Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 4

Liczba wyników na stronie
first rewind previous Strona / 1 next fast forward last
Wyniki wyszukiwania
Wyszukiwano:
w słowach kluczowych:  coastal aquifer
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 1 next fast forward last
EN
Deterioration of water quality is of great concern, particularly in coastal aquifers where it has become difficult to meet water quality standards with appropriate salt content. As groundwater is the only alternative source of freshwater in the coastal plain of Ghiss-Nekor in northern Morocco, there is a need to assess its sustainability and suitability for drinking and irrigation purposes. For this purpose, data obtained from ABHL, corresponding to 13 monitoring wells existing in the downstream part of Ghiss-Nekor aquifer, were gathered and analyzed using a combination of statistical methods and GIS mapping tools. Various qualitative parameters namely; pH, turbidity, salinity, dissolved oxygen, conductivity, Chloride (Cl-), Sulphate (SO4) and some Nitrogen compounds were investigated and compared according to World Health Organization standards. These results suggest that groundwater samples are chemically dominated by chloride anions followed by sulphate anions; high levels of SO4 result from the mineral dissolving of evaporites in addition to the impact of seawater intrusion and the discharge of wastewater without adequate pre-treatment, while Cl- concentrations (408.3–1512.3 mg/L), strongly correlated with electrical conductivity, are related to the impact of seawater intrusion. A few samples along the Nekor River, considered as the aquifer’s recharge zone, showed the lowest salinity levels (<1.5 g/L) compared to the coastal samples which were classified as the most conductive and mineralized (EC greater than 3000 μS/cm) due to the combined impact of mixing with seawater and high evaporation rates. The outcome of this study reveals that the major dissolved anions assessed in the groundwater of the Ghiss-Nekor aquifer do not respect the stipulated criteria in terms of human consumption; therefore, all possible measures should be taken to protect and restore the water quality in this vulnerable coastal aquifer.
EN
The population increase, urbanization and intensification of agriculture and demands for water supply in the coastal plain of Collo led to excessive pumping of the unconfined aquifer with limited dimensions. This study aimed to characterize the effect of the overexploitation of the groundwater from the only unconfined aquifer in the region, what resulted in the inversion of the groundwater flow and the rise the possible seawater pollution that is shown in the water table map. The causes and effects of the saltwater intrusion were discussed. The interpretation of the electrical conductivity measurements, chloride and sodium maps have shown clearly the areas where values were the highest with tighter curves towards the sea, the wadis Guebli and Cherka. These values distribution indicated a marine source of salinity in wells and boreholes close to the sea and wadis.
PL
Rosnąca liczba ludności, urbanizacja i intensyfikacja rolnictwa spowodowały większe zapotrzebowanie na dostawy wody na przybrzeżnej równinie Collo i doprowadziły do nadmiernego pompowania wody z warstwy wodonośnej o swobodnym zwierciadle i ograniczonych rozmiarach. Celem badań było scharakteryzowanie skutków nadmiernej eksploatacji wód gruntowych z jedynego w regionie poziomu wodonośnego o swobodnym zwierciadle. Wynikiem eksploatacji była inwersja przepływu wód gruntowych i zwiększone prawdopodobieństwo ich zanieczyszczenia przez wodę morską, co przedstawiono na mapie poziomów wód. Przedyskutowano przyczyny i skutki intruzji wód słonych. Interpretacja pomiarów przewodności elektrycznej i mapy rozmieszczenia jonów chlorkowych i sodowych ujawniły obszary o wartościach tych parametrów rosnących w kierunku morza i uedów Guebli i Cherka. Rozmieszczenie wartości stężenia badanych składników wskazuje na morskie źródło zasolenia studni w pobliżu morza i obu rzek.
EN
The study focuses on the characterization of the groundwater salinity on the Nador coastal aquifer (Algeria). The groundwater quality has undergone serious deterioration due to overexploitation. Groundwater samplings were carried out in high and low waters in 2013, in order to study the evolution of groundwater hydrochemistry from the recharge to the coastal area. Different kinds of statistical analysis were made in order to identify the main hydrogeochemical processes occurring in the aquifer and to discriminate between different groups of groundwater. These statistical methods provide a better understanding of the aquifer hydrochemistry, and put in evidence a hydrochemical classification of wells, showing that the area with higher salinity is located close to the coast, in the first two kilometers, where the salinity gradually increases as one approaches the seaside and suggests the groundwater salinization by seawater intrusion.
EN
The aquifer of Nador has suffered significant salinization due to seawater intrusion. It was strongly exploited during the 1980s and 1990s. A piezometric analysis in April 2012 showed the piezometric level to lie at 0 m a.s.l. over the plain; as a result, this aquifer is highly sensitive to the marine intrusion with an electrical conductivity of the groundwater in of exceeds 2500 μS/cm and so there are no abstractions for irrigation or drinking purpose from these sectors. The geoelectric study also showed the lateral variation in the electrical resistivity for two moments separated in time by more than 45 years. The fall in resistivity may be due to the encroachment of seawater into previously freshwater zones and/or infiltration during the era of pumped abstractions downstream. The resistivity surveys reveal two distinct sectors: the saturated aquifer in brackish and saltwater having resistivity values to 36-10 Ωm, which extends nearly 1600 m inland.
first rewind previous Strona / 1 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.