COBSI is a simple irrigation technology that uses only locally available materials, such as wooden poles, grass, stones, and farmers’ basic tools. With these, farmers can build a simple weir and earth canals to divert perennial river water to their fields. The system is low-cost, easy to construct, maintain, and reconstruct if damaged.

COBSI was first developed in Malawi, then expanded to Zambia, and now its dissemination is also progressing in Mozambique. COBSI enables smallholder farmers to irrigate their crops by gravity and rotation, helping them become more resilient compared to relying only on rainfed agriculture.