The status of geography in Saudi universities with special reference to King Saud University

Although there are several departments and subdepartments of geography in Saudi universities and other institutions, these departments have so far failed to produce professionals who are capable of filling the posts offered by the employers in both the public and private sectors. This paper suggests that since the demand for geography graduates with general training is rather low at presents, it is time for geography departments to turn to professionalism in the field so that geography graduates can compete favourably for the available posts. This calls for a new look into the geography curriculum, particularly at university level with a view of improving the skills and aptitude of geographers to assume a more positive role in the process of development. The paper also calls for the regional specialisation of geography departments in Saudi Arabia as a step forward towards solving the existing job problem for geography graduates, as well aas underlining the involvement and commitment of geographers to issues of development at the local, regional and national scales.     

Permanent versus temporary rural migrants in Riyadh,Saudi Arabia

"The aim of this paper is to investigate the factors affecting intentions of rural-migrants to return to their rural origins. Several socioeconomic, demographic, spatial, and temporal variables will be introduced to explore their explanatory power and interrelationship with the migrants' intentions. These variables are: Years lived in Riyadh, the current place of parents' residency, land ownership in the village, home ownership in the urban area, income, household size, and the area of origin. The data, which come from a sample survey of migrants conducted in Riyadh in 1983, will be analyzed by the means of binary logit model."     

Geo-environmental effect of landfill site, southeast of Riyadh, Saudi Arabia

Landfilled wastes manifest slow decomposition, producing emanation of gases, and outflow of leachate. Waste mass shows various chemical reactions and complex evolutions that occur under the influence of natural agents, as rain and microorganisms. These reactions lead to biological, physical, and chemical transformations of wastes. The intensity of the phenomenon is related to the air and the humidity. These factors originate from the initial composition of the solid waste, the operating mode of the landfill, and the geological and hydrogeological conditions. Leachate is considered a major source of groundwater pollution. It has a complex nature; it typically contains high concentrations of chemical hazardous including heavy metals, chemical compounds that may severely pollute the environment. These challenges are faced all over the world by environment protection agencies and waste management bodies. The challenge differs according to the specific situation of the site, the climatic, environmental, and geological factors. The international literature is rich with studies in this concern. Each country or region of the world has its own legislation and laws governing waste management, e.g., the European Commission Legislation, the US Environmental Agency, and so forth. The main objective of this study is to shed light on the environmental consequences of a landfill site located in the southeast of Riyadh City, Saudi Arabia. It constitutes a peculiar case because of its situation, its exploitation mode, and nature of buried wastes. The study made use of satellite MSS, TM, ETM and SPOT image 2007, and Digital Elevation Model (DEM), respectively. Geological, morphological, hydrological, hydrochemical, and detailed drainage analyses were performed. Records of meteorological stations were also used in this study. The satellite images illustrate the evolution of the site through time since its start in the 1990s of the twentieth century. The main geological units outcropping in the area are the Sulaiy Formation, the Yamama Formation, Khabra deposits, floodplain deposits, alluvium, and sheet gravel. Drainage analyses shows a dendritic nature for the network, a total area of 2,113 km², basin slope of 0.016, perimeter of 430?×?10³, and a mean elevation of 635 m. Annual rainfall is around 100 mm, evapotranspiration is about 2,900 mm, wind speed averages at 5.1 km/h, and runoff peak is within 2.7–4.7 m³/s. A plume of total dissolved solids and nitrates was observed to initiate from the landfill site. Heavy metal concentration confirms the same result. Planners, environmentalists, decision makers, and other interest groups can use the findings of this study for environmental management of the landfill and protection of the downstream part of the Sulaiy tributary from leachate contamination. The results indicate the importance of monitoring landfills through the combined use of ground and satellite monitoring.     

Geophysical characteristics of Wadi Hanifah water system, Riyadh, Saudi Arabia

Integrated geophysical techniques including resistivity image, vertical electrical sounding (VES), and seismic refraction have been conducted to investigate the Wadi Hanifah water system. The groundwater in Wadi Hanifah has problems caused by the high volumes of sewage water percolating into the ground. The combination of VES, resistivity image, and seismic refraction has made a valuable contribution to the identification of the interface between the contaminated and fresh water in Wadi Hanifah area. The contaminated groundwater has lower resistivity values than fresh groundwater due to the higher concentration of ions which reduces the resistivity. Resistivity image and sounding in this area clearly identified the nature of the lithological depth and proved useful at identifying water-bearing zones. Fresh groundwater was found in the study area at a depth of 100 m within the fractured limestone. Water-bearing zones occur in two aquifers, shallow contaminated water at 10 m depth in alluvial deposits and the deeper fresh water aquifer at a depth of about 100 m in fractured limestone. The interface between the contaminated water (sanitary water) and fresh water marked out horizontally at 100 m distance from the main channel and vertically at 20 m depth.     

Earth Fissures in Wadi Najran,Kingdom of Saudi Arabia

The formation of earth fissures due to groundwater depletion has been reported in many places in North America, Europe, and Asia. Najran Basin is in the southern part of the Kingdom of Saudi Arabia, and agricultural activities and other groundwater uses have caused significant groundwater depletion there. The basin recently experienced a sudden appearance of numerous earth fissures. An interdisciplinary study consisting of an evaluation of land-use changes, and hydrological, hydrogeological, and geophysical investigations was conducted to determine the reason for the formation of the earth fissures. The hydrological analysis strongly revealed that the groundwater level is decreasing with time. Groundwater depletion would lead to the accumulation of subsurface stress, causing soil hydro-consolidation which creates the ideal condition for the formation of earth fissures. Electrical resistivity, data indicated that there are anomalies in the profiles, which are most probably due to the presence of subsurface topography, another key factor for the formation of the earth fissures.     

Population density pattern and change in the city of Riyadh,Saudi Arabia

"This paper examines and assesses the changes in the population density pattern in the city of Riyadh, the capital of Saudi Arabia where the city has undergone dramatic changes in its physical as well as its social structure. Analysis of data revealed a decline in population density at an exponential rate from the city center with variation between city sectors and zones. The city's rapid horizontal expansion and dispersal of population is the result of factors such as increases in city population and in size and number of single family dwellings, widening of streets, rise in income and residential mobility rates, mass use of automobiles, change in family size, zoning regulations, leapfrogging, and huge governmental city development projects."     

Population density pattern and change in the City of Riyadh,Saudi Arabia

This paper examines and assesses changes in the population density pattern in the city of Riyadh, the capital of Saudi Arabia where the city has undergone dramatic changes in its physical as well as its social structure. Analysis of data revealed a decline in population density at an exponential rate from the city center with variation between city sectors and zones. The city's rapid horizontal expansion and dispersal of population is the result of factors such as increases in city population and in size and number of single family dwellings, widing of streets, rise in income and residential mobility rates, mass use of automobile, change in family size, zoning regulations, leapfrogging, and huge governmental city development projects. The resulting low population density pattern made it difficult for city officials to provide necessary services and facilities for the dispersed residential development. This paper recommends that city officials make real efforts and workable programs to stop or slow this uneconomical growth by improving quality of life in the central areas to make them residentially desirable by some city residents and reduce the high residential turnover the central area has experienced in last years, and to centralize peripheral growth by planning for self-sufficient satellite communities in outer areas.     

Lead in drinking water and human blood in Riyadh City, Saudi Arabia

Concentrations of lead (Pb) in domestic water and blood plasma in the Olya and Al-Batha regions of Riyadh City, Saudi Arabia were correlated (r ²?=?0.03, p?<?0.0072 and r ²?=?0.37, p?<?0.00092, respectively). Greater concentrations of Pb in domestic water of Olya and Al-Batha (0.0119 and 0.03 mg/l, respectively) were greater than concentrations of Pb in bottled water and was also greater than the concentration of 0.01 mg Pb/l recommended by both the World Health Organization US Environmental Protection Agency (USEPA). In Al-Batha, 52.2 % of the population had concentrations of Pb in blood that exceeded 10 μg Pb/dl, which is the concentration used by USEPA to classify people as being at risk from effects of Pb. In Al-Batha, 17.5 and 22.5 % of the population exceeded 20–40 and >40 μg Pb/dl, respectively. In Olya, 37 and 10 % of the population had concentrations of Pb in blood that exceeded 10 and 20–40 μg Pb/dl, respectively, while none of the concentrations of PB exceeded 40 μg Pb/dl.     

Land degradation risk assessment in Al-Sawda terraces,Kingdom of Saudi Arabia

Monitoring of soil properties is a significant process and plays an important role about how it can be used sustainably. This study was performed in a local area in Sawda Mountains KSA to map out some soil properties and assess their variability within the area under different land cover. Soil sampling was carried out in four different sites using the grid sampling technique. Ten samples were collected in each location within a 10 by 10 km area; soil was sampled at 0–30-cm depth. The soil samples were air-dried, crushed, and passed through a 2-mm sieve before analyzing it for pH, EC, CaCO₃, organic matter contents, and bulk density. The thematic maps of these characteristics were produced using ArcGIS 10.0 software. Finally, the land degradation was assessed using three factors: soil salinization, compaction, and edibility. The obtained results showed that the high risk of soil compaction, salinization, and erodibility occupied an area 5.6 ha (17.5%), 3.7 ha (11.54%), and 8.1 ha (25.3%), respectively, in the surface soil layer. The land degradation risk in the study area due to salinization was low to high; however, the degree of soil compaction was moderate to very high. The K-factor (soil erodibility) in the area ranged between 0.1 and 0.35 Mg h MJ^?1 mm^?1, and most of the study area was located in moderate to high erodibility classes.     

Seismic vulnerability assessment in the new urban area of Diriyah Governorate,Riyadh, Saudi Arabia

Nine seismic refraction profiles were conducted and processed to study the near-surface sediments in the new urban area of Diriyah. The 2D geoseismic models illustrate two layers: a surface layer of soft sediments and weathered to hard limestone bedrock. Moreover, microtremor measurements were performed at 38 sites for 40 min using three-component seismographs and processed to assess the peak spectral amplitude and the corresponding fundamental resonance frequency. The seismic vulnerability index at each measurement site was estimated. These results correlate well with the geotechnical borehole data. The north-western zone is highly vulnerable due to the great thickness of the soft sediments.     

Impacts of karst phenomena on engineering properties of limestone foundation bed,Ar Riyadh,Saudi Arabia

Evaluation of mechanical and petrophysical properties of the karst limestone became essential to avoid future risks in the construction of new urban cities built on limestones. Therefore, this study aims to evaluate the impact of karsts phenomena on engineering properties of limestone foundation bed at Ar Riyadh in Saudi Arabia. Three hundred core plugs were obtained by rotary drilling at depths ranging from the ground surface to 20 m collected from 24 boreholes in two sites: (1) karst limestone (KL) at Al Aziziyah district and (2) massive hard limestone (HL) at Hittin district in Ar Riyadh city, Saudi Arabia. Petrographic, SEM, EDX, and XRD analyses are used to identify the mineralogical composition and microstructures of limestone samples. The petrophysical properties included the ovendry density, P-wave, and porosity where the mechanical properties covered the uniaxial compressive strength (UCS), point load strength index (PLI), and rock quality designation (RQD) for the karst and hard limestone samples. KL is characterized by 17.11% total porosity, 14.71% water absorption, 32.1 MPa UCS, 1.70 g/cm³ ovendry density (γ dry), 51% weathered RQD, 5.49 MPa medium shear strength, and low modulus of deformation of the plate loading test. HL showed 11.63% total porosity, 9.45% water absorption 43.1 MPa UCS, 2.50 g/cm³ ovendry density (γ dry), 78% hard to fresh rock affinity RQD, and 9.93 MPa high strength and high modulus of deformation of the plate loading test. For the water absorption (%), KL at Al Aziziyah district showed a range of 12.85–17.80% averaged 14.71%. HL at Hittin district varied between 7.04 and 11.29% with an average of 9.45%. KL proved to be dense with ovendry density (γ dry) averaged at 1.70 g/cm³ while HL showed very dense affinity of 2.50 g/cm³. KL clarified a UCS range from 22.5 to 40.1 MPa and an average of 32.1 MPa while HL showed a range from 35.4 t o 48.1 MPa with an average of 43.1 MPa. KL is moderately weathered with RQD average of 51% while HL showed a hard to fresh rock affinity of 78%. Point load test clarified a medium shear strength with 5.49 MPa for KL and high strength of 9.93 MPa for HL. Plate loading tests indicated low and high modulus of deformation for KL and HL, respectively. Results of petrographical analyses and XED of limestone samples showed that the strength parameters of samples mostly composed of micrite (mudstone/wackestone) and dolomite in hard limestone of Hittin district. In Al Aziziyah district (KL), the samples mostly consist of foraminifera and high amount of calcite as in karst limestone (wackestone/packstone). Rock mechanical tests with combination of fabric analyses have shown that strength parameters depend not only on the amount of karst but also on the amount of allochem. Major geomechanical differences between the two types of limestone provide the proper base for prioritizing areas to alleviate future risks and sustainable urban planning for decision makers. The karstic limestone, therefore, is considered as an acceptable foundation bed for light engineering structures. However, for heavy structures and buildings, improving the foundation bed strength by grouting, cement injection, and mat foundations is necessary to avoid future failure risks.     

Air quality and elemental enrichment factors of aerosol particulate matter in Riyadh City, Saudi Arabia

Air particulate matter (PM) samples were collected from June 2006 to May 2007 for determination of chemical elements. PM samples were taken in two size fractions (PM_2.5 and PM₁₀) with MiniVolume air samplers on rooftops of various buildings (15–25 m above ground) in the city of Riyadh. The samples were subjected to X-ray fluorescence analysis to measure major (Na, Mg, Al, K, Ca, Si, P, S, and Fe) and trace elements (Mn, Ni, Cu, Zn, and Ba). The results showed that the PM concentrations were higher for PM₁₀ compared to PM_2.5, indicating that the major PM source was local dust. Also the spatial distribution with high PM concentrations was observed in the south and southeast of the city and the lowest levels were in the center and northeast of the city. This spatial distribution was attributed to different factors such as wind direction and velocity, emission from cement factories, and the presence of buildings, trees, and paved streets that reduce the amount of dust resuspended into the atmosphere. The air quality of the city was found to range from good to hazardous based on PM_2.5, and from good to very hazardous based on PM₁₀. The element-enrichment factors revealed two element groups according to their changing spatial behavior. The first group showed no significant spatial changes indicating they have the same common source. The second group (mainly S and Ni) exhibited significant changes as expected from anthropogenic inputs. The origin of S is possibly a combination of minerals (CaSO₄) and fossil fuel combustion. The source of Ni is probably from fossil fuel combustion.