The regional government of Afar state, Ethiopia, has adopted an innovative approach for turning potentially destructive floodwaters into a source of irrigation in the Ethiopian drylands.

The practice, developed by the CGIAR Research Program on Water, Land and Ecosystems (WLE) and the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), takes advantage of interconnected weirs – small dams – that capture and distribute water to revive grazing lands and boost crop productivity by up to 500%. And the approach has been integrated into a large, proposed World Bank project.

About 60% of Ethiopia’s land is dry lowland. Home to pastoralist communities, these areas experience alternating droughts and floods, making them inhospitable to crops or grazing. In recent years, extreme floods have affected hundreds of thousands of people in sub-Saharan Africa – many of them pastoral communities. In 2017, dams and rivers in Kenya overflowed, submerging crops, forcing over 300,000 people to flee, and killing 186. In 2019, floods were the major cause of displacement in Mozambique, Malawi and Zimbabwe.

In order to turn this seasonal flooding into an advantage, and restore degraded landscapes, GIZ (Gesellschaft fur Internationale Zusammenarbeit) has invested in a system of 50- to 300-m concrete or stone barriers (water-spreading weirs) in a cascading system in Chifra district since 2015. As the weirs redirect the floodwaters, water and nutrients are deposited across larger areas.

Recognizing the potential to grow forages and dryland crops on this suddenly nutrient-rich and temporarily moist soil, ICRISAT was charged with assessing how best to cultivate and manage this newly arable land. Creating GIS maps of water and nutrient deposits, the scientists developed recommendations on growing schedules and what forages and crops to grow where.

Such interventions rarely bring major impacts for agriculture. But in Afar, crop and forage yields increased abundantly over just three years, despite minimal fertilizer inputs – all while reducing the risk of water-related disasters.

The local community used these crops for domestic consumption and livestock fodder. And they distributed fodder to surrounding pastoralists, reducing local conflict. The project also reduced the amount of sedimentation entering local water sources.

The regional government is looking at expanding the approach to Yallo and Awra districts. And satellite data is currently being used to determine what locations would be appropriate for scaling up the project to other areas of sub-Saharan Africa. ( This brief is an excerpt from WLE's 2018-19 Annual Report, titled "Agricultural Challenges Are Meeting Their Match." )