How to design a water system for your permaculture garden
Water is an essential ingredient for plant growth and abundance, and as such, it should be the first element to integrate in a garden design. In permaculture, water is to be collected and reused, and earthworks should be designed to optimise the use of this precious resource. Here are our top tips to design an efficient water system for your permaculture garden.
- Observe your land
Spend some time observing and understanding water patterns on your land. Study average rainfall in your region, and observe the direction of water flows off your roof and in your backyard. In times of low rainfall, you will want water to percolate slowly into your plants, keeping it at the highest point of your property for as long as possible. In times of high rainfall, you may need to direct excess water to a tank or pond to limit erosion and stock up for the dry season. What patches of soil are wetter than others and why? Notice the microclimates in your garden so you can create the best design.
2. Assess your water source
Where will you get your water from? If rainfall is abundant and well spread out throughout the year, it may be your main source of irrigation. If not, are there streams that run across your property? A communal well nearby? Is your water source perennial or seasonal? Think about how much control you have over water flows into your property and what permits you might need to get to irrigate your land. Make sure you understand where your site is on the local watershed (the area of land that drains rainwater or snow downhill from hills and mountains to rivers or lakes): where does the water that gets to your site run off from, and where does it run off to? You want to ensure the water is clean both when you get it and when it leaves your site.
3. Make a water budget
Based on your site’s average rainfall and access to surface or underground streams, calculate how much water you will have access to throughout the year. That is your water budget. Then, calculate how much water your need to make your permaculture dreams come true — and adjust your plans to fit your water budget.
4. Slow, spread and sink
Before you start building water tanks or ponds, create a water path on your site to maximise the use of rainwater. Make it as long and windy as possible, using techniques such as swales on contour or keyline plowing. For these earthworks to be successful, you will also need to ensure your soil is rich in organic matter, so it has the capacity to absorb as much water as possible.
5. Store water
It is now time to design a storage system for the water that does not get absorbed by your earthwork system. For small quantities of water, place a tank near the highest point on your property: you will be able to use gravity to spread the stored water to the rest of your land when needed. Make sure debris such as rocks, twigs or small animals are filtered out of the water before it gets to the tank, and cover it to avoid the proliferation of mosquitoes. For larger quantities, consider building a pond, somewhere that is protected from the sun and wind to avoid evaporation. Once these storage solutions are put in place, it’s time to harvest water: build the right gutter to collect runoff from your roof, or dig trenches to direct soil water to your tank or pond.
For more information on water management in permaculture, check out this article by Permaculture Apprentice or watch this video by the Oregon State University e-campus.
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