Sand dams to fight against food insecurity in the South

To mitigate the impacts of climate change and water shortages in southern Madagascar, Action contre la Faim teams are building sand dams in the Anosy and Atsimo Andrefana regions, a sustainable solution to improve access to water in the area and support local agriculture.

Water crisis in the south of Madagascar

Madagascar’s deep south suffers from extreme climatic conditions, characterized by prolonged periods of drought, high temperatures and scarce rainfall. Soils are depleted and water resources are extremely limited, making farming and living conditions increasingly difficult.

Access to water for domestic consumption and agriculture is a major challenge in the region. Water management is therefore an imperative for improving the living conditions of local populations and fostering community resilience in the face of increasingly recurrent climatic hazards.

Ifotaka, a commune located on the banks of the Mandrare River and 45 km from the town of Amboasary Sud district, like many communities in the area, is suffering the full force of this water crisis, exacerbated by the impacts of climate change.

“Without clean water, people find it difficult to stay hydrated and maintain basic hygiene, leading to serious health risks and an increase in malnutrition, particularly among young children”, explains Tantely Andriamiantra RAMONJISON, Water, Hygiene and Sanitation Department Manager for Action contre la Faim in Madagascar.

“Even outside periods of extreme drought, access to drinking water is often inadequate. As a result, most people are forced to rely on water sources such as roadside puddles, unprotected wells, rivers and ponds, exposing them to water-borne diseases such as diarrhea and cholera“.

An innovative and ecological solution

To tackle this crisis in an innovative and sustainable way, Action contre la Faim teams have set up sand dams with the help of its partners and local communities. In concrete terms, a sand dam is a structure built across a seasonal riverbed in arid or semi-arid regions. The operating principle of the sand dam is based on the accumulation of sand transported by river floods upstream of the structure. Water is then stored in this sand, where it is naturally filtered by biological processes, making it drinkable, while reducing evaporation by up to 80%. The sand dam then becomes a large water reservoir, with 40% of the sand volume made up of water, which is made available to communities for drinking, cooking, farming and other uses, even during long periods of drought.

“These structures capture and store rainwater in dry areas. For example, a 30-metre-long sand dam can hold up to 18,000 cubic metres of water. As the water is stored in the sand, evaporation is considerably reduced, providing communities with a more reliable, long-term water supply,” explains Tantely.

These sand dams improve access to drinking water, while reducing the burden of water collection – particularly for women and children – and promoting irrigation for agriculture. They also empower women, who are often responsible for water resources, restore soil health, improve food security and help communities adapt to climate change by building resilience and improving rural livelihoods.

A positive social and environmental impact

In addition to significantly improving local communities’ access to water and thus their quality of life, sand dams have a direct impact on food security by enabling more efficient irrigation and increasing agricultural productivity.

Farmers can use the available water to irrigate their crops during the dry season, enabling them to diversify their crops and better withstand periods of drought. By increasing local agricultural production, communities become less dependent on costly food imports, which can improve their self-sufficiency and resilience.

Also, by allowing water to seep into the ground, these dams encourage vegetation and help maintain soil moisture, which is essential for the regeneration of farmland.

“Sand dams are really beneficial on all levels, especially in helping people adapt to climate change. By capturing rainwater and storing it in the soil, these dams enable communities to better manage prolonged periods of drought, as well as mitigating the risk of flooding by regulating the flow of water during heavy rains“, explains Tantely.

Community participation at the heart of the project

The construction and management of sand dams represent much more than a simple technical response to water-related challenges. They are part of a dynamic of sustainable local development, actively involving communities and promoting participatory management of natural resources.

Sand dams are generally designed and implemented with the direct involvement of local populations. This involvement not only strengthens the sense of belonging, but also stimulates solidarity between community members. By taking ownership of these projects, local people become actors in their own development.

The implementation of these infrastructures offers significant economic opportunities, particularly in rural areas. Temporary jobs are created, especially for young people and women, helping to improve local living conditions. The construction of sand dams in the south of the country has led to the recruitment of more than 470 people at community level.

Such is the case of Tananaze, 52, married with 14 children, who relies on agriculture to support his large family. “When ACF came to explain the sand dam project, I immediately saw that it was a real opportunity for us,” he recalls. As village chief, his involvement came naturally: coordinating the work, mobilizing the population and ensuring that the project ran smoothly. But he didn’t just supervise, he led by example. He hauled stones, dug trenches and mixed cement. “It was hard work, but I could already see the future it would bring us,” he says with a smile.

Thanks to this project, Tananaze earned around 54 USD, which enabled him to buy livestock (chickens, goats and sheep) and improve his family’s living conditions. “For the first time in a long time, my children have enough to eat and we feel safer,” he explains. The sand dam has also transformed his farming methods. “My fields are nearby. Now that there’s water, I can irrigate them even during the dry season. My harvests have improved and that changes everything,” he says proudly.

A response that comes up against funding problems

The decline in funding from international donors represents a major challenge for the humanitarian sector as a whole. In Madagascar, it primarily affects the most vulnerable populations, already weakened by poverty, climate and health crises. Essential services such as nutrition, health and access to water and sanitation (WASH) are being reduced or even halted, with direct consequences for the direct beneficiaries. These changes, often misunderstood by communities, lead to a loss of confidence in the organizations present on the ground. Civil society organizations, whether local or international, are then forced to review their priorities, reduce the size of their interventions or terminate certain projects. This affects the quality of services, links with communities and infrastructure management, and jeopardizes the know-how acquired over the years. Local organizations, which are close to the realities on the ground, are the hardest hit, as they are heavily dependent on external aid and face great uncertainty when planning for the future.

Since 2024, 3 sand dams have been built in Bekompitsy, Beza and Ianabinda. The construction of these infrastructures depends essentially on aid from international donors. “The sand dam at Ianabinda was affected by cyclones Jude and Honde at the beginning of the year, in particular the erosion of the river banks. Rehabilitations will be completed in August following delays related to the USAID funding crisis”, warns Tantely.