Influence of Tide‐Induced Unstable Flow on Seawater Intrusion and Submarine Groundwater Discharge

2021 ◽  
Vol 57 (4) ◽  
Author(s):  
Yunhai Fang ◽  
Tianyuan Zheng ◽  
Xilai Zheng ◽  
Huiyu Yang ◽  
Huan Wang ◽  
...  
Keyword(s):  
Seawater Intrusion ◽  
Submarine Groundwater Discharge ◽  
Groundwater Discharge ◽  
Unstable Flow ◽  
Submarine Groundwater

scholarly journals Seawater Intrusion into Coastal Aquifers

Water ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 2719
Author(s):  
Eyal Shalev
Keyword(s):  
Seawater Intrusion ◽  
Coastal Aquifers ◽  
Submarine Groundwater Discharge ◽  
Groundwater Discharge ◽  
Climate Variations ◽  
Special Issue ◽  
Groundwater Exploitation ◽  
Major Constraint ◽  
Highly Sensitive ◽  
Submarine Groundwater

This editorial presents a representative collection of 11 papers presented in the Special Issue on Seawater Intrusion into coastal aquifers. Coastal aquifers are one of the most important water resources in the world. In addition, the natural discharge of freshwater to the sea as submarine groundwater discharge (SGD) has an important role in the ecology of marine environments. The dynamics of seawater and freshwater within coastal aquifers are highly sensitive to disturbances, and their inappropriate management may lead to the deterioration of water quality. In many coastal aquifers, seawater intrusion has become the major constraint imposed on groundwater utilization. Groundwater exploitation and climate variations create dynamic conditions, which can significantly increase seawater intrusion into aquifers and may result in the salinization of wells.

scholarly journals Quantification of Submarine Groundwater Discharge in the Gaza Strip

Water ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1818 ◽  
Author(s):  
Ashraf Mushtaha ◽  
Kristine Walraevens
Keyword(s):  
Mediterranean Sea ◽  
Seawater Intrusion ◽  
Submarine Groundwater Discharge ◽  
Gaza Strip ◽  
Groundwater Discharge ◽  
Unconfined Aquifer ◽  
The North ◽  
Submarine Groundwater ◽  
The Mediterranean ◽  
The Gaza Strip

Gaza Strip has suffered from seawater intrusion during the past three decades due to low rainfall and high abstraction from the groundwater resource. On a yearly basis, more than 170 million m3 of groundwater is abstracted, while the long-term average recharge from rainfall is 24.4 million m3/year. Submarine groundwater discharge (SGD) has never been studied in the Gaza Strip, due to lack of experience in this field, next to the ignorance of this subject due to the seawater intrusion process taking place. Continuous radon measurements were carried out in six sites along the Gaza Strip to quantify the SGD rate. The final result shows SGD to occur in all sampled sites. The range of SGD rates varies from 0.9 to 5.9 cm·day−1. High values of SGD are found in the south (Rafah and Khan Younis governorates). The high values are probably related to the shallow unconfined aquifer, while the lowest values of SGD are found in the middle of Gaza Strip, and they are probably related to the Sabkha formation. In the north of Gaza Strip, SGD values are in the range of 1.0 to 2.0 cm·day−1. Considering that SGD would occur with the measured rates in a strip of 100 m wide along the whole coast line, the results in a quantity of 38 million m3 of groundwater being discharged yearly to the Mediterranean Sea along Gaza coast. Nutrient samples were taken along Gaza Strip coastline, and they were compared to the onshore wells, 600 m away from the Mediterranean Sea. The results show that SGD has higher NO3− + NO2− than nutrient-poor seawater, and that it is close to the onshore results from the wells. This confirms that the source of SGD is groundwater, and not shallow seawater circulation. In a coastal strip of 100 m wide along the Gaza coast, a yearly discharge of over 400 tons of nitrate and 250 tons of ammonium occurs from groundwater to the Mediterranean Sea.

scholarly journals Impact of Over-exploitation in Coastal Groundwater on the Variations in Submarine Groundwater Discharge Rate in a Complex Two Aquifer System by Finite Element Modelling: A Case Study From South India

2021 ◽  
Author(s):  
Sundara Pandian Rajaveni ◽  
Sumadevi Nair Indu ◽  
Karthikeyan Brindha ◽  
Lakshmanan Elango
Keyword(s):  
Seawater Intrusion ◽  
Submarine Groundwater Discharge ◽  
Discharge Rate ◽  
Groundwater Discharge ◽  
Aquifer System ◽  
Coastal Groundwater ◽  
Submarine Groundwater ◽  
Over Exploitation ◽  
The Impact

Abstract The purpose of this study is to understand the impact of coastal groundwater over-exploitation on the variations in submarine groundwater discharge (SGD) flux rate and seawater exchange flux across the seabed. As a case study, numerical modelling techniques were applied to a complex multi-aquifer system located north of Chennai, India, which has been affected since the mid-1970s by overexploitation and seawater intrusion. Because of the relatively high hydraulic conductivity, the model shows a higher amount of seawater inflow in the central part of the region. From 2000 to 2012, the movement of seawater has increased from 17,000 m3/day to 24,500 m3/day due to groundwater overexploitation from the semi-confined aquifer. However, the quantum of flux from the sea to the aquifer has been reduced from the year 2006 due to the termination of pumping from a well field supplying a part of the city’s water supply. Model simulations show that fresh groundwater of 43,312 m3/day and saltwater of 43,815 m3/day will be discharged to the aquifer by the end of 2030. In addition to the prevailing condition, various management scenarios were also predicted to prevent the degradation of groundwater quality due to seawater intrusion. By adopting managed aquifer recharge methods, saltwater intrusion (rate of 4408 m3/day) can be reduced and SGD (rate of 22414 m3/day) rate increased. Findings from this study are expected to enhance the understanding of SGD and freshwater budget in coastal areas and in creating integrated coastal management plans.

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