scholarly journals Offshore fresh groundwater in coastal unconsolidated sediment systems as a potential fresh water source in the 21st century

2021 ◽  
Author(s):  
Daniel Zamrsky ◽  
Gualbert Oude Essink ◽  
Edwin Sutanudjaja ◽  
Rens van Beek ◽  
Marc F P Bierkens
Keyword(s):  
Fresh Water ◽  
Coastal Aquifers ◽  
Groundwater Resources ◽  
Water Source ◽  
Groundwater Exploration ◽  
Coastal Areas ◽  
Fresh Groundwater ◽  
Sea Levels ◽  
Long Run ◽  
Groundwater Reserves

Abstract Coastal areas worldwide are often densely populated and host regional agricultural and industrial hubs. Strict water quality requirements for agricultural, industrial and domestic use are often not satisfied by surface waters in coastal areas and consequently lead to over-exploitation of local fresh groundwater resources. Additional pressure by both climate change and population growth further intensifies the upcoming water stress and raise the urgency to search for new fresh water sources. In recent years, offshore fresh groundwater reserves have been identified as such a potential water source. In this study, we quantify, for the first time, the global volume of offshore fresh groundwater in unconsolidated coastal aquifers and show that it is a viable option as additional fresh water source in coastal areas. Our results confirm previously reported widespread presence of offshore fresh groundwater along the global coastline. Furthermore, we find that these reserves are likely non-renewable as they were deposited during glacial periods when sea levels were substantially lower compared to current sea level. We estimate the total offshore fresh groundwater volume in unconsolidated coastal aquifers to be approximately 1.06 ± 0.2 million km³, which is roughly three times more than estimated previously and about 10% of all terrestrial fresh groundwater. With extensive active and inactive offshore oil pumping present in areas of large offshore fresh groundwater reserves, they could be considered for temporary fresh groundwater exploration as part of a transition to sustainable water use in coastal areas on the long run.

scholarly journals Estimating the thickness of unconsolidated coastal aquifers along the global coastline

2018 ◽  
Author(s):  
Daniel Zamrsky ◽  
Gualbert H. P. Oude Essink ◽  
Marc F. P. Bierkens
Keyword(s):  
Groundwater Flow ◽  
Coastal Aquifers ◽  
Groundwater Resources ◽  
Regional Scale ◽  
Unconsolidated Sediments ◽  
Coastal Zones ◽  
Fresh Groundwater ◽  
Flow Models ◽  
Groundwater Flow Modelling ◽  
Groundwater Reserves

Abstract. Knowledge of the thickness of aquifers is crucial for setting up numerical groundwater flow models in support of the management and control of groundwater resources. Fresh groundwater reserves in coastal aquifers are particularly under threat of salinization and depletion as a result of climate change, sea-level rise, and excessive groundwater withdrawal under urbanization. To correctly assess the possible impacts of these pressures we must have better information about subsurface conditions in coastal zones. Here, we propose a method that combines available global datasets to estimate, along the global coastline, the thickness of aquifers formed by unconsolidated sediments. To validate our final estimation results, we collected both borehole and literature data. Additionally, we performed a numerical modelling study of the effects of varying aquifer thickness and geological complexity on simulated saltwater intrusion. The results show that our aquifer thickness estimates can indeed be used for regional scale groundwater flow modelling but that for local assessments additional geological information should be included. The final dataset can be downloaded via https://doi.pangaea.de/10.1594/PANGAEA.880771.

Density-dependent 3D FE modelling of a recharge drain to mitigate saltwater contamination at the Venice farmland

2021 ◽  
Author(s):  
Maria Elisa Travaglino ◽  
Pietro Teatini
Keyword(s):  
Coastal Aquifers ◽  
Saltwater Intrusion ◽  
Sea Water ◽  
Transport Model ◽  
Saline Water ◽  
Numerical Models ◽  
Groundwater Resources ◽  
Fe Modelling ◽  
Fresh Groundwater ◽  
Density Dependent

<p>Saltwater intrusion in coastal aquifers is one of the most challenging and worldwide environmental problems, severely affected by human activities and climate change. It represents a threat to the quality and sustainability of fresh groundwater resources in coastal aquifers. Saline water is the most common pollutant in fresh groundwater which can also compromise the agriculture and the economy of the affected regions. Therefore, it is necessary to develop engineering solutions to restore groundwater quality or at least to prevent further degradation of its quality.</p><p>For this purpose, the goal of the Interreg Italy – Croatia MoST (MOnitoring Sea-water intrusion in coastal aquifers and Testing pilot projects for its mitigation) project is to test possible solutions (such as underground barriers, cut-off walls, recharge wells and recharge drains) against saltwater intrusion properly supported by field characterization, laboratory experiments, monitoring of hydrological parameters, and numerical models.</p><p>This works shows the preliminary results of an ongoing modelling study carried out for a coastal farmland at Ca’ Pasqua, in the southern part of the Venice lagoon, in Italy. A three-dimensional finite-element density-dependent groundwater flow and transport model is developed to simulate the dynamics of saltwater intrusion in this lowlying area. The model is used to assess the potential effects of a recharge drain recently established at 1.5 m depth along a sandy paleochannel crossing the organic-silty area. The goal of the intervention is to mitigate the soil and groundwater salinization by spreading freshwater supplied by a nearby canal. The beneficial consequences of the recharge drain should be enhanced by the higher permeability of the paleochannel.</p>

scholarly journals Management of Seawater Intrusion in Coastal Aquifers: A Review

Water ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2467 ◽  
Author(s):  
Mohammed S. Hussain ◽  
Hany F. Abd-Elhamid ◽  
Akbar A. Javadi ◽  
Mohsen M. Sherif
Keyword(s):  
Seawater Intrusion ◽  
Coastal Aquifers ◽  
Arid Regions ◽  
Saline Water ◽  
Groundwater Resources ◽  
Management Strategies ◽  
Environmental Costs ◽  
Fresh Groundwater ◽  
Advantages And Disadvantages ◽  
And Control

Seawater intrusion (SWI) is one of the most challenging and widespread environmental problems that threaten the quality and sustainability of fresh groundwater resources in coastal aquifers. The excessive pumping of groundwater, associated with the lack of natural recharge, has exacerbated the SWI problem in arid and semi-arid regions. Therefore, appropriate management strategies should be implemented in coastal aquifers to control the impacts of SWI problems, considering acceptable limits of economic and environmental costs. The management of coastal aquifers involves the identification of an acceptable ultimate landward extent of the saline water body and the calculation of the amount of seaward discharge of freshwater that is necessary to keep the saline–freshwater interface in a seacoast position. This paper presents a comprehensive review of available hydraulic and physical management strategies that can be used to reduce and control SWI in coastal aquifers. Advantages and disadvantages of the different approaches are presented and discussed.

scholarly journals Modeling Seawater Intrusion to Coastal Aquifers in South Coast of Laizhou Bay, China

2018 ◽  
Vol 54 ◽  
pp. 00004
Author(s):  
Yawen Chang ◽  
Bill X. Hu ◽  
Xue Li
Keyword(s):  
Seawater Intrusion ◽  
Coastal Aquifers ◽  
Saline Water ◽  
Groundwater Resources ◽  
Water Area ◽  
Laizhou Bay ◽  
Precipitation Condition ◽  
Fresh Groundwater ◽  
Depression Cone ◽  
Error Method

In this study, a two-dimensional SEAWAT 2000 model is developed to simulate the seawater intrusion to coastal aquifers and brine water/fresh water interaction in the south of Laizhou Bay, Shandong Province, China and forecast the seawater intrusion and brine water/freshwater interface development in the coming years. The model profile is perpendicular to the coastal line, about 40 km long and 110 m in depth, and consists of two interfaces, freshwater-saline water interface and brine water-saline water-seawater interface. The parameters of aquifers in the SEAWAT-2000 model are calibrated by trial-error method repeatedly to fit the head and salinity measurements. Based on the historical groundwater and brine water exploration and natural precipitation condition, the prediction results indicate that equivalent freshwater head in shallow freshwater-saline water area will decrease year by year and decline 2.0 m in the forecasting period, caused by groundwater over-pumping for irrigating farmlands. The groundwater head in the brine-saline water area will also decrease about 1.8 m in forecasting period. A larger depression cone appears in the brine area, with smaller funnels in other areas. The salinity in the brine area finally drops below 105g/l. In the meanwhile, the salinity increases in other areas, damage fresh groundwater resources.

scholarly journals Coastal Ground Water Flow and Management: A State-of-the-Art Review

2020 ◽  
Vol 14 ◽  
Keyword(s):  
Water Supply ◽  
Saline Water ◽  
Groundwater Resources ◽  
Industrial Effluents ◽  
Cost Effective ◽  
Fresh Groundwater ◽  
Local Climate ◽  
Indiscriminate Disposal ◽  
Groundwater Reserves ◽  
Anthropogenic Intervention

Seawater intrusion has led to salinization of fresh groundwater reserves in coastal areas worldwide and has forced the closure of water supply wells. There is a paucity of well-documented studies that report on the reversal of SWI after the closure of a well field. Saline water from a storm surge can flow down storm-damaged submerged water supply wells and contaminate boreholes and surrounding aquifers. Water is an invaluable commodity in nature and can be a limiting resource to man and other living beings. Water quality is influenced by both natural and anthropogenic intervention where the former includes local climate, geology etc., and the latter covers the construction of dams and embankments, irrigation practices, indiscriminate disposal of industrial effluents etc. Therefore, it is highly desirable to properly manage groundwater resources for drinking-water supply by controlling saltwater intrusion. A cost effective method Abstraction, Desalinization and Recharge was found to be efficient.

scholarly journals Estimating the thickness of unconsolidated coastal aquifers along the global coastline

2018 ◽  
Vol 10 (3) ◽  
pp. 1591-1603 ◽  
Author(s):  
Daniel Zamrsky ◽  
Gualbert H. P. Oude Essink ◽  
Marc F. P. Bierkens
Keyword(s):  
Groundwater Flow ◽  
Coastal Aquifers ◽  
Regional Scale ◽  
Unconsolidated Sediments ◽  
Coastal Zones ◽  
Fresh Groundwater ◽  
Flow Models ◽  
Groundwater Flow Modelling ◽  
Groundwater Reserves ◽  
Geological Complexity

Abstract. Knowledge of aquifer thickness is crucial for setting up numerical groundwater flow models to support groundwater resource management and control. Fresh groundwater reserves in coastal aquifers are particularly under threat of salinization and depletion as a result of climate change, sea-level rise, and excessive groundwater withdrawal under urbanization. To correctly assess the possible impacts of these pressures we need better information about subsurface conditions in coastal zones. Here, we propose a method that combines available global datasets to estimate, along the global coastline, the aquifer thickness in areas formed by unconsolidated sediments. To validate our final estimation results, we collected both borehole and literature data. Additionally, we performed a numerical modelling study to evaluate the effects of varying aquifer thickness and geological complexity on simulated saltwater intrusion. The results show that our aquifer thickness estimates can indeed be used for regional-scale groundwater flow modelling but that for local assessments additional geological information should be included. The final dataset has been made publicly available (https://doi.pangaea.de/10.1594/PANGAEA.880771).

scholarly journals Effect of Groundwater Pumping on Seawater Intrusion in Coastal Aquifers

2002 ◽  
Vol 7 (2) ◽  
pp. 61 ◽  
Author(s):  
M.M. Sherif ◽  
V.P. Singh
Keyword(s):  
Seawater Intrusion ◽  
Coastal Aquifers ◽  
Nile Delta ◽  
Saline Water ◽  
Dynamic Balance ◽  
Coastal Areas ◽  
Groundwater Pumping ◽  
Fresh Groundwater ◽  
Piezometric Head ◽  
Increasing Demand

Many aquifers around the globe are located in coastal areas and are thus subjected to the seawater intrusion phenomenon. The growth of population in coastal areas and the conjugate increase in human, agricultural, and industrial activities have imposed an increasing demand for freshwater. This increase in water demand is often covered by extensive pumping of fresh groundwater, causing subsequent lowering of the water table (or piezometric head) and upsetting the dynamic balance between freshwater and saline water bodies. The classical result of such a development is seawater intrusion. This paper presents a review for the seawater intrusion phenomenon in coastal aquifers. The effect of pumping activities on the seawater intrusion in the Nile Delta aquifer of Egypt is investigated. It was concluded that any additional pumping should be located in the middle Delta and avoided in the eastern and western sides of the Delta. 

Groundwater and salinization risk: tapping works and management experience in the Mediterranean Area

2021 ◽  
Author(s):  
Giorgio De Giorgio ◽  
Livia Emanuela Zuffianò ◽  
Maurizio Polemio
Keyword(s):  
Seawater Intrusion ◽  
Coastal Aquifers ◽  
Groundwater Resources ◽  
Regional Scale ◽  
Mediterranean Area ◽  
Management Approach ◽  
Fresh Groundwater ◽  
Groundwater Exploitation ◽  
Saline Groundwater ◽  
The Mediterranean

<p>The progressive population growth in coastal areas constitutes a huge worldwide problem, particularly relevant for coastal aquifers of the Mediterranean basin.</p><p>The increasing use of groundwater and the effect of seawater intrusion makes the study of coastal aquifers extremely relevant.</p><p>There are various measures, practices, and actions throughout the world for managing groundwater when this natural resource is subject to salinization risk.</p><p>This research focused on the seawater intrusion, classifies the different practical solutions protecting the groundwater through salinization mitigation and/or groundwater salinity improvements along the Mediterranean Area.</p><p>The literature review was based on 300 papers, which are mainly international journal articles (76%). The rest includes conference papers (11.8%), reports and theses (7%), and books or chapters of a book (25%).</p><p>Three main schematic groundwater management approaches can be distinguished for the use of groundwater resources at risk of salinization.</p><p>The <strong>engineering approaches</strong> pursue locally the discharge increase avoiding or controlling the salinity increase.</p><p>The most recent experiences of tapping submarine springs were realized using underground concrete dams, tools shaped like a parachute or tulip, or a fiberglass telescopic tube-bell, especially in the case of karstic aquifers.</p><p>The current widespread form of the engineering approach is to address the issue of groundwater exploitation by wells.</p><p>More complex solutions use subhorizontal designs. Subhorizontal tapping schemes were realized using tunneling and/or boring in combination with wide-diameter wells or shafts.</p><p>These works include horizontal drains or radial tunnels bored inside the saturated aquifer, shafts excavated down to the sea level with radial galleries or drains realized together with weirs to improve the regulation of the discharge rate and of salinization. Application of these solutions in areas where a thin fresh groundwater lens floats on the saline groundwater, as in the case of narrow and highly permeable islands, can yield high discharges, thus causing a very low drawdown over very wide areas. These solutions were successfully applied in Malta Islands.</p><p>The <strong>discharge management approach</strong> encompasses at least an entire coastal aquifer and defines rules concerning groundwater utilization and well discharge.</p><p>A multi-methodological approach based on monitoring networks, spatiotemporal analysis of groundwater quality changes, and multiparameter well logging is described in Apulian karstic coastal aquifers (Italy). The core is the definition of the salinity threshold value between pure fresh groundwater and saline groundwater mixture. The basic tools were defined to be simple and cost-effective to be applicable to the widest range of situations.</p><p>The <strong>water and land management approach</strong> should be applied on a regional scale. The main choice for this approach is pursuing water-saving measures and water demand adaptation. A multiple-users and multiple-resources-water supply system model was implemented to evaluate the effectiveness of the increasing maximum capacity of the surface reservoir and managed aquifer recharge in Apulia, a semi-arid region of Southern Italy.</p>

CURRENT STATE OF THE RESOURCE POTENTIAL OF FRESH GROUNDWATER OF THE KHANTY-MANSI AUTONOMOUS OKRUG

2021 ◽  
pp. 110-116
Author(s):  
A. R. Kurchikov ◽  
◽  
M. V. Vashurina ◽  
V. I. Kozyrev ◽  
◽  
...  
Keyword(s):  
Natural Resources ◽  
Groundwater Resources ◽  
Economic Sectors ◽  
Fresh Groundwater ◽  
Resource Potential ◽  
Current State ◽  
History Of ◽  
Hydrogeological Studies ◽  
Groundwater Reserves ◽  
Khanty Mansi Autonomous

This article examines the resource potential and modern extraction of fresh groundwater for the needs of population and economic sectors in the Khanty-Mansi Autonomous Okrug – Yugra. The history of regional hydrogeological studies on the assessment of natural resources and exploitation reserves of groundwater reserves of the West Siberian mega-basin (WSMB) is revealed. The research results are shown and their comparative analysis is carried out. The article highlights the issue of formation and distribution of natural resources over the area of the considered territory. In conclusion, it is noted that the territory of the Khanty-Mansi Autonomous Okrug – Yugra is sufficiently supplied with natural resources of fresh groundwater (the predicted useful groundwater resources supply is 66.86 m3/day per person). However, more than 20 years have passed since the implementation of regional works on the assessment of predicted groundwater resources in the territory of the Khanty-Mansi Autonomous Okrug. During this period, the water-economic situation in the region has changed significantly, a large amount of factual material, which makes it possible to clarify and probably to revise the previously obtained results has been accumulated.

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