Investigating Climate Change Effects on Evapotranspiration and Groundwater Recharge of the Nile Delta Aquifer, Egypt

Abstract

Climate change (CC) directly affects crops’ growth stages or level of maturity, solar radiation, humidity, temperature, and wind speed, and thus crop evapotranspiration (ETc). Increased crop ETc shifts the fraction of discharge from groundwater aquifers, while long-term shifts in discharge can change the groundwater level and, subsequently, aquifer storage. The long-term effect of CC on the groundwater flow under different values of ETc was assessed for the Nile Delta aquifer (NDA) in Egypt. To quantify such impacts, numerical modeling using MODFLOW was set up to simulate the groundwater flow and differences in groundwater levels in the long term in the years 2030, 2050, and 2070. The model was initially calibrated against the hydraulic conductivity of the aquifer layers of the groundwater levels in the year 2008 from 60 observation wells throughout the study area. Then, it was validated with the current groundwater levels using an independent set of data (23 points), obtaining a very good agreement between the calculated and observed heads. The results showed that the combination of solar radiation, vapor pressure deficit, and humidity (H) are the best variables for predicting ETc in Nile Delta zones (north, middle, and south). ETc among the whole Nile Delta will increase by 11.2, 15.0, and 19.0% for the years 2030, 2050, and 2070, respectively. Zone budget analysis revealed that the increase of ETc will decrease the inflow and the groundwater head difference (GWHD). Recharge of the aquifer will be decreased by 19.74, 27.16, and 36.84% in 2030, 2050, and 2070, respectively. The GWHD will record 0.95 m, 1.05 m, and 1.40 m in 2030, 2050, and 2070, respectively when considering the increase of ETc. This reduction will lead to a slight decline in the storage of the Nile Delta groundwater aquifer. Our findings support the decision of the designers and the policymakers to guarantee a long-term sustainable management plan of the groundwater for the NDA and deltas with similar climate conditions.

Spatiotemporal Variation of Evapotranspiration and Its Driving Factors in the Urumqi River Basin

“…Elevation is a basic terrain feature whose changes alter soil moisture and surface runoff, thereby affecting ET [58,59]. Spatial overlay analysis was conducted on land-cover types and elevation data in the watershed to calculate the average ET for each land-cover type at different elevation levels (Figure 11a).…”

Vetiver Grass (Chrysopogon zizanoides L.): A Hyper-Accumulator Crop for Bioremediation of Unconventional Water

“…Global warming and decreased precipitation have led to climate change and the consequent water shortage, specifically in arid areas [1]. The increased human population as well as expanded agricultural and industrial activities have also decreased the freshwater resources and increased pollution [2].…”

“…Compared to other technologies, the following advantages are recognized for phytoremediation: (1) phytoremediation can be used in large areas for a wide range of pollutants due to its economic feasibility, low energy consumption [12], and environmental compatibility [10,11,13,14]; (2) being publicly acceptable and practical [15]; (3) the decreasing effects on wind and water erosion on a site; and (4) feedstock generation for a variety of different applications [12]. However, this method has several limitations, including: (1) the limited range of the affected contaminants, relatively prolonged time scale, and inappropriate achievable levels of the residual contaminant [16]; (2) although the method is not technically complex, considerable experience and expertise may be required to design and implement a successful phytoremediation program due to the need of a complete evaluation of a site for suitability and to optimize the conditions to achieve a satisfactory result [17]; (3) limitations of the depth of root-occupied phytoremediation; as well as (4) contamination of the food chain which resulted from the toxic-compound-absorbed plants [18].…”

Assessing the impact of artificial recharge on groundwater in an over-exploited aquifer: A case study in the Cheria Basin, North-East of Algeria

“…Effective decision-making groundwater management can be facilitated through groundwater modelling (Glass et al 2018;Qin, 2021). In this context, a conceptual groundwater flow model was developed to assess the feasibility of implementing managed aquifer recharge, and numerical transient flow model was built using Visual MODFLOW Flex (Samanta et al 2020;Mushtaq et al 2023;Eltarabily et al 2023).…”