Around 40% of the rural Mae Hong Son province are without a supply of clean drinking water. Villagers have to collect water from the polluted rivers and boil it.

The Trust works with the Karen people to install and maintain clean water systems for the villages. We employ locally-based staff who, together with the villagers, install an average of 10 systems a year. The outcome of the Trust's potable water projects has been a dramatic improvement in health.

KHT has worked closely with Nick Spencer, WF Southall, TOIC, BCTFN and Mishcon De Reya in bringing about the necessary funding for these essential projects and would like to thank all of them for their significant contributions.

Salahae, our Karen manager, has designed an effective gravity fed system that is easy to use and maintain. Tests at Chiang Mai University demonstrate that water from one of our systems is ten times cleaner than water from other sources. To install a clean water system for 250 villagers will cost £6,000. One tap will serve 3 houses. 4 latrines will also be installed.

Installing a water System

1. Evaluating the site:

Suggested sites for water projects are surveyed by our Karen manager, who assesses where there is most urgent need for installation of potable water systems. Consideration must be given to the current water situation, local health, population, and the willingness of the villagers to participate and maintain the system once installed. Accessibility has to be taken into account during the rainy season, as many of these villages are some distance from a hard road. The timing of the projects is also important: rice harvests play an important part in determining whether or not the villagers can help. Once this information has been gathered, a report is sent to the UK Trustees, who decide whether to go ahead with the proposed project. A natural source has to be found above the levels of pollution. The villagers are usually aware of a clean water source, often several kilometres away, which has been running for many years.

2. Preparing the source:

Once identified, part of the natural spring must be dammed in order to channel the water down to the village. Care is taken to leave a flow of water so the source can continue along its natural path. Villagers collect sand and gravel from the river bed below, and carry boulders and rocks up the mountain to dam the source. Concrete, cement and pipes are also carried by hand from the village. The source is dammed by surrounding the water with boulders and holding them together with concrete and gravel. If there is not enough gravel then the boulders must be pounded down into small pieces.

3. Filtering the water:

Once dammed, the water is transported a few meters to a filter tank, where the water is purified. Gauze is used to stop debris entering the pipe system. The filter tank is made from concrete and covered in cement, measuring approximately 1m². The water passes through a simple yet effective filtration system of sand, gravel and charcoal, which are layered in the bottom of the tank. This improves the physical nature of the water, removing much of the silt and sediment.

4. Getting the water to the village:

The water is transported by plastic pipes from the filter tank to the village, which can be anything between 1-12 km in distance. The terrain is often very difficult as the pipes may need to be laid on the side of a steep mountain or across roads and rivers. Trenches have to be dug (about 50 cm deep) into which the pipes will normally be laid. They need to be covered over with top soil to protect them from the heat of the sun. This is essentially a gravity fed system, dependent on the right pressure to take the water over the distance, and this is dependent on the size of the pipes and the lie of the land.

5. Storing the water:

Once the pipes reach the village, large storage tanks are built. These can hold up to 20,000 litres of water. The water enters the tanks through the top and continually flows throughout the year. Each family will use around 500/600 litres per day for drinking, cooking and for hygiene. As this is a gravity fed system, the tanks have to be built at a strategic height above the village and on sufficiently firm ground to avoid subsidence. A large area is prepared with boulders and cement. Wires are put in place to support the height of the tank and strengthen the concrete. Concrete is poured into ring moulds which makes the cylindrical shape of the storage tanks. Once dry, the ring moulds are placed on top and another layer of concrete is filled in to give it extra height. A lid is made by folding the wires across and concreting over the top. The water enters the tank through a gauze lined hole which gives an extra form of filtration. This is covered with a small concrete lid to allow access for cleaning.

6. Turning on the taps:

Pipes take the water from the base of the tank into the village to standpipes, which are placed one to every three households. Taps can be turned on giving clean water to the village. Village records show that typhoid is reduced by 90% once there is access to clean potable water. There is also more time in the day to spend on other jobs and the general morale and confidence amongst the villagers improves.

Volunteers

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