Resilient Systems & Properties

A system is a set of interacting or interdependent component parts forming a complex/intricate whole. The components that make up your rainwater supply are a system. The elements that are put together to provide for your shelter, water, waste and food needs can be thought of as a system: e.g. our homes are systems. Our neighbourhoods and our cities are also systems. Everywhere you look, systems are nested within systems and it’s really just a question of where you draw the boundary.

Resilience is the capacity for a system to adapt (and we would argue to continue to thrive) in the face of change or disruption.

It’s an excellent complement to sustainability, and arguably you can’t have resilience without sustainability. However, we like to present and think about systems in terms of their resilience. Fundamentally, for many of our clients and students, their absolute primary motivation for taking action is to increase their personal resilience.

To expand on these resiliency criteria, in the table below we present design choices and examples for each criterion of a resilient property and contrast these against design choices for most conventional modern-day homes (i.e., a fragile property).

*Think of how inappropriate it is to cut butter with a chainsaw. The same idea applies to heating your home with natural gas, or using drinking quality water to flush a toilet. These are poor matches of energy density and water quality to end-use.

The property illustrated in the Figure shown below is an example of a resilient property located in a cold-climate. Note that you can apply the same resiliency characteristics to each individual sub-system for water, energy and food.

The Water Systems

• Efficient: All fixtures high efficiency/low volume, water re-use used to reduce irrigation and toilet flushing volumes. Gutters and roof designed to prevent rainwater losses. Water-wise landscaping.
• Productive: All water captured (building and landscape) and stored for use. Water employed to grow abundant biology.
• Appropriate: Highest quality filter located at drinking water tap. Greywater used for toilet flushing and irrigation. Rain used for irrigation.
• Interconnected: Wastewater is a resource and nutrients from wastewater are used to grow plants and soil both in the greenhouse and in the landscape. Monitoring in place for water usage, rain forecasts and storage volumes.
• Includes Redundancy: Water storage designed for appropriate low rainfall conditions. Back-up plan in place.

The Energy Systems

• • Efficient: High insulation walls and windows and careful design of the building envelope. Energy efficient lighting and appliances.
  • Productive: House orientated to capture passive solar energy. Careful design and selection of glazing. Attached greenhouse provides supplemental heating. Solar photovoltaics for electricity and solar thermal for hot water.
  • Appropriate: Passive solar gain as primary heating source, biomass as back-up heating, photovoltaic electricity used for high energy density needs, solar thermal used for domestic hot water and ancillary space heat. Irrigation is provided passively (using gravity vs being pumped).
  • Interconnected: Heat recovery ventilator use to pre-heat intake air. Warm stale air from the house cycled to the greenhouse. Excess heat energy from the greywater captured in greenhouse. Monitoring systems in place for energy production and storage.

  Includes Redundancy: Grid-tied power for back-up electricity. Heating provided by three sources: passive solar, active solar and biomass.

The Food Systems

• Efficient: Local food and seasonal food prioritized. Food grown onsite is harvested, preserved and stored for later use when in periods of abundance.
• Productive: Perennial forest gardening, annual vegetable production and four season production in the attached greenhouse. Micro-livestock systems (such as chickens) for eggs and meat. Biodiverse and abundant biology grown not only for the occupants but to support surrounding ecosystems.
• Appropriate: Food that supplies the occupants is grown with appropriate energy (human-scale vs large manufacturing-scale) and appropriate water (local and captured water vs imported water). Gardens designed for passive irrigation instead of pumped irrigation.
• Interconnected: Food scraps, plant and other wastes cycled to create compost, soil and/or to feed micro-livestock.
• Includes Redundancy: Not purely reliant on industrialized food system. Occupants grow some of their own food and support the local food economy as much as possible.

If your motivation is resilience, you’ll want to keep these criteria in mind as you are designing your rainwater harvesting system, but also particularly as you consider your rainwater harvesting system in the context of full-property water security and overall property design.