Twenty five years of operational experience using GW modeling to evaluate sustainable use of coastal aquifers for major water supplies

2015 ◽  
Vol 10 (3) ◽  
pp. 465-473
Author(s):  
B. M. Harley ◽  
M. Gamache ◽  
K. K. Masterson ◽  
R. H. Fitzgerald
Keyword(s):  
Sustainable Development ◽  
Coastal Aquifers ◽  
Saltwater Intrusion ◽  
Large Scale ◽  
Groundwater Resources ◽  
Management Strategies ◽  
Operational Experience ◽  
Aquifer System ◽  
Southeastern Us ◽  
Groundwater Supply

The sustainable development and management of groundwater resources in coastal aquifers is complex and, historically, challenging to accomplish. Groundwater models play an essential role in addressing these complexities and providing the basis for planning future sustainable development. For more than 25 years, the authors have applied three-dimensional groundwater models to manage large scale coastal aquifers. The paper will present case studies demonstrating the application of groundwater models to evaluate conditions in complex coastal environments and to develop sustainable groundwater management strategies. These studies include Long Island, a sole source aquifer system in New York serving nearly 3 million people; aquifers in Southern California where injection barriers are used to prevent saltwater intrusion; and Savannah, Georgia in the southeastern US, where concentrated groundwater pumping has contributed to saltwater intrusion at a nearby resort island, and planning is underway to ensure a sustainable groundwater supply to both local industries and municipalities.

Application and evaluation of electromagnetic methods for imaging saltwater intrusion in coastal aquifers: Seaside Groundwater Basin, California

Geophysics ◽  
2013 ◽  
Vol 78 (2) ◽  
pp. B77-B88 ◽  
Author(s):  
Vanessa Nenna ◽  
Daan Herckenrath ◽  
Rosemary Knight ◽  
Nick Odlum ◽  
Darcy McPhee
Keyword(s):  
Coastal Aquifers ◽  
Saltwater Intrusion ◽  
Groundwater Resources ◽  
Management Strategies ◽  
Geophysical Methods ◽  
Unconfined Aquifer ◽  
Data Sets ◽  
Data Set ◽  
Aquifer System ◽  
Spatial Coverage

Developing effective resource management strategies to limit or prevent saltwater intrusion as a result of increasing demands on coastal groundwater resources requires reliable information about the geologic structure and hydrologic state of an aquifer system. A common strategy for acquiring such information is to drill sentinel wells near the coast to monitor changes in water salinity with time. However, installation and operation of sentinel wells is costly and provides limited spatial coverage. We studied the use of noninvasive electromagnetic (EM) geophysical methods as an alternative to installation of monitoring wells for characterizing coastal aquifers. We tested the feasibility of using EM methods at a field site in northern California to identify the potential for and/or presence of hydraulic communication between an unconfined saline aquifer and a confined freshwater aquifer. One-dimensional soundings were acquired using the time-domain electromagnetic (TDEM) and audiomagnetotelluric (AMT) methods. We compared inverted resistivity models of TDEM and AMT data obtained from several inversion algorithms. We found that multiple interpretations of inverted models can be supported by the same data set, but that there were consistencies between all data sets and inversion algorithms. Results from all collected data sets suggested that EM methods are capable of reliably identifying a saltwater-saturated zone in the unconfined aquifer. Geophysical data indicated that the impermeable clay between aquifers may be more continuous than is supported by current models.

scholarly journals Trained meta-models and evolutionary algorithm based multi-objective management of coastal aquifers under parameter uncertainty

2018 ◽  
Vol 20 (6) ◽  
pp. 1247-1267 ◽  
Author(s):  
Dilip Kumar Roy ◽  
Bithin Datta
Keyword(s):  
Coastal Aquifers ◽  
Parameter Uncertainty ◽  
Saltwater Intrusion ◽  
Management Strategies ◽  
Groundwater Extraction ◽  
Aquifer Recharge ◽  
Meta Model ◽  
Aquifer System ◽  
Multi Objective ◽  
Input Parameters

Abstract Meta-model based coupled simulation-optimization methodology is an effective tool in developing sustainable saltwater intrusion management strategies for coastal aquifers. Such management strategies largely depend on the accuracy, reliability, and computational feasibility of meta-models and the numerical simulation model. However, groundwater models are associated with a certain amount of uncertainties, e.g. parameter uncertainty and uncertainty in prediction. This study addresses uncertainties related to input parameters of the groundwater flow and transport system by using a set of randomized input parameters. Three meta-models are compared to characterize responses of water quality in coastal aquifers due to groundwater extraction patterns under parameter uncertainty. The ensemble of the best meta-model is then coupled with a multi-objective optimization algorithm to develop a saltwater intrusion management model. Uncertainties in hydraulic conductivity, compressibility, bulk density, and aquifer recharge are incorporated in the proposed approach. These uncertainties in the physical system are captured by the meta-models whereas the prediction uncertainties of meta-models are further addressed by the ensemble approach. An illustrative multi-layered coastal aquifer system is used to demonstrate the feasibility of the proposed approach. Evaluation results indicate the capability of the proposed approach to develop accurate and reliable management strategies for groundwater extraction to control saltwater intrusion.

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 Managing saltwater intrusion in coastal arid regions and its societal implications for agriculture

2016 ◽  
Vol 373 ◽  
pp. 31-35 ◽  
Author(s):  
Jens Grundmann ◽  
Ayisha Al-Khatri ◽  
Niels Schütze
Keyword(s):  
Saltwater Intrusion ◽  
Saline Water ◽  
Management Strategies ◽  
Point Of View ◽  
Decision Makers ◽  
Societal Implications ◽  
Irrigated Agriculture ◽  
Natural Rate ◽  
Aquifer System ◽  
Management Interventions

Abstract. Coastal aquifers in arid and semiarid regions are particularly at risk due to intrusion of salty marine water. Since groundwater is predominantly used in irrigated agriculture, its excessive pumping – above the natural rate of replenishment – strengthen the intrusion process. Using this increasingly saline water for irrigation, leads to a destruction of valuable agricultural resources and the economic basis of farmers and their communities. The limitation of resources (water and soil) in these regions requires a societal adaptation and change in behaviour as well as the development of appropriate management strategies for a transition towards stable and sustainable future hydrosystem states. Besides a description of the system dynamics and the spatial consequences of adaptation on the resources availability, the contribution combines results of an empirical survey with stakeholders and physically based modelling of the groundwater-agriculture hydrosystem interactions. This includes an analysis of stakeholders' (farmers and decision makers) behaviour and opinions regarding several management interventions aiming on water demand and water resources management as well as the thinking of decision makers how farmers will behave. In this context, the technical counter measures to manage the saltwater intrusion by simulating different groundwater pumping strategies and scenarios are evaluated from the economic and social point of view and if the spatial variability of the aquifer's hydrogeology is taken into consideration. The study is exemplarily investigated for the south Batinah region in the Sultanate of Oman, which is affected by saltwater intrusion into a coastal aquifer system due to excessive groundwater withdrawal for irrigated agriculture.

scholarly journals Approach to Groundwater Management towards Sustainable Development in India

2018 ◽  
Vol 7 (1) ◽  
Author(s):  
Y.D. Khare ◽  
Abhay M. Varade
Keyword(s):  
Sustainable Development ◽  
Drinking Water ◽  
Groundwater Management ◽  
Water Conservation ◽  
Management Practices ◽  
Groundwater Resources ◽  
Management Strategies ◽  
Controlling Factors ◽  
Factors Affecting ◽  
Groundwater Assessment

The management of groundwater resources for sustainable development is a challenging task in India because of its vast geographical extent (3287000 km2), where about 1250 million people live. As a result, the Country is facing scarcity of drinking water quite often. This situation compels to adopt management practices for the development of sustainable groundwater resources. The objective of the paper is to focus on need of adoption of appropriate management strategies for sustainable development of groundwater resources. In view of this the groundwater situation in India as reflected through published literature has been discussed, in which the causes of scarcity, aquifer situation, and groundwater assessment in India have been explained. Based on this study the future approach for groundwater management to achieve the objective of sustainable development has been suggested. This paper provides insight to all the controlling factors affecting groundwater resources in India. Based on this, suggestions for future implementation of water conservation programmes have also been discussed. The present study shows that despite availability of ample groundwater resources the country faces drinking water scarcity quite often. This fact needs further analysis of scarcity situation to provide everlasting solution of problems related to groundwater.

scholarly journals Effects of Aquifer Bed Slope and Sea Level on Saltwater Intrusion in Coastal Aquifers

Hydrology ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 5 ◽  
Author(s):  
Hany F. Abd-Elhamid ◽  
Ismail Abd-Elaty ◽  
Mohsen M. Sherif
Keyword(s):  
Sea Level ◽  
Groundwater Level ◽  
Coastal Aquifers ◽  
Saltwater Intrusion ◽  
Groundwater Resources ◽  
The Other ◽  
Henry Problem ◽  
Dispersion Zone ◽  
Bed Slope

The quality of groundwater resources in coastal aquifers is affected by saltwater intrusion. Over-abstraction of groundwater and seawater level rise due to climate change accelerate the intrusion process. This paper investigates the effects of aquifer bed slope and seaside slope on saltwater intrusion. The possible impacts of increasing seawater head due to sea level rise and decreasing groundwater level due to over-pumping and reduction in recharge are also investigated. A numerical model (SEAWAT) is applied to well-known Henry problem to assess the movement of the dispersion zone under different settings of bed and seaside slopes. The results showed that increasing seaside slope increased the intrusion of saltwater by 53.2% and 117% for slopes of 1:1 and 2:1, respectively. Increasing the bed slope toward the land decreased the intrusion length by 2% and 4.8%, respectively. On the other hand, increasing the bed slope toward the seaside increased the intrusion length by 3.6% and 6.4% for bed slopes of 20:1 and 10:1, respectively. The impacts of reducing the groundwater level at the land side and increasing the seawater level at the shoreline by 5% and 10% considering different slopes are studied. The intrusion length increased under both conditions. Unlike Henry problem, the current investigation considers inclined beds and sea boundaries and, hence, provides a better representation of the field conditions.

scholarly journals Enhanced groundwater recharge rates and altered recharge sensitivity to climate variability through subsurface heterogeneity

2017 ◽  
Vol 114 (11) ◽  
pp. 2842-2847 ◽  
Author(s):  
Andreas Hartmann ◽  
Tom Gleeson ◽  
Yoshihide Wada ◽  
Thorsten Wagener
Keyword(s):  
Climate Variability ◽  
Groundwater Recharge ◽  
Carbonate Rock ◽  
Large Scale ◽  
Groundwater Resources ◽  
Management Strategies ◽  
Important Variable ◽  
Hydrological Models ◽  
Subsurface Heterogeneity ◽  
Recharge Rates

Our environment is heterogeneous. In hydrological sciences, the heterogeneity of subsurface properties, such as hydraulic conductivities or porosities, exerts an important control on water balance. This notably includes groundwater recharge, which is an important variable for efficient and sustainable groundwater resources management. Current large-scale hydrological models do not adequately consider this subsurface heterogeneity. Here we show that regions with strong subsurface heterogeneity have enhanced present and future recharge rates due to a different sensitivity of recharge to climate variability compared with regions with homogeneous subsurface properties. Our study domain comprises the carbonate rock regions of Europe, Northern Africa, and the Middle East, which cover ∼25% of the total land area. We compare the simulations of two large-scale hydrological models, one of them accounting for subsurface heterogeneity. Carbonate rock regions strongly exhibit “karstification,” which is known to produce particularly strong subsurface heterogeneity. Aquifers from these regions contribute up to half of the drinking water supply for some European countries. Our results suggest that water management for these regions cannot rely on most of the presently available projections of groundwater recharge because spatially variable storages and spatial concentration of recharge result in actual recharge rates that are up to four times larger for present conditions and changes up to five times larger for potential future conditions than previously estimated. These differences in recharge rates for strongly heterogeneous regions suggest a need for groundwater management strategies that are adapted to the fast transit of water from the surface to the aquifers.

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