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Groundwater Quality Assessment in the Coastal Mediterranean Aquifer of Northeastern Morocco – A GIS-Based Approach

Bouhout Sara, Haboubi Khadija, El Hammoudani Yahya, El Abdouni Aouatif, Haboubi Chaimae, Dimane Fouad, Hanafi Issam, Elyoubi Mohamed Salahdine

Ecological Engineering & Environmental Technology

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2024

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Vol. 25, iss. 1

22--45

EN

Groundwater quality degradation is a pressing concern in semi-arid coastal regions, exemplified by the Ghiss-Nekor aquifer in northeastern Morocco, spanning 100 km2. This study adopts a comprehensive approach, utilizing chloro-alkaline indices, hydrochemical facies diagrams, the water quality index (WQI), and the synthetic pollution index (SPI) to assess the groundwater quality and its evolution. Key findings reveal that the Ghiss-Nekor ground-water is brackish, primarily suitable for irrigation due to high total dissolved solids (TDS). Salinization stems from reverse cation exchange, as indicated by hydrochemical analyses. WQI assessments highlight the inadequacy of this groundwater for drinking purposes, with SPI classifying 54% of wells as moderately polluted. Fine particles mitigate marine intrusion in the northwest. Overlaying land-use and electrical conductivity maps identifies the areas with poor-quality groundwater, notably near an unregulated landfill, a coastal tourist site, and a wastewater treatment facility. Ionic analysis identifies multiple saline sources, with nitrate and sulfate contributions standing out. While the study offers valuable insights, limitations include the need for ongoing data collection and source identification challenges. Nonetheless, the research underscores the urgency of effective water management, particularly around the landfill site situated above permeable deposits, offering an innovative approach with global applicability for addressing groundwater quality issues in semi-arid coastal areas.

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Understanding Saltwater Origins and Mechanisms in the Coastal Aquifers of Da Nang Area (Central Vietnam)

Nguyen Thao Bach, Duc Nhan Dang, Dao Bang Duc

Inżynieria Mineralna

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2023

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no. 2, vol. 1

281--288

EN

Saltwater intrusion in the rapidly developing city of Da Nang in central Vietnam is currently causing various water-related challenges, including inadequate water supply and water pollution. An integrated SWAT-MODFLOW numerical model was used to investigate the origin and mechanism of saltwater in Holocene and Pleistocene aquifers. Geophysical and isotopic approaches were used to validate the SEAWAT model applied for simulating saltwater intrusion. The results suggest that the ebb and flow of tides, as well as water levels in rivers primarily impact coastal aquifers. However, effective water resource planning and management, along with maintaining the natural recharge of fresh water from local rain during the rainy season, could enable the rational and efficient utilization of groundwater, reducing saltwater intrusion in many areas. During the dry season, groundwater is recharged from higher altitude areas. The current saltwater intrusion mainly occurs along the rivers up to the hydraulic dam. Simulated models, using scenarios of stop abstracting groundwater, but changing to the use of surface water for drinking water, show that the area of saline water shrinks quickly after 30 years, reducing from 59.6 km2 to 39.5 km2 and from 40.2 km2 to 28.6 km2 in the Holocene and Pleistocene, respectively.

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Using Vertical Electrical Soundings to characterize seawater intrusions in the southern area of Romanian Black Sea coastline

Mihai Niculescu Bogdan, Andrei Gina

Acta Geophysica

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2019

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Vol. 67, no. 6

1845--1863

EN

Seawater intrusions are a major environmental hazard for coastal freshwater aquifers. They are generated mainly by the uncontrolled exploitation of freshwater in pumping stations, if the aquifers are in hydraulic connection with the sea. In Romania, such marine intrusions have occurred in the southern part of Black Sea’s coastline, in Costinești and Vama Veche resorts, contaminating the main aquifers hosted in Sarmatian (late Middle Miocene) limestones, at distances ranging from hundreds of meters to over 2 km inland. For the study of these salinization phenomena, Vertical Electrical Sounding (VES) surveys were performed in the affected areas. These surveys allowed the delineation and spatial–temporal monitoring of the intrusions and offered information related to faults that may have provided pathways for seawater migration toward the exploitation wells. The 1D interpretation of VES apparent resistivity data was performed via a set of novel software applications. The forward modeling component of the applications uses digital linear filtering and allows the simulation of theoretical VES responses for horizontally-layered geological media with virtually unlimited number of layers. The pseudo-inversion component of the applications is based on a random sampling of the parameters space of the geoelectrical models. The interpretation of VES surveys recorded in Vama Veche area by using the elaborated software indicates that the seawater intrusion occurs at more than 40 m depth. This agrees with a well flow test which produced saltwater at 40–60 m depth in that area.

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Systemy krążenia wód podziemnych w rejonie Zalewu Kamieńskiego, Pomorze Zachodnie

Krawiec A., Sadurski A., Burzyński K.

Biuletyn Państwowego Instytutu Geologicznego

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2012

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nr 451 Hydrogeologia z. 13

153--159

PL

Systemy krążenia wód podziemnych w rejonie Zalewu Kamieńskiego zależą od budowy geologicznej, ukształtowania terenu a także ascenzji solanek i ingresji wód morskich. Do obliczenia czasu przepływu wody w rozpatrywanych warstwach w ośrodku o znanej porowatości aktywnej posłużono się programem TFS opracowanym przez K. Burzyńskiego. Model przepływu wód podziemnych opracowano dla przekroju hydrogeologicznego wzdłuż linii Międzywodzie–Kamień Pomorski–Golczewo. Czasy przepływu i wymiany wód podziemnych obliczono dla dwóch przypadków, pierwszy dla okresu przed transgresją litorynową (7500 lat temu) oraz drugi – dla współczesnych warunków przepływu wód podziemnych. Czas wymiany wód podziemnych w rejonie Zalewu Kamieńskiego jest obecnie prawie dwa razy dłuższy niż przed tą transgresją.

EN

The study area is located in the north-western part of the Pomeranian sector of the Mid-Polish Anticlinorium. Factors influencing groundwater circulation systems in the area of the Kamieński Lagoon depend on the geological structure, ascension of brines from Mesozoic strata and the sea water encroachment. The calculation of groundwater flow time along the stream line was carried out for rocks of specified active porosity using a mathematical program developed by K. Burzyński. The groundwater flow model was used for a hydrogeological cross-section line along: Międzywodzie–Kamień Pomorski–Golczewo in the south. The numerical calculations of the flow path from the recharge area to the discharge base level of the present Baltic Sea and the base level in the beginning of the Littorina Sea (7500 years BP) were done to define the groundwater flow time. It has been stated that the current flow time in the fresh groundwater circulation system in the area of the Kamieński Lagoon is nearly twice longer than it was 7500 years ago.