Groundwater recharge and salinization in the arid coastal plain aquifer of the Wadi Watir delta, Sinai, Egypt

Eissa, Mustafa; Thomas, James M.; Pohll, Greg; Shouakar-Stash, Orfan; Hershey, Ronald L.; Dawoud, Marwa M.

doi:10.1016/j.apgeochem.2016.05.017

Cited by 47 publications

(15 citation statements)

References 43 publications

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“…In addition, the oolitic aquifer is dissected by several elongated ridges running parallel to the shoreline, which act as barriers for surface water flow and consequently enhance the entrapment of recharge water. On the other hand, the groundwater samples with higher TDS values indicate the occurrence of leaching and dissolution processes of marine origin deposits, as well as mixing with seawater [45].…”

Section: Groundwater Chemistrymentioning

confidence: 99%

Geochemical and Isotopic Evidence of Groundwater Salinization Processes in El Dabaa Area, Northwestern Coast, Egypt

et al. 2018

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El Dabaa city is located along the northwestern coast ridge zone of Egypt, where the groundwater is the major water source for drinking, domestic, and agricultural purposes. The groundwater salinity increased over the last decades, therefore, geochemical techniques and environmental isotopes have been utilized to identify the main groundwater recharge and salinization sources. The study area comprises two main groundwater aquifers: the porous oolitic Pleistocene and the fractured limestone Miocene aquifers. The groundwater salinity of the Pleistocene aquifer ranges from 751 to 27,870 mg/L, with an average value of 6006 mg/L. The salinity of the Miocene aquifer ranges from 3645 to 41,357 mg/L, with an average value of 11,897 mg/L. Fresh and brackish groundwater have been recorded in the shallow hand-dug wells, while saline groundwater has been found in deeper wells close to the shoreline. Groundwater samples have been categorized into two distinct groups according to the salinity ranges, hydrochemical ion ratios, and stable isotopic content. Group I is composed of groundwater with salinity less than 10,000 mg/L, and depleted stable isotopic content (−5.64 < δ18O < −2.45; −23.5 < δ2H < −0.02), while Group II contains groundwater with salinity values above 10,000 mg/L and relatively enriched stable isotopic content (−1.86 < δ18O < −0.48; −10.3 < δ2H < −2.0). The weight mass balance mixing model shows that Group I falls close to the rain and/or water extract samples, indicating meteoric water origin that has evolved due to leaching and dissolution processes. Group II is mostly located between the rainwater and the seawater samples, revealing mixing with water of marine origin due to groundwater overexploitation. The estimated seawater mixing index (SMI) of groundwater samples of Group II is greater than one, which confirms mixing with seawater. The water-rock reaction NETPATH (geochemical groundwater reaction and mixing code) model scenarios representing Group I suggests that gypsum, dolomite, and halite are dissolved, while calcite is formed with a slight influence from evaporation processes. Six mixing models representing Group II are used to investigate seawater mixing scenarios. The models suggest that illite and dolomite are dissolved, while calcite and gypsum are precipitated with a seawater mixing ratios ranging from 28% to 98%. In conclusion, due to the scarcity of annual groundwater recharge in the El Dabaa area, groundwater withdrawal should be well managed to avoid groundwater salinization and further seawater intrusion.

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Section: Groundwater Chemistrymentioning

confidence: 99%

Geochemical and Isotopic Evidence of Groundwater Salinization Processes in El Dabaa Area, Northwestern Coast, Egypt

et al. 2018

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“…Interests in surface and groundwater salinity modeling using a variety of approaches (numerical modeling, stochastic analysis, and machine learning) have steadily grown. For example, the Hydrus and MOD-FLOW numerical models coupled with MT3D have been used to evaluate salinity dynamics (Hanson and Hopmans 2008;El-Bihery 2009;Kanzari et al 2012;Ibrahimi et al 2014;Eissa et al 2016;Ghorbani et al 2017). More recently, Wu et al (2018) presented spatial distribution and severity of salinity by combining satellite and radar datasets using machine learning.…”

Section: Introductionmentioning

confidence: 99%

Evaluate River Water Salinity in a Semi‐Arid Agricultural Watershed by Coupling Ensemble Machine Learning Technique with SWAT Model

Jung¹,

Ahn²,

Sheng³

et al. 2021

J American Water Resour Assoc

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This study is to establish a new approach to estimate river salinity of semi‐arid agricultural watershed and identify drivers by using hydrologic modeling and machine learning. We augmented the limitations of the Soil and Water Assessment Tool (SWAT) to model salinity by coupling with eXtreme Gradient Boosting (XGBoost), a decision‐tree‐based ensemble machine learning algorithm. Streamflow, precipitation, elevation, main reach length, and dominant soil texture of the top two layers were used along with NO3, NO2, and total phosphorus (TP) output from a calibrated SWAT model are used as predictors to Total Dissolved Solids (TDS) in the XGBoost algorithm. Then, the SWAT model simulations of streamflow, NO3+NO2, and TP from 2000 to 2015 are used as inputs of the XGBoost model to predict monthly water TDS distribution along the river. The predicted river water TDS showed a higher concentration as going downstream from El Paso (inlet) through the Hudspeth canal to Fort Quitman (outlet). Finally, this study carried out cause analysis focusing on soil physical characteristics. The soil salinity level is directly affected by the soil permeability and irrigation water. As a result, the highest TDS is shown in sites with silt loam, whereas the lowest TDS was shown in sites with very cobbly soil. Silt soils can hold more water and are slower to drain than soils of a sand type. These analyses can be used to better understand the mitigation of water salinity.

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“…While this study has also addressed the present risk of salinization of wells by assessing multiple geomorphological and physical parameters, there are other factors that additionally can affect the risk, including the overpumping of groundwater, withdrawal from deep drill holes [26], the quality of the well construction, climate change, drought, storm surges [22], or cracks in the limestone formations [10]. In particular, the withdrawal of freshwater and the depth of the well affect the flow pattern of the groundwater through aquifers-causing saltwater to migrate to the artificially created low-pressure area underground [21,30]. Furthermore, although tides are negligible (in the order of a centimeter), in the studied part of the semiclosed basin of the Baltic Sea, well salinization may be impacted by sea level variations in the order of decimeters that occur in response to weather and wind conditions [31].…”

Section: A Precautionary Approachmentioning

confidence: 99%

Well Salinization Risk and Effects of Baltic Sea Level Rise on the Groundwater-Dependent Island of Öland, Sweden

Eriksson

Ebert

Jarsjö

2018

Water

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Abstract:In this study, we estimate baseline conditions in terms of the current risk of well salinization on the Baltic Sea island of Öland, Sweden, and assess the effects of future sea level rise on the land area, infrastructure and cultural values. We use a multicriterion geographical information systems (GIS) approach. Geomorphological and physical parameters affect the risk of saltwater intrusion into freshwater aquifers, including their hydrology, geomorphology, and climatology; the spatial distribution of the current risk of salinization is mapped in this study. In the event of a future 2 m sea level rise, a total land area of 67 km 2 will be inundated on Öland, corresponding to approximately 5% of the island's land surface. Inundation includes urban areas, nature reserves, and animal protection areas, implying the loss of environmental and socioeconomic values. A future 2 m sea level rise will also cause direct inundation of 3% of all wells on the island. Currently, 17.5% of all wells are at a high risk of becoming saltwater contaminated. More generally, the present results add evidence showing a relatively high vulnerability of major Baltic Sea islands and their infrastructure to future sea level rise. The approach used here and related results, including salinization risk maps, may prove useful for decision-makers in the planning of infrastructure. Drilling of new wells could for instance preferably be done in areas with identified lower risk-index values, which would facilitate an overall higher freshwater withdrawal in the interest of the entire island.

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Groundwater recharge and salinization in the arid coastal plain aquifer of the Wadi Watir delta, Sinai, Egypt

Cited by 47 publications

References 43 publications

Geochemical and Isotopic Evidence of Groundwater Salinization Processes in El Dabaa Area, Northwestern Coast, Egypt

Geochemical and Isotopic Evidence of Groundwater Salinization Processes in El Dabaa Area, Northwestern Coast, Egypt

Evaluate River Water Salinity in a Semi‐Arid Agricultural Watershed by Coupling Ensemble Machine Learning Technique with SWAT Model

Well Salinization Risk and Effects of Baltic Sea Level Rise on the Groundwater-Dependent Island of Öland, Sweden

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