Impacts of Seawater Rise on Seawater Intrusion in the Nile Delta Aquifer,Egypt

Several investigations have recently considered the possible impacts of climate change and seawater level rise on seawater intrusion in coastal aquifers. All have revealed the severity of the problem and the significance of the landward movement of the dispersion zone under the condition of seawater level rise. Most of the studies did not consider the possible effects of the seawater rise on the inland movement of the shoreline and the associate changes in the boundary conditions at the seaside and the domain geometry. Such effects become more evident in flat, low land, coastal alluvial plans where large areas might be submerged with seawater under a relatively small increase in the seawater level. None of the studies combined the effect of increased groundwater pumping, due to the possible decline in precipitation and shortage in surface water resources, with the expected landward shift of the shore line. In this article, the possible effects of seawater level rise in the Mediterranean Sea on the seawater intrusion problem in the Nile Delta Aquifer are investigated using FEFLOW. The simulations are conducted in horizontal view while considering the effect of the shoreline landward shift using digital elevation models. In addition to the basic run (current conditions), six different scenarios are considered. Scenarios one, two, and three assume a 0.5 m seawater rise while the total pumping is reduced by 50%, maintained as per the current conditions and doubled, respectively. Scenarios four, five, and six assume a 1.0 m seawater rise and the total pumping is changed as in the first three scenarios. The shoreline is moved to account for the seawater rise and hence the study domain and the seaside boundary are modified accordingly. It is concluded that, large areas in the coastal zone of the Nile Delta will be submerged by seawater and the coast line will shift landward by several kilometers in the eastern and western sides of the Delta. Scenario six represents the worst case under which the volume of freshwater will be reduced to about 513 km³ (billion m³).     

Geochemistry characterization of groundwater in an agricultural area of Razan,Hamadan, Iran

This study was conducted to evaluate factors regulating groundwater quality in an area with agriculture as main use. Thirty groundwater samples have been collected from Razan area (Hamadan, Iran) for hydrochemical investigations to understand the sources of dissolved ions and assess the chemical quality of the groundwater. The chemical compositions of the groundwater are dominated by Na⁺, Ca²⁺, HCO₃ ⁻, Cl⁻ and SO₄ ²⁻, which have been derived largely from natural chemical weathering of carbonate, gypsum and anthropogenic activities of fertilizer’s source. The production of SO₄ ²⁻ has multiple origins, mainly from dissolution of sulphate minerals, oxidation of sulphide minerals and anthropogenic sources. The major anthropogenic components in the groundwater include Na⁺, Cl⁻, SO₄ ²⁻ and NO₃ ⁻, with Cl⁻ and NO₃ ⁻ being the main contributors to groundwater pollution in Razan area.     

Geochemistry and mineral chemistry of pyroxenite xenoliths and host volcanic alkaline rocks from north west of Marand (NW Iran)

Mineralogy and Petrology - The Plio-Quaternary alkaline volcanic rocks from the northwest of Marand (NW Iran) consist of trachy-andesites, trachy-basaltic andesites, leucite-tephrites and...     

Structural pattern and emplacement mechanism of the Neka Valley nappe complex,eastern Alborz,Iran

International Journal of Earth Sciences - The Neka Valley nappe complex is exposed in the south of Gorgan County in the eastern Alborz fold-and-thrust belt. We use the results of a regional survey...     

Validation of TRMM 3B42 V6 for estimation of mean annual rainfall over ungauged area in semiarid climate

This research compares data from the Tropical Rainfall Measuring Mission 3B42 V6 with data obtained from 19 synoptic rain gauges during the period 1998–2010 over the semiarid climate of Khorasan Razavi, Iran. Validation was performed using three spatial extents, including 1 TRMM grid face from the synoptic station (1PTRM), 3 TRMM points surrounding the synoptic station (3PTRM) and 5 TRMM points surrounding the synoptic station (5PTRM), using ArcGIS 10.2 software. The perfect and poor r were obtained at stations S08 and S19, with values of 0.92 and 0.26, respectively. According to the Nash–Sutcliffe efficiency coefficient, the TRMM satellite can predict the spatial variation of the mean annual rainfall by 0.23, 0.43 and 0.38 for 1PTRM, 3PTRM and 5PTRM, respectively, at 19 stations. The agreement significantly increases by 0.88, 0.83 and 0.80 for 1PTRM, 3PTRM and 5PTRM, respectively, when gauges S05, S07, S11 and S13 are excluded from the dataset, which may be associated with orographic or instrumental error at the stations.     

Seismotectonics and consequences of the 1930s large earthquakes in eastern Mazandaran,north of Iran

Early in the 1930s,two relatively large earthquakes (Kosout,magnitude 6.8,and Talarrud,magnitude 5.8) shook the eastern Mazandaran,northern Iran.Despite the his...     

Dynamics of charged dust particles in protoplanetary discs

We study the effect of an imposed magnetic field on the motion of charged dust particles in magnetically active regions of a protoplanetary disc. Assuming a power law structure for the vertical and the toroidal components of the magnetic field for the regions beyond magnetically dead region of the disc, the radial and the vertical velocities of the charged particles, in the asymptotic case of small particles, are calculated analytically. While grains with radii smaller than a critical radius significantly are affected by the magnetic force, motion of the particles with larger radii is independent of the magnetic field. The critical radius depends on the magnetic geometry and the charge of the grains. Assuming that a grain particle has one elementary charge and the physical properties of the disc correspond to a minimum-mass solar nebula, we show that only micron-sized grains are affected by the magnetic force. Also, charge polarity determines direction of the radial velocity. For such small particles, both the radial and the vertical velocities increase due to the magnetic force.     

Anthropogenic Decline of Ancient,Sustainable Water Systems: Qanats

Qanat is an ancient underground structure to abstract groundwater without the need for external energy. A recognized world heritage, Qanat has enabled civilization in arid and semi-arid regions that lack perennial surface water resources. These important structures, however, have faced significant challenges in recent decades due to increasing anthropogenic pressures. This study uses remote sensing to investigate land-use changes and the loss of 15,983 Qanat shafts in the Mashhad plain, northeast of Iran, during the past six decades. This entails obtaining a rare aerial imagery from 1961, as well as recent satellite imagery, over a region with the highest density of Qanats in Iran, the birthplace of Qanat. Results showed that only 5.59% of the Qanat shafts in 1961 remained intact in 2021. The most prominent Qanat-impacting land-use changes were agriculture and urban areas, that accounted for 42.93 and 31.81% Qanat shaft destruction in the study area, respectively. This study also showed that groundwater table decline, demographic changes, and reduction in the appeal of working in the Qanat maintenance and construction industry among the new generation are existential threats to Qanats, and may result in the demise of these ancient structures in the future. Findings of this study can be used for urban planning in arid and semi-arid areas with the aim of protecting these historic water structures.     

Spatial correlation between groundwater seepage faces and fault zone in high bedrock channel: method and application

The groundwater may recharge the surface water bodies through seepage faces and springs.The spatial correlation between the fault zones and the groundwater seepage faces results in deep understanding of the hydrogeologic regime,especially where there is no monitoring boreholes.Locating these recharging zones by conventional methods is a challenging task;particularly in areas where(1)there is no hydrogeologic monitoring boreholes or reliable data,(2)private pumps withdraw the stream,and(3)intense canopy limits the use of drones and satellite images.This paper aims to study the relationship between the fault zones and occurrence of the groundwater seepage faces by using the high resolution handheld thermal imaging cameras as a tool to locate the seepage faces along a small river in the Damavand County,north of Iran.The correlation between the structural geology features and occurrence of the groundwater seepage faces revealed that the stream in the study area is being recharged by the groundwater at extensive fault zones.Additionally,this study suggests that the handheld thermal imaging cameras are a useful robust tools to evaluate the surface-groundwater interaction.However,it is essential to use the field structural geologic and hydrogeologic observations to interpret the thermal images.     

Association between cloudiness and rainfall over Fars province in Iran

Relationship between precipitation sum and cloud properties over Fars province in Iran was analyzed for the cases of light (4 mm), moderate (17 mm), and heavy (62 mm) precipitation. The cloud properties (temperature and pressure at the top, cloud optical thickness and cloud water path) were obtained from satellite data of spectoradiometer MODIS (MODO6). The spatial distribution of rainfall was obtained from the 3-hourly data of TRMM (3B42). The multivariate regression model was developed to predict the spatial distribution of rainfall. A strong significant positive association between the spatial distribution of cloud characteristics and heavy precipitation was found, while no clear correlation was revealed between light precipitation and cloud properties. The developed regression model comprised 64, 47, and 24% of spatial variance of heavy, moderate, and light rainfall, respectively. The influence of cloud water path on the spatial distribution of rainfall dominates.