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1.
A modeling study of seawater intrusion in Alabama Gulf Coast,USA 总被引：4，自引：0，他引：4
A numerical model of variable-density groundwater flow and miscible salt transport is developed to investigate the extent
of seawater intrusion in the Gulf coast aquifers of Alabama, USA. The SEAWAT code is used to solve the density-dependent groundwater
flow and solute transport governing equations. The numerical model is calibrated against the observed hydraulic heads measured
in 1996 by adjusting the zonation and values of hydraulic conductivity and recharge rate. Using the calibrated model and assuming
all the hydrogeologic conditions remain the same as those in 1996, a predictive 40-year simulation run indicates that further
seawater intrusion into the coastal aquifers can occur in the study area. Moreover, the predicted intrusion may be more significant
in the deeper aquifer than the shallower ones. As the population continues to grow and the demand for groundwater pumping
intensifies beyond the 1996 level, it can be expected that the actual extent of seawater intrusion in the future would be
more severe than the model prediction. Better strategies for groundwater development and management will be necessary to protect
the freshwater aquifers from contamination by seawater intrusion.
相似文献
| Jin LinEmail: |
2.
Jaouher Kerrou Philippe Renard Fabien Cornaton Pierre Perrochet 《Hydrogeology Journal》2013,21(2):425-440
A stochastic study of long-term forecasts of seawater intrusion with an application to the Korba aquifer (Tunisia) is presented. Firstly, a geostatistical model of the exploitation rates was constructed, based on a multi-linear regression model combining incomplete direct data and exhaustive secondary information. Then, a new method was designed and used to construct a geostatistical model of the hydraulic conductivity field by combining lithological information and data from hydraulic tests. Secondly, the effects of the uncertainties associated with the pumping rates and the hydraulic conductivity field on the 3D density-dependent transient model were analysed separately and then jointly. The forecasts of the impacts of two different management scenarios on seawater intrusion in the year 2048 were performed by means of Monte Carlo simulations, accounting for uncertainties in the input parameters as well as possible changes of the boundary conditions. Combining primary and secondary data allowed maps of pumping rates and the hydraulic conductivity field to be constructed, despite a lack of direct data. The results of the stochastic long-term forecasts showed that, most probably, the Korba aquifer will be subject to important losses in terms of regional groundwater resources. 相似文献
3.
Ahmed Y. S. Mansour Alper Baba Orhan Gunduz Celalettin Şimşek Alper Elçi Alim Murathan Hasan Sözbilir 《Environmental Earth Sciences》2017,76(22):775
Seawater intrusion is a major problem to freshwater resources especially in coastal areas where fresh groundwater is surrounded and could be easily influenced by seawater. This study presents the development of a conceptual and numerical model for the coastal aquifer of Karareis region (Karaburun Peninsula) in the western part of Turkey. The study also presents the interpretation and the analysis of the time series data of groundwater levels recorded by data loggers. The SEAWAT model is used in this study to solve the density-dependent flow field and seawater intrusion in the coastal aquifer that is under excessive pumping particularly during summer months. The model was calibrated using the average values of a 1-year dataset and further verified by the average values of another year. Five potential scenarios were analyzed to understand the effects of pumping and climate change on groundwater levels and the extent of seawater intrusion in the next 10 years. The result of the analysis demonstrated high levels of electrical conductivity and chloride along the coastal part of the study area. As a result of the numerical model, seawater intrusion is simulated to move about 420 m toward the land in the next 10 years under “increased pumping” scenario, while a slight change in water level and TDS concentrations was observed in “climate change” scenario. Results also revealed that a reduction in the pumping rate from Karareis wells will be necessary to protect fresh groundwater from contamination by seawater. 相似文献
4.
将改进后的遗传算法GA（添加了小生境、Pareto解集过滤器等模块）与变密度地下水流及溶质运移模拟程序SEAWAT-2000相耦合,新开发了变密度地下水多目标模拟优化程序MOSWTGA。将MOSWTGA应用于求解大连周水子地区以控制抽水井所在含水层不发生海水入侵为约束的地下水开采多目标优化管理模型,得到地下水最大开采量与海水入侵面积之间一系列Pareto近似最优解。研究成果不仅为实行合理的地下水资源配置提供了科学的实用模型,同时也为解决多个优化目标下的变密度地下水优化管理问题提供高效可靠的模拟优化工具,具有重要的潜在环境经济效益。 相似文献
5.
Sang Yong Chung Venkatramanan Senapathi Selvam Sekar Tae Hyung Kim 《Hydrogeology Journal》2018,26(6):1875-1885
Monitoring and time-series analysis of the hydrological parameters electrical conductivity (EC), water pressure, precipitation and tide were carried out, to understand the characteristics of the parameter variations and their correlations at a coastal area in Busan, South Korea. The monitoring data were collected at a sharp interface between freshwater and saline water at the depth of 25 m below ground. Two well-logging profiles showed that seawater intrusion has largely expanded (progressed inland), and has greatly affected the groundwater quality in a coastal aquifer of tuffaceous sedimentary rock over a 9-year period. According to the time series analyses, the periodograms of the hydrological parameters present very similar trends to the power spectral densities (PSD) of the hydrological parameters. Autocorrelation functions (ACF) and partial autocorrelation functions (PACF) of the hydrological parameters were produced to evaluate their self-correlations. The ACFs of all hydrologic parameters showed very good correlation over the entire time lag, but the PACF revealed that the correlations were good only at time lag 1. Crosscorrelation functions (CCF) were used to evaluate the correlations between the hydrological parameters and the characteristics of seawater intrusion in the coastal aquifer system. The CCFs showed that EC had a close relationship with water pressure and precipitation rather than tide. The CCFs of water pressure with tide and precipitation were in inverse proportion, and the CCF of water pressure with precipitation was larger than that with tide. 相似文献
6.
Seawater intrusion in the Salalah plain aquifer,Oman 总被引：2，自引：0，他引：2
Salalah is situated on a fresh water aquifer that is replenished during the annual monsoon season. The aquifer is the only
source of water in Salalah city. The rainfall and mist precipitation in the Jabal AlQara recharges the plain with significant
renewable fresh groundwater that has allowed agricultural and industrial development to occur. In Salalah city where groundwater
has been used extensively since the early 1980s for agricultural, industrial and municipal purposes, the groundwater has been
withdrawn from the aquifer more rapidly than it can be replenished by natural recharge. The heavy withdrawal of large quantities
of the groundwater from the aquifer has led to the intrusion of seawater. Agricultural activities utilize over 70% of the
groundwater. For the study of the saltwater intrusion, the area has been divided into four strips, A, B, C and D, on the basis
of land-use in the area. Water samples were collected from 18 water wells. Chemical analysis of major ions and pollution parameters
in the groundwater was carried out and compared to the previous observed values. The electrical conductivity and chloride
concentrations were highest in the agricultural and residential strips and Garziz grass farm. Before 1992 the aquifer was
in a steady state, but presently (2005) the groundwater quality in most of the agricultural and residential strips does not
meet drinking water standards. In addition, model simulations were developed with the computer code MODFLOW and MT3DMS for
solute transport to determine the movement of the freshwater/saltwater interface. The study proposes the protection of the
groundwater in Salalah plain aquifer from further encroachment by artificial recharge with reclaimed water, preferably along
the Salalah coastal agricultural strip. This scheme can also be applied to other regions with similar conditions. 相似文献
7.
The Batinah coastal plain in northern Oman has experienced a severe deterioration of groundwater quality due to seawater intrusion as a result of excessive groundwater abstraction for agricultural irrigation. Upgrading all farms to fully automated irrigation technology based on soil moisture sensors may significantly reduce the water demand and lead to recovering groundwater levels. This study compares the effects of smart irrigation technology, recharge dams, and a combination of both on seawater intrusion in the coastal aquifer of the Batinah. A groundwater flow and transport model is used to simulate the effect of reduced pumping rates on seawater intrusion for various intervention scenarios over a simulation period of 30 years, and an economic analysis based on cost-benefit analysis is conducted to estimate the potential benefits. Results indicate that a combination of smart irrigation and recharge dams may prevent further deterioration of groundwater quality over the next 30 years. In conjunction with increased efficiency, this combination also generates the highest gross profit. This outcome shows that the problem of seawater intrusion needs to be tackled by a comprehensive, integrated intervention strategy. 相似文献
8.
Numerical simulation of sea water intrusion near Beihai, China 总被引：6，自引：0，他引：6
A leaky aquifer system occurs in the coastal plain near Beihai, China. Seawater intrusion into the confined aquifer took
place along the northern coast. Chloride concentrations at some observation wells increased steadily from 1988 and were at
their peak in 1993. A quasi-three-dimensional element model has been developed to simulate the spatial and temporal evolution
of hydraulic heads and chloride concentrations of the groundwater near the northern coast. The simulation model was based
on the transition zone approach, which requires simultaneous solution of the governing water flow and solute transport equations.
An irregular grid of a quadrangle was used to discretize the flow domain. Various aquifer parameters were verified with the
numerical model in order to obtain satisfactory matches between computed values and observed data from an investigation. Three
pumpage schemes were designed to use the calibrated model for prediction of future changes in water levels and chloride concentrations
in groundwater in the study area. Results show that seawater intrusion would worsen in the confined aquifer if the current
rates of groundwater pumpage continue. The alternative, to eliminate pumpage in the intruded area and to moderate pumpage
rates from water supply wells far from the seashore, may limit seawater intrusion significantly and is considered attractive
in the area.
Received: 27 September 1999 · Accepted: 27 December 1999 相似文献
9.
10.
Combined simulation-optimization modeling is an essential tool for coastal groundwater management. However, determining the appropriate simulation-optimization approach for specific seawater intrusion problems remains a significant challenge, especially for the real-world conditions associated with management of complex groundwater systems, competing management objectives, and global concerns of future climate change. In this study, a linked multi-objective simulation-optimization framework, the MOSWTGA (multi-objective optimal code, coupling SEAWAT and an improved genetic algorithm), was applied to a coastal groundwater system in Zhoushuizi district of Dalian City in northern China. The system has fractured karst aquifers and is modelled for the next 20 years (from 2010) under the moderate greenhouse gas concentration scenario RCP4.5 (representative concentration pathways) in the CNRM (Centre National de Recherches Météorologiques) and MIROC (Model for Interdisciplinary Research on Climate) climate modes derived from the Coupled Model Intercomparison Project Phase 5 (CMIP5). The MOSWTGA was developed by integrating the density-dependent groundwater flow and solute transport code SEAWAT with a genetic algorithm improved by adding the Pareto-dominated ranking module, Pareto solution set filter, and fitness sharing procedure. A set of near Pareto-optimal solutions of the trade-off between the maximum of the total pumping rate and the minimum of the extent of seawater intrusion was obtained. The study tried to provide a theoretical basis for real-world groundwater management under the given conditions.
相似文献11.
Hans-Dieter Vosteen Volker Rath Andreas Schmidt-Mumm Christoph Clauser 《Tectonophysics》2004,386(1-2):81-95
The thermal regime and the distribution of heat flow at the base of sedimentary basins is fundamental to the understanding of the process of basin evolution and the associated mobilization and migration of hydrocarbon and other fluids. For the Northeastern-German sedimentary basin, available information on structure, temperature, and thermal properties along a seismic DEKORP reflection profile allow high resolution 2-D forward and inverse simulations. This approach is attractive in situations where much information is available, if only with considerable uncertainty. In particular, this allows to introduce “soft” information into the analysis. In our case, forward simulations yield initial a priori estimates of the parameters while inversion calculations yield a posteriori estimates of the parameters and their uncertainty. The a priori parameters as well as their assumed uncertainty are input for a Bayesian parameter estimation scheme. In respect to the Northeastern-German sedimentary basin, the inverse analysis postulates a significant and characteristic a posteriori variation of thermal conductivity of the Zechstein unit along the entire profile as well as a generally large a posteriori thermal conductivity of the (pre-Permian) basement in the northern part of the basin. For inverse calculations, we used two alternative scenarios: One assumes the thermal conductivity of the Zechstein unit to be homogeneous along the profile while the other allows a lateral variation. A posteriori heat flow across the base of the model varies from 40 to 60 and 50 to 65 mW m−2 for models in which values for thermal conductivity and radiogenic heat generation rate were either based on literature values or direct measurements, respectively. 相似文献
12.
Bordbar Mojgan Neshat Aminreza Javadi Saman Pradhan Biswajeet Dixon Barnali Paryani Sina 《Natural Hazards》2022,110(3):1799-1820
The main objective of this study is to integrate adaptive neuro-fuzzy inference system (ANFIS), support vector machine (SVM) and artificial neural network (ANN) to design an integrated supervised committee machine artificial intelligence (SCMAI) model to spatially predict the groundwater vulnerability to seawater intrusion in Gharesoo-Gorgan Rood coastal aquifer placed in the northern part of Iran. Six hydrological GALDIT parameters (i.e., G groundwater occurrence, A aquifer hydraulic conductivity, L level of groundwater above sea level, D distance from the shore, I impact of the existing status of seawater intrusion in the region, and T thickness of the aquifer) were considered as inputs for each model. In the training step, the values of GALDIT’s vulnerability index were conditioned by using the values of TDS concentration in order to obtain the conditioned vulnerability index (CVI). The CVI was considered as the target for each model. After training the models, each model was tested using a separate TDS dataset. The results indicated that the ANN and ANFIS algorithms performed better than the SVM algorithm. The values of correlation were obtained as 88, 87, and 80% for ANN, ANFIS, and SVM models, respectively. In the testing step of the SCMAI model, the values of RMSE, R2, and r were obtained as 6.4, 0.95, and 97%, respectively. Overall, SCMAI model outperformed other models to spatially predicting vulnerable zones. The result of the SCMAI model confirmed that the western zones along the shoreline had the highest vulnerability to seawater intrusion; therefore, it seems critical to consider emergency protection plans for study area.
Graphic abstract13.
GIS-based GALDIT method for vulnerability assessment to seawater intrusion of the Quaternary coastal Collo aquifer (NE-Algeria) 总被引：1，自引：0，他引：1
Boulabeiz Mahrez Stefan Klebingat Belgacem Houha Bousnoubra Houria 《Arabian Journal of Geosciences》2018,11(4):71
The overexploitation of groundwater in coastal aquifers is often accompanied by seawater intrusion, intensified by climate change and sea level rise. Heading long-term water quality safety and thus the determination of vulnerable zones to seawater intrusion becomes a significant hydrogeological task for many coastal areas. Due to this background, the present study focussed the established methodology of the GIS-based GALDIT model to assess the aquifer vulnerability to seawater intrusion for the Algerian example of the Quaternary coastal Collo aquifer. According to the result analysis overall, more than half of the total surface of the northern study area can be classified as highly vulnerable. Besides the coastline, the areas nearby the local wadis of Guebli and Cherka occur to be the most vulnerable in the region. In view of further map removal performance as well as single-parameter sensitivity analyses from a coupled perspective respectively the GALDIT parameters, distance from the shore (D) and aquifer hydraulic conductivity (A) have been found to be of key significance regarding the model results (mean effective weightings ~?18–19%). Overall, the study results provide a good approximation basis for future management decisions of the Collo aquifer region, including various perspectives such as identification of suitable settings for prospective groundwater pumping wells. 相似文献
14.
An iterative inverse method, the sequential self-calibration method, is developed for mapping spatial distribution of a hydraulic
conductivity field by conditioning on nonreactive tracer breakthrough curves. A streamline-based, semi-analytical simulator
is adopted to simulate solute transport in a heterogeneous aquifer. The simulation is used as the forward modeling step. In
this study, the hydraulic conductivity is assumed to be a deterministic or random variable. Within the framework of the streamline-based
simulator, the efficient semi-analytical method is used to calculate sensitivity coefficients of the solute concentration
with respect to the hydraulic conductivity variation. The calculated sensitivities account for spatial correlations between
the solute concentration and parameters. The performance of the inverse method is assessed by two synthetic tracer tests conducted
in an aquifer with a distinct spatial pattern of heterogeneity. The study results indicate that the developed iterative inverse
method is able to identify and reproduce the large-scale heterogeneity pattern of the aquifer given appropriate observation
wells in these synthetic cases. 相似文献
15.
C. Singaraja S. Chidambaram P. Anandhan M. V. Prasanna C. Thivya R. Thilagavathi J. Sarathidasan 《Arabian Journal of Geosciences》2014,7(3):939-950
A hydrogeochemical study was conducted in Thoothukudi district situated in the southeast coast of Tamil Nadu, India to identify the influence of saltwater intrusion and suitability of groundwater for domestic and agricultural purposes. Scattered studies of this coastal region have reported signs of seawater intrusion, salt pan and industrial activity together with natural weathering process. To have a holistic picture of geochemical processes in the entire district, a total of 135 groundwater samples were collected and analyzed for major cations and anions. The geochemical parameters were compared with world and Indian standards and it was found that most samples are unsuitable for drinking purpose. The geochemical facies of the groundwater showed Na–Cl as the dominant water type indicating the saline nature of the groundwater. Chadda’s plots show that most of the samples fall in the Na–Cl type of water due to seawater intrusion. The samples were classified with parameters like sodium absorption ratio, residual sodium carbonate, total hardness, chloride, index to base exchange, electrical conductivity and facies to determine their suitability for irrigation purpose. It was inferred that the samples falling along the coast are not suitable for the irrigation purpose. The seawater-mixing percentage indicates that strong mixing was observed in the near shore and at the proximity of the salt pan. The permanent hardness was predominant in all the samples compared to the carbonate hardness reducing its domestic usability. 相似文献
16.
Evaluation of groundwater quality in coastal areas: implications for sustainable agriculture 总被引：4，自引：1，他引：4
Seawater intrusion is a problem in the coastal areas of Korea. Most productive agricultural fields are in the western and
southern coastal areas of the country where irrigation predominantly relies on groundwater. Seawater intrusion has affected
agricultural productivity. To evaluate progressive encroachment of saline water, the Korean government established a seawater
intrusion monitoring well network, especially in the western and southern part of the peninsula. Automatic water levels and
EC monitoring and periodic chemical analysis of groundwater help track salinization. Salinization of fresh groundwater is
highly associated with groundwater withdrawal. A large proportion of the groundwaters are classified as Na–Cl and Ca–Cl types.
The Na–Cl types represent effects of seawater intrusion. The highest EC level was over 1.6 km inland and high Cl values were
observed up to 1.2 km inland. Lower ratios of Na/Cl and SO4/Cl than seawater values indicate the seawater encroachment. A linear relation between Na and Cl represents simple mixing
of the fresh groundwater with the seawater. The saline Na–Cl typed groundwaters showed Br/Cl ratios similar to or less than
seawater values. The Ca–HCO3 type groundwaters had the highest Br/Cl ratios. Substantial proportions of the groundwaters showed potential for salinity
and should be better managed for sustainable agriculture. 相似文献
17.
Xiaoru Su Longcang Shu Xunhong Chen Chengpeng Lu Zhonghui Wen 《Hydrogeology Journal》2016,24(8):2035-2047
Interactions between surface waters and groundwater are of great significance for evaluating water resources and protecting ecosystem health. Heat as a tracer method is widely used in determination of the interactive exchange with high precision, low cost and great convenience. The flow in a river-bank cross-section occurs in vertical and lateral directions. In order to depict the flow path and its spatial distribution in bank areas, a genetic algorithm (GA) two-dimensional (2-D) heat-transport nested-loop method for variably saturated sediments, GA-VS2DH, was developed based on Microsoft Visual Basic 6.0. VS2DH was applied to model a 2-D bank-water flow field and GA was used to calibrate the model automatically by minimizing the difference between observed and simulated temperatures in bank areas. A hypothetical model was developed to assess the reliability of GA-VS2DH in inverse modeling in a river-bank system. Some benchmark tests were conducted to recognize the capability of GA-VS2DH. The results indicated that the simulated seepage velocity and parameters associated with GA-VS2DH were acceptable and reliable. Then GA-VS2DH was applied to two field sites in China with different sedimentary materials, to verify the reliability of the method. GA-VS2DH could be applied in interpreting the cross-sectional 2-D water flow field. The estimates of horizontal hydraulic conductivity at the Dawen River and Qinhuai River sites are 1.317 and 0.015 m/day, which correspond to sand and clay sediment in the two sites, respectively. 相似文献
18.
Application of a newly developed column test device to analyze seawater transport in sandy soils 总被引：2，自引：1，他引：1
Xiaoqiang Dong Heesoo Woo Hisoo Park Junboum Park 《Environmental Earth Sciences》2013,70(5):2397-2404
To verify the applicability of the time-continuous electrical conductivity (EC) measurement in analyzing the contaminant movement in the subsurface, a new column test device employing non-destructive four-electrode sensors was developed. Using the seawater to create a simple one-dimensional steady-flow condition, laboratory transport experiments were conducted and the EC breakthrough curves at different distances were obtained. Comparison between the EC breakthrough curves obtained from the EC sensors and those from the effluent solute chemical analysis showed that the estimated resident concentration from the EC breakthrough curves are useful in understanding solute transport in soils. The pore water velocity and longitudinal dispersion coefficient estimated using the computer code, CXTFIT, were found to be slightly underestimated, especially at sensors located at smaller distances from the outlet boundary. Results showed that the developed column test device employing the four-electrode sensors proposed in this study provides a non-destructive, convenient, and inexpensive means of evaluating the seawater transporting in soils. 相似文献
19.
20.
Khomine Abedelrahem Allow 《Arabian Journal of Geosciences》2011,4(3-4):645-653
Overexploitation of shallow aquifers on the Syrian coast, north of Latakia (Damsarkho) for irrigation and tourism has caused an intrusion of seawater. The seawater intrusion into this aquifer has been presented by a three-dimensional finite element model using the FEFLOW numerical code. This conceptual model is based on field and laboratory data collected during the period 1966–2003. Meteoric infiltration and flows from the adjoining carbonate aquifer recharge the aquifer; natural outflow occurs through a diffuse flow into the sea; and artificial outflow occurs through intensive extraction of groundwater from wells. Water exchanges in the aquifer occur naturally (leakage) and artificially (multi-screened wells). The model was calibrated for transient conditions. The model helped establish that seawater intrusion is essentially due to withdrawals near the coast during the irrigation season and that it mainly occurs in the Damsarkho plain. The effects of hypothetical aquifer exploitation were assessed in terms of salt budget. 相似文献