Stochastic Forecasting Models of the Monthly Streamflow for the Blue Nile at Eldiem Station

Egypt is almost totally dependent on the River Nile for satisfying about 95% of its water requirements. The River Nile has three main tributaries: White Nile, Blue Nile, and River Atbara. The Blue Nile contributes about 60% of total annual flow reached the River Nile at Aswan High Dam. The goal of this research is to develop a reliable stochastic model for the monthly streamflow of the Blue Nile at Eldiem station, where the Grand Ethiopian Renaissance Dam (GERD) is currently under construction with a storage capacity of about 74 billion m³. The developed model may help to carry out a reliable study on the filling scenarios of GERD reservoir and to minimize its expected negative side effects on Sudan and Egypt. The linear models: Deseasonalized AutoRegressive Moving Average (DARMA) model, Periodic AutoRegressive Moving Average (PARMA) model and Seasonal AutoRegressive Integrated Moving Average (SARIMA) model; and the nonlinear Artificial Neural Network (ANN) model are selected for modeling monthly streamflow at Eldiem station. The performance of various models during calibration and validation were evaluated using the statistical indices: Mean Absolute Error, Root Mean Square Error and coefficient of determination (R2) which indicate the strength of fitting between observed and forecasted values. The results show that the performance of the nonlinear model (ANN) was much better than all investigated linear models (DARMA, PARMA and SARIMA) in forecasting the monthly flow discharges at Eldiem station.     

Finding Science with Science: Evaluating a Domain and Scientific Ontology User Interface for the Discovery of Scientific Resources

Current approaches to the discovery of scientific resources (publications, data sets and web services) are dominated by keyword search. These approaches do not allow scientists to search on the deeper semantics of scientific resources, or to discover resources on the basis of the scientific approaches taken. This article evaluates a user interface that allows users to discover scientific resources through structured knowledge in the form of ontologies describing the domain and the scientific knowledge inherent within the scientific resource, and also through informal user tags. These combined capabilities provide scientists with new and powerful options for resource discovery. A qualitative user evaluation explored how scientists felt about the approach for resource discovery in the context of their scientific work. The study showed that marine scientists were enthusiastic about the capabilities of such an approach and appreciated the ability to browse the visual structure of the knowledge and query on scientific method but, overall, preferred the use of tags over ontologies. The exploratory nature of the user study was used to identify future directions for such improvements.     

Influence of geological structures on groundwater accumulation and groundwater salinity in Musandam Peninsula,UAE and Oman

The hydrological setting and groundwater quality of Musandam Peninsula was studied to investigate the influence of geological structures on the groundwater accumulation and groundwater salinity. Five sets of modified morphometric maps were used to reduce errors and carry out the geological structures. The modification was modified by applying mean filter to the Digital Elevation Model (DEM) then applying Soble filter with 10% threshold and equalization enhancement. D8 and algorithms were used to reveal the drainage basins and drainage networks of the entire area. The algorithm determines into which neighbouring pixel any water in a central pixel will flow naturally. Flow direction in a DEM is calculated for every central pixel of input blocks of a 3 × 3 window, all the time comparing the value of the central pixel in the window with the value of its eight neighbours. The spatial association between geological structures and drainage networks was studied using 2D graph and rose diagrams. Flood basin model was applied to simulate the Arabian Gulf water intrusion into the coastal aquifer. The concentrations of solutes in groundwater samples collected from Wadi Al Bih well field and well locations were correlated with the geological structure trends and intersections. The results of the study reveal that the drainage basins, drainage network and groundwater quality are structurally controlled by subsurface geological structure displacements.     

Integrated Storage and Querying of Spatially Varying Data Quality Information in a Relational Spatial Database

This article investigates a new, integrated technique for storing and retrieving spatially varying data quality information in a relational spatial database. Rather than storing global data quality statements, the system enables data quality information to be referenced to a spatial framework, individual spatial objects, or even parts of spatial objects. The integrated model, called as RDBMS for Spatial Variation in Quality (RSVQ), allows flexible storage of spatially varying data quality information, and seamless querying irrespective of the underlying storage model. RSVQ is founded on a formal model of relational databases, defining a new derived, polymorphic query operator      to join quality data with spatial data. The      operator is implemented in an extension to SQL as a new WITHQUALITY keyword. A performance evaluation of RSVQ was conducted, using an Oracle Spatial database and a case study of cadastral data for parts of Victoria, Australia. The results of this evaluation demonstrated that the system is practical and efficient for a wide range of queries, as well as indicating the performance trade-offs associated with the different data quality storage models. Using the integrated RSVQ approach provides the potential for a single, consistent, database engine for a wide range of existing and proposed spatial data quality management systems.     

Voronoi Meshing to Accurately Capture Geological Structure in Subsurface Simulations

Mathematical Geosciences - Mesh generation lies at the interface of geological modeling and reservoir simulation. Highly skewed or very small grid cells may be necessary to accurately capture the...     

The development of integrated water resource information management system in arid regions

Water and land-use tension are growing with the growing population of the world especially in arid region. To develop an efficient, sustainable, and integrated water and land-use resource management policy, accurate and complex information about available resources and demand centers is required. Geographical information system (GIS) provides a means of representing the real world through integrated layers of constituent spatial information using overlaying and indexing operations. In Abu Dhabi, Water Resources Information System (AWRIS) was developed. AWRIS is a centralized, GIS-based, Web-enabled integrated information management system that allows storage and management of all water resource information. The system integrates a comprehensive set of tools and applications that facilitate the efficient management of the water resources of the Emirate. All historical water resource information from more than ten existing databases and 10,000 Excel workbooks have now been compiled, quality controlled, and migrated into the central database. AWRIS is built as an Integrated Information Management System and hence designed to improve productivity by linking all relevant applications for data handling to a centralized data repository and management system. This paper outlines the main features of AWRIS which are three-folds. First, it provides full support for the Arabic language. Second, it is the first of its kind in bringing unrestricted data types into a centralized information management system, and third, it provides a wide range of tools to effectively manage information on water resources.     

Tracing subsurface oil pollution leakage using 2D electrical resistivity tomography

This study provides an evaluation of the subsurface oil contaminant flow in an oil production field at the Wadi Feiran fan, along the Gulf of Suez, Egypt. The 2D electrical resistivity tomography technique has been applied along four profiles surrounding the spill location of oil dump site. Theoretical soil resistivity response versus fluid resistivity for different cation exchange capacity values has been studied. Then, a physical model for the current situation of flowing the oil over the groundwater (sea invaded water) of saturated fluvial sediments has been introduced. It was supposed that the crude oil has higher resistivity values and turned to be conductive far away from the oil spill source under the effect of microbial biodegradation. Such conditions of contaminated distribution and its resistivity values have been considered during the inversion and interpretation of the acquired data sets. The processed 2D resistivity profiles reveal that oil plumes are accumulated in the seawater invasion direction, whereas it has low signatures along the profiles parallel to the shore line.     

Deformed dike swarms as an implication of transpression deformation in Western Arabian shield,Wadi Fatima,Saudi Arabia

Utilization of satellite images and field observations of dike swarms in pre-Fatima basement show that these dikes are older than the overlaying Fatima Formation. Dikes digitization and orientation analysis on satellite images show that the prevailing trend of the dikes is ENE-WSW. The granitic rocks of pre-Fatima basement and its hosted dikes expose evidences of completely a different deformation regime from the overlaying Fatima Formation. These evidences include shearing, dextral shear indicators, isoclinal folds, deflection and rotation of crystals, mineral elongation, and mylonitic and gneissose textures. Strain analysis results of using Fry method on quartz and feldspar grains support the presence of deformation in these ENE-WSW dikes. These results gave a strain ratio of 2.1:1.3:1, which suggest an amount of 40% stretching in the ENE-WSW direction parallel to the dike walls, and an amount of 30% shortening in the NNW-SSE direction. Mesoscopic and microscopic scale structures confirm the existence of dextral ductile-brittle shearing followed the emplacement of the dikes and before the pure shear deformation that caused the thrusting and folding of Fatima Formation. This ductile-brittle deformation is correlated with the dextral transpression that formed the Fatima Shear Zone (FSZ).     

Airborne γ-ray spectrometric characteristics of lithological units and environmental issues in the Bahariya Oases area in the northern part of western desert, Egypt

Two significant airborne gamma ray spectrometic (AGRS) statistical parameters, i.e., the arithmetic mean and the standard deviation, were computed for all lithologic units and formations of the Bahariya Oases area, Northern Western Desert, Egypt. The results ascertain that the maximum AGRS values are associated with sabkha sediments, Bahariya Formation, basalt flows and sand dunes. The intermediate values are correlated with El-Heiz, El-Hefhuf, Qazzun and Naqb formations. The minimum values are connected with Khoman Chalk and El-Hamra formations. The AGRS records were found to vary from one type of rock to another and to some extent between units of the same rock type too. On the aerial total-count (TC) radiometric maps, the records change from 6.2 to 69.36 μR/h. On the potassium map, the values range from 0.05% to 4.35%. On the equivalent uranium (eU) and equivalent thorium (eTh) maps, the records oscillate from 0.12 to 7.4 ppm and from 0.28 to 8.4 ppm, respectively. Concerning the Bahariya Oases area, the calculated arithmetic mean natural dose rate values originating from the terrestrial gamma radiation were found to range from 0.14 to 0.26 mSv/year and where the maximum value attains 0.62 mSv/year. These values remain on the safe side and within the maximum permissible safe radiation dose without harm to individuals, with continuous external irradiation of the whole body.     

Effects of soil-structure interaction on seismic response of elevated tanks

Models of two-dimensional x-braced elevated tanks supported on isolated footings are analyzed to investigate the effects of dynamic interaction between the tower and the supporting soil-foundation system. Static, dynamic elastic, and dynamic inelastic responses of towers under horizontal ground motions are evaluated. Effects of soil properties, represented by the shear wave velocity, on joint displacements and on member end actions are studied. In general, soil-tower interaction reduces member end actions except near the base of tower.