Investigation of Some Potential Parameters and Its Impacts on Saltwater Intrusion in Nile Delta Aquifer

Abstract

Coastal aquifers represent an important source of freshwater in arid and semi-arid regions. The increased extraction from coastal aquifers decreases the freshwater spilled out to the sea. Consequently, seawater intrusion increases inland and wells become contaminated. Nile delta aquifer in Egypt is one of these aquifers which subject to sever seawater intrusion from Mediterranean Sea. Saltwater intrusion is considered one of the main processes that degrade waterquality by raising salinity. It may occur due to human activities and/or by natural events. Overpumping is considered the main cause of saltwater intrusion. Moreover, sea level rise accelerates saltwater intrusion. Due to climate change, it is expected a rise in temperature which would lead to an increase in the rates of evaporation and this will be accompanied by decrease in water level of the Nile, also this change would lead to sea level rise (SLR) .A result to rise in population intensity and expected shortage in surface water would lead to an increase of extraction rate from groundwater. In this paper 3-D model (SEAWAT) is used to study seawater intrusion in Nile delta aquifer considering different scenarios, the first scenario is the increase of sea level by 25, 50 and 100 cm, the second is to decrease the surface water system by 25, 50 and 100 cm, the third is to increase the extraction rate by 25, 50 and 100 % and fourth scenario is a combination of while the three scenarios. The results show that saltwater intrusion in East Nile delta reach 76.25 km from shore line for base case, but reaches to 79.25 km, 79 km, 82 km and 83 km for Equiconcentration line 35 and reaches to 92.25 km, 92 km, 91.75 km and 92.75 km for scenarios1, 2, 3 and 4 respectively after 100 year for Equiconcentration line 1.00. It is also observed that salt water intrusion in the Middle reaches to 63.75 km from shore line for base case, but reaches to 67.75 km, 67.25 km, 65.75 km and 67.50 km for Equiconcentration line 35 and reaches to 97 km, 97.50 km, 107.75 km and 110 km for scenarios1, 2, 3 and 4 respectively after 100 year for Equiconcentration line 1.00. It is clear that saltwater intrusion in the West reaches to 48.00 km from shore line for base case, but reaches to 49.00 km, 48.75 km, 45.50 km and 47.75 km for Equiconcentration line 35 and reaches to 73.75 km, 74 km, 79.50 km and 79.50 km for scenarios1, 2, 3 and 4 respectively after 100 year for Equiconcentration line 1.00. Finally increasing SLR or decreasing recharge from Ismail M. Abdelaty et al., Investigation of some potential parameters and its impacts on………… surface water or increasing extraction rate from wells increases saltwater intrusion in land direction but applying combination of these scenarios will damage large quantity of fresh water in the aquifer.

Associations between climate variables and water quality in low- and middle-income countries: A scoping review

“…Increased groundwater extraction was predicted to increase saltwater intrusion caused by sea level rise in coastal Argentina (Carretero et al 2013). Simulations by Abd-Elhamid et al (2016a, 2016b, Abdelaty et al (2014) and Mabrouk et al (2018) for different parts of the Nile Delta aquifer in Egypt detected comparable or greater landward shifts from increased groundwater pumping than from sea level rise. The freshwater lens in Kish Island in Iran was projected to shrink by less than 10% under three sea level rise scenarios -0, 1 and 4m.…”

Modelling the impact of lining and covering irrigation canals on underlying groundwater stores in the Nile Delta, Egypt

“…The model was calibrated for the steady‐state condition with a 60 observed values of groundwater heads (Figure 3a), then model was validated with an independent set of data (23 points) (Figure 3b). Abd‐Elaty et al (2014a, 2014b) presented the sensitivity analysis results for the Nile Delta area where the most sensitive parameters are the vertical hydraulic conductivity, net recharge (from the return flow from irrigation), and the model grid size.…”

“…The rehabilitation involves placing 15 cm concrete liners over a 30 cm layer of dolomite stones. Geocell grid material is used in some canals' sections to prevent excessive displacements of the infilled soil because of cell confinement and redistribution of stresses to the underlying soil (Leshchinsky & Ling, 2013) with the same value for reduction in surface water levels by 50 cm (Abd‐Elaty et al, 2014a; Abd‐Elaty et al, 2014b).…”

“…The rehabilitation involves placing 15 cm concrete liners over a 30 cm layer of dolomite stones. Geocell grid material is used in some canals' sections to prevent excessive displacements of the infilled soil because of cell confinement and redistribution of stresses to the underlying soil(Leshchinsky & Ling, 2013) with the same value for reduction in surface water levels by 50 cm(Abd-Elaty et al, 2014a;Abd-Elaty et al, 2014b).Under the third scenario, the canal lining is combined with the solar PV panel covers. This technique reduces incoming solar radiation leading to lower canal water temperatures and decreased evaporation(Ranjbaran et al, 2019).…”

Impact of Increasing Pumping Discharge on Groundwater Level in the Nile Delta Aquifer, Egypt

“…The hydraulic gradient of GW flows beginning the south (Cairo city) towards the north (Mediterranean Sea) in the ND aquifer is 11.0 cm/km in the south and 7.0 cm/km in the north. The literature specified a constant head of 16.96 above msl for the southern boundary of the ND model [12], [22]. A zero value was also specified for the upper boundary condition along the Mediterranean Sea's shore in the north.…”