scholarly journals Scrutinizing Relationships between Submarine Groundwater Discharge and Upstream Areas Using Thermal Remote Sensing: A Case Study in the Northern Persian Gulf

2021 ◽  
Vol 13 (3) ◽  
pp. 358
Author(s):  
Aliakbar Nazari Samani ◽  
Mohsen Farzin ◽  
Omid Rahmati ◽  
Sadat Feiznia ◽  
Gholam Abbas Kazemi ◽  
...  
Keyword(s):  
Sustainable Development ◽  
Persian Gulf ◽  
Submarine Groundwater Discharge ◽  
Groundwater Discharge ◽  
Coastal Areas ◽  
Sensor Data ◽  
Landsat 8 ◽  
Assessment Procedure ◽  
Topographic Wetness Index ◽  
Submarine Groundwater

Nutrient input through submarine groundwater discharge (SGD) often plays a significant role in primary productivity and nutrient cycling in the coastal areas. Understanding relationships between SGD and topo-hydrological and geo-environmental characteristics of upstream zones is essential for sustainable development in these areas. However, these important relationships have not yet been completely explored using data-mining approaches, especially in arid and semi-arid coastal lands. Here, Landsat 8 thermal sensor data were used to identify potential sites of SGD at a regional scale. Relationships between the remotely-sensed sea surface temperature (SST) patterns and geo-environmental variables of upland watersheds were analyzed using logistic regression model for the first time. The accuracy of the predictions was evaluated using the area under the receiver operating characteristic curve (AUC-ROC) metric. A highly accurate model, with the AUC-ROC of 96.6%, was generated. Moreover, the results indicated that the percentage of karstic lithological formation and topographic wetness index were key variables influencing SGD phenomenon and spatial distribution in the northern coastal areas of the Persian Gulf. The adopted methodology and applied metrics can be transferred to other coastal regions as a rapid assessment procedure for SGD site detection. Moreover, the results can help planners and decision-makers to develop efficient environmental management strategies and the design of comprehensive sustainable development policies.

scholarly journals Application of Stable Isotopes of Water to Study Coupled Submarine Groundwater Discharge and Nutrient Delivery

Water ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1842 ◽  
Author(s):  
Duque ◽  
Jessen ◽  
Tirado-Conde ◽  
Karan ◽  
Engesgaard
Keyword(s):  
Stable Isotopes ◽  
Submarine Groundwater Discharge ◽  
Water Quality Management ◽  
Groundwater Discharge ◽  
Coastal Areas ◽  
Anthropogenic Activity ◽  
Submarine Groundwater ◽  
Negative Effect ◽  
Stable Isotopes Of Water ◽  
Inorganic Phosphorous

Submarine groundwater discharge (SGD)—including terrestrial freshwater, density-driven flow at the saltwater–freshwater interface, and benthic exchange—can deliver nutrients to coastal areas, generating a negative effect in the quality of marine water bodies. It is recognized that water stable isotopes (18O and 2H) can be helpful tracers to identify different flow paths and origins of water. Here, we show that they can be also applied when assessing sources of nutrients to coastal areas. A field site near a lagoon (Ringkøbing Fjord, Denmark) has been monitored at a metric scale to test if stable isotopes of water can be used to achieve a better understanding of the hydrochemical processes taking place in coastal aquifers, where there is a transition from freshwater to saltwater. Results show that 18O and 2H differentiate the coastal aquifer into three zones: Freshwater, shallow, and deep saline zones, which corresponded well with zones having distinct concentrations of inorganic phosphorous. The explanation is associated with three mechanisms: (1) Differences in sediment composition, (2) chemical reactions triggered by mixing of different type of fluxes, and (3) biochemical and diffusive processes in the lagoon bed. The different behaviors of nutrients in Ringkøbing Fjord need to be considered in water quality management. PO4 underneath the lagoon exceeds the groundwater concentration inland, thus demonstrating an intra-lagoon origin, while NO3, higher inland due to anthropogenic activity, is denitrified in the study area before reaching the lagoon.

scholarly journals Applicability of Landsat 8 Thermal Infrared Sensor to Identify Submarine Groundwater Discharge Springs in the Mediterranean Sea Basin

2020 ◽  
Author(s):  
Sònia Jou-Claus ◽  
Albert Folch ◽  
Jordi Garcia-Orellana
Keyword(s):  
Mediterranean Sea ◽  
Submarine Groundwater Discharge ◽  
Regional Scale ◽  
Groundwater Discharge ◽  
Thermal Infrared ◽  
Landsat 8 ◽  
Infrared Sensor ◽  
Hydrogeological Characteristics ◽  
Submarine Groundwater ◽  
The Mediterranean

Abstract. Submarine groundwater discharge (SGD) has received increasing attention over the past two decades as a source of nutrients, trace elements and pollutants to the ocean that may alter coastal biogeochemical cycles. Assessing submarine groundwater flows and their impacts on coastal marine environments is a difficult task since it is not easy to identify and measure these water flows discharging into the sea. The aim of this study is to prove the great usefulness of the freely-available thermal infrared (TIR) imagery of the Landsat 8 thermal infrared sensor (TIRS) as an exploratory tool to identify SGD springs worldwide, from local to regional scales, for long-term analysis. The use of satellite thermal data as a technique to identify SGD springs in seawater is based on the identification of thermally-anomalous plumes obtained from the thermal contrasts between groundwater and sea surface water. We propose a conceptual framework to apply this technique worldwide and also discuss the limitations of using this technique in SGD studies. The study was developed on a regional scale in karstic coastal aquifers in the Mediterranean Sea basin at different seasons and diverse meteorological conditions. Although this study demonstrates that the freely-available satellite TIR remote sensing is a useful method to identify coastal springs in karst aquifers both locally and regionally, the limiting factors include technical limitations, geological/hydrogeological characteristics, environmental and marine conditions and coastal geomorphology.

scholarly journals Investigation of Submarine Groundwater Discharge using Thermal Satellite and Radon mapping along the East Coast of the Tamil Nadu and Pondicherry Region, India

2021 ◽  
pp. 1-18
Author(s):  
Rajesh Kanna A ◽  
Srinivasamoorthy K ◽  
Ponnumani G ◽  
Babu C ◽  
Prakash R ◽  
...  
Keyword(s):  
Submarine Groundwater Discharge ◽  
Tamil Nadu ◽  
Hydrological Cycle ◽  
Chemical Constituents ◽  
Groundwater Discharge ◽  
Thermal Infrared ◽  
Landsat 8 ◽  
Infrared Images ◽  
Thermal Infrared Images ◽  
Submarine Groundwater

Submarine groundwater discharge (SGD) demarcated as a significant component of hydrological cycle found to discharge greater volumes of terrestrial fresh and recirculated seawater to the ocean associated with chemical constituents (nutrients, metals, and organic compounds) aided by downward hydraulic gradient and sediment-water exchange. Delineating SGD is of primal significance due to the transport of nutrients and contaminants due to domestic, industrial, and agricultural practices that influence the coastal water quality, ecosystems, and geochemical cycles. An attempt has been made to demarcate the SGD using thermal infrared images and radon-222 (222Rn) isotope. Thermal infrared images processed from LANDSAT-8 data suggest prominent freshwater fluxes with higher temperature anomalies noted in Cuddalore and Nagapattinam districts, and lower temperature noted along northern and southern parts of the study area suggest saline/recirculated discharge. Groundwater samples were collected along the coastal regions to analyze Radon and Physico-chemical constituents. Radon in groundwater ranges between 127.39 Bq m-3 and 2643.41 Bq m-3 with an average of 767.80 Bq m-3. Calculated SGD fluxes range between -1.0 to 26.5 with an average of 10.32 m day-1. Comparison of the thermal infrared image with physio-chemical parameters and Radon suggest fresh, terrestrial SGD fluxes confined to the central parts of the study area and lower fluxes observed along with the northern and southern parts of the study area advocate impact due to seawater intrusion and recirculated seawater influence.

scholarly journals Applicability of Landsat 8 thermal infrared sensor for identifying submarine groundwater discharge springs in the Mediterranean Sea basin

2021 ◽  
Vol 25 (9) ◽  
pp. 4789-4805
Author(s):  
Sònia Jou-Claus ◽  
Albert Folch ◽  
Jordi Garcia-Orellana
Keyword(s):  
Remote Sensing ◽  
Mediterranean Sea ◽  
Submarine Groundwater Discharge ◽  
Groundwater Discharge ◽  
Thermal Infrared ◽  
Limiting Factors ◽  
Landsat 8 ◽  
Infrared Sensor ◽  
Submarine Groundwater ◽  
The Mediterranean

Abstract. Submarine groundwater discharge (SGD) has received increasing attention over the past 2 decades as a source of nutrients, trace elements and ocean pollutants that may alter coastal biogeochemical cycles. Assessing SGD flows and their impact on coastal marine environments is a difficult task, since it is not easy to identify and measure these water flows discharging into the sea. The aim of this study is to demonstrate the significant usefulness of the freely available thermal infrared (TIR) imagery of the Landsat 8 thermal infrared sensor (TIRS) as an exploratory tool for identifying SGD springs worldwide, from local to regional scales, for long-term analysis. The use of satellite thermal data as a technique for identifying SGD springs in seawater is based on the identification of thermally anomalous plumes obtained from the thermal contrasts between groundwater and sea surface water. In this study, we use the TIR remote sensing (TIR-RS) imagery provided by Landsat 8 at a regional scale and discuss the principle limiting factors of using this technique in SGD studies. The study was developed in karstic coastal aquifers in the Mediterranean Sea basin during different seasons and under diverse meteorological conditions. Although this study demonstrates that freely available satellite TIR remote sensing is a useful method for identifying coastal springs in karst aquifers both locally and regionally, the limiting factors include technical limitations, geological and hydrogeological characteristics, environmental and marine conditions and coastal geomorphology.

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