Principle: Clean, conserve and reuse water
Water is a unique, abundant, life-supporting substance. Understanding water’s properties and effectively managing its use are critical to the success of your permaculture site. Some unique properties of water include:
- Thermal mass. Water resists temperature change and acts as a battery for heat.
- Expands and contracts, when it freezes and melts.
- Capillary action. An example of capillary action is when you dip a piece of string in a cup of water. The water wicks upwards. Water defies gravity, in some words.
Some estimates show Americans consume an average of 350 liters of water per person per day, Europeans consume 120 liters and Africans consume 3 liters. While this statistic varies among people, communities and countries, it is important to note we need to find a balance. How much do we really need? The United Nations decided 30L is a good amount of water per person per day. A daily average is a good method to determining the size of your site’s water storage capacity (number of people x daily consumption x number of days of the dry season = needed volume of storage).
Of all of the water in the world
97% is salt water and 3% is fresh water. Of the 3% fresh water:
- 75% is frozen in snow and ice
- 24% is in aquifers (deep and shallow),
- .5% is in rivers and lakes, .3% is in forests and soil and .2% is the in atmosphere
Good permaculture design water strategies
Here are a few strategies to conserve and store water in tanks and in the soil. Keep these in mind when designing your water site plan:
- Create the longest path, moving as slowly as possible (the most passive friction), passing through as many living things as possible is the most fertile design.
- Overall, a good water design has 10-15% of a site include water (PA Yeomans)
- Dig effective Earthworks to slow, stop and soak water into the soil,
- Plant layers in your forest. Rain soaks into the vegetation before it hits the ground. This allows trees and plants to absorb water. (more in Trees)
Water follows a similar pattern as it rises and falls from the sky. The hydrological cycle goes as follows:
Human water cycle
Water also follows a similar pattern in relation to humans. The human water cycle goes from the source to filtration to transport to consumption to recycling.
We can procure water by catching and storing water from the air, from the ground or from below the ground:
- Collecting water from the rain and fog – rainwater capture and storage strategies are present in nearly every permaculture site.
Rainwater catchment is a gutter system installed on the bottom edge of a roof to collect rainwater. When the water is collected in a gutter, it channels the water to a downspout and collect in a bucket or cistern.
1st flush system
A first flush system is a drain built into a rainwater catchment system to wash away the fallen debris on the roof at the start of a rain. There are several designs for a first flush system.
Fog net systems catch water from the air. They are most appropriate on mountain ridges where clouds frequently pass over. Large plastic mesh nets are flown 3-10m in the air to capture water from the passing clouds. At the base of the nets, a 10cm PVC pipe catches the water and channels it to a collection tank.
- Collecting water in ponds and tanks on the surface of the earth – Storing water on the surface of the earth provides habitats, fish, food, irrigation, recreation, etc.
Building ponds increases the aesthetics of a site, as well as plant and fish diversity. Small ponds are great for edge effect, enabling greater species diversity to take place. (See the earthworks section for methods on lining ponds.)
Water equilibrium principle: If you want to store water in multiple places in your site, you can connect cisterns using PVC pipes. Water tanks level out when connected by pipes. Consider this when designing and installing your site’s water system.
An above ground water tower uses gravity to create water pressure throughout a site. Note: Each 30cm (1’) of water raised creates .43 psi (pounds per square inch) of water pressure. Water pressure in conventional public water supply systems are about 40psi. If designing your own water tower system, 8 psi is a good minimum, or between 6-8m as a minimum height for decent pressure.
Ferro-cement is a great method of building water tanks or cisterns. With this construction technique, you can design any shape you like. Lightweight <500 gallons (2000 liters) = use 1/4” rebar. Medium 500-2000 gallons = use ½” rebar.
Cistern, above or below ground
A cistern is a vessel for storing water. Cisterns are often connected to rainwater catchment systems to store water and provide water security. Cisterns can be built above or below ground:
- Above ground cisterns can be built with mud bricks or earthbags and lined with cement mortar.
- An underground cistern is a large hole lined with cement or plastic and covered with a cement top.
- Below the surface of the earth
Wells are underground holes dug to pull water from the water table. The cost of drilling can be expensive, but wells provide a steady source of water for a community. Pulling water from underground in wells is a last resort for sourcing water.
Once water is ready for consumption, it is transported to our communities and homes either through metal or PVC piping systems, trucks or fetched on foot. Here are a few methods to get water to where you need it:
A water pump is any mechanical device that forces water to flow in some direction. There are many types of water pumps and designs. A few common water pump designs are hand pumps, ram pumps, jet pumps, submersible pumps and siphons. The most economical and simple water pump is powered by gravity.
Canals can be built above or below ground. For a hidden water canal (often called a French drain), dig a trench in the low area of your site about 30-60cm deep and wide. Then line the trench with small and medium-sized gravel. Cover with dirt. For a visible water canal, you can dig the same sized trench and line it with concrete or clay (if you have a high percentage of clay in the soil). This can be used to channel water.
A windmill is a structure with vanes that rotate in the wind to pump water or grind grain into flour. Wind turbine usually refers to machines that generate electricity and windmill refers to powering more mechanical devices.
Water wheels are devices placed in rivers to slowly and consistently pull water from the rivers. As the current flows, the wheel scoops up water and raises it to a higher elevation. Here is a good video of a water wheel: http://www.youtube.com/watch?v=LbklIccv2CI. This constant source of water can be used to fill a cistern.
Plumbing is a system of PVC pipes and drains to distribute water where it is needed. This his how most developed communities transport water. One good rule of plumbing to remember – water (and poo!) roll downhill. Use gravity to your advantage.
Here are a few low-energy, low-cost methods to producing clean water:
Solar distillation is the process of capturing evaporated, or distilled, water using solar energy. A solar collection box heats water There are several designs of solar stills. This method works however has proven not to have the highest output.
Ceramic Water Filter
Filterpure ceramic filters are 20L charcoal/silver-lined clay pots which can filter up to 20 liters/water a day. The ceramic filter can filter out all bacteria and some viruses including e coli, salmonella and cholera. Go to www.filterpurefilters.org for more information on the Filterpure filter. To increase the clean water output, a 5-gallon bucket was glued to the top of the filter with silicone puddy. When the bucket is filled, the added water pressure increases the output to 60 liters/day.
Bio Sand Filters are a multi-barrier system to filter water. Water is poured into the top and trickles through several layers of sand and bacteria to produce several liters of clean water a day. This is a good system for residential use and can work for a long time as long as the filter remains wet.
Multi-barrier water filtration system
This filter, designed by Aqueous Solutions (www.aqsolutions.org) filters 2000L of water/day (about 1 L/minute) when running properly. It is very cheap to make, easy to construct and effective water solution for a community of up to 100 people. This system is expected to last 5 years before needing to change the filtration material.
Note: When installing the filter, you may want to add an additional 1 or 2 sand filters. This is the slowest part of the system. If you add additional sand basins, the system should reach the potential output of 1L per minute.
Here are a few unique ways to heat water for showers:
Solar water heater coil
A solar water heater can heat water for the shower, washing clothes or cooking. One simple way to build a solar water heater is to wrap black hose in a large coil and place it on a roof that receives a lot of sun. As you use the hot water, cold water will replace the hot water in the tube and begin heating. Google Greenpowerscience – solar hot water for more information on a solar water heater coils.
Solar water heater box
For a good, immobile solar water collector, build a box out of cement and mud mortar, add insulation to retain the heat. Build the structure facing the sun. Then install one or two 200-liter metal drums, depending on how much water you want to heat. A two-barrel box structure would measure about 2m x 2m x .8m on the interior. Connect the bottom of the drums to a cold input line. Run another line for the hot water to exit the drum on the top. Then cover the box with a sheet of glass or clear plastic.
Long-term compost water heater
For a cheap, reliable source of hot water build a long-term compost pile and wrap a 50m garden hose through the pile as you stack the pile. For the long term compost pile, first lay large sticks or branches on the ground, then stack brown and green material (as you would a normal compost pile), add lots of manure or other high nitrogen additives. Add water with each layer. This pile won’t be flipped, it will slowly decompose. Connect one end to a water source and run the other end into your shower or wherever you need it to go.
Outdoor showers provide a great place to bathe in the sun. The structure just needs access to water, adding a hot water heater is a bonus. Grey water can be passed through a sand filter and used to water plants. Make sure to tell people to use natural soap. If you use strictly natural soap, you could pour the greywater directly onto a garden bed. Otherwise, it may be best to run the water through a greywater system (also in water). Here’s an interesting portable shower design: https://www.youtube.com/watch?v=FC4nihIuKAM&feature=fvwrel.
A covered outdoor laundry area is an area to wash clothes. This area must have access to water, proper drainage and several large bins for washing clothes. Grey water from this system, like the showers, can be used for irrigation. You may also want to include a clothesline or clotheshorse, an area for drying clothes.
A drip hand-washing station provides people a place to wash their hands. This element can be installed near a toilet facility for people to use after using the toilet.
After you consume water for basic needs, it is important to recycle the water.
Greywater is the effluent from a kitchen, shower or laundry area. The drain of a shower or a kitchen sink can be connected to a grey water system to recycle the water or filter it for use in the gardens. Blackwater is effluent water from flush toilets (more in sanitation). Here are a few ways you can recycle your greywater: Check out Creating a Greywater Oasis for more information.
First for the kitchen greywater, you can install a grease trap: A grease trap is an essential element for any kitchen. Here is a picture of a homemade grease trap using a 20L bucket drain system to filter out the grease.
From the grease trap, run the water into a 1m x 40cm concrete ring (in Thailand). Sediment in the water will stick to the rocks and slowly break down. Then you can direct the overflow water into a pond (more in aquaculture).