I finished up Sim Van der Ryn and Stuart Cohen's book Ecological Design (2007, Tenth Anniversary Edition).

Overall I found it a worthwhile read. It is a well crafted discussion on what ecological design is and what its main principles are. Many of the ideas in this book have been assimilated into mainstream sustainability thinking so the ideas are probably not as novel as they were when first articulated. Something that has started to sink in after reading the book is the idea that ecological design informs not just how we do building, landscape and urban design, but can also inform everyday decision making such as how to source food for your family and what type of soap to buy. It is when we try to apply some of these principles outside of the usual built environment context that things become more challenging and interesting.

According to Sim and Stuart, the 5 main principles of ecological design are:

1. Solutions Grow from Place
2. Ecological Accounting Informs Design
3. Design with Nature
4. Everyone is a Designer
5. Make Nature Visible

In today's blog I wanted focus on the second principle, that "Ecological Accounting Informs Design". I am a bit hesitant to discuss this principle for a couple of reasons. One reason is that I'm not much of an accountant (I do, however, prepare and file my own personal taxes) so can't draw upon a deep knowledge of the accounting field. This would be useful. The second reason that I am hesitant is because it is challenging to understand how ecological accounting might be implemented in a practical way. I've decided to tackle this challenge today and see where it goes.

The basics of ecological accounting involve setting up accounts for the different types of "impacts" you want to manage - soil, water, energy, pollution, biodiversity, etc... You can already see that putting such a system into practice might be difficult. Estimating and measuring all the different types of ecological impacts associated with your design is not a trivial undertaking. In practice, we might only be worried about a few of the most obvious impacts. If we limit our scope, the prospect of performing an ecological accounting becomes more realistic. We can always add another dimension when we have management of the obvious impacts under control.

Ecological accounting comes into play when we are evaluating design alternatives. There is not much point of doing ecological accounting on a product or process just for the sake of doing it. Ecological accounting is useful for evaluating whether you should go with one design alternative over another because it minimizes some impacts (e.g., co2 emissions) or maximizes some benefits (e.g., improves soil) which collectively suggest which design is the most appropriate.

One important dimension to include in your accounting is the cost dimension. You may have a great ecological design but what happens when you discover that it costs alot more than a less ecological design? How do we manage the tradeoffs? How do we equate costs and levels of pollutants? Is one more ton of co2 produced equal to -$44 USD in your balance of accounts?

Putting a price tag on ecological services is a big field these days. The Natural Capital Project has a huge number of Ph.D researches developing software to estimate the value of the many ecological services that nature provides.

Ecological accounting can also be viewed as a way to engage in design that specifically involves 1) life-cycle analysis and 2) following the flow.

A life-cycle analysis involves an examination of impacts over time and encourages us to examine what happens to the design after it has served its useful life. What will become of it? If one design generates landfill waste and another involves composting, then the latter design is to be preferred.

Follow the flows means understanding the material flows, energy flows, transportation flows, pollution flows, heat flows, and water flows that are required for one design versus another.

Following the flows encourages us to ask questions such as:

• Where do the materials for the product come from?
• How much transportation is required?
• How much energy will be used at each stage of production?
• How will waste streams be managed?
• How will water usage be managed?
• How will heating be managed?

When we follow the main flows we have better ecological accounting to use for evaluating our design alternatives.

How do we find designs that have the best ecological accounting?

One approach would have us carefully evaluating our design with respect to all our ecological accounts and picking the design with the best ecological accounting score. I don't think the process of ecological design is or has to be this rational to succeed. Instead it can rely upon heuristics that while not guaranteed to produce good ecological accounting scores often end up doing so.

Here I enter uncharted territory. I'll propose a couple of practical heuristics for your consideration:

1. Do it cheaply. Within reason.
2. Apply zonation.

The heuristic that you should do it cheaply forces you to act under resource constraints that often produces a design with good, and sometimes optimal, ecological accounting. The "within reason" part is a reminder that if you are too cheap you may sacrifice quality to an unacceptable extent. You might have to back off from the cheapest design for this reason but finding the cheapest design is a worthwhile design activity to engage in to find a design with good ecological accounting to begin with. You can back off from there to optimize on other dimensions that are important to you besides cost.

The second heuristic that will often lead us to finding a design with the best ecological accounting is to apply zonation. Zonation is a concept from Permaculture and is generally used to design the layout of a farm in a way that minimizes travel time based upon how frequently we have to visit different parts of the farm. So put your garden, which you must attend to everyday, in zone 1, which is next to your home, which is in zone 0. Put the apple trees which you need to tend to visit less in zone 3 or 4, just within the zone 5 which is your wild zone which you need to visit even less frequently.

Toby Hemmenway has been creatively applying zonation to many different areas from transportation to foodsheds. His zonation of foodsheds has resulted in a foodshed design that arguably has better ecological accounting along many dimensions than our current foodshed design. This is a diagram from Toby's new book, The Permaculture City (2015), which is also about ecological design but from a more permaculturally inspired perspective.