall after the first year, score highly.

Row 2
More questions follow.

The calculator keeps a running total and at the end of the series of questions presents an overall score. We suggest that if a design scores> 50% this means that reasonable attention has been paid to ensuring a sustainable landscape design.

Our users report that this tool helps focus on issues of sustainability that are easy to overlook while they may be concentrating on other design issues.

Tip: If the question does not apply to the design being assessed, simply leave unchecked.

YouTube movie We take a design for the rear of a Dutch house and apply the gCADPlus sustainability calculator to improve the design.

Sustainability – some thoughts from Ross Uebergang –

Sustainability in the landscape is a must. We live in a world of finite resources.

  • Reflect: If I want a deck, do you really need one this size? How often will I have 80 people on my deck? Could I go without or could I use a substitute?
  • Reduce: Can I set my areas up to use less energy?
  • Refuse: If what is proposed is a bad idea say no. You may not need it or there may be a suitable substitute.
  • Reuse: In the rebuild, is this material really at the end of its useable life? Can I find another use for it? Can I find someone else who has a use for it?
  • Recycle: Can this material be processed to have a new life? This is the next alternative to reusing. Can I use a recycled product instead?
Tips for gardeners

Mulch and Compost – Go to a local landscape supplies center and use their courtesy trailer or get it delivered. The mulch will mean less watering, better soil structure, and healthier plants while limiting the number of weeds that pop up in your garden and spread throughout your neighbourhood. Depending on the style of mulch you choose you could spend as little as $30 per 10m2 if you use your local council mulch or around $60 for decorative mulches. Compost will create healthy soil that needs much fewer additives.

Choose sustainable materials – If you must put in hard surfaces like decking, paving, pergolas, etc, choose materials that have low embodied energies. This is the energy needed to extract, manufacture, transport and install your product. Not only should the materials you use in the landscape be low in embodied energy, but they should also have reasonable longevity. A fantastic choice for low to medium use paths is local toppings.

Limit the use of hardscapes – How often will you actually have 80 people in your backyard to fill a massive deck? Consider if space could be filled with plants instead.

Line your fences with Fruit Trees – Fruit trees keep on giving with low maintenance. If you don’t have the time to be putting in vegetables every 12 weeks and maintaining a vegetable garden, perhaps fruit trees are for you. They require limited maintenance and you do not have to replant every season. Each year more dwarf varieties come out that take up less space which is fantastic for the small garden. Generally in the Australian garden, fruit trees require sun for most of the day to provide fruit that is plentiful and tastes good. A fence line is a great spot to find this sun.

Can I fix it? – Your deck might be looking a little ragged at the moment, but perhaps all it needs is a smarter choice of decking boards. Perhaps it just needs a fresh coat of oil. Maybe a coat of paint on the back fence will revitalize the plantings that you have in front of them.

We love the philosophy adopted by one of our gCADPlus users. Visit sparethoughts landscape design.