Data for: Improving irrigation efficiency is not sufficient to meet future water demand in the Nile Basin

The Nile River Basin covers an area of approximately 3.2 million km2 and is shared by 11 countries. Rapid population growth is expected in the region. The irrigation requirements of Nile riparian countries of existing (6.4 million ha) and additional planned (3.8 million ha, 2050) irrigation schemes were calculated, and the likely water savings through improved irrigation efficiency were evaluated. We applied SPARE:WATER to calculate irrigation demands on the basis of the well-known FAO56 Crop Irrigation Guidelines. Egypt (67 km3 yr-1) and Sudan (19 km3 yr-1) consume the highest share of the 84 km3 yr-1 total (2011). Assuming today’s poor irrigation infrastructure, the total consumption was predicted to increase to 123 km3 yr-1 (2050), an amount far exceeding the total annual yield of the Nile Basin. Therefore, a key challenge for water resources management in the Nile Basin is balancing the increasing irrigation water demand basin-wide with the available water supply. We found that water savings from improved irrigation technology will not be able to meet the additional needs of planned areas. Under a theoretical scenario of maximum possible efficiency, the deficit would still be 5 km3 yr-1. For more likely efficiency improvement scenarios, the deficit ranged between 23 and 29 km3 yr-1. Our results suggest that that improving irrigation efficiency may substantially contribute to decreasing water stress on the Nile system but would not completely meet the demand.

尼罗河流域（Nile River Basin）总面积约320万平方千米，由11个国家共享。该区域预计将迎来快速人口增长。研究人员核算了尼罗河流域沿岸国家现有灌溉面积（640万公顷）及规划新增灌溉面积（预计2050年达380万公顷）的灌溉需水量，并评估了通过提升灌溉效率可实现的潜在节水潜力。本研究采用SPARE:WATER模型，基于知名的FAO56作物灌溉指南（FAO56 Crop Irrigation Guidelines）开展灌溉需水量核算。2011年，流域总灌溉用水量为84立方千米每年，其中埃及（67立方千米每年）与苏丹（19立方千米每年）占比最高。若维持当前落后的灌溉基础设施水平，预计到2050年总灌溉用水量将增至123立方千米每年，该数值远超尼罗河流域的年可供水总量。因此，尼罗河流域水资源管理面临的核心挑战，是如何在全流域范围内平衡日益增长的灌溉需水与可用供水总量。研究发现，通过改进灌溉技术实现的节水潜力，无法满足规划新增灌溉区域的额外需水需求。在理论上的最大效率提升场景下，仍将存在5立方千米每年的用水缺口；而在更贴合实际的效率改进场景中，用水缺口介于23至29立方千米每年之间。研究结果表明，提升灌溉效率虽可显著缓解尼罗河水系统的水资源压力，但无法完全覆盖全部灌溉需水需求。