A Review of Surrogate Models and Their Ensembles to Develop Saltwater Intrusion Management Strategies in Coastal Aquifers

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.

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

Journal of Hydroinformatics ◽

10.2166/hydro.2018.087 ◽

2018 ◽

Vol 20 (6) ◽

pp. 1247-1267 ◽

Cited By ~ 3

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.

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Development and Implementation of Support Vector Machine Regression Surrogate Models for Predicting Groundwater Pumping-Induced Saltwater Intrusion into Coastal Aquifers

Water Resources Management ◽

10.1007/s11269-018-1936-2 ◽

2018 ◽

Vol 32 (7) ◽

pp. 2405-2419 ◽

Cited By ~ 19

Author(s):

Alvin Lal ◽

Bithin Datta

Keyword(s):

Support Vector Machine ◽

Coastal Aquifers ◽

Saltwater Intrusion ◽

Surrogate Models ◽

Support Vector ◽

Groundwater Pumping ◽

Support Vector Machine Regression

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

Geophysics ◽

10.1190/geo2012-0004.1 ◽

2013 ◽

Vol 78 (2) ◽

pp. B77-B88 ◽

Cited By ~ 13

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.

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