Ancient Water Harvesting Solutions

Introduction

Our ancestors understood that water was the difference between life and death. Those who lived in hotter, drier, harsher, or less predictable climates developed a variety of ways to save and provide water for entire communities. 

Some of these are in terrible disrepair after hundreds or thousands of years of neglect, but the fact that their remnants can still be found, and some are still functional is a testament to their efficacy.

According to a South African case study, "Small, local solutions can crack water crises"

The following sections explore a variety of ways, both ancient and new which have are helping people collect water even as our water cycle becomes increasingly disrupted.

Before you get started on any project, always be careful to check your local legal codes and policies. Some types of water harvesting are forbidden in certain places for a variety of reasons. 

North America


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Learn about which activities use the most water, to develope a plan on curring your own water footprint. In many cases consuming less will have a greater impact than harvesting water, though water collection may be your first step in your water conservation journey.

Ancient Water Harvesting Methods

Higher Altitude Harvesting 

"A dew pond is an artificial pond usually sited on the top of a hill, intended for watering livestock. Dew ponds are used in areas where a natural supply of surface water may not be readily available. The name dew pond (sometimes cloud pond or mist pond) is first found in the Journal of the Royal Agricultural Society in 1865. Despite the name, their primary source of water is believed to be rainfall rather than dew or mist."

"They are usually shallow, saucer-shaped and lined with puddled clay, chalk or marl on an insulating straw layer over a bottom layer of chalk or lime. To deter earthworms from their natural tendency of burrowing upwards, which in a short while would make the clay lining porous, a layer of soot would be incorporated or lime mixed with the clay. The clay is usually covered with straw to prevent cracking by the sun and a final layer of chalk rubble or broken stone to protect the lining from the hoofs of sheep or cattle. To retain more of the rainfall, the clay layer could be extended across the catchment area of the pond. If the pond's temperature is kept low, evaporation (a major water loss) may be significantly reduced, thus maintaining the collected rainwater. According to researcher Edward Martin, this may be attained by building the pond in a hollow, where cool air is likely to gather, or by keeping the surrounding grass long to enhance heat radiation. As the water level in the basin falls, a well of cool, moist air tends to form over the surface, restricting evaporation." - Wikiwand: Dew Pond 

Ice Stupas

Traditional Stone Stupas were built from stone sometimes with a metal piece on top. You can still find examples of high-altitude stupas encrusted with ice, however the modern versions are lighter, easier to build, and seem to be more effective than their predecessors.

Recently a new version was developed: "The ice stupa is created using no power or pumps, only physics: "the ingredients are a downstream, an upstream and a gradient," says Wangchuk.

The freezing air temperature does the rest, immediately crystallizing the water droplets into ice that falls right below, forming a cone.

Puquios

Nasca Puquios and Aqueducts (PDF) 

These puzzling holes in the arid valleys of southern Peru tell us there was once a flourishing, sophisticated society here. 

Rock Catchments

"In Marsabit County, Northern Kenya, Caritas Switzerland has, together with communities, constructed three rock catchment systems. In this region, there are no permanent rivers and the dry seasons can get severe. Moreover, not all groundwater sources are suitable for human consumption and people often rely on scarce and mostly unprotected water sources. Only about 35% of the population have access to safe water."

"The rock catchments collect rainwater from large bare rock surfaces before it gets channeled to storage tanks. The three systems serve 3,500 people and can store a total of 2.34 million litres of water per rainy season. This covers for approximately three months of human water consumption."

Life Expectancy: unknown

Pro: Uses natural processes to capture rain water, and store it in large cisterns for future use. Owner ship is given to a trained individual who accepts payment from community members that go towards maintenance and repairs of the system.

Con: Requires rain to recharge. Payment system may exclude people who need water most.

Solution: 

Fuel Types: Water Cycle + Gravity

Harvesting on Slopes

The following focus more on systems to boost soil permeability, rather than harvesting drinking or irrigation water. By sequestering water within the soil, we can (to an extent) remove the need for irrigation.

Systems such as swales double as a measure to sequester water in the soil, and when full enough, they can help transport excess water to a secondary location such as body of water, a rain garden, or regular flowerbeds.

Plants to Increase Permeability

Native Grasses

Every species is different, but those which evolved to live in hot, dry countries have developed very deep root systems. By planting in swale-like patterns landscapers can help create a non-intrusive, water catchment system which will improve water infiltration into the soil. 

This system is ideal for creating a tree nursery, where tree-planting projects may easily fail due to harsh weather and/or lack of easily-transportable water.

How to Reforest a Steep Slope Without Swales or Irrigation

12:35 minute video shows how native grasses can be planted in lines or curves to help slow down water enough to help it penetrate a hillside slope without disrupting the soil integrity.

The lady explains her choices of native tree species interplanted within the native grass, how the evergreens provide shade and protection to the rainforest species. She explains how the grasses help protect her saplings from freezing and baking hot weather. However she comes along periodically to weed away vines and grasses to prevent them from strangling the saplings, then uses the weeded materials as free mulch to further lock in moisture.

This example is in Australia so she also explains how the different species will support local natives including koalas.

Earthworks

Key Lines

Swales

Trees

Tree cover of around 30% was found to provide 

Rooftop Harvesting 

"Civilisations in the Indus Valley were far more advanced than we may think nowadays. In many of the ancient cities that still remain, we can still find huge vats that were cut into the rock to collect water when there was torrential rainfall. These were used to keep the population and local vegetation going in hotter, dryer times and were fed by numerous stone gullies that weaved their way through the city. Some of these rock vats are still used today in parts of India. Another technique that has been used for hundreds of years in India is to build water harvesting systems on top of the roofs of houses. It’s a simple technology that has spread across the world, particularly to countries such as Brazil and China." - History of Rainwater Harvesting 

Modern rooftop harvesting options are much more diverse now including passive and powered systems, green vs non-green solutions, with sealants to help convert existing roofs into green roofs, while still preventing water damage.

How safe is roof-water to drink?

Green Roofs 

Historically, sod roofs were lines with birch bark for it's water repellent properties, before sod was applied on top to provide insulation. Green roofs use plants to absorb rain, instead of adding to run off. The plants absorb carbon, provide additional insulation for us, but also provide habitat and food for wildlife.

Community Accessible & Ground Level

Air Well (Condensers)

Khadin 

These have been used for over 5,000 years, and some ancient remnants of them still visible in places like Peru and India.

Life Expectancy: centuries with little maintenance

Pro: Uses natural such as rocks and dirt, rainfall, and gravity. This makes them cheap and easy to construct

Con: A lot of water can be lost to evaporation.

Solution: Modern versions of condensers work much better, using active components like fans to boost efficiency.

Fuel Types: Water cycle + gravity

Stepwells/Bawaries/Baolis

India's ancient stepwells (which go by many regional names) have been a vital source of water, as well as a gathering point for communities to wash, relax, communicate, and participate in religious rituals. They fell out of use after British colonization. As plumbing became more available, these amazing stepwells were increasingly considered "unsanitary" which increased their loss of popularity, and eventually led to their decline as people forgot about their value, and started to use them as landfills. 

As droughts and water shortages become increasingly dire, some communities are rediscovering their ancestors solution to survival, and are taking it upon themselves to revitalize these ingenious water management systems. During the monsoon season, rain water fills these massive reservoirs, and for the rest of the year, clean drinking water stays in the community the stepwell serves.

SUDS 

SUDs are systems that help guide water once it has made contact with the ground, including swales, water gardens, road-side drainage, dams, reservoirs, etc. There will be another post on this massive topic later, but until then, the following talks about simple, practical ways to get started on the topic. 

Peru’s ancient water systems can help protect communities from shortages caused by climate change.

Life Expectancy:  35-1,000s of years with proper maintenance.

Pro: Safely diverts fallen precipitation and flood water to less problematic locations, allowing water to be harvested or diverted to wetlands.

Con: Can cause serious flooding problems if not maintained, and blockages form. This is most likely if debris from a previous storm was not cleared out before the next (sometimes lesser) rain/flood event.

Solution: Ensure proper maintenance including de-clogging, dredging, trash removal, and invasive plant removal.

Fuel Types: Water Cycle + Gravity.

Practical Information & Guides  

We have a huge file of notes on landscaping practices to help slow and sequester rainwater. Please check back here in the future, as we are planning to include a link to that information here, once it is available!

Complimentary Options

Rain Barrels/Butts & Cisterns 

Today we can still find examples of ancient cisterns, but today's models often contain synthetic parts including washers which help prevent leaks, but mush be replaced over time. Modern alternatives include metal, plastic, and other materials which are more portable than ancient versions.

Life Expectancy: 20 years.

Pro: Safely stores rain or grey water for later use.

Con: An turn into a breeding ground for mosquitoes, or be contaminated with dead animals that can fall/get trapped inside. I've found dead frogs who might have hatched but not been able to get out. Dead leaves can build up, leaching tannins into the water.

Solution: Install fixtures that will help keep wildlife and leaves out of the system. Make sure to clean these to prevent plugging and backups. Empty and clean out the container periodically.

Fuel Types: Water Cycle + Gravity

Water Recycling 

Toilet to Tap Water Recycling

Many of us are unaware if our communities already use this system, but as water shortages increase, ground water disappears, and rivers dry up, more are turning to water recycling to ensure citizens have enough for daily activities.

Some of the resources below specifically focus on creating potable water, while others simply focus on reducing pollutants before releasing waste water back into waterways, where down-stream neighbors may use it for drinking, bathing, and irrigation. 

These systems often use reservoirs and grate systems to settle and remove solids. 

The more expensive systems use technology, chemicals, and specialize filtration systems. The cheaper type can involve nothing more than a channel and some wetland plants, though dividers with removable grates can help increase their effectiveness, allow for safer/easier maintenance (such as clearing out rubbish or branches that might be causing backups). 

The second type can be build by anyone including farmers wanting to prevent livestock waste from becoming dangerous run off, or a small family ensuring waste from a latrine or septic system has extra time to break down before potentially seeping into ground water. Here is a PDF presentation: "Phytorid Technology and Implemented Projects Across India" which shows the benefits for water quality, as well as the simplicity which could make such systems a practical solution for communities around the world.

Life Expectancy:  ___________

Pro: Reduces overall water use by recycling used water.

Con: Often requires electricity, filters, and chemicals to process waste into safe drinking water. There is an "ick factor" which can make people hesitant about this option.

Solution: Wetland plants can be used to naturally reduce nitrites and other problematic chemicals. Passive system design can help remove sediments with gravity instead of electricity, meaning that the system will be able to work even in the event of grid failure or for places that don't have grid access.

Fuel Types: Fossil fuels, renewables, and/or gravity.

Nallah Biological Solutions

Nallah | Sewage treatment plant | Constructed Wetland | STP | Green STP | Natural Treatment System 4:24 minute video shows the design and plants used to naturally clean water before it is released back into waterways.

This 3:01 minute video is in English and Hindi, demonstrating how a plant-powered sewage treatment plant can successfully clean sewage without electricity.

Non-Recommended Methods

These methods should generally be avoided or (at the very least) used with caution.

Wells

How Wells & Aquafers Actually Work

14:12 minute video shows how both water and pollution can move through soil, gravel, sand, and rocks. Other dangers like erosion, land subsidence, and injection wells (putting water back into the ground) are also covered.

Life Expectancy:  20-30 years depending on maintenance vs sediment buildup. There are some wells that are over 100 years old, but these are generally indoor wells, or wells that started outside and later had a building built around it.

Pro: Can take advantage of clean water readily available below ground.

Con: Ground water is increasingly contaminated by livestock waste, PFAS, fossil fuels, landfill seepage, mining and fracking waste. When many people use wells in an area, the ground level begins to sink and the entire aquifer can run out of water, leaving everyone without a personal or backup supply.

Solution: If you use or rely on ground water, you should absolutely incorporate water harvesting methods to help recharge the well. We'll have more about this on our Ground Recharge page, when it is finished.

Fuel Types: Water cycle + gravity.

Quanat 

"In the Maghreb, qanats are called foggara; Moroccons call them khettara; the people of the Persian Gulf call them falaj; a Persian synonym is karez."  - https://www.livius.org/articles/misc/qanat/

Quanats have been built since at least the Iron and Bronze Ages, but are suspected to be even older. They are essentially horizontal wells, with a line of shafts dug down allowing air flow, sand and dirt removal, and to prevent the bottom/horizontal tunnel from becoming dangerously long. The tunnel starts where the ground it damp or another known source of water such as a lake in a cave exists. The other end generally becomes a shallow ditch as it approaches it's destination. They need to be serviced every spring to remove debris. A dangerous job that was traditional done by young boys with their fathers nearby to rescue them if there was a collapse.

"Being about 1½ meter high and ¾ meter wide, qanats are rather narrow, but they can reach depths of 30 meters (the record seems to be 60) and can cover distances of many kilometers (the longest Iranian qanat is said to be 70 kilometers long.) The trick is to make the angle of the qanat not too steep, because in that case, the water will grind itself down into the bottom and create pools that will make the qanat collapse; on the other hand, if the angle is not steep enough, the water will be tainted. Everything depends, therefore, on the correct angle. The diggers or muqannis were brilliant surveyors. " - https://www.livius.org/articles/misc/qanat/

These can have a very long lifespan if properly built and maintained, but has been placed in the Not Recommended section because of the reliance on groundwater which is currently under threat from over-extraction and pollution from agriculture, factories, etc.

Pro: No pumps or energy needed to move water.

Con: Animals and people can fall into the holes, debris and dead animals can contaminate water, plus ground water issues may make this a potentially problematic option. Angle of slope is vital to attain a safe rate of water flow, and to control erosion.

Solution: Concrete quanats might reduce erosion and maintenance costs. Robotic cleaners might provide people with jobs minus the danger of fatal structure collapse.

Resources: Natural rock channel or concrete. Gravity, natural air flow, and ground water.

Tools & Resources

Landscaping Know-How

Organizations

International

Africa

Asia

India

Europe

UK

North America

Mexico

USA

Oceana

South America

Maps

North America

USA

Grants & Funding

Oceana

Australia

Western Australia

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