Micro-Dams: Addressing Water Scarcity in Rural Brazil

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A group of ‘barraghinas’, the micro-dams that retain water that runs off into the ground, benefiting vegetation and accumulating water in the soil to supply lagoons. Credit: Courtesy of Lucyan Vieira Listo

Water shortage is over, springs have emerged or become perennial, small ponds with fish have formed and pastures have become greener and more permanent, all thanks to the ‘barraginhas’, the Portuguese name given in Brazil to micro-dams that retain rainwater and infiltrate it into the soil.

This is a common claim among the many farmers who have adopted the technique developed and promoted by Luciano Cordoval, an agronomist and researcher at the Brazilian Agricultural Research Corporation (Embrapa), a public entity comprising 43 research centres throughout the country.

Cordoval has worked since 1983 at the Embrapa Maize and Sorghum unit, based in Sete Lagoas (Seven Lagoons, in Portuguese), a municipality with a population of 227,397 in the southern state of Minas Gerais, where he further specialised in irrigation and soil conservation.

His Barraginhas Project was launched in 1997 with government investment. But the specialist has been promoting micro-dams long before as a way to “capture water from streams and promote its storage in the soil, avoiding erosion, sedimentation and environmental pollution, with increased volume in the springs”, according to his resumé.

Luciano Cordoval explains the functions of barraginhas in his office at the Maize and Sorghum unit of the Brazilian Agricultural Research Corporation in Sete Lagoas, a municipality in central Brazil. Credit: Mario Osava / IPS

One hundred micro-dams create a lagoon

Antonio Alvarenga, a pioneer of the initiative, built 28 micro-dams on his 400-hectare farm in Sete Lagoas in 1995, with the support of Cordoval’s project. “These were degraded and dry lands, affected by major erosion,” he recalled.

In a short time, the barraginhas filled and emptied several times and water began to flow in the lower part of the farm, which had previously been totally dry. The engineer by profession, who became a part-time cattle farmer, was then able to have his dream pond, which after extensions now covers 42,000 square metres of his land.

With the other micro-dams already built, he now has “more than 100” and has plans for another 40. The effect can be seen in the recovered springs and the abundance of water that allows him to irrigate the pastures in the dry season and double his livestock productivity.

“Before I used to raise only one cow on two hectares, today there are two animals on each hectare,” he told IPS in Sete Lagoas, highlighting the good results of the innovation.

“I became a producer of water, which fills my ‘artificial’ lagoon. Water is everything,” he praised. The benefits visible to the naked eye encouraged his neighbours to build their own micro-dams, with help from the mayor’s office. In addition, a television report helped spread the word about this ‘social technology’, as it is called.