WATER TECHNOLOGY FOR THE MOBILIZER
Getting Water to the People
By Phil Bartle, PhD
Dedicated to Andrew Livingstone
Managing its water supply, a community is encouraged to have a mix of technologies
Moving the Water:
Whatever the source of water, it has to be moved or transported to where it can be consumed. Whether it is carried, pumped or piped, that means technology is used. Some water needs to be processed to make it drinkable; more technology. Recall the paper on what is community and how it works: technology is a cultural dimension, transmitted and developed by symbols rather than genes. How people transfer drinking water from its source to where it can be used, is very much a matter of traditions, concepts, values, customs and other human constructs.
To move a community towards thinking of the management of water in a rational, cost/benefit, analytical way, therefore, is, like all mobilization, the stimulation and guidance of social change. To believe that technology itself is cold, rational, and independent of culture (as many engineers do), is to not understand the nature of technology as cultural, and may result in failure in sustaining a water supply.
In the process of mobilizing the community, if it has selected a water supply as its highest priority, you need to help community members to develop a way of thinking about water supply. Common assumptions include that there is only one right way to provide water, and that mechanized is always better than manual labour. Attitudes are important, too. Community members, perhaps motivated by pride or a desire to appear modern, often wish for a sophisticated and expensive machine, when their available resources for operation and maintenance dictate that a manual system may be more appropriate.
Community members need to develop a perspective that sees various alternatives for water sources and technologies for bringing the water.
It is important that this perspective is not dictated to them from outside the community. You, as a mobilizer must draw these points out of the community members, through their executive, as part of the planning process for a community project.
A Range of Technological Sophistication:
Perhaps the simplest water technology consists of dipping a container into some surface water and carrying the container to the mouth. Among the most complicated, expensive and sophisticated are the piped water systems of large cities like New York. There are many degrees of complication in between.
Community members must realize that they have a range of water technologies open to them. They need to look at their resources, and themselves calculate their options. This should be done in tandem with their assessment of various water sources open to them, as described in the companion document, Water Sources.
There is a prevailing attitude which you, the mobilizer, may find. It is sometimes identified as pride, and it is related to the desire to have more sophisticated technology. It is sometimes identified as pride, and it is related to the desire to have more sophisticated technology. It is not related to the appropriateness of the technology, neither its physics and engineering nor its cost in relation to resources the community can acquire.
You do not break down this attitude by preaching or lecturing against it. You let it wither away by challenging the community members to justify their choices, and analyse the relationships between costs, benefits, and available resources.
Let us review several types of water technology, with an emphasis on low income communities located in poor countries. These include:
You as a mobilizer should review all these with community members, listing them on the board, and naming the benefits and drawbacks of each, along with estimates of costs of both constructing and maintaining. Demonstrate that there are variations within each of the categories. Communities should be encouraged to obtain a mix of different technologies.
This list may appear too obvious to some, too simplistic for others. It is to be used as a management tool, an open ended check list, to aid you in guiding community members through making an inventory of available technological possibilities, the benefits and restraints of each, in order to make informed management decisions.
Nearby Puddles and Streams:
Scooping up water from nearby puddles and streams is probably the simplest water technology. It is among the most dangerous, nevertheless, with a high risk of providing water contaminated by micro-organisms that produce disease. It is very common, and practised where there is no other water technology available, or where clean water is too distant or too costly.
In some areas, people will pay for clean groundwater during the dry season, but gather contaminated surface water during the rainy season because the clean ground water is sold and household finance is limited. This is a case where people are choosing clean water not for its health benefits, but because of its availability.
As noted elsewhere (See: Water and PHC), clean water by itself will not reduce disease and poverty, it must be accompanied by an understanding of how it reduces disease and behaviour that separates faecal borne disease from drinking water.
Digging a shallow well is a very common technology for obtaining drinking water. It is usually at least a few metres deep, so the groundwater in it is likely to be uncontaminated.
Earth is a good filter. There are exceptions, however, according to how nearby some sources of contamination may be. The water in it can be easily contaminated if the well is uncovered. Waste, small animals, insects and the faeces of passing birds may easily get into the well. Trapped animals may die in the well.
Shallow wells vary by how the water is drawn out of them. A bucket sent down by rope can scoop the water, and that rope may be pulled up directly by hand, or may be on a pulley that is cranked. The latter is more costly than the former. The well can be covered for most of the time, and opened only when a rope is sent down to collect water. This will assist in keeping out contaminants. A pipe might be run down to the water, and it could be powered by a hand or mechanized pump. The former is less costly that the latter. An important benefit of using a pipe is that the well can be permanently covered, greatly reducing contamination.
While both are costly to install, a hand pump is cheaper but less convenient to operate than a motorized pump. A mechanized pump requires fuel and more lubricants which have to be purchased. Operating costs are higher.
Many elders would prefer to use human labour which requires less money to be spent. They overlook the important economic fact that the women and girls who provide the human labour are expending energy and time (ie wealth) that could be used for other productive activities.
Surprisingly, many shallow aquifers might run underground well into the area under an ocean. This produces the interesting situation where, at low tide, one can dig in the sand below what would be salt water during the high tide, and find sweet drinkable water.
As they sit, technically there is little difference between a shallow borehole and a shallow well. A borehole is usually drilled, not dug. The hand dug well usually has a wider diameter. The machine dug borehole usually has a narrow (eg 40 cm) diameter. The big difference is in cost of construction. A truck with a mechanized borehole drill on it can cost upward of a million dollars or more, and hiring or renting it to drill a hole is therefore expensive.
Water is usually drawn from a shallow borehole by hand pump, although it is also possible to put a mechanized pump onto it. It is usually covered, which contributes to it more likely producing uncontaminated water.
A deep borehole may be necessary when there are no aquifer sources near to the surface.
As mentioned in the Sources document, a deep aquifer is less likely to be sweet (nice tasting, without salts and minerals) than a shallow aquifer. It is also more costly to construct than a shallow well, requiring more drilling time. It is also more likely to require a mechanized pump if a hand pump can not efficiently draw water from a low water table.
The main advantage is the high likelihood that its water will not be contaminated by micro-organisms, so long as the well remains covered, and people are not frequently looking into the well. Unfortunately, it does not taste so pleasant.
Where there is no groundwater, and where there are no nearby rivers and lakes, the only remaining source of water might be the rain.
A common way to harvest the rain is to build eaves troughs along the bottom edges of roof eaves, and run those troughs to storage containers. Rain is caught by the roof and channelled down into the troughs.
More elaborate rain harvesting systems include large underground cement tanks (cisterns), and pumps to bring the water up to overhead tanks, where a pipe can allow gravity flow of water when it is needed. Simpler and cheaper technology includes just having a barrel or two to take the water directly from the eaves, from which people scoop up water as needed. The advantage of the first is that it is easier to keep the water clean and uncontaminated, but it is more expensive to construct than just finding a few barrels. Using barrels are practicable where it rains every week throughout the year, so that the barrels small storage space does not mean them becoming dry.
Where there are distinct rainy and dry seasons, and longer storage is needed, the underground cisterns are more practicable than barrels above ground.
This is closely related to rainwater harvesting, and is invoked where rains occur only a few days every year.
Often, where there are broad flat plains, and where the rains come with vigour and quantity, but only during a few days or weeks in a year, the solution is to dig catchments. A good knowledge of where flood waters flow is needed.
A horseshoe shaped hollow is dug, often with a bulldozer, and a wall (dam) around three sides (the three sides from where the water does not flow) to catch flowing flood waters.
There are many disadvantages to this technology. Sometimes the little human-made lake will not last through the dry season until the following year's rains. If it does, the water becomes very muddy, and contaminated with many micro-organisms. This is made even more problematic by a custom of herding cows right into the little lake.
Where there are no feasible alternatives, however, it is the best available choice.
As mentioned in the sources document, sometimes an aquifer will break through the surface, and water will miraculously appear from the ground. Where water appears like that, it is called a spring. A spring is a magical-seeming condition of nature; it is a marvellous place to meditate, or to just stare into the emerging water.
To use this as a source of clean drinking water, the essential technology is something that will protect the spring. It can become contaminated with micro organisms when humans and animals come too close to it in their search for water. The spring itself may be easily destroyed when semi-informed individuals try to widen the opening, clean the plants from around it, or otherwise modify its architecture.
The best protection is a strong cement wall around the spring, which is then covered over with a reinforced cement ceiling, so no person or animal has access to the area around the spring. The cement wall can be fitted with short pipes or holes to allow the water to flow out.
The essence of protection is to prevent anybody or anything from disturbing the water or the immediate land around the spring. The interesting and challenging aspect is that every spring is unique, and many offer challenges in how and where to construct their protection.
After protection, many springs can be fitted with tanks for water storage, troughs for scooping out water, covered storage cisterns, and/or pipes for gravity flow transport.
Piped Water Extension:
Some communities are blessed with nearby water supply systems, and all they need to do is to construct a pipe system for gravity flow, and perhaps a pump to raise the water to a high tank from which water can flow by gravity. One example is a rural community nearby to a city or town with a developed water supply. Another is a slum or disorganized neighbourhood within the town or city limits that so far does not have a water supply.
The community (not you) must obtain permission and rights to use the water, then construct a pump to put the water high enough for gravity flow (if needed), then install pipes top carry the water to the community.
Another example is where a lake or river is in nearby mountains, which can be tapped in order to pipe the water to the community. Sometimes this will require installing a dam in the river, and/or a pump to lift the water out of the lake or river, then directing that water through pipes to the community.
Similarly, water may be available where a spring has been protected. It may need a pump. It may depend upon gravity for transport. It will require pipes.
Making Salt Water Drinkable:
Where water is taken from the ocean, or from wells that are very deep, the water is too salty. It contains too many slats and minerals to be potable (drinkable) although it can be good for washing and some cooking.
Removing the salts from the water is more simple than many people imagine. Boiling and condensing, whicih is called distillation, is not practical, mainly because of the cost of fuel to do so. But the sun can provide the fuel.
What you need is a large pan in which you put the salty water. It can be about the size of the floor of a room in a house. Over this pan of salty water, you stretch some clear plastic, allowing it to sag in the center. The sun will evaporate the water in the pan, and it will condense on the sheet of clear plastic above the pan. Where the clear plastic sheet sags in the centre, you attach a small catchment bowl a few centimetres below the plastic. Then you run a pipe from that catchment bowl out to the edge of the plastic, for the unsalted water to flow, where you again catch it in a container. You need to refill the large pan of salty water, and you might do this with a pump from the salty groundwater or the ocean.
Making Water Clean:
Where water has been contaminated, or potentially contaminated with disease micro-organisms, it will require a purification system perhaps relying on chemicals or sand filtering, before it can be considered potable (drinkable). Where water is full of many salts and minerals, as mentioned above, it will need desalination (removing the salts) to make it potable. This may involve evaporation and re condensing.
Processing of water to make it drinkable costs money and/or other resources. Before a community can embark on such an activity it must review its available resources to see if it is feasible.
Conclusion; Community Management of Water:
Your job, as a community mobilizer, is to guide a community in managing its water supply. This is best done in meetings where the sources are reviewed as part of a participatory appraisal, then the possible technologies and their costs, and then a review of available resources for constructing and maintaining each possible system.
In doing this you must remember that this process is part of breaking down attitudes. These include attitudes that favour inappropriate technologies based upon pride rather than feasibility. They may be based upon unthinking or unexamined practices, "just because that is how it always has been done." They may include inappropriate technologies based upon unfair assignment (eg to women) of carrying water, too much time and energy being allocated to carrying water. They can include those which will promote disease instead of health.
Break them down not by preaching, but by promoting a management approach to water.
A Trench for a Water Pipe:
© Copyright 1967, 1987, 2007 Phil Bartle