scholarly journals Optimized Pumping Strategy for Reducing the Spatial Extent of Saltwater Intrusion along the Coast of Wadi Ham, UAE

Water ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1503 ◽  
Author(s):  
Modou A. Sowe ◽  
Sadhasivam Sathish ◽  
Nicolas Greggio ◽  
Mohamed M. Mohamed
Keyword(s):  
Saltwater Intrusion ◽  
Transport Model ◽  
Saline Water ◽  
Anthropogenic Impacts ◽  
Optimum Number ◽  
Constant Number ◽  
Pumping Rate ◽  
Discharge Rates ◽  
Pumping Wells ◽  
Pumping Rates

Many coastal aquifers are facing severe anthropogenic impacts such as urbanization, industrialization and agricultural activities are resulting in a saltwater intrusion. This establishes the need for a sustainable groundwater management strategy aimed to overcome the situation. Pumping of brackish/saline water to mitigate saltwater intrusion is a major potential approach to effectively control saltwater intrusion. However, this method has many challenges including selection of appropriate discharge rates under an optimum number of pumping wells and at specified wells distance from the shoreline. Hence, this study developed a Finite Element Flow and solute transport model (FEFLOW) to simulate three scenarios to assess the most appropriate pumping rates, number of wells and optimum well locations from the shoreline. These parameters were assessed and evaluated with respect to the change in groundwater saline concentration at different distance from the coastline. The 15,000 mg L−1 isosalinity contour line was used as a linear threshold to assess the progression of saltwater intrusion along three major locations in the aquifer. Scenario One was simulated with a constant number of wells and rate of pumping. Shifting of pumping wells to several distances from the shoreline was conducted. Scenario Two assessed the most appropriate number of pumping wells under constant pumping rates and distances from the shoreline and in scenario 3, the optimum pumping rates under a constant number of wells and distance from the shoreline were simulated. The results showed that the pumping of brackish/saline water from a distance of 1500 m from the shoreline using 16 pumping wells at a total pumping rate of 8000 m3 d−1 is the most effective solution in contrasting the saltwater intrusion in the Wadi Ham coastal aquifer.

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>

Modeling saltwater intrusion with SUTRA 3.0 in Almonte-Marismas aquifer coast (Doñana Natural Space, Southern Spain). 

2021 ◽  
Author(s):  
Carmen Serrano-Hidalgo ◽  
Ana Fernandez-Ayuso ◽  
Carolina Guardiola-Albert ◽  
Javier Heredia-Diaz ◽  
Francisco Javier Elorza-Tenreiro
Keyword(s):  
Seawater Intrusion ◽  
Saltwater Intrusion ◽  
Transport Model ◽  
Saline Water ◽  
Dynamic Balance ◽  
Groundwater Resources ◽  
Southern Spain ◽  
Geological Survey ◽  
Potential Threat ◽  
2D Model

<p> </p><p>The Almonte-Marismas aquifer is a multilayer alluvial groundwater body constituted of silts, sands and gravel of fluvial-deltaic and marine origin. It supports Doñana Natural Space (Southern of Spain). It is in direct hydraulic contact with the Atlantic Ocean to the Southwest. Nowadays, the aquifer is subjected to important losses in terms of regional groundwater resources caused by the excessive groundwater pumping for crop irrigation, as well as for tourism water supply in two coastal resorts. This fact causes a subsequent lowering of the phreatic head, and therefore, the water requirements of the ecosystems in this protected area.</p><p>Although up to date there is no evidence of saltwater intrusion in this area, there have been several studies warning that seawater advance through the deep layers would likely happen under the present exploitation pattern (Custodio, 1993). The aim of this study is to analyze the possible destabilization of the dynamic balance between the freshwater and saline water in the aquifer. This goal is assessed through numerical simulations of different seawater intrusion scenarios using a 2D model, where the density flow and solute transport model is considered using the SUTRA 3.0 package (Voss et al., 2002) of Modelmuse (Winston, 2014). This work enables the evaluation of the hydrodynamical conceptual model in the aquifer coast, the potential threat of seawater intrusion caused by coastal resort extractions and the consequences that it entails for the nearby natural environment.</p><p>Key issues: saltwater intrusion,2D model, SUTRA, Doñana, overexploitation.</p><p><strong> </strong></p><p><strong>References</strong></p><p>Custodio E. 1993. Preliminary outlook of saltwater intrusion conditions in the Doñana National Park (Southern Spain). Study and Modelling of Saltwater Intrusion into Aquifers. Proceedings 12th Saltwater Intrusion Meeting, Barcelona, Nov. 1992. CIHS.CIMNE. Barcelona, 1993: 295-315.</p><p>Voss, C. I., and Provost, A.M., 2002 (Version of September 22, 2010), SUTRA, A model for saturated-unsaturated variable-density ground-water flow with solute or energy transport, U.S. Geological Survey Water-Resources Investigations Report 02-4231, 291 p.</p><p>Winston, R.B., 2014, Modifications made to ModelMuse to add support for the Saturated-Unsaturated Transport model (SUTRA): U.S. Geological Survey Techniques and Methods, book 6, chap. A49, 6 p., https://dx.doi.org/10.3133/tm6a49.</p>

An evaluation of alternative procedures using the Bou-Rouch method for sampling hyporheic invertebrates

2000 ◽  
Vol 57 (8) ◽  
pp. 1545-1550 ◽  
Author(s):  
Gary W Hunt ◽  
Emily H Stanley
Keyword(s):  
Sample Volume ◽  
Taxon Richness ◽  
Sediment Composition ◽  
Density Estimates ◽  
Pumping Rate ◽  
Well Design ◽  
Alternative Procedures ◽  
Pumping Rates ◽  
Larger Sample

This study assesses the influence of well design, pumping rate, and sample volume on hyporheic invertebrate density and richness estimates in three streams differing in sediment composition. A comparison of five well designs, i.e., temporary wells with no pores and with 4-, 6-, and 8-mm pores along the lower 15 cm and permanent wells with 6-mm pores, revealed no significant differences in either total invertebrate densities or taxon richness. Pumping rates, i.e., 1.5 versus 4 L·min-1, significantly affected density estimates at two streams and taxon richness at one of the three streams, shown by higher values at the faster pumping rate. A comparison of five sample volume sizes, i.e., 0.5, 1.0, 1.5, 2.0, and 2.5 L, indicated that smaller sample volumes produced significantly higher estimates of density, while larger sample volumes gave significantly higher estimates of taxon richness. These results underscore the importance of maintaining consistent pumping rates and sample volume sizes throughout the course of a study.

scholarly journals Thermal-Plume fibre Optic Tracking (T-POT) test for flow velocity measurement in groundwater boreholes

2015 ◽  
Vol 5 (1) ◽  
pp. 161-175 ◽  
Author(s):  
T. Read ◽  
V. F. Bense ◽  
O. Bour ◽  
T. Le Borgne ◽  
N. Lavenant ◽  
...  
Keyword(s):  
Flow Velocity ◽  
Fractured Rock ◽  
Electrical Heating ◽  
Multiple Point ◽  
Thermal Plume ◽  
Fibre Optic ◽  
Distributed Temperature Sensing ◽  
Pumping Rate ◽  
Average Flow Velocity ◽  
Pumping Rates

Abstract. We develop an approach for measuring in-well fluid velocities using point electrical heating combined with spatially and temporally continuous temperature monitoring using Distributed Temperature Sensing (DTS). The method uses a point heater to warm a discrete volume of water. The rate of advection of this plume, once the heating is stopped, equates to the average flow velocity in the well. We conducted Thermal-Plume fibre Optic Tracking (T-POT) tests in a borehole in a fractured rock aquifer with the heater at the same depth and multiple pumping rates. Tracking of the thermal plume peak allowed the spatially varying velocity to be estimated up to 50 m downstream from the heating point, depending on the pumping rate. The T-POT technique can be used to estimate the velocity throughout long intervals provided that thermal dilution due to inflows, dispersion, or cooling by conduction do not render the thermal pulse unresolvable with DTS. A complete flow log may be obtained by deploying the heater at multiple depths, or with multiple point heaters.

scholarly journals Hydroxyl layer: trend of number density and intra-annual variability

2015 ◽  
Vol 33 (6) ◽  
pp. 749-767 ◽  
Author(s):  
G. R. Sonnemann ◽  
P. Hartogh ◽  
U. Berger ◽  
M. Grygalashvyly
Keyword(s):  
Atomic Hydrogen ◽  
Middle Atmosphere ◽  
Transport Model ◽  
Anthropogenic Impacts ◽  
Number Density ◽  
Hemispheric Differences ◽  
Chemical Transport Model ◽  
Mesopause Region ◽  
Production Term

Abstract. The layer of vibrationally excited hydroxyl (OH*) near the mesopause in Earth's atmosphere is widely used to derive the temperature at this height and to observe dynamical processes such as gravity waves. The concentration of OH* is controlled by the product of atomic hydrogen, with ozone creating a layer of enhanced concentration in the mesopause region. However, the basic influences on the OH* layer are atomic oxygen and temperature. The long-term monitoring of this layer provides information on a changing atmosphere. It is important to know which proportion of a trend results from anthropogenic impacts on the atmosphere and which proportion reflects natural variations. In a previous paper (Grygalashvyly et al., 2014), the trend of the height of the layer and the trend in temperature were investigated particularly in midlatitudes on the basis of our coupled dynamic and chemical transport model LIMA (Leibniz Institute Middle Atmosphere). In this paper we consider the trend for the number density between the years 1961 and 2009 and analyze the reason of the trends on a global scale. Further, we consider intra-annual variations. Temperature and wind have the strongest impacts on the trend. Surprisingly, the increase in greenhouse gases (GHGs) has no clear influence on the chemistry of OH*. The main reason for this lies in the fact that, in the production term of OH*, if atomic hydrogen increases due to increasing humidity of the middle atmosphere by methane oxidation, ozone decreases. The maximum of the OH* layer is found in the mesopause region and is very variable. The mesopause region is a very intricate domain marked by changeable dynamics and strong gradients of all chemically active minor constituents determining the OH* chemistry. The OH* concentration responds, in part, very sensitively to small changes in these parameters. The cause for this behavior is given by nonlinear reactions of the photochemical system being a nonlinear enforced chemical oscillator driven by the diurnal-periodic solar insolation. At the height of the OH* layer the system operates in the vicinity of chemical resonance. The solar cycle is mirrored in the data, but the long-term behavior due to the trend in the Lyman-α radiation is very small. The number density shows distinct hemispheric differences. The calculated OH* values show sometimes a step around a certain year. We introduce a method to find out the date of this step and discuss a possible reason for such behavior.

scholarly journals Groundwater Evaluation and Management in Ain Sukhna, Egypt

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Alaa Nabil El-Hazek ◽  
Neveen B. Abdelmageed ◽  
Hatem M. Mekhemer ◽  
Dalia H. Amin
Keyword(s):  
Economic Development ◽  
Steady State ◽  
Conceptual Model ◽  
Groundwater Management ◽  
The Other ◽  
Solid Model ◽  
Pumping Rate ◽  
Pumping Rates ◽  
State Case ◽  
Good Agreement

Ain Sukhna has become one of the most important economic areas in Egypt recently. As a result of this economic development, the demand for water has increased, with special emphasis on groundwater. Therefore, in this paper, several scenarios are assessed in order to reach the best scenario for groundwater management giving the opportunity to achieve the development needs of that region.Groundwater Modeling System (GMS) software is used to construct the solid model forsimulating the geometry of the aquifer layers. Then, a conceptual model is developed and calibrated in steady state case. The calibration results are satisfactory showing a good agreement between the calculated and observed heads. Finally, four scenarios are simulated with different pumping possibilities ranging from -25% to + 50% of the current pumping rates. The results show that it will be better if the current pumping rate is reduced by 25% which can make the drawdown values less than the other possibilities. It is also shown that the best recommended places to drill more wells can be in the east and south directions where the least drawdown values are found.

scholarly journals The Interrelations between a Multi-Layered Coastal Aquifer, a Surface Reservoir (Fish Ponds), and the Sea

Water ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1426 ◽  
Author(s):  
Adi Tal ◽  
Yishai Weinstein ◽  
Stuart Wollman ◽  
Mark Goldman ◽  
Yoseph Yechieli
Keyword(s):  
Seawater Intrusion ◽  
Coastal Aquifer ◽  
Saline Water ◽  
Fish Ponds ◽  
Pumping Rate ◽  
Geophysical Surveys ◽  
Electro Magnetic ◽  
Study Sites ◽  
Surface Reservoir ◽  
Hydrogeological System

This research examines the interrelations in a complex hydrogeological system, consisting of a multi-layered coastal aquifer, the sea, and a surface reservoir (fish ponds) and the importance of the specific connection between the aquifer and the sea. The paper combines offshore geophysical surveys (CHIRP) and on land TDEM (Time Domain Electro Magnetic), together with hydrological measurements and numerical simulation. The Quaternary aquifer at the southern Carmel plain is sub-divided into three units, a sandy phreatic unit, and two calcareous sandstone (‘Kurkar’) confined units. The salinity in the different units is affected by their connection with the sea. We show that differences in the seaward extent of its clayey roof, as illustrated in the CHIRP survey, result in a varying extent of seawater intrusion due to pumping from the confined units. FEFLOW simulations indicate that the FSI (Fresh Saline water Interface) reached the coastline just a few years after pumping has begun, where the roof terminates ~100 m from shore, while no seawater intrusion occurred in an area where the roof is continuous farther offshore. This was found to be consistent with borehole observations and TDEM data from our study sites. The water level in the coastal aquifer was generally stable with surprisingly no indication for significant seawater intrusion although the aquifer is extensively pumped very close to shore. This is explained by contribution from the underlying Late Cretaceous aquifer, which increased with the pumping rate, as is also indicated by the numerical simulations.

scholarly journals Management of the saltwater intrusion phenomenon in the alluvial aquifer of Katapola, Amorgos, Greece

2017 ◽  
Vol 18 (3) ◽  
pp. 936-949 ◽  
Author(s):  
M. Siaka ◽  
Z. Dokou ◽  
G. P. Karatzas
Keyword(s):  
Saltwater Intrusion ◽  
Flow Model ◽  
Climatic Conditions ◽  
Alluvial Aquifer ◽  
Hydrodynamic Dispersion ◽  
Management Scenarios ◽  
Management Options ◽  
Drinking And Irrigation ◽  
Pumping Wells

Abstract The purpose of this study is to investigate the saltwater intrusion phenomenon in the alluvial aquifer of Katapola, on Amorgos Island, under current and future climatic conditions and to provide groundwater management options for alleviating this problem. To this end, a groundwater flow model was developed and the sharp-interface approximation combined with the Ghyben–Herzberg equation was used. A correction factor that accounts for the hydrodynamic dispersion occurring at the brackish zone was also incorporated in the analysis. The model results show that under the current pumping strategy, the saltwater intrusion front extent is vast, posing a serious threat to the quality of groundwater used for drinking and irrigation in the area. The management goal is to find the alternative pumping scenarios for the existing well network that will prevent further spreading of saltwater intrusion. Several water management scenarios were developed, taking into account the effects of climate change, the increase in water supply demand and the expected population growth. The results indicate that controlling the propagation of seawater intrusion in Katapola necessitates the periodic deactivation of most of the pumping wells and the design of alternative plans in order to meet the increasing water demand.

scholarly journals Semi-analytical 3D solution for assessing radial collector well pumping impacts on groundwater–surface water interaction

2017 ◽  
Vol 49 (1) ◽  
pp. 17-26 ◽  
Author(s):  
Ali A. Ameli ◽  
James R. Craig
Keyword(s):  
Surface Water ◽  
Transport Model ◽  
Water Remediation ◽  
Pumping Rate ◽  
River Bank ◽  
Meandering River ◽  
Unconfined Aquifers ◽  
Well Location ◽  
Head Protection ◽  
Radial Collector Well

Abstract We present a new semi-analytical flow and transport model for the simulation of 3D steady-state flow and particle movement between groundwater, a surface water body and a radial collector well in geometrically complex unconfined aquifers. This precise and grid-free Series Solution-analytic element method approach handles the irregular configurations of radial wells more efficiently than grid-based methods. This method is then used to explore how pumping well location and river shape interact and together influence (1) transit time distribution (TTD) of captured water in a radial collector well and TTD of groundwater discharged into the river and (2) the percentage of well waters captured from different sources. Results show that meandering river shape plays a significant role in controlling the aforementioned metrics and that increasing the pumping rate has different consequences in different situations. This approach can also inform the design of water remediation and groundwater protection systems (e.g., river bank filtration and well head protection area).

Optimal groundwater contamination monitoring using pumping wells

2010 ◽  
Vol 62 (3) ◽  
pp. 556-569 ◽  
Author(s):  
Shahar Shlomi ◽  
Avi Ostfeld ◽  
Hillel Rubin ◽  
Christine Shoemaker
Keyword(s):  
Groundwater Quality ◽  
Transport Model ◽  
Decision Variable ◽  
Unsteady State ◽  
Study Objective ◽  
Monitoring Wells ◽  
Pumping Wells ◽  
Contaminant Sources ◽  
Contaminant Distribution ◽  
Optimal Evaluation

This study presents a new method for selecting monitoring wells for optimal evaluation of groundwater quality. The basic approach of this work is motivated by difficulties in interpolating groundwater quality from information collected for only few sampled wells. The well selection relies on other existing data relevant to contaminant distribution in the sampling domain, e.g. predictions of models which rely on past measurements. The objective of this study is to develop a method of selecting the optimal wells, from which measurements could best serve some external model, e.g. a kriging system for characterizing the entire plume distribution, a flow-and-transport model for predicting a future distribution, or an inverse model for locating contaminant sources or estimating aquifer parameters. The decision variable at each sampling round determines the specific wells to be sampled. The study objective is accomplished through a spatially-continuous utility density function (UDF) which describes the utility of sampling at every point. The entire methodology which utilizes the UDF in conjunction with a sampling algorithm is entitled the UDF method. By applying calculations in steady and unsteady state sampling domains the effectiveness of the UDF method is demonstrated.

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