Investigation of water delivery performance considering irrigation time as well as water volume: a case in the North Nile Delta of Egypt

In the North Nile Delta, over-planting paddy fields by upstream farmers results in low canal water levels downstream during the daytime, and downstream farmers frequently cannot pump water. Consequently, downstream farmers' night irrigation has become more frequent. This study investigated daytime and nighttime irrigation practices and how they differed between upstream, midstream, and downstream tertiary canals along a selected branch canal in the Northern Nile Delta of Egypt. A scenario was developed to determine the area that could be irrigated during the daytime by comparison of actual (varied pumps’ discharge capacities) and controlled pumps’ discharge capacities (216 m³ h⁻¹ and 324 m³ h⁻¹) between all locations. Canal water levels and pump operation hours were monitored in 2013 and 2014. The period from 06:00 PM to 06:00 AM EST (Egypt Standard Time) is considered nighttime and others are daytime. Results showed that downstream received more than 30% of the total water supply during the nighttime, while upstream received 13%. Further, some upstream farmers received 6% at night during the peak water demand in July. Consequently, the nighttime irrigation days upstream were less than downstream by 11 and 20 days each year, respectively. The numbers of irrigation events downstream from 12:00 AM to 03:00 AM EST were more than upstream by eight and seven events each year, respectively. Under the conditions of controlled pumps’ discharge capacities, downstream farmers could irrigate 41% and 46% of the total irrigated area during the daytime rather than 28% and 32% under the actual conditions each year, respectively. Eventually, controlling pumps’ discharge capacities between locations could achieve equity of water distributions in terms of time and water volume during the daytime.