Global food demand is projected to increase by upwards of 70% by 2050 and the importance of water for agriculture cannot be underestimated.
Water withdrawals for irrigation represent 69% of all abstractions worldwide. Although irrigation today covers only about 20 percent of the world’s cropland, it contributes 40 percent of total food production. The pressures on irrigated agriculture are apparent.
Crop productivity per unit area and per unit of water applied will need to increase to meet this increased demand, as there is little scope for increasing the total area under irrigation, which is projected to increase by only 9% between 2000 and 2050 (World Bank). This has to come from either higher yielding crop varieties or improvements in the efficiency and reliability of irrigation systems.
Irrigation efficiencies lower than 40% have led many to believe that there is enormous scope for saving water through improved management practices and rehabilitation or upgrading of irrigation systems. This is true where misapplied water is truly lost, and may result in very large savings of water by, say, switching from open channel delivery to drip irrigation. However, in cases where water is apparently lost, in practice it often either seeps to groundwater or back to the river and is then re-used. Therefore some water efficiency improvement initiatives, such as some projects for lining of canals to save “lost” water, have not actually saved water. They have in practice led to a redistribution of water as the return flows that were subsequently re-used by other irrigators may reduce.
Nevertheless, despite the fact that on average the percentage savings are often smaller than some believe, there is considerable scope for saving water in agriculture simply because agriculture uses the largest volumes of water. The point to note is that effective improvements in agricultural water efficiency need a good understanding of the underlying hydrology to determine how the water balance will respond to proposed changes.
Halcrow’s experience in agricultural water efficiency for irrigation covers a period of more than 50 years, and includes projects in Europe, Asia, Africa, the Middle East and South America. Our services include:
- hydrological analysis
- water balance analysis and modelling
- hydro-geological analysis and modelling
- system control improvements and automatic control
- efficiency audits and economic analysis
- social studies
- rehabilitation design
- design of unlined and lined irrigation channels down to farm level
- design of surface and subsurface drainage systems
- design of control and other hydraulic structures
- design of drip and sprinkler systems
- irrigation rotations and scheduling
- agricultural extension
- human resource development
- institutional strengthening
- formation and support of water user associations
- capacity building, including technical and management training
- preparation of scheme agreements, group constitutions and bye-laws