Irrigation Water Management in A Water-Scarce Environment in the Context of Climate Change

Abstract

In this study, in the context of climate change simulation models were employed to compute the reference evapotranspiration (ETo), net irrigation water requirement (NIWR) and design a new sprinkler irrigation system for two arid sites (Siwa Oasis and West Elminya fields) inside the 1.5-million acres reclamation project in the Egyptian western desert. The CROPWAT 8 model was used to compute NIWR and the irrigation schedule for the main crops wheat, barley, maize, sugar beet, potato, tomato, and date palm, five scenarios were employed the current (1991-2022) scenario, representative concentration path (RCP) 8.5 greenhouse gas emission for the 2040s, 2060s, 2080s, and 2100s scenarios, corresponding to 1.6, 2.1, 3.3, and 4.4 oC expansion with respect to the current baseline 1991-2022. The WaterGEMS model was utilized to run long-term simulations of hydraulic behavior within pressurized pipe networks to irrigate 43 acres using deep groundwater well. ETo values for the current scenario show 4.56 and 5.7 mm for the Siwa Oasis and West Elminya fields respectively. The climate changes cause an increase of the ETo by 4.6, 5.9, 9.4, and 12.7% for RCP: 8.5 greenhouse gas emissions for the 2040s, 2060s, 2080s, and 2100s scenarios respectively for the Siwa Oasis field. On the other hand, an increased ratio for the ETo by 4.2, 5.4, 8.6, and 11.6% for the West Elminya field respectively. The designed sprinkler system indicated a capacity of 111.4 m3 h-1 and 167 m3 h-1 for Siwa and West Elminya fields, respectively. The study suggests the application of modern irrigation systems and crop patterns for wheat, barley, potato, and sugar beet to save irrigation water.