Careful consideration of water is now a critical part of design as we confront increasing floods and droughts due to climate change.

In today's episode, we move on to our next sustainable design theme - Water and Ecosystems.

We'll investigate the design of a small extension to an old timber home located in suburban subtropical Brisbane. This project has a very challenging site with overland flow and stormwater flooding issues. I talk with architect Tim Bennetton, the director of Tim Bennetton Architects, who will share the inside story on his Yeronga House project.

Tim has successfully transformed this problem site into a valuable asset that not only brings joy to the homeowners, but also provides much needed habitat for local flora and fauna.

Today we'll learn about:

• The importance of retaining stormwater and rainwater on site and appreciating water as a very valuable resource.
• Ideas that improve the resilience of cities to heavy rainfall and flooding, while also improving water quality and biodiversity, and
• We'll also cover a wealth of other insights from Tim's years of experience.

Australian Architects can claim formal CPD hours the time they spend listening to the podcasts.

MORE INFORMATION

Find everything you need on the Renovation Collaborative website.

www.renovationcollaborative.com.au

• PODCASTKey points summary, timestamps and resource links
• FREE RESOURCESTranscript edited into clear Q&A.
• CPDAustralian architects can find more information on CPD, and
• COURSESEleven easy to read courses demystifying the entire home design and construction process.

KEY POINTS SUMMARY

1. This site was affected by overland flow or water that runs or ponds on the site after rainfall. Overland flow may occur before the stormwater enters a creek, or when the stormwater leaves the creek as floodwater, or in some cases when stormwater rises to the surface naturally from underground. Overland flow typically occurs in natural low lying drainage paths. And as we discover today with good design, overland flow can become a positive asset because water is a valuable resource, particularly into the future as droughts increase.

2. Urban development in low lying stormwater flow channels leads to multiple problems such as:

• Increased flood levels, meaning that buildings take up space causing water to pile up, increasing flood depth and velocity,  
• Reduction of natural absorption processes, meaning that a natural soft landscape of grasses, trees and other vegetation absorbs water and slows its movement, whereas hard surfaces and buildings prevent this from occurring, and
• Increased impervious surfaces, meaning that urban built surfaces like concrete, asphalt and roofs cause rapid and increased runoff. When it reaches the local waterways. The additional fast forward moving water causes erosion of banks and destruction of waterway ecosystems.

3. Sponge cities are urban areas designed to absorb, store and reuse water to mitigate flooding and manage water resources. A combination of features like wetlands, permeable pavements, green roofs and urban gardens are used to help control stormwater runoff. Instead of relying solely on traditional drainage systems. The goal is to create cities that are more resilient to heavy rainfall and climate change while also improving water quality and biodiversity.

4. This project followed the principles of sponge cities and overland flow and rainwater tank overflow was captured in vegetated seasonal creek beds.

• They removed the nutrients from the water, improving water health in the river and Moreton Bay.
• They reduced the amount and speed of stormwater runoff.
• They allowed the water to slow down and improve absorption into the soil, and
• They retained water and moisture in the soil and on the site longer, supporting the growth of wildlife habitat.

5. The goal of sponge cities is to have the upstream properties and the downstream properties all part of the same natural stormwater ecosystem. In other words, to expand this concept across multiple properties, linking the entire overland flow catchment and also linking across multiple catchments. In addition to the multiple waterway benefits, this would create beneficial wildlife corridors.

And finally,

6. If you're looking to reuse water on your property, the first step is to find out what's allowable under the local council regulations. If you're seeking a complex solution for an off grid site, Tim recommended engaging a hydraulic engineer for design and to recommend the best products for rain harvesting and sewage treatment suited to your needs and site.

INTERVIEW QUESTIONS

[00:00] Introduction

[01:28] How did you get started into sustainable design?

[02:39] Tell us about your practice

[04:00] Has interest in knowledge in sustainable design been increasing?

[05:05] What was the project brief?

[06:33] Tell us about the Brisbane climate

[07:28] Tell us about the climate responsive design solutions you used.

[11:14] Tell us about the site issues.

[14:30] How did you design to accommodate the overland flow?

[17:23] What are the benefits of Sponge Cities approach

[20:22] Tell us about the exterior form and materials

[27:07] Tell us about the doors and windows you used

[30:03] Tell us about the interior design decisions

[31:16] Tell about your strategies for household water use and reuse

[38:47] What advice do you have for anyone wanting to build sustainably or maximise use of water on site.

[42:45] Key points summary

IN THE NEXT EPISODE

This was our last case study project for the season.

Next week, we move on to Getting Started, and over the next two episodes I wrap up the key learnings from the season to help you move forward.

I talk with environmental architect, artist and well known Australian climate advocate Lucy Humphrey. Lucy is a director of the climate-active architecture practice, Studio Ecology, she teaches at the School of Architecture at the University of Sydney and the Sydney University of Technology and was a co founder of the Australian branch of ACAN.

Lucy gives us a powerful wakeup call about the current state of our planet and the urgency to act. And She helps us understand building carbon emissions, plus how to measure them and how to reduce them to hit our targets so together we can bring about change. 

RESOURCE LINKS

TIM BENNETTON ARCHITECTS - Project Page (images) Yeronga House

https://www.timbennetton.com.au/projects/yeronga-house

PROJECT INFO

Project Hydraulic Engineer (and project owner) - Water Technology https://www.watertech.com.au/

Finlayson Envirowood Timber Doors and Windows https://www.finlayson.com.au/products/envirowood/

Feast Watson Black Japan Stain https://www.feastwatson.com.au/colour/black-japan

Whittle Wax Evolution hard wax oil https://www.whittlewaxes.com.au/collections/hardwax-oils?srsltid=AfmBOoqI8M1sHDOffMIzbVf5NQFt4Ki5u-LHMhk950NH_iE6TYGA3NfJ

OTHER INFORMATION

Gabriel Poole Architect https://gabrielpoole.com.au/

Gabriel Poole – Lake Weyba House https://www.sunshinecoastopenhouse.com.au/building/22-lake-weyba-house/

REVIEW

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GET IN TOUCH

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