Research

23 pages, 11126 KiB

Open AccessArticle

Integrated Flood Hazard Vulnerability Modeling of Neluwa (Sri Lanka) Using Analytical Hierarchy Process and Geospatial Techniques

by W. M. D. C. Wijesinghe, Prabuddh Kumar Mishra, Sumita Tripathi, Kamal Abdelrahman, Anuj Tiwari and Mohammed S. Fnais

Water 2023, 15(6), 1212; https://doi.org/10.3390/w15061212 - 20 Mar 2023

Cited by 8 | Viewed by 3012

Abstract

This research aimed to apply the geospatial techniques and Analytical Hierarchy Process (AHP) approach to find vulnerable areas in terms of flooding in the Neluwa area, Sri Lanka. The study incorporated nine relevant criteria for the vulnerability classification under three sub-criteria; the built [...] Read more.

This research aimed to apply the geospatial techniques and Analytical Hierarchy Process (AHP) approach to find vulnerable areas in terms of flooding in the Neluwa area, Sri Lanka. The study incorporated nine relevant criteria for the vulnerability classification under three sub-criteria; the built environment, physical environment, and socio-economic environment. Under the built environment, road networks and buildings were chosen as sub-criteria. The Normalized Difference Vegetation Index (NDVI), slope, elevation, water bodies, and stream density were taken as physical criteria. Land use and population density were considered as socio-economic criteria. All the criteria are set correctly in raster data, and their contents were well adduced. The study consisted of the use of different levels of criteria and combinations of different processes. The analytical results reveal that 14.24% and 30.24% of the total area are at a very-high risk and high risk for flooding, respectively. Only 5.17% of the land was classified as a risk-free area. Eastern, central, and western divisions of the study area are highly vulnerable to floods due to their low slopes. Based on the produced maps, the spatial extents and levels of risk were systematically identified. Data obtained through qualitative judgments related to the field were validated based on the approach used. The potential of this approach is effective in assessing the spatial vulnerability of these flood-affected areas. Using such criteria and a model-based approach will be constructive in identifying different flood scenarios and in providing a remunerative guideline for potential anticipatory measures and better land-based planning in the area. Full article

(This article belongs to the Special Issue Assessment and Management of Hydrological Risks Due to Climate Change)

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23 pages, 56741 KiB

Open AccessArticle

Environmental Sustainability of Water Resources in Coastal Aquifers, Case Study: El-Qaa Plain, South Sinai, Egypt

by Hossam H. Elewa, Ahmed M. Nosair, Martina Zelenakova, Viktoria Mikita, Nermeen A. Abdel Moneam and Elsayed M. Ramadan

Water 2023, 15(6), 1118; https://doi.org/10.3390/w15061118 - 14 Mar 2023

Cited by 2 | Viewed by 2371

Abstract

Water resources management is a vital need in arid and semi-arid regions such as Sinai Peninsula, Egypt. Accordingly, the sustainability of water resources in this arid environment should be examined in terms of the possibility of groundwater recharge, particularly through runoff water, while [...] Read more.

Water resources management is a vital need in arid and semi-arid regions such as Sinai Peninsula, Egypt. Accordingly, the sustainability of water resources in this arid environment should be examined in terms of the possibility of groundwater recharge, particularly through runoff water, while identifying the most appropriate potential sites for drilling new water wells to cover current and future needs. The aquifer system of El-Qaa Plain in South Sinai is considered one of the structural basins associated with the tectonic setting of the Gulf of Suez. It is the main source of high-quality water in South Sinai. The present work provided an integration of mathematical flow modeling, hydrochemical composition, environmental isotopic signature, watershed modeling system (WMS), and remote sensing (RS) tools to determine the aquifer sustainability and recharge mechanisms. The obtained results indicated the following: (a) the salinity of the water ranged between 326.4 and 2261 ppm, while the environmental isotope values ranged between −6.28 to −4.48‰ for δ¹⁸O and −29.87 to −21.7‰ for δ²H, which reveals the phase of recharge and mixing between ancient water and recent rainwater; (b) sites for three dams in three sub-watersheds were proposed to harvest approximately 790,000 m³/y of runoff water to enhance groundwater recharge of the aquifer system; (c) and five scenarios using MODFLOW indicated that water drawdown is acceptable by adding 10 new production wells (discharge rate increased by 3600 m³/day). Moreover, increasing the recharge rate by 2% from the base case, leads to an increase in the piezometric water level with an average value of 0.13 masl, which reflects the positive effects of the proposed runoff water harvesting facilities. The integration applied in this work represents an integrated management system for water resources (surface and groundwater) which is suitable for application in arid or semi-arid coastal and similar areas. Full article

(This article belongs to the Special Issue Assessment and Management of Hydrological Risks Due to Climate Change)

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18 pages, 3833 KiB

Open AccessArticle

Value Engineering Approach to Evaluate the Agricultural Drainage Water Management Strategies

by Walaa Elnashar, Hany F. Abd-Elhamid, Martina Zeleňáková and Ahmed Elyamany

Water 2023, 15(4), 831; https://doi.org/10.3390/w15040831 - 20 Feb 2023

Cited by 3 | Viewed by 2148

Abstract

Excessive irrigating water that has not been adequately drained may cause more water to enter the crop root zone than is necessary. As a result, issues with increasing water table levels, waterlogging, and salinity get worse and cause crop productivity losses. Agricultural drainage [...] Read more.

Excessive irrigating water that has not been adequately drained may cause more water to enter the crop root zone than is necessary. As a result, issues with increasing water table levels, waterlogging, and salinity get worse and cause crop productivity losses. Agricultural drainage water management strategies (ADWMS) can be used to protect the quality of groundwater, guarantee that crops have better moisture conditions, and provide irrigation water by reusing agricultural water drainage and using sub-irrigation practices. In order to decrease the effects of poor drainage, mitigate climate change, conserve the environment, and achieve food security, this study proposes a framework for choosing the most effective ADWMS in Egypt’s Nile Delta as well as the new lands. The value engineering approach is used to ensure the strategy’s functionality and to present some innovation in the process of developing alternative solutions that are financially evaluated using the life cycle cost technique. According to the study results, the most effective strategy (ADWMS-3) prioritizes improving drainage effectiveness, controlling groundwater table rise, and providing another irrigation water source while maintaining environmental protection. This strategy encompasses the use of a control drainage system, timing of fertilizer application, regulating groundwater table variation, and using sub-irrigation practices. ADWMS-3 achieves the highest values for the technical score of 8.06 and the value index of 18.59. This study advances the understanding of the topic by providing policymakers with a tool to (i) evaluate ADWMS and (ii) incorporate the added value and functionality into their policies regarding agricultural drainage water. Full article

(This article belongs to the Special Issue Assessment and Management of Hydrological Risks Due to Climate Change)

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16 pages, 5014 KiB

Open AccessEditor’s ChoiceArticle

Investigating Climate Change Effects on Evapotranspiration and Groundwater Recharge of the Nile Delta Aquifer, Egypt

by Mohamed Galal Eltarabily, Ismail Abd-Elaty, Ahmed Elbeltagi, Martina Zeleňáková and Ismail Fathy

Water 2023, 15(3), 572; https://doi.org/10.3390/w15030572 - 01 Feb 2023

Cited by 4 | Viewed by 3350

Abstract

Climate change (CC) directly affects crops’ growth stages or level of maturity, solar radiation, humidity, temperature, and wind speed, and thus crop evapotranspiration (ET_c). Increased crop ET_c shifts the fraction of discharge from groundwater aquifers, while long-term shifts in [...] Read more.

Climate change (CC) directly affects crops’ growth stages or level of maturity, solar radiation, humidity, temperature, and wind speed, and thus crop evapotranspiration (ET_c). Increased crop ET_c shifts the fraction of discharge from groundwater aquifers, while long-term shifts in discharge can change the groundwater level and, subsequently, aquifer storage. The long-term effect of CC on the groundwater flow under different values of ET_c was assessed for the Nile Delta aquifer (NDA) in Egypt. To quantify such impacts, numerical modeling using MODFLOW was set up to simulate the groundwater flow and differences in groundwater levels in the long term in the years 2030, 2050, and 2070. The model was initially calibrated against the hydraulic conductivity of the aquifer layers of the groundwater levels in the year 2008 from 60 observation wells throughout the study area. Then, it was validated with the current groundwater levels using an independent set of data (23 points), obtaining a very good agreement between the calculated and observed heads. The results showed that the combination of solar radiation, vapor pressure deficit, and humidity (H) are the best variables for predicting ET_c in Nile Delta zones (north, middle, and south). ET_c among the whole Nile Delta will increase by 11.2, 15.0, and 19.0% for the years 2030, 2050, and 2070, respectively. Zone budget analysis revealed that the increase of ET_c will decrease the inflow and the groundwater head difference (GWHD). Recharge of the aquifer will be decreased by 19.74, 27.16, and 36.84% in 2030, 2050, and 2070, respectively. The GWHD will record 0.95 m, 1.05 m, and 1.40 m in 2030, 2050, and 2070, respectively when considering the increase of ET_c. This reduction will lead to a slight decline in the storage of the Nile Delta groundwater aquifer. Our findings support the decision of the designers and the policymakers to guarantee a long-term sustainable management plan of the groundwater for the NDA and deltas with similar climate conditions. Full article

(This article belongs to the Special Issue Assessment and Management of Hydrological Risks Due to Climate Change)

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18 pages, 6606 KiB

Open AccessArticle

Supplementing Missing Data Using the Drainage-Area Ratio Method and Evaluating the Streamflow Drought Index with the Corrected Data Set

by Evren Turhan and Serin Değerli Şimşek

Water 2023, 15(3), 425; https://doi.org/10.3390/w15030425 - 20 Jan 2023

Viewed by 1768

Abstract

In water resources management, it is essential to have a full and complete set of hydrological parameters to create accurate models. Especially for long-term data, any shortcomings may need to be filled using the appropriate methods. Moving the recorded observed data using the [...] Read more.

In water resources management, it is essential to have a full and complete set of hydrological parameters to create accurate models. Especially for long-term data, any shortcomings may need to be filled using the appropriate methods. Moving the recorded observed data using the drainage-area ratio (DAR) method to different points is considered one of these methods. The present study used data from six different flow observation stations in the Asi River sub-basin, known as the fertile agricultural areas in Turkey, and transferred the data to various other locations that already have existing observations. This study tested how close the values this method produced were to the actual values and investigated the question “how is missing data imputation improved by the determination of method bias coefficients?” to analyze the method’s accuracy, the streamflow drought index (SDI)—a hydrological drought index—was applied over a 12 month timescale. Contour maps were formed according to both the obtained index results by using the original data from the target station and the transferred streamflow data. As a result of this study, a severe divergence from the actual values was observed in the data directly transferred to the target stations in proportion to their area. The distance of the existing stations between each other produced a very high correlation coefficient, both in the direct transfer process and after the correction was applied. Similarly, in terms of drought index calculations, values close to 97% were seen in the original and transferred flow rates. Consequently, from the perspective of the effective management processes of water resources, the transportation of the data from basin-based observation stations corrected according to the drainage areas can be thought to positively affect the design stages and cost calculations for future water structures. Full article

(This article belongs to the Special Issue Assessment and Management of Hydrological Risks Due to Climate Change)

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27 pages, 16928 KiB

Open AccessFeature PaperArticle

Spatial and Temporal Variability of Rainfall Trends in Response to Climate Change—A Case Study: Syria

by Martina Zeleňáková, Hany F. Abd-Elhamid, Katarína Krajníková, Jana Smetanková, Pavol Purcz and Ibrahim Alkhalaf

Water 2022, 14(10), 1670; https://doi.org/10.3390/w14101670 - 23 May 2022

Cited by 6 | Viewed by 2889

Abstract

Recent climate changes have prompted changes in the hydrological cycle at a global scale, creating instability when predicting future climate conditions and related changes. Perturbations in global climate models have created the need to concentrate consequent changes in hydro climatic factors to comprehend [...] Read more.

Recent climate changes have prompted changes in the hydrological cycle at a global scale, creating instability when predicting future climate conditions and related changes. Perturbations in global climate models have created the need to concentrate consequent changes in hydro climatic factors to comprehend the regional and territorial impacts of climate and environmental changes. Syria, as a Middle East country, is exposed to extreme climate events such as drought and flood. The aim of this study is to analyze rainfall trends in Syria in response to the likely climate change. The analysis was conducted for rainfall data collected from 71 stations distributed all over the country for the period (1991–2009). The trend analysis was performed in monthly and seasonal scales using Mann–Kendall non-parametric statistical tests. The results attained from Mann–Kendall trend analysis revealed decreasing trends at most of the stations. Additionally, rainfall analysis was conducted for the stations with significant trends for wet and dry periods, which also revealed decreasing trends at almost all the stations. From the analysis of the results, it is obvious that slight increasing trends in rainfall in Syria occurred in the fall period. However, in the winter and spring periods, significant decreasing trends have been observed at almost all the stations. This reveals that the country will suffer from shortage of water, because most rainfall occurs in the winter and spring, infrequently in fall and rarely in summer. The results are consistent with the IPCC’s fifth report that predicted a decrease in rainfall in the Mediterranean and southern Asia. The results of this paper could help the management of water resources in Syria considering future climate changes. Full article

(This article belongs to the Special Issue Assessment and Management of Hydrological Risks Due to Climate Change)

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15 pages, 4119 KiB

Open AccessFeature PaperArticle

Assessing the Hazards of Groundwater Logging in Tourism Aswan City, Egypt

by Ismail Abd-Elaty, Abdelazim Negm, Ali M. Hamdan, Ahmed S. Nour-Eldeen, Martina Zeleňáková and Hickmat Hossen

Water 2022, 14(8), 1233; https://doi.org/10.3390/w14081233 - 12 Apr 2022

Cited by 3 | Viewed by 1954

Abstract

This paper studies the groundwater logging problem in the Quaternary aquifer in Aswan city, Upper Egypt. Groundwater levels are already very high in Aswan city, but this has not been exploited, and it causes damage to the environment and infrastructure for roads, building, [...] Read more.

This paper studies the groundwater logging problem in the Quaternary aquifer in Aswan city, Upper Egypt. Groundwater levels are already very high in Aswan city, but this has not been exploited, and it causes damage to the environment and infrastructure for roads, building, and templets. Rising groundwater leads to the deterioration and poor quality of agricultural lands. The main objective of this study is to assess and investigate the main reasons for the groundwater logging in the tourist city of Aswan using field investigation during different periods and gain a better understanding of the water dynamics in the study area. This study investigated the surface water levels in the High Dam Lake (HDL), the Kima Lake water levels, the recharge in the fish hatchery, the abstraction well rates in Kima and El-Shalal, and the leakage from the drinking water and wastewater network in Aswan city within the study area using field investigation. The results of this study show that the HDL is one of the most important sources feeding the aquifer in the study area, and it affects the rise and fall of the groundwater levels, but it is not the only factor that affects this problem. Moreover, the rise in the groundwater levels was due to the infiltration from the unlinking fish hatchery, the reduction in abstraction well rates from Kima Lake, the lack of abstraction from El shallal region, the increase in the leakage from drinking water pipelines, sewage networks and septic underground wastewater tanks; these factors are affecting groundwater logging in Aswan city. Potential groundwater level maps for the study area were generated using field data and ArcGIS technique for the years 2010, 2012, 2014, 2017, 2018, and 2020. Based on the results of the potential groundwater maps, the maximum and minimum difference for the groundwater levels in the study area between 2017 and 2012 reached 12.56 m and 0.83 m, respectively; also, between 2018 and 2017, the levels were 4.34 m and 0.25 m, respectively. Moreover, between 2020 and 2018, they were 8 m and 0.38 m, respectively. Full article

(This article belongs to the Special Issue Assessment and Management of Hydrological Risks Due to Climate Change)

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25 pages, 6784 KiB

Open AccessFeature PaperArticle

An Integrated Approach for Deciphering Hydrogeochemical Processes during Seawater Intrusion in Coastal Aquifers

by Hend S. Abu Salem, Khaled S. Gemail, Natalia Junakova, Amin Ibrahim and Ahmed M. Nosair

Water 2022, 14(7), 1165; https://doi.org/10.3390/w14071165 - 06 Apr 2022

Cited by 15 | Viewed by 3410

Abstract

For managing the freshwater in the worldwide coastal aquifers, it is imperative to understand the hydrogeochemical processes and flow patterns in the mixing freshwater/saltwater zone. The Egyptian Nile Delta aquifer is a typical example. The management of seawater intrusion (SWI) requires detailed investigations [...] Read more.

For managing the freshwater in the worldwide coastal aquifers, it is imperative to understand the hydrogeochemical processes and flow patterns in the mixing freshwater/saltwater zone. The Egyptian Nile Delta aquifer is a typical example. The management of seawater intrusion (SWI) requires detailed investigations of the intrusion wedge and the dynamic processes in the mixing zone. Thus, a multidisciplinary approach was applied based on holistic hydrogeochemical, statistical analysis, and DC resistivity measurements to investigate the lateral and vertical changes in groundwater characteristics undergoing salinization stressor. The results of cross plots and ionic deviations of major ions, hydrochemical facies evolution diagram (HFE-D), and seawater mixing index (SMI) were integrated with the resistivity results to show the status of the SWI where the intrusion phase predominates in ~2/3 of the study are (~70 km radius) and the compositional thresholds of Na, Mg, Cl, and SO₄ are 600, 145, 1200, and 600 mg/L, respectively, indicating that the wells with higher concentrations than these thresholds are affected by SWI. Moreover, the results demonstrate the efficiency of combining hydrogeochemical facies from heatmap and resistivity investigations to provide a large-scale characterization of natural and anthropogenic activities controlling aquifer salinization to support decision-makers for the long-term management of coastal groundwater. Full article

(This article belongs to the Special Issue Assessment and Management of Hydrological Risks Due to Climate Change)

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17 pages, 5862 KiB

Open AccessFeature PaperArticle

Investigation of Groundwater Logging for Possible Changes in Recharge Boundaries and Conditions in the City of Aswan, Egypt

by Hickmat Hossen, A. S. Nour-Eldeen, Abdelazim Negm, Ali M. Hamdan, Mohamed Elsahabi, Martina Zelenakova and Ismail Abd-Elaty

Water 2022, 14(7), 1164; https://doi.org/10.3390/w14071164 - 05 Apr 2022

Cited by 5 | Viewed by 2434

Abstract

Groundwater is of great importance in our daily life, and its importance is due to its multiple uses, whether in agriculture, industry or other uses. Increasing the Groundwater Levels (GWL) in any area is a great benefit for its importance and multiplicity of [...] Read more.

Groundwater is of great importance in our daily life, and its importance is due to its multiple uses, whether in agriculture, industry or other uses. Increasing the Groundwater Levels (GWL) in any area is a great benefit for its importance and multiplicity of uses, but in the city of Aswan, it is different, as the increase in the GWL causes severe damage to buildings and leads to poor quality of agricultural land and the destruction of infrastructure due to the lack of good management. The main objective of this study is to develop a conceptual model of the groundwater system to gain better understanding of water dynamics in the study area and to investigate different management scenarios of the use of groundwater. The model was developed using MODFLOW code to achieve the objective of the study, where the necessary field data were collected to feed the model from the study area, such as Surface Water Levels (SWL) in the Aswan Dam lake and the Nile River, GWL in the Aswan Aquifer and the different characteristics of the layers constituting the aquifer, such as porosity and recharge for different periods to ensure obtaining the most accurate and best results from the model. The model was calibrated with mean residual and absolute mean residual which reached −0.08 and 0.629 m, respectively, with a Root Mean Square Error (RMSE) of 0.737m and a normalized RMSE of 4.319%. Two future scenarios have been developed to arrive at a future vision of GWL in the Aswan aquifer. The first scenario investigated GWL in the study area by changing the values of recharge to the aquifer resulting from an increase in the drinking water and sewage networks’ leakage values, which were predicted in the future for years 2025, 2030, 2035 and 2040. The GWL in the study area are increasing as a result of the increase in the amount of leakage in the years 2025, 2030, 2035 and 2040 compared to the GWL in the study area for the year 2020 by 0.29%, 1.31%, 2.01% and 3.16%, respectively. The second scenario investigated GWL by changing the water levels in El hebs (the lake between the High Dam and the Aswan Dam) as follows (108 m, 110 m, 112 m, 114 m, 116 m and 118 m), where the groundwater levels were calculated in the Aswan Aquifer corresponding to each level. The percentage of increase in groundwater levels corresponding to the levels 108 m, 110 m, 112 m, 114 m, 116 m and 118 m compared to the groundwater levels at the level of 106 m was found as follows: 0.92%, 2%, 2.87%, 4.05%, 4.91% and 5.67%, respectively. The simulation results are intended to support integrated groundwater modeling for the components of the hydrological water budget in the city of Aswan. Furthermore, the model provides us with a better understanding of long-term scenarios for the waterlogging in the city. The results are useful for managing the water logging problems and planning the future infrastructure in the city of Aswan. Full article

(This article belongs to the Special Issue Assessment and Management of Hydrological Risks Due to Climate Change)

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19 pages, 4529 KiB

Open AccessFeature PaperArticle

Assessment of Changing the Abstraction and Recharge Rates on the Land Subsidence in the Nile Delta, Egypt

by Hany F. Abd-Elhamid, Basant S. Abd-Elkader, Osama Wahed, Martina Zeleňáková and Ismail Abd-Elaty

Water 2022, 14(7), 1096; https://doi.org/10.3390/w14071096 - 30 Mar 2022

Cited by 2 | Viewed by 2582

Abstract

The majority of residential, agricultural, and industrial areas are situated on cohesive soil in the Nile Delta, Egypt. Excessive pumping from the Nile Delta aquifer to meet the increasing demands for water could lead to aquifer system compaction and land subsidence. Land subsidence [...] Read more.

The majority of residential, agricultural, and industrial areas are situated on cohesive soil in the Nile Delta, Egypt. Excessive pumping from the Nile Delta aquifer to meet the increasing demands for water could lead to aquifer system compaction and land subsidence. Land subsidence endangers infrastructure such as buildings, bridges, canals, and roads, as well as deteriorating lands and agricultural resources. The objective of this research is to investigate the land subsidence and predict the future behavior of the middle Nile Delta. The study goals are met by using a numerical model (MODFLOW) to simulate groundwater flow and an analytical solution to calculate land subsidence conditions. In this study, three scenarios are considered including; decreasing aquifer recharge, increasing abstraction and combination of the two. The results reveal that decreasing recharge by 94.4%, 88.8%, and 83.2% led to 30-, 60-, and 90-mm land subsidence, respectively, while increasing abstraction by 146%, 193%, and 233% led to land subsidence by 190, 380, and 560 mm, respectively, in the Nile delta. However, the combination of the two scenarios led to 220-, 440-, and 650-mm land subsidence. According to the results the future land subsidence due to over pumping from the Nile Delta should be considered in the future development plans of the country which intend to increase the abstraction from the Nile Delta aquifer. Increasing abstraction could increase the land subsidence that may cause many damages in different properties. Full article

(This article belongs to the Special Issue Assessment and Management of Hydrological Risks Due to Climate Change)

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24 pages, 25621 KiB

Open AccessFeature PaperArticle

Spatial and Temporal Effects of Irrigation Canals Rehabilitation on the Land and Crop Yields, a Case Study: The Nile Delta, Egypt

by Sherien Abd-Elziz, Martina Zeleňáková, Branislav Kršák and Hany F. Abd-Elhamid

Water 2022, 14(5), 808; https://doi.org/10.3390/w14050808 - 04 Mar 2022

Cited by 7 | Viewed by 3171

Abstract

Shortage of surface water is considered an international problem that has even extended to countries that have rivers, in particular countries sharing the same river basins and downstream countries, such as Egypt. This issue requires intensive management of available water resources. Irrigation Canals [...] Read more.

Shortage of surface water is considered an international problem that has even extended to countries that have rivers, in particular countries sharing the same river basins and downstream countries, such as Egypt. This issue requires intensive management of available water resources. Irrigation Canals Rehabilitation (ICR) has become essential to protect surface water in irrigation canals from losses due to seepage. Egypt is one of the countries that has started using this technique. This paper aims to evaluate the impact of ICR using concrete on the land and on crop yields. The SEEP/W model is used in the current study to estimate changes in the groundwater table and moisture in the root zone. Three cases studies have been simulated and compared including unlined, lined, and lined canals with a drainage pipe. The methodology is applied to three canals in the Nile Delta: Sero, Dafan, and New-Aslogy. The results demonstrate that ICR has decreased the losses from canals which resulted in lowering the groundwater, where the case of lining gave a higher reduction than the case of lining with a drainage pipe. In addition, the water table underneath the embankment was lowered. Decreasing the groundwater table could help to protect the land from logging and increase crop yields, but it may reduce the recharging of groundwater aquifers. Such a study is highly recommended in arid regions to decrease water losses where many countries are suffering from water shortage. Full article

(This article belongs to the Special Issue Assessment and Management of Hydrological Risks Due to Climate Change)

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16 pages, 5116 KiB

Open AccessFeature PaperArticle

Experimental and Numerical Study to Investigate the Impact of Changing the Boundary Water Levels on Saltwater Intrusion in Coastal Aquifers

by Hany F. Abd-Elhamid, Gamal M. Abdel-Aal, Maha Fahmy, Mohsen Sherif, Martina Zeleňáková and Ismail Abd-Elaty

Water 2022, 14(4), 631; https://doi.org/10.3390/w14040631 - 18 Feb 2022

Cited by 3 | Viewed by 1933

Abstract

Experimental and numerical models can be used to investigate saltwater intrusion (SWI) in coastal aquifers. Sea level rise (SLR) and decline of freshwater heads due to climate change are the two key variables that may affect saltwater intrusion. This study aims to give [...] Read more.

Experimental and numerical models can be used to investigate saltwater intrusion (SWI) in coastal aquifers. Sea level rise (SLR) and decline of freshwater heads due to climate change are the two key variables that may affect saltwater intrusion. This study aims to give a better understanding of the impact of increasing seawater levels and decreasing freshwater heads due to climate change and increasing abstraction rates due to overpopulation using experimental and numerical models on SWI. The experimental model was conducted using a flow tank and the SEAWAT code was used for the numerical simulation. Different scenarios were examined to assess the effect of seawater rise and landside groundwater level decline. The experimental and numerical studies were conducted on three scenarios: increasing seawater head by 25%, 50% and 75% from the difference between seawater and freshwater heads, decreasing freshwater head by 75%, 50% and 25% from the difference between seawater and freshwater heads, and a combination of these two scenarios. Good agreement was attained between experimental and numerical results. The results showed that increasing the seawater level and decreasing freshwater head increased saltwater intrusion, but the combination of these two scenarios had a severe effect on saltwater intrusion. The numerical model was then applied to a real case study, the Biscayne aquifer, Florida, USA. The results indicated that the Biscayne aquifer is highly vulnerable to SWI under the possible consequences of climate change. A 25 cm seawater rise and 28% reduction in the freshwater flux would cause a loss of 0.833 million m³ of freshwater storage per each kilometer width of the Biscayne aquifer. This study provides a better understanding and a quantitative assessment for the impacts of changing water levels’ boundaries on intrusion of seawater in coastal aquifers. Full article

(This article belongs to the Special Issue Assessment and Management of Hydrological Risks Due to Climate Change)

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