Irrigation

Irrigation (also called water distribution) is the practice of conveying water to cultivated land so that plants receive the moisture they need, when rainfall alone is insufficient or cannot be relied upon. Water may be drawn from rivers, wells, boreholes, ponds, or stored runoff, and is then distributed through canals, ditches, or furrows.

The purpose of irrigation is to make crop production independent of rainfall patterns. Irrigated land can support two or three harvests per year, making it possible to grow water-intensive crops such as rice, sugarcane, and vegetables. In regions of high aridity, such as the Horn of Africa, irrigation is among the most important measures for mitigating drought damage.

Types of irrigation

Common types include flood irrigation (water is directed across flat or sloped ground), sprinkler irrigation (water is distributed by machines that spray it like rain), and drip irrigation (water is delivered systematically through small tubes to tree roots). Flood irrigation is the cheapest to build but loses much water to evaporation and soil percolation; drip irrigation saves water but requires equipment and constant maintenance.

System design and structure

A large irrigation system typically consists of a water source (a reservoir or a diverted section of river), a main canal carrying water, secondary canals that distribute it, gates controlling water flow, and drainage channels that remove excess water from the land. If drainage fails, salt and waterlogging accumulate in the soil, damaging crops.

Management and water disputes

Irrigation requires clear agreements on water allocation, timing, and volume. In many places, farmer associations or local committees manage irrigation schedules and canal maintenance. Where a river is shared by multiple countries or regions, water distribution becomes a political question, especially when new dams are built upstream. Excessive irrigation can also lower the water table underground.

Somalia's situation

Somalia's permanent irrigation depends on two rivers, the Shabelle and the Juba, which flow through the central and southern regions. Farmers use canals, underground infiltration systems, and mechanical pumps. Large systems built in earlier periods have often fallen into disrepair, leading to clogged canals and altered water flow. In other areas, particularly the north and centre, water retention methods such as terraces, cisterns, and runoff-fed ponds are used instead.