97.5 percent of water on earth is salt, and 2.5 percent is fresh water.  Of that fresh water, only 1 percent is readily available for human use.

Fresh mountain water, Kootenays, BC

Some water use and mis-use:
  • Globally, fresh water is used for: agriculture (70%), industry (19%) and domestic (11%) (AQUASTAT database , the FAO's global water information system)
  • With rising population, and increasing levels of industrialization in developing countries, there is increased demand for fresh water, and increased production of waste water from domestic and industrial use. (Florke et al, 2013)
  • Every day two million tonnes of industrial and agricultural waste are poured into the earth´s waters. (Corcoran et al., 2010
  • 90% of all wastewater in developing countries are discharged untreated directly into rivers, lakes or oceans (Katko and Hukka 2015)
  • 0.8 billion people do not have access to safe drinking water (Katko and Hukka 2015)
  • For basic needs, each person requires a minimum of 2,000 cubic meters of water per year. People who live in drylands, only have access to 1,300 cubic meters, and this will decrease due to population increases, land degradation and climate change. In some arid and semi-arid areas, lack of water is estimated to displace between 24 million and 700 million people by 2030. (UN Decade for Desertification, 2010-2020)

Lake Mugesera, Eastern Province, Rwanda, Where locals fill yellow jerry cans with water.

"....We're not separate from it (the earth's ecosystem). We don't live on Mars yet. We still live here. We still drink this water, we still need this water. The fish need it. The animals need it. The plants need it. Our kids need it.
-Chad Eneas, Traditional Knowledge Keeper of the Okanagan Nation, 1h34min of Occupied Cascadia

Ralph showing us a secret waterfall in the mountains, 2014

Water is an important sector to observe in your home and in your designs. What happens when it rains or snows? Do you have alternate sources of water besides municipal water, or a creek or a well? Do you have any areas where water sits? Do you have any roofs that have the potential to catch water that you are not using right now? What about catching water off the road? Does water currently pool in difficult areas? What is the water quality of each of your sources? What is the pattern of rainfall in your region? Does it come all at once? Is it spread out? How much? What is vulnerability of your water source? Is it a forested watershed? Are there any sources of development or industrial activity that could impact it?

Observing water during a particularly wet spring in Creston, 2013.  Notice
 the contour of the land, where the water sits, mulch, roofs that
are catching water, roofs that aren't, permeable and impermeable surfaces

The Siq, or entrance to Petra, Jordan, where ancient aquaducts
 were carved along the sandstone walls to deliver water into the
city that was estimated to have 30, 000 people. People who
live in arid areas, need to be very careful with water. There is
 an increasing trend towards desertification.
24% of land globally is degraded.
Rainfall in Costa Rica, image courtesy of Durga.  Notice how water
 moves through the landscape.  Tropical environments typically
 have one or two seasons of heavy rains per year.

We had a really low snowfall year and now we are having a really hot dry spring/summer. How can you mitigate climate extremes at your home and in your community?

Creek that runs through Lost Valley, near Eugene, Oregon.  This creek used
 to run year round and now it dries up in the summer due to
 logging in the surrounding mountains.

One permaculture principle is that: "Each function is supported by multiple elements." Redundancy protects when one or more elements fail. Multiple rain barrels, mulch, catchment in a pond, multiple water sources (creek, tanks, well), rain water capture in the soil, greywater systems, are all ways that water may be sourced, conserved or cycled into our living systems.

Greywater area for laundry water in Rwanda

Some tips for water:

  • start high on your landscape and catch water as high as you can so you can use gravity
  • allow overflow for each of your water catchment areas, and manage the overflow as a resource
  • The 3 S's:
  • SLOW 
    • by sinuous long winding paths, swales on contour, mulch, check dams. Water can't sink if it's going really fast.  Slowing also reduces erosion.
  • SPREAD, 
    • direct water to multiple rain barrels, ponds, trees so you don't get water all in one place
  • SINK
    • water sinks the best in healthy soils, a mulched basin, or in a garden.  Water only sinks in permeable surface areas, and if the soil is not already saturated by water.
  • Think of how resources are used in your system.  Does water:
    • increase with use
    • lost when not used
    • unaffected by use
    • lost by use
    • polluted or degraded with use
  • What types of water can be used for drinking and cooking versus watering the garden?  How can you create connections between water uses?

Overflow from water pump spilling into a pond that will be used
 to raise tilapia, Bwalira School, Western Kenya

Rain water catchment

You can catch rain water off the roof of your house, or off many impermeable surfaces.  The calculations are below, and often times you would add in a run-off coefficient for how much water actually flows off that surface.

Harvested water (gal) = catchment area (ft2) x rainfall depth (in) x 0.623 conversion factor

or for those of us in the metric system

Harvested water (L)= catchment area (m2) *rainfall depth (mm)

In Creston we get around 524.5mm of rainfall per year (20.7 in).  

For example, the roof of our house is approximately 83 m2, so we could capture:
83 m2 roof *524.5mm = 43, 5334 L per year. 

Large cistern to catch water from the roof above it.  The cistern is
located on the slope above the vegetable garden so
 it can be fed by gravity. Ginger Hill Farm, Big Island, HI

But most of the time you don't need to store all the water you catch on your roof.  Calculate the number of days that you have drought.  In Creston, this is usually from end of June to mid/late September.  This is around 3 months of drought in the worse case scenario. Then multiple by how much water you need.

An average garden needs 0.1 gallons per sq ft per day or 4.07 L per sq m per day.  If you are using the rain water in your house for showers, laundry, drinking, you will need more storage and more calculations.  Brad Landcaster has written a series of excellent books called  Rainwater Harvesting for Drylands, and it goes into great depth about water harvesting.  Anyone interested in harvesting rainwater should consult these books.  Here is the appendix from the first volume which lists a number of calculations that can be used for figuring out your rain water system.

If my garden was 80 sq m then I would need:

80 sq m *4.07L/sq m per day= 326L per day to generously water my garden

for 3 months this would be 326L per day *90 days = 29, 340 L of water

However, I probably don't need that much water if I am using mulch, drip irrigation, and have good organic matter in my soil.

Two weeks of water would fit nicely in a 5000L tank, which is about 2 m in diameter and 2 m tall.

5000L water tank to catch water off Buduma School roof, Western Kenya. Ditches
 are to direct overflow water to plantings. There are shade trees  around the school
to cool it.  The sheep are lawn mowers and provide manure, meat, more sheep
and some revenue for some of their products.

Tanks come in all different sizes and proportions.  You can make them yourself out of food grade 55 gallon drums, or buy them, or make a ferro-cement tank.  You can have ponds for water storage or underground cisterns.  They all have their advantages and disadvantages depending on your topography, the soil, the amount of rainfall, secondary sources of water, your skills, your needs, quality of the water, and budget.

Ferro-cement rain water tank, at Sat Yoga Institute in Costa Rica

Watch this great video with Rosemary Morrow about how she retrofitted her house in Australia with all kinds of brilliant ideas.  She goes into great depth of how she designed her water catchment systems with rain water tanks and ponds.

Measuring the Land

One of the easiest places to store, and purify water is in the soil. Creating catchment basins, swales or ponds on the landscape may involve a bit of surveying.  Know where you water flows to and from, and then creating a swale (a mounded ditch on contour) will go a long way to slowing, spreading and sinking water in the landscape.

To find the contour (or the place where all the points are level) there are many different techniques.  Here are just a few.

1. Surveying rod and surveying level
2. A-frame
3. Bunyip

All are pretty simple, choose the method that suits you the most.

Surveying with a sight- level, use a stick to keep your level stable and even

Your partner holds a surveying rod straight up and down at the start point
 where you want your swale to be positioned
You gaze through your level at the point on the surveying rod that matches
 your sight level.  You tell your partner to move her fingers up or down
 to the point where they match.  The reading on the surveying rod will indicate
the spot you need to match at the next point on the landscape where it will
be level.
An A-frame can be made out of anything in the shape of an A.
 You have some kind of weight in the middle, a rock, a water bottle or other weight.
Calibrate the A-frame so you know where the two feet are on the same level
 by placing the legs and marking where the plumb line falls. Then switch the
 legs so that the legs of the frame are in exactly the opposite location.
Mark the position where the string falls. In-between the two marks make
 a distinct and solid mark, this mark is your level mark.

 To find the contour flip flop the A-frame across the landscape, each time
 finding the place where the string lines up with your level mark.
 Put stakes along the line to mark the contour.

A bunyip level is essential a clear plastic tube attached to two measuring sticks, with water in the tube.  The water will level out at the same point when the sticks are on the same level ground.  Brad Lancaster explains in detail the bunyip and the A-frame in this Appendix to Rain Water Harvesting for Drylands and Beyond, Volume 2.

Making a swale

A swale can be different depths and widths depending on how much rain you get per rainfall event, your slope and your soils.  The more rainfall, the steeper the slopes and more compacted the soils,  the closer the swales should be placed  along the slope and the deeper and wider the depressions. Digging a swale on contour means that water can infiltrate evenly.  Sometimes people will dig a swale slightly off contour if they want to direct water to a certain area like a pond or a garden.

Once you have marked your contour using your surveying tools of choice, you can start digging.  The uphill portion of the swale can be angled 45 degrees into the depression, or can be straight up and down.  I have seen both work well.  Again, it depends on your slope, soil, rainfall.

Swale in the food forest, Creston, BC

In my region, I generally dig a trench 30 cm (1ft) deep by 45cm (1.5ft) wide. Or for a more gentle swale, dig it 15cm (0.5 ft) deep and 60 to 90cm (2 to 3ft) wide. Mound the soil on the downhill side of the trench. You can fill the depression partially with mulch to help hold water and make it less noticeable or keep it open. Planting the berm will stabilize it and allow those plants to access the water. The shade from the plants will also slow evaporation. In tropical areas I would leave the depression free of mulch because of the quantity of rainfall they get. Remember to leave an area for overflow that can either be directed to another swale or element that may need water.

This is a nice article on making garden beds on contour.

Sheet mulching the swale and surrounding area, adding mulch
Swale in the food forest above the quince tree and below the bench, planted with new asparagus crows

Asparagus growing on the berm of the swale above the quince tree,
 and below the tree

Swale to catch roof water from our house, ASYV, Rwanda

When despair for the world grows in me
and I wake in the night at the least sound
in fear of what my life and my children's lives may be,
I go and lie down where the wood drake
rests in his beauty on the water, and the great heron feeds.
I come into the peace of wild things
who do not tax their lives with forethought
of grief. I come into the presence of still water.
And I feel above me the day-blind stars
waiting with their light. For a time
I rest in the grace of the world, and am free.
— Wendell Berry


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