Factors controlling mechanisms of groundwater salinization and hydrogeochemical processes in the Quaternary aquifer of the Eastern Nile Delta, Egypt

In this study, combining interpretations of conservative dissolved ions and environmental isotopes in water were used to investigate the main factors and mechanisms controlling groundwater salinization and hydrogeochemical processes in the Eastern Nile Delta, Egypt. Hydrogeochemical and isotopic study has been carried out for 61 water samples from the study area. Total dissolved solid (TDS) contents of groundwater are highly variable rising along flowpath from the south (410 mg/L) to the north (14,784 mg/L), implying significant deterioration and salinization of groundwater. Based on TDS and ionic ratios, groundwater samples were classified into three groups. In low-saline groups, water chemistry is greatly influenced by cation exchange, mineral dissolution/precipitation, anthropogenic pollutants and mixing with surface water. Whilst, in high-saline groups, water chemistry is affected by salt-water intrusion, reverse cation exchange and evaporation. The chemical constituents originating from saline water sources, reverse ion exchange and mineral dissolution are successfully differentiated using ionic delta and saturation index approaches. The δ¹⁸O–δ²H relationship plots on a typical evaporation line, suggesting potential evaporation of the recharging water prior to infiltration. Isotope evidence concludes that the groundwater have been considerably formed by mixing between depleted meteoric water recharged under different climatic conditions and recently infiltrating enriched surface water and excess of irrigation water. The δ¹⁸O data in conjunction with chloride concentrations provide firm evidence for impact of dissolution of marine-origin evaporite deposits, during past geologic periods, on groundwater salinity in the northern region. Moreover, the relation between ¹⁴C activities and Cl^? concentration confirms this hypothesis.     

Complex impact assessment of coastal development in the United Arab Emirates using GIS: a case study of Wurayah Biosphere Reserve

Wadi Wurayah area is one of the major wadis originating and running on the Oman Mountains and drains into the Oman Gulf. These wadis in general and Wadi Wurayah in particular are characterized with a rich diversity of rare and mountainous and freshwater habitats and species. These wadis contain unequal, representative, and sensitive areas of the dry lands ecosystem with natural, outstanding landscapes and cultural heritage, while the socioeconomic situation indicates that it has enough socioeconomic infrastructures to develop new alternatives ecologically and economically sustainable. As most of the United Arab Emirates and the region, the study area is undergoing dramatic changes linked to economic diversification and promotion of tourism. Established under the UNESCO’s Man and the Biosphere Program, Wurayah Biosphere Reserve represents protected areas intended to demonstrate well-balanced relationship between conservation of biodiversity and an appropriate local development. The main objectives of this study are to develop an environmental information system to understand the dynamics of human activities associated to land use in the study area, highlight the threats to the environment, educate people about the basic environmental issues and positive traditional practices, and promote tourism. Based on the gained results, the concept of biosphere reserve as a model is to implement ideas of sustainable land use in practice.     

Use of satellite data and GIS for assessing the agricultural potentiality of the soils South Farafra Oasis, Western Desert, Egypt

Overpopulation and food security are the main global problems alert decision makers. In developing countries, such problem put extra pressure for horizontal expansion for agricultural development. The rapid sprawl of urbanized areas on the alluvial land of the River Nile and delta to accommodate the population growth has encouraged governmental and private sector for agricultural expansion in the desert. Unless there are reliable information and accurate studies for land and soil suitability, there will be a collapse of such investment. To evaluate the potential suitability of soil for agriculture development in areas of the western desert, satellite images, geographic information, and field survey including soil profiles and artesian water samples with laboratory analysis were integrated to classify the soils according their suitability for specific crop. The main land qualities of the different mapping units and the crop requirement were rated and matched to obtain the current and potential land suitability using Automated Land Evaluation System “ALES”. The study found that the main physiographic units are plateaus, hilland, mountain, and depression floor. But there are three limiting parameters for land suitability which are the lack of nutrient elements, wind erosion vulnerability, and soil texture. The study concluded that the best crops adapted with the soil conditions and could be feasible for economic use are: (1) native vegetation such as agol, sand trees, sammar, halfaa, bawaal, qordaob, bardi, and qortom; (2) filed crops such as onion, garlic, watermelon and wheat; and (3) fruits such as olive and date palms.     

Scenario Reduction Applied to Geostatistical Simulations

Having a large number of geostatistical simulations of a mineral or petroleum deposit provides a better idea of its upside potential and downside risk; however, large numbers of simulated realizations of a deposit may pose computational difficulties in subsequent decision-making phases. Hence, depending on the specific case, there can be a need to select a representative subset of conditionally simulated deposit realizations. This paper examines and extends an approach developed by the stochastic optimization community based on stochastic mathematical programming with recourse and is discussed here in the context of mineral deposits while it is possibly suitable for other earth science applications. The approach is based on measuring the “distance” between simulations and the introduced distance measure between simulated realizations of a mineral deposit is based on the metal above a given set of cutoff grades while a pre-existing mine design is available. The approach is tested on 100 simulations of the Walker Lake data with promising results.     

Using GIS modeling to assess the agricultural sustainability in Kafr El-Sheikh governorate, Nile Delta, Egypt

The evaluation of agricultural sustainability status helps in identifying specific indicators that constrain the achievement of sustainable agriculture. The agricultural sector in Egypt is facing major sustainability constraints such as scarce land and water resources, environmental degradation, and rapid population growth as well as institutional arrangement including land tenure and farm fragmentation, agricultural administration, lack of infrastructure, and credit utilization and high interest rates. This study aims to evaluate the agricultural sustainability in some areas in Kafr El-Sheikh governorate, north of the Nile Delta; the international framework for evaluating sustainable land management was used for realizing this objective. The map of the physiographic soils of the studied area was produced depending upon Landsat ETM⁺ images analysis; the results indicate that the area includes three main landscapes, i.e., alluvial, lacustrine, and marine plains. The characteristics of productivity, security, protection, economic viability, and social acceptability in the different mapping units were assessed. The obtained results show that the studied area includes two different class types, the first are the lands that are marginally below the requirement of sustainability and the second are those lands that do not meet sustainability requirements. The former class is represented by the physiographic units of alluvial plain, whereas the latter class is represented by the physiographic units of the lacustrine and marine plains. The sustainability constrains in the studied area are related to the soil productivity, economic viability, and social acceptability.     

A Parametric Study on Stability of Open Excavations in Alluvial Soils of Lahore District, Pakistan

Rapid urbanization and expansion of metropolitans in the developing world is pressing the need of tall structures with multiple basements. In several such projects, open land is available around excavation site and unsupported deep excavations by maintaining appropriate side slopes offer economical solution. In this research, subsoil stratigraphy of Lahore district was established to be comprising of a top clay stratum 1.5–8 m thick, followed by a sand layer. Considering subsoil data from several geotechnical investigation reports, the effect of four key parameters viz., cohesion of clay layer, friction angle of sand layer, thickness of clay layer at the top and slope inclination of underlying sand layer on safety factor of open excavations was studied. Six hundred twenty-five slope stability analyses were conducted by considering different geometries and soil properties. Based on the results of these analyses, a regression model was suggested to estimate safety factor of open excavations in similar stratigraphy which would be useful in feasibility studies and preliminary design of deep excavations. It was established that the clay layer cohesion was the most dominant contributor to safety factor.     

利用NOAA-AVHRR数据分析1982-2001年间中国植被的动态变化

The authors derived the normalized difference vegetation index (NDVI) from the NOAA/AVHRR Land dataset, at a spatial resolution of 8km and 15-day intervals, to investigate the vegetation variations in China during the period from 1982 to 2001. Then, GIS is used to examine the relationship between precipitation and the Normalized Difference Vegetation Index (NDVI) in China, and the value of NDVI is taken as a tool for drought monitoring. The results showed that in the study period, China’s vegetation cover h...     

The construction of a third-order secular analytical J-S-U-N theory by the Hori-Lie technique

We expand both parts, the principal and indirect, of the Hamiltonian function up to the third order in the masses for the four major planets Jupiter-Saturn-Uranus-Neptune. Accordingly we write down the secular terms ofF ₁,F ₂,F ₃ and the critical terms ofF ₁,F ₂ in terms of the canonical variables of H. Poincaré neglecting powers higher than the second inH, K, P, Q.     

Padé approximant calculations for dispersive,isotropic scattering,homogeneous media

Exact relations for radiation heat flux at the boundaries of a slab with diffusely reflecting boundary conditions and internal source are obtained in terms of the reflection and transmission coefficients of a source free slab with isotropic boundary conditions. The integral equation defining the radiation heat flux contains explicitly the internal source. So, the particular solution for radiative transfer equation is not required. Available exact values for albedos give exact values of radiation heat flux. Padé approximant technique is used to obtain numerical values for homogenous media.