scholarly journals Experimental and Numerical Analysis on Hydraulic Characteristics of Coastal Aquifers with Seawall

Water ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2343 ◽  
Author(s):  
Woo-Dong Lee ◽  
Young-Jae Yoo ◽  
Yeon-Myeong Jeong ◽  
Dong-Soo Hur
Keyword(s):  
Numerical Analysis ◽  
Pressure Gradient ◽  
Groundwater Flow ◽  
Seawater Intrusion ◽  
Flow Rate ◽  
Groundwater Level ◽  
Coastal Aquifers ◽  
Coastal Aquifer ◽  
Hydraulic Characteristics ◽  
Tank Experiment

In this study, hydraulic model experiments were conducted to measure the saltwater–freshwater equilibrium interface in a coastal aquifer with underground obstructions such as an impermeable seawall. To analyse the hydraulic characteristics inside the coastal aquifer, numerical analysis was conducted using a non-hydrostatic Navier-Stokes solver based on the Porous Body Model (PBM), which can directly analyse groundwater flow. A unique saltwater–freshwater equilibrium interface that does not appear in typical coastal aquifer analyses was observed in a sandy tank experiment. In the experiment, the rise of the groundwater level behind the seawall increased the pressure gradient and groundwater flow rate, causing the saltwater–freshwater interface to move towards the sea and a freshwater region to form on the seabed in front of the seawall. The numerical analysis enabled close examination of the groundwater level distribution, groundwater flow, seawater–freshwater interface, and pore water pressure characteristics of the coastal aquifer with underground obstructions. The sandy tank experiment also provided an understanding of the hydraulic characteristics of groundwater in the coastal aquifer with a seawall, which previously could not be accurately analysed. The experimental and analytical results demonstrated that the rise of groundwater level due to underground obstructions in the coastal aquifer increased the pressure gradient and groundwater flow rate and slowed seawater intrusion. This principle can be employed to sufficiently reduce seawater intrusion of coastal aquifers.

scholarly journals Investigating Groundwater Condition and Seawater Intrusion Status in Coastal Aquifer Systems of Eastern India

Water ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 1952
Author(s):  
Subrata Halder ◽  
Lingaraj Dhal ◽  
Madan K. Jha
Keyword(s):  
Groundwater Quality ◽  
Seawater Intrusion ◽  
Groundwater Level ◽  
Coastal Aquifer ◽  
Quality Data ◽  
Confined Aquifer ◽  
Groundwater Levels ◽  
Post Monsoon ◽  
Aquifer Systems ◽  
Sustainable Water Supply

Providing sustainable water supply for domestic needs and irrigated agriculture is one of the most significant challenges for the current century. This challenge is more daunting in coastal regions. Groundwater plays a pivotal role in addressing this challenge and hence, it is under growing stress in several parts of the world. To address this challenge, a proper understanding of groundwater characteristics in an area is essential. In this study, spatio-temporal analyses of pre-monsoon and post-monsoon groundwater-levels of two coastal aquifer systems (upper leaky confined and underlying confined) were carried out in Purba Medinipur District, West Bengal, India. Trend analysis of seasonal groundwater-levels of the two aquifers systems was also performed using Mann-Kendall test, Linear Regression test, and Innovative Trend test. Finally, the status of seawater intrusion in the two aquifers was evaluated using available groundwater-quality data of Chloride (Cl−) and Total Dissolve Solids (TDS). Considerable spatial and temporal variability was found in the seasonal groundwater-levels of the two aquifers. Further, decreasing trends were spotted in the pre-monsoon and post-monsoon groundwater-level time series of the leaky confined and confined aquifers, except pre-monsoon groundwater-levels in Contai-I and Deshpran blocks, and the post-monsoon groundwater-level in Ramnagar-I block for the leaky confined aquifer. The leaky confined aquifer in Contai-I, Contai-III, and Deshpran blocks and the confined aquifer in Nandigram-I and Nandigram-II blocks are vulnerable to seawater intrusion. There is an urgent need for the real-time monitoring of groundwater-levels and groundwater quality in both the aquifer systems, which can ensure efficient management of coastal groundwater reserves.

scholarly journals Analysis of Water Cycle in Weizhou Island of Beihai City, Guangxi Province, Part II: Study On Groundwater Exploitation Plan

2018 ◽  
Vol 246 ◽  
pp. 02047
Author(s):  
Shunfu Zhang ◽  
Changjun Liu ◽  
Chuanke Li ◽  
Sili Long ◽  
Jian Zhou ◽  
...  
Keyword(s):  
Groundwater Flow ◽  
Ground Water ◽  
Seawater Intrusion ◽  
Groundwater Level ◽  
Water Cycle ◽  
Variable Density ◽  
Analysis Model ◽  
Guangxi Province ◽  
Groundwater Exploitation ◽  
Groundwater Levels

To relieve the drop of groundwater and seawater intrusion in Weizhou Island caused by overexploitation, the analysis model of precipitation-runoff and variable-density groundwater flow in Weizhou Island was established and the model’s parameter identification results were used to investigate groundwater level and seawater/freshwater interface changes under different groundwater exploitation plans. Thereafter, a rational groundwater exploitation plan could be made to prevent the lowering of groundwater levels caused by ground water overexploitation and ecological deterioration caused by seawater intrusion. This could help accelerating the recovery of ground water and maintaining ecological system.

scholarly journals Analysis of Saline Intrusion into a Coastal Aquifer: A Case History of Legacy Issues and Challenges to Water Security

2018 ◽  
Vol 8 (2) ◽  
pp. 16 ◽  
Author(s):  
Nara Somaratne ◽  
Glyn Ashman
Keyword(s):  
Seawater Intrusion ◽  
Coastal Aquifers ◽  
Coastal Aquifer ◽  
Discharge Rate ◽  
Analytical Models ◽  
Original Position ◽  
Saline Intrusion ◽  
Groundwater Extraction ◽  
Supply Source ◽  
Freshwater Lenses

Coastal aquifers are subject to seawater intrusion. Therefore, managing freshwater aquifers in coastal areas remain challenging. At present, determining safe yields from the coastal aquifers to prevent seawater intrusion is primarily based on the use of numerical simulation-optimization models or by the use of analytical models based on the Ghyben-Herzberg principle. This study examines the cause and effects of seawater intrusion into a coastal aquifer, Lincoln Basin in southern Eyre Peninsula, South Australia and shows that application of simple techniques would have prevented seawater intrusion. Three freshwater lenses, Lincoln A, B, and C of the Lincoln Basin, located about 13 km southwest of Port Lincoln township, have been developed as a town water supply source in 1960. The capacity of the basin has been assessed by three long-term pumping tests. Based on pump tests results, three areas were developed to supply 2×106 m3 per year distributed across three lenses as lens A : four wells to supply 0.84×106 m3, lens B: four wells to supply 0.5×106 m3 and lens C: four wells to supply 0.66 ×106 m3. Neither recharge to the freshwater lenses nor a water balance had been assessed, and a precautionary approach to groundwater extraction was not followed. The apparent driver for managing the basin was demand for the township. In this study, we assessed the recharge using two methods; water-table fluctuation (WTF) and the conventional chloride mass balance (CMB) method. Total recharge to the freshwater lenses is estimated at 1.6×106 m3 per year which is less than the average annual groundwater extraction from the basin during the 1961-1977 periods (average 2.14×106 m3). As a result mining of the groundwater storage has occurred in the basin leading to saline intrusion, upconing and lateral flow of brackish water into wellfield areas. The total volume extracted from the basin was 35×106 m3, which exceeded the average recharge over the 15 year period, 24×106 m3. Using analytical methods, the seawater/freshwater interface movement from its original position was estimated to be 35 m in lens A, 337 m in lens B and 188 m in lens C. For each pumping well at maximum discharge rate, the transient interface location directly underneath the well was calculated. This results in interface rises under pumping wells in lens A of 3.8 m, lens B of 0.5 m, and in lens C about 0.7 m. According to the risk-based groundwater allocation method, maximum extraction would have been as a proportion of 25% of the annual recharge. Thus, maximum annual abstraction limits for lens A, B and C would have been 210×103 m3, 72×103 m3 and 130×103 m3, totaling 412×103 m3.

Calculation of the Pressure Gradient, Velocity, and Wall Shear in Arteries for a Given Flow Rate

2011 ◽  
Vol 2 (2) ◽  
Author(s):  
A. S. Abdalla Wassf Isaac
Keyword(s):  
Fourier Series ◽  
Numerical Analysis ◽  
Pressure Gradient ◽  
Mathematical Models ◽  
Flow Rate ◽  
Input Data ◽  
Inverse Method ◽  
Experimental Measurements ◽  
Artery Flow

The aim of this study was to build an inverse method, which best fits a model of artery flow and experimental measurements, and to provide a good quality of input data for the mathematical models so that proper inferences can be drown from the models. Using numerical analysis to convert the flow rate profiles to the pressure gradient profiles, a Fourier series for this profile (∂p/∂z−t) is then obtained. The results obtained were compared with pressure gradient profile in Fourier series.

scholarly journals NUMERICAL ANALYSIS OF EFFECTS OF HYDRAULIC GRADIENT ON MASS FLUX OF SALTWATER INTRUSION IN COASTAL AQUIFERS

2016 ◽  
Vol 22 (3) ◽  
pp. 7-17
Author(s):  
JAMES A. ADEGOKE ◽  
OLATUNDE I. POPOOLA ◽  
OLUDOTUN O. FALUY
Keyword(s):  
Numerical Analysis ◽  
Contaminant Transport ◽  
Mass Flux ◽  
Coastal Aquifers ◽  
Coastal Aquifer ◽  
Saltwater Intrusion ◽  
Hydraulic Head ◽  
Hydraulic Gradient ◽  
Coastal Regions ◽  
High Level

Coastal aquifers are distinguished from other aquifers because of saltwater intrusion effects, which cause contamination of groundwater in coastal regions. This study addressed the significance of hydraulic gradient and porosity of the coastal aquifers on contaminant transport of saltwater. Results showed hydraulic gradient of the aquifer has significant impact on the contaminant transport in coastal aquifer. When the hydraulic gradient between freshwater and saltwater is high and directed toward the sea, diffused rate of saltwater into the groundwater would be low. Therefore, hydraulic head of freshwater in coastal aquifer must be maintained at high level to control saltwater intrusion.

STUDY OF EVOLUTION OF THE SEAWATER INTRUSION IN COASTAL AQUIFERS. CASE STUDY: THE COASTAL AQUIFER SYSTEM OF NW ACHAIA

2004 ◽  
Vol 36 (4) ◽  
pp. 1952 ◽  
Author(s):  
K. Βουδούρης ◽  
K. Νίκας ◽  
A. Αντωνάκος
Keyword(s):  
Seawater Intrusion ◽  
Coastal Aquifers ◽  
Coastal Aquifer ◽  
Chemical Analyses ◽  
Salinity Distribution ◽  
Aquifer System ◽  
Hydrogeochemical Process ◽  
Groundwater Samples ◽  
Hydrochemical Types

Seawater intrusion problems are recorded in coastal aquifers, which constitute the main sources of drinking water and agricultural irrigation in many countries. The aim of this work is to describe the evolution of the salinity distribution by seawater intrusion, based on results from chemical analyses, of 29 groundwater samples in the NWAchaia area (Peloponnesus, Greece). The study of these data indicates that aquifer waters in large part of area reflect salinization related to seawater intrusion. The occurrence of Ca-CI hydrochemical types of groundwater indicates active seawater intrusion. Cation exchange is the most noticeable hydrogeochemical process in the movement of the saline front in the coastal aquifer. Geographical distribution of Careact index was mapped. The areas with advance or decline of the seawater intrusion front are defined from this map.

scholarly journals Experiment and Numerical Simulation of Seawater Intrusion under the Influences of Tidal Fluctuation and Groundwater Exploitation in Coastal Multilayered Aquifers

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-17 ◽  
Author(s):  
Qiaona Guo ◽  
Jiangwei Huang ◽  
Zhifang Zhou ◽  
Jinguo Wang
Keyword(s):  
Seawater Intrusion ◽  
Groundwater Level ◽  
Coastal Aquifers ◽  
High Tide ◽  
Salt Transport ◽  
Level Fluctuation ◽  
Tidal Fluctuation ◽  
Monitoring Point ◽  
Groundwater Exploitation ◽  
Groundwater Level Fluctuation

The dynamic behavior of groundwater flow and salt transport is affected by tide and pumping in coastal multilayered aquifers. In this paper, two groups of experiments were conducted considering different constant head inland boundaries. The fluctuation of the groundwater level and the process of seawater intrusion in the multilayered aquifers were observed. A two-dimensional SEAWAT model is developed to simulate the seawater intrusion to coastal aquifers under the influences of tidal fluctuation and groundwater exploitation. The hydrogeological parameters in the model are calibrated by the records of the groundwater level and salinity measurements. The results showed that the simulated groundwater level and salt concentration match the observation well. The groundwater level has the characteristics of periodic fluctuation with tide. The lag time of the groundwater level fluctuation in each monitoring point increases slightly with the increasing distance from the saltwater chamber. For the low tide, the inland freshwater recharge has main effect on groundwater level fluctuation. The rising tide has a negative effect on the drawdown of the groundwater level induced by pumping. For the high tide, the tide plays a major role on groundwater level fluctuation, compared with the inland freshwater recharge. Compared with the condition of high head of inland recharge, larger saltwater intrusion lengths and area have been observed and simulated in the aquifer, which means that faster inland motion of the seawater wedge would occur when the inland recharge is small in the coastal aquifers. It revealed that inland recharge plays a major role in the seawater intrusion for the same pumping rate of groundwater in different seasons. The analysis provides insights into how the tide fluctuation, groundwater pumping, and inland recharge effect on the area and rates of seawater intrusion.

scholarly journals NUMERICAL ANALYSIS OF EFFECTS OF HYDRAULIC GRADIENT ON MASS FLUX OF SALTWATER INTRUSION IN COASTAL AQUIFERS

2017 ◽  
Vol 22 (3) ◽  
Author(s):  
JAMES A. ADEGOKE ◽  
OLATUNDE I. POPOOLA ◽  
OLUDOTUN O. FALUY
Keyword(s):  
Numerical Analysis ◽  
Contaminant Transport ◽  
Mass Flux ◽  
Coastal Aquifers ◽  
Coastal Aquifer ◽  
Saltwater Intrusion ◽  
Hydraulic Head ◽  
Hydraulic Gradient ◽  
Coastal Regions ◽  
High Level

<p>Coastal aquifers are distinguished from other aquifers because of saltwater intrusion effects, which cause contamination of groundwater in coastal regions. This study addressed the significance of hydraulic gradient and porosity of the coastal aquifers on contaminant transport of saltwater. Results showed hydraulic gradient of the aquifer has significant impact on the contaminant transport in coastal aquifer. When the hydraulic gradient between freshwater and saltwater is high and directed toward the sea, diffused rate of saltwater into the groundwater would be low. Therefore, hydraulic head of freshwater in coastal aquifer must be maintained at high level to control saltwater intrusion.</p>

Modeling Groundwater Flow and Seawater Intrusion in the Coastal Aquifer of Wadi Ham, UAE

2011 ◽  
Vol 26 (3) ◽  
pp. 751-774 ◽  
Author(s):  
Mohsen Sherif ◽  
Anvar Kacimov ◽  
Akbar Javadi ◽  
Abdel Azim Ebraheem
Keyword(s):  
Groundwater Flow ◽  
Seawater Intrusion ◽  
Coastal Aquifer
Sign in / Sign up

Export Citation Format

Share Document