Sand dams store water and save thousands of lives

Tamy piaskowe

Worldwide, 74 percent of the The poor population lives in dry, mostly rural areas. In a climate where there are two seasons – dry and rainy – they have free access to water only during one of them. The beds of seasonal rivers then fill with a strong flow, carrying with them the valuable soil directly into the ocean. In times of drought, women and children march for days to distant water intakes to bring water home in heavy vessels. Fortunately, there is an ancient way for them to secure access to clean water all year round. These are traditional sand dams.

What are sand dams?

Sand dams are concrete dams built across the bed of a seasonal river. When the rainy season comes, water fills the trough, but does not flow quickly into the sea. It remains together with the sand in the channel above the dam, forming a body of water. However, it is not a total blockage of the river, because the excess water, with a slight silt, overflows above the dam. As much as 97 to 99 percent. The water continues to flow to the estuary. Sometimes after just one or at most four rainy seasons, a reservoir is created to store sand and up to 40 million liters of water, available later in the dry season. This amount is enough to meet the year-round needs of more than 1,000. individuals.

The fact that water accumulates in the sand is very beneficial, as it is a natural filter that traps impurities. It also protects it from animals and insects that can transmit malaria, reduces evaporation and allows for long-term storage. But how do you get water out of a sand dam? A pipeline built into the dam is used for this purpose. The solar-powered system pumps water to a nearby tap or sealed shallow well with a hand pump. This is the cheapest and most effective method of rainwater harvesting in dry areas. It was established as early as ancient Rome, in 400. B.C., and continues to perform admirably.

How are sand dams formed?

Dryland residents build sand dams with the hard work of their hands, only to become owners later. The project is managed by representatives of the foundations, which help to finance and smoothly carry out the entire process. These include. Polish Humanitarian Action (PAH), Unicef, Sand Dams Worldwide or the local Africa Sand Dam Foundation (ASDF). PAH with ASDF has supported the construction of 26 sand dams in Kenya, and Sand Dams Worldwide since 2002. has built 1,308 dams in ten countries, giving more than 1 million people access to clean water.

For a dam to be built, three technical site conditions must be met: the presence of a seasonal river (flowing for a few weeks a year at most), sandy river sediment, and bedrock in which to dig. Sand Dams Worldwide has established additional rules for designing sand dams. First, the dams must be built on bedrock (or, in exceptional cases, on impermeable, compacted ground), and second, the dam must allow the river to flow as it did before.

Building a sand dam costs an average of 110,000. PLN, and the time depends on local conditions, weather and the size of the investment. In most cases, a month or two is enough. It can be significantly shortened by the help of volunteers. Working together, they can build a dam in as many as four days. They talk about their impressions in a video posted on the YouTube channel of the Sand Dams Worldwide foundation.

How do sand dams save lives?

In areas where sand dams have not yet been built, water has to be carried from very far away during the drought. Usually women and children are sent to fetch the heavy canisters home. It is drawn from, among others. From shallow wells dug in the beds of seasonal rivers. However, it is quite dangerous. The wells are open, so the water may be contaminated, and deep holes in the ground threaten to collapse.

Sand dams allow you to create shots close to the village. The water is piped from the riverbed to the taps, known as the “water taps. water kiosks. Its download is safe, convenient and takes little time. The mechanism is powered by solar energy, and installations can be brought even to villages miles away from the dam. On top of that, the water filtered through the sand is clean and will not become a cause of disease.

How does the dam affect the environment and the community?

Sand dams make the local ecosystem flourish. The resource behind the sand dam raises the groundwater level in the area. This improves soil quality and creates better conditions for crops and grazing. The water stored in the sand is also available to plants and animals – the trees are green even in the dry season. More of them can be planted, which increases the amount of water infiltrating the ground and reduces soil leaching. This creates a virtuous cycle of soil and water conservation. It is again possible to cultivate land that was previously dry and barren. Access to water also allows the raising of livestock.

A supply of water can be brought home in 30-90 minutes, as the water intake is close by. This allows children to spend their time at school and women to grow fruits and vegetables. This allows you to diversify your diet and provide better nutrition for entire families. Proceeds from the sale of crops help, among other things. pay tuition. This changes the lives of the entire community for the better and gives hope for the future.

Resilience to climate change

Global warming is bringing climate change to every corner of the Earth. The rainy and dry seasons are evolving in East Africa, including Kenya. There are intense and short rainfalls, with increasingly long periods of drought in between, with high temperatures that are dangerous to people and nature.

Building sand dams in such areas helps local communities cope with climate change. The dams and associated infrastructure are a long-term solution that serves for many years. It allows drawing water in a way that is safe for people and does not burden the environment. Their mechanism of operation is simple, so they require almost no maintenance. They can quietly operate for up to 60 years, and the oldest of them is already more than 100 years old. All indications are that they will function reliably despite the changes taking place.

Education of the local community

Foundations that build sand dams in Africa also conduct educational activities among locals. Its goal is to impart knowledge on how to take care of the dam and conserve water. But not only that. For example, PAH, working in Kenya’s Makueni County, is helping to establish hydroponic crops that enable more efficient and organic food production. It was planned to establish such installations in two schools and two cooperatives. They will also receive greenhouses with troughs for tomatoes and staggered box systems for vegetables.

In addition, Polish Humanitarian Action is organizing training in Makueni on food processing, compost production, crop management, business and marketing. This aid covers a total of more than 558 students and teachers, as well as 365 members of agricultural cooperatives. It will provide them with food security, regardless of the season.


Photo source: PAH

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