High Rate Of Urbanization Research Articles

Working in underground spaces: Architectural parameters, perceptions and thermal comfort measurements

Rapid economic growth and high urbanization rates create an urgent need for more space in major cities in China. Further development of underground spaces (UGS) is a viable solution that the Chinese government is promoting. For instance, the 13th 5-year Plan for Urban Underground Space Planning suggests that a comprehensive system for UGS planning and management should be established in at least 50% of Chinese cities by 2020. It is thus imperative to better understand how the architectural and engineering aspects of UGS affect human worker’s performance, well-being, health, and preferences. The present study reports a comprehensive examination of spaces and occupants of UGS in four major Chinese cities (Beijing, Shanghai, Nanjing and Fuzhou). We investigated thermal comfort conditions in UGS without heating and cooling, and estimated the potential of energy saving during transitional seasons. The results indicate that local climate – and especially the humidity level - is a key factor affecting the thermal behaviour of underground structures. In-depth interviews with workers in UGS indicated that immediate access to above ground greenery, indoor plants, and individual control over the environment compensate for a windowless workspace, and those working in UGS did not perceive to have any sleep disturbances. Previous experience with UGS improved the perception of current underground environments. UGS might even be appreciated as working environments with a good acoustic quality. Overall, the present study challenges the uniformity of standards for the construction of UGS, as it suggests that both climatic conditions as well as user preferences should be taken into account.

Urban Economic Growth in the Chinese Heterogeneity Space

The purpose of the study is to assess the factors of urban economic growth in People’s Republic of China (PRC) in the framework of heterogeneous space, meaning as the regional diversity of economic systems, in the context of the current period of market reforms. The article shows that urban development is a way to achieve a sustainable rate of China’s high economic growth. The author presents the description of the model and spatial characteristics of economic growth & urbanization in China. Using numerous statistical sources, the author has revealed that the high values of China’s economic growth were observed in the conditions of high urbanization rates & low per capita income. I have estimated the factors of urban economic growth in the framework of PRC’s heterogeneous space based on the neoclassical approach. In accordance with the assessment, the author found that spatial heterogeneity has a significant impact on the differences in the ratio of the factors of economic growth in Chinese cities. The contribution of extensive factors continues to play a key role in China’s urban economic growth, with the highest proportion of capital input for coastal cities & towns, and labour input — for interior region’s urban areas. As the assessment showed, intensive factors have a visible impact on economic growth only for coastal cities & towns. The author suggests that the economic growth in China is generated mainly coastal cities & towns, and investments in the interior region’s urban areas only maintain the required employment growth for ensuring social stability. For this reason, the Russian economy needs the extension of relations with agglomerations placed in seaside regions of China as well as the development of innovative and technological joint projects.

African Megacities As Emerging Innovation Ecosystems

The unprecedented population growth in Africa and its projections followed by a high rate of urbanization are resulting in a growing number of huge urban agglomerations – cities and megacities. That phenomenon creates opportunities for the continent, but it also raises concerns about low levels of development and diminished quality of life among the majority of urban residents. African cities are characterized by overcrowding, poor infrastructure, and limited connectivity to the international economic system. They are essentially underperforming as potential centres of creativity and innovation. This paper argues that despite these challenges, Africa’s emerging megacities can unleash their potential as drivers of economic transformation if they can be viewed and managed less as static administrative regions and more as dynamic innovation ecosystems rather than a collection of discrete geographical enclosures that encroach on each other and neighbouring regions without adequate urban planning.

Vegetation cover change in growing urban agglomerations in Chile

Cities in Latin America expose high rates of urbanization and poorly controlled processes of creation of new urban peripheries. In this study we evaluated the changes in vegetation cover as a proxy of the success of urban planning in the creation or conservation of elements able to provide ecosystem services to citizens and therefore strengthening urban sustainability. Three urban agglomerations in Chile located in different climates were analysed. Four indicators were processed to understand the changes and correlations between vegetation and urban dynamics: normalized difference vegetation index (NDVI), vegetation cover, normalized difference built-up index (NDBI) and built-up area. The indicators were calculated for a period over 20 years covering two parts of the city as an urban development: the urban core and the new peripheries. An overall loss of vegetation was observed in all cities has a consequence of urban expansion despite their geographical location. Moreover, the greatest losses were in new peripheries. Santiago broke this pattern of change. First its urban core showed a small increase in indicators for vegetation cover despite the increase in indicators for urban dynamics. Secondly, despite their peripheries experiencing a decrease in vegetation cover, a more detailed analysis found differences on the northern and eastern peripheries where increases of vegetation cover were observed, and other new peripheries where vegetation loss was massive. Urban planning needs to play a role not only to facilitate the creation of green spaces or other public spaces able to host vegetation, but also to form an urban structure supported by regulations that facilitate the planting and maintenance of vegetation in private spaces.

Reprint of: The impact of urbanization on carbon emissions in developing countries: a Chinese study based on the U-Kaya method

Urbanization results in a considerable economic disparity between urban and rural areas in developing countries, which has had a consequent significant impact on CO2 emissions. To accommodate this directly, this paper presents a modified version of the Kaya Identity formula, U-Kaya, that includes a direct urbanization factor to determine the relationship between energy consumption intensity, population growth, urbanization rates, urban and rural GDP per capita and the volume of carbon emissions, for application in the dynamic forecasting of carbon emissions by Monte Carlo simulation. The method is demonstrated in forecasting China’s likely carbon emissions in 2020 by three different modes of urbanization policy: the government-dominant mode, market-dominant mode and a hybrid government market-dominant mode. The results indicate that a higher urbanization rate, energy carbon emission coefficient and energy intensity will lead to increased carbon emissions. Finally, three policy implications are identified, comprising the narrowing of the economic gap between urban and rural areas, adjustments to the energy structure and technical innovation, which will provide a valuable reference for developing countries in their efforts to reduce carbon emissions.

Lithogenic and anthropogenic pollution assessment of Ni, Zn and Pb in surface soils of Mashhad plain, northeastern Iran

Mashhad in northeastern Iran, is a fast-growing metropolitan city which has been faced with a high rate of urbanization and industrial activities during recent decades. Despite the high geological diversity of Mashhad plain, the effect of anthropogenic and lithogenic factors on concentrations of potentially toxic elements (PTEs) in the soil have not yet been documented. The objectives of this study were to investigate spatial distribution, anthropogenic and lithogenic origins, and soil pollution intensity of Ni, Zn and Pb in Mashhad plain. A total of 178 soil samples (0–10cm) were collected across an area of about 1500km2. The aqua-regia extractable concentrations of selected PTEs were determined. Results showed concentration for Ni, Zn, and Pb ranged from 33.3–415.8, 35.4–149, and 19.6–69.1mgkg−1 with mean values of 61.4, 74.1, and 31.6mgkg−1, respectively. Calculated background (median+2MAD) concentrations of Ni, Zn and Pb were 60.1, 78 and 28.6mgkg−1, respectively. Pb concentration in 70% of total soil samples was greater than background value; as for Ni and Zn, this figure was 16% and 35%, respectively. The highest concentration of Ni was found in soils formed on ultramafic rocks, whereas the highest concentrations of Zn and Pb occurred in the urban cities of Mashhad and Chenaran. Maximum pollution indices of Ni, Zn and Pb were 6.39, 1.91, and 2.42 with mean values of 0.94, 0.95, and 1.11, respectively. Spatial distribution maps indicated high concentrations of Pb and Zn in Mashhad and Chenaran. The concentration of these elements measured highest in the center of the city. Ni concentration decreased as the distance from ultramafic rocks increased. Results indicated that Ni concentration in the studied soils was controlled by parent material whereas increasing concentrations of Pb and Zn were under the influence of anthropogenic sources. The spread of urbanization and industrial activities in recent decades seem to be responsible for the contamination of soils by Pb and Zn. Although PI values revealed that the soil was not highly polluted, certain strategies must be considered to prevent further pollution in the future.

Relationships Between Land Use and Stream Nutrient Concentrations in a Highly Urbanized Tropical Region of Brazil: Thresholds and Riparian Zones.

Nutrient enrichment in streams due to land use is increasing globally, reducing water quality and causing eutrophication of downstream fresh and coastal waters. In temperate developed countries, the intensive use of fertilizers in agriculture is a main driver of increasing nutrient concentrations, but high levels and fast rates of urbanization can be a predominant issue in some areas of the developing world. We investigated land use in the highly urbanized tropical State of Rio de Janeiro, Brazil. We collected total nitrogen, total phosphorus, and inorganic nutrient data from 35 independent watersheds distributed across the State and characterized land use at a riparian and entire watershed scales upstream from each sample station, using ArcGIS. We used regression models to explain land use influences on nutrient concentrations and to assess riparian protection relationships to water quality. We found that urban land use was the primary driver of nutrient concentration increases, independent of the scale of analyses and that urban land use was more concentrated in the riparian buffer of streams than in the entire watersheds. We also found significant thresholds that indicated strong increases in nutrient concentrations with modest increases in urbanization reaching maximum nutrient concentrations between 10 and 46% urban cover. These thresholds influenced calculation of reference nutrient concentrations, and ignoring them led to higher estimates of these concentrations. Lack of sewage treatment in concert with urban development in riparian zones apparently leads to the observation that modest increases in urban land use can cause large increases in nutrient concentrations.

Migrants and the Making of America: The Short- and Long-Run Effects of Immigration During the Age of Mass Migration

We study the effects of European immigration to the United States during the Age of Mass Migration (1850-1920) on economic prosperity today. We exploit variation in the extent of immigration across counties arising from the interaction of fluctuations in aggregate immigrant flows and the gradual expansion of the railway network across the United States. We find that locations with more historical immigration today have higher incomes, less poverty, less unemployment, higher rates of urbanization, and greater educational attainment. The long-run effects appear to arise from the persistence of sizeable short-run benefits, including greater industrialization, increased agricultural productivity, and more innovation.

The Impact of a Warming Micro‐Climate on Muooni Farmers of Kenya

Rainfed agriculture has become highly vulnerable to the depleting water resources in most arid and semi‐arid tropics (ASATs) under the effect of climate change. The impact has certainly been very high in Muooni catchment where more than 99% of the natural forest has been cleared. The warming micro‐climate is accelerated by extended deforestation, unsustainable irrigation, and water over‐abstraction in the catchment by eucalyptus and other exotic trees. The dwindling crop yields add to the farmer’s suffering. Farming communities have created various innovative ways of coping with a warming environment to increase their agriculture resiliency. These include, among others, rain water management, reforestation and agro‐forestry. To what extent have these practices been disturbed by the increasing temperatures, and decreasing rainfalls and river discharges in Muooni catchment? This study used statistical forecast techniques to unveil the past, current and future variations of the micro‐climate in Muooni catchment, and relevant factors determining farmers’ vulnerability to drought. Muooni catchment is warming by 0.8 to 1.2 °C in a century as a result of a changing micro‐climate. These changes are mainly driven by deforestation due to the high urbanization rate and agricultural practices in Muooni catchment. Centennial rainfall is subsequently plummeting at 30 to 50 mm while discharges are decreasing from 0.01 to 0.05 m3∙s−1, with unmet water demands of 30% to 95% and above. In view of the current trends of the population growth and urbanization in Muooni, agricultural expansion is seriously threatened if no appropriate policy, extension service and science based emergency measures are put in place by the Government of Kenya.

Dielectric Indexes of Tilia cordata Mill. and Tilia platyphyllos Scop. in Various Conditions of lviv City

High rates of urbanization in recent years have led to the deterioration of environmental conditions of the city, and thus, the biological productivity decrease, disturbing of physiology processes and duration of ontogenesis. To assess the vitality of plants the authors use different methods. One of them is the electrophysiological method which applies measuring the impedance and polarization capacitance. Genus Tilia L. is one of the most widespread in Lviv dendroflora. During our research we have found that the most common of its representatives in the green areas of the city is T. cordata Mill. and T. platyphyllos Scop. They are highly resistant to the urban environment. We have chosen two most common species of the genus Tilia in green spaces of Lviv city – T. cordata and T. platyphyllos to be the object of the study. During the study, the city was roughly divided into three zones – the central, middle and peripheral. Thus, in each of them we picked up streets, parks and squares. The results of the studt are as follows. Firstly, the dielectric indexes of lindens have the clearly expressed seasonal dynamics and characterize the seasonal changes of intensity of processes of vital functions. We observed a gradual decline of value of impedance and increase of polarization capacity at the transition trees from dormancy to vegetation, and vice versa increase of impedance and decline of polarization capacity in a period a physiological calmness. Secondly, in March and April, in T. cordata and T. platyphyllos that grow in the open spaces the processes of vital functions are activated because of the higher temperature of air, than outside the city and in public gardens and parks. This led to the decline for them of impedance and increase of polarization capacity, comparatively with control variants. Thirdly, during June – August, lindens in planting of the street showed substantial increase in relation to control of indexes of impedance and decline indexes of polarization capacity. Trees in middle and peripheral parts of the city are characterized by higher vital potential, than in central. To conclude, urban environment conditions influence the vital functions of lindens and the competitive relationship between tree species in the conditions of public gardens and parks on the vital functions of lindens.

Determination of Trip Attraction Rates of Shopping Centers in Uttara Area, Dhaka

Due to the high growth rate of urbanization in developing countries like Bangladesh leads to increase in vehicular traffic. Travel demand models are useful in managing the increased travel demand. So, Trip generation step is essential in planning of transportation facilities for Dhaka the capital of Bangladesh. In this study, the trip attraction rates of the shopping centers at Uttara Road, Uttara area of Dhaka are estimated by using trip rate analysis method. As part of this study, a total of six shopping centers are surveyed, for which the number of vehicles (car) and persons entering the shopping center during peak hour for every 15 minutes time interval are counted. The surveyed data deals with the relationship of trip attraction rates of the shopping center as a whole. Various physical features of the shopping centers are considered of this study, e.g total parking spaces, gross floor area, and the number of stores in the shopping center. This study will help for estimating the traffic volume of newly constructed shopping centers which has remarkable impact on the geometric design of roadways in the contiguous area.

Examining the Challenges of Bicycle Use in Jeddah City

In the presence of high rates of urbanization, sustainable transportation solutions are vital. Due to its social, economic and environmental benefits, bicycle is getting more attention in fast growing and high-dens cities. This paper attempts to examine the challenges of bicycle use in Jeddah city, Saudi Arabia. A survey has been conducted to collect the data for examining the challenges that face Jeddah residents for bicycle use. Visual assessment was conducted to observe the barriers for using the bicycle in Jeddah city. In conjunction to that, questionnaire was distributed to assess the attitude toward bicycle use and the perception of obstacles for using bicycle for different age groups of Jeddah city residents.

Correlation or cause? The limitations of population density as an indicator for public transport viability in the context of a rapidly growing developing city

Abstract In response to high urbanization rates in developing countries, many city authorities are embarking upon large scale public transport improvement programmes. Supportive land use environments will be necessary to reduce operating subsidies to within sustainable limits for these developing economies. In past decades, the literature on the relationship between land use and public transport viability has been dominated by city population density, which is posited to have a strong causal link. This has led to the recommendation of minimum density thresholds for viability. However, for some rapidly growing cities in developing countries, public transport systems have not attained sustainable subsidy levels despite city population densities significantly above the purported thresholds. The aim of this paper is to investigate the significance of population density as an indicator of public transport viability in rapidly growing developing city contexts generally, and in South African cities in particular. A public transport corridor operating cost model was developed for this purpose. The cost modelling results suggest that the causal link between city population density and public transport viability is only leveraged through particular land use and density distributions, and that many rapidly growing cities have land use and density distributions that are unsupportive. It is estimated that when densification occurs on the periphery of a low-density city, the resulting changes in public transport trip lengths, departure profile and seat renovation can in fact be detrimental to the overall viability of services. The paper demonstrates that population density distribution, land use mix and corridor length can each have considerably stronger causal links to public transport viability, than city population density in isolation. Integrated land use-transport strategies should therefore give equal attention to these three land use characteristics and city population density.

Spatiotemporal patterns of urban change and associated environmental impacts in five Saudi Arabian cities: A case study using remote sensing data

Urban growth is a serious threat and challenge worldwide due to its role in altering ecosystem processes and contributing to negative environmental impacts. The natural environment of Saudi Arabia has been affected by the increased pace of urban and economic development, which has been supported by large oil revenues in recent years. Measuring the spatiotemporal patterns of urban growth is important to better understand the qualitative and quantitative impacts of urban spatial distribution over periods of time. Optical remote sensing can be a reliable data source that provides valuable information regarding the spatial and temporal distributions of urban growth. This research used two sets of Landsat images from 1985 and 2014 to map and monitor the spatial distribution of the urban extent among five Saudi Arabian cities: Riyadh, Jeddah, Makkah, Al-Taif and Eastern Area. A decision tree classifier was applied using object-based image analysis (OBIA) to analyze urban land cover in the five cities. The accuracy assessment of the urban change detection maps indicated a high overall accuracy and Kappa coefficient. The results of this research show a high rate of urbanization and complex dynamics across the five cites. The significant changes were the result of a rapid increase in land development, exhibiting complex patterns in the urbanization process across the five cities. The government's policy and increased oil revenues significantly contributed to increasing the urban cover in the five selected cities.

Peri-urban agriculture in Southern Africa: miracle or mirage?

Peri-urban farming is a common phenomenon across much of Africa. The extant literature describes it as a critical source of household food, a trend that is intertwined with such factors as declining incomes of urban households, high rates of urbanization, and a need to serve an emerging niche market in African cities. However, the literature indicates that the practice does not play a major role in Southern Africa. Triangulating research methods and methodologies, and critically examining the literature, this paper argues that peri-urban agriculture is a viable livelihoods response to the complex challenge of feeding a burgeoning mass of urban residents amidst declining food production. The paper concludes that the apparent lack of political will necessary to promote peri-urban agriculture is reflected in weak or absent policy frameworks, resulting from enormous capacity deficit. African states must be able to balance the need to preserve physical esthetics of the cityscape with the promotion of peri-urban agriculture needed to mitigate the negative impacts of changes resulting from the changing urban landscape. African cities need the capacity to develop and implement policies that foster ecologically sound peri-urban agriculture, including appropriate land use reforms.

Long-term visibility variation in Athens (1931–2013): a proxy for local and regional atmospheric aerosol loads

Abstract. This study explores the interdecadal variability and trends of surface horizontal visibility at the urban area of Athens from 1931 to 2013, using the historical archives of the National Observatory of Athens (NOA). A prominent deterioration of visibility in the city was detected, with the long-term linear trend amounting to −2.8 km decade−1 (p < 0.001), over the entire study period. This was not accompanied by any significant trend in relative humidity or precipitation over the same period. A slight recovery of visibility levels seems to be established in the recent decade (2004–2013). It was found that very good visibility (> 20 km) occurred at a frequency of 34 % before the 1950s, while this percentage drops to just 2 % during the decade 2004–2013. The rapid impairment of the visual air quality in Athens around the 1950s points to the increased levels of air pollution on a local and/or regional scale, related to high urbanization rates and/or increased anthropogenic emissions on a global scale at that period. Visibility was found to be negatively/positively correlated with relative humidity/wind speed, the correlation being statistically valid at certain periods. Wind regime and mainly wind direction and corresponding air mass origin were found to highly control visibility levels in Athens. The comparison of visibility variation in Athens and at a non-urban reference site on Crete island revealed similar negative trends over the common period of observations. This suggests that apart local sources, visibility in Athens is highly determined by aerosol load of regional origin. AVHRR and MODIS satellite-derived aerosol optical depth (AOD) retrievals over Athens and surface measurements of PM10 confirmed the relation of visibility to aerosol load.

Sustainable human capacity development in the African built environment

Purpose A growing recognition that human capital is a more critical factor than physical capital in wealth creation has led to the drive for individuals, organisations, industries and societies to become knowledge producing entities. Africa’s growing population, high rate of urbanisation and demand for sustainable infrastructure development have highlighted the need for human capacity development (HCD). However, studies indicate that the supply systems for learning which African construction organisations rely on are weak and immature generating wide spread reports of skills shortages, skills mismatches, skill deficiencies and concomitant high unemployment. This paper forms the prologue in a wider research aimed at developing a workforce capability optimising model for construction firms and the purpose of this paper is to review literature relating to HCD to highlight needs and to explore the applicability of emerging workforce development (WD) approaches in project-based construction workplaces. Design/methodology/approach Literature review, limited to peer reviewed academic publications in English from 2000 to 2016. Findings Much of the literature reviewed focus on educational aspects and consequently basic entry skills into the construction workforce. Workplace learning (WL), though acknowledged, is not given much attention. However, life-long learning, WL and self-directed learning have taken on greater significance because of the transient nature of knowledge in the Knowledge Age. WD practices of construction firms in Africa range from non-existent to average particularly at intermediate skills levels. Originality/value The paper makes a case for improved WD systems applicable to the African construction workplace and introduces elements of a proposed capability optimising framework that supports sustained effective learning environments and learners. Significantly, the model will incorporate HCD for intermediate skills and learning at the project level of the organisation.

Trip Attraction Rates of Commercial Land Use: A Case Study

Background: Due to the high growth rate of urbanization in developing world leads to increase in vehicular traffic. Travel demand models are useful in managing the increased travel demand. Statistical Analysis: Trip generation step is essential in planning of transportation facilities for any city. This paper mainly focuses analyzing the trip attraction rates of commercial land use in different cities of Andhra Pradesh and Telangana states. As a part of the study, a total of seven commercial centres are studied by defining the four broad commercial centre typologies. Various factors considered for defining these typologies are physical features of study area (sq. ft), parking spaces, number of employees, number of stores, number of people attracting etc. Findings: The very first step in traditional travel demand modelling process is trip generation. It is very important for a planner to estimate the impact of changes due to establishment of new facilities like offices, shopping centres and any residential land use. In the study area, the shopping trips constitute the second largest share of trips after the work trips. Because of its major share, these trips not only influence the individual travel behaviour but also showing great impact on transport network. Unlike the previous studies, this study defined the typologies for commercial areas based on their physical characteristics and the same is used for the analysis. These typologies are defined based on the various characteristics of commercial area like floor area, number of stores and number of employees. Improvements: The accuracy of this analysis can be improved by considering more number of commercial areas. Since there are no earlier studies reported in estimating trip attraction rates in the study area, this study might provide an insight to the future researchers. Also the in depth literature study while defining typologies of commercial areas and more factors for analysing trip rates might further helpful in accurate prediction of trip rates.

Flood prevention dams for arid regions at a micro-scale sub-catchment, case study: Tabuk, Saudi Arabia.

Unexpected flash flooding is one of the periodic hydrological problems affecting the city of Tabuk in Saudi Arabia. The region has high potential for floods as it suffers high rainfall intensity in a short time and also has high urbanization rates and topographic complexity. Constructing flood prevention dams is one option to solve this problem. A cost-effective design requires a detailed feasibility study and analysis for the selection of suitable sites. The aim of this study was to develop a method for selecting a suitable site for flood protection dams in the Abu Saba'a district, the most affected part of the city of Tabuk during the flash flood in January 2013. Spatial analysis was applied using Landsat Thematic Mapper images and Shuttle Radar Topography Mission digital elevation model to select a site in the Abu Saba'a area. A simple model using ArcGIS was built including all suggested parameters. The results showed the best site for a dam was 2 km distance backfrom the area, where all parameter values matched. The results showed that the dynamic properties of land cover can affect site selection. It is therefore suggested that more field and hydrological data should be gathered for greater accuracy.

The Impact of the Utilization of Riparian Area for Settlements (Case Study of North Jayapura District, Jayapura City)

The limitedness of area and plot of land in Jayapura City which are allocated for settlements has become a problem in Jayapura city. Population growth and high-rate of urbanization are impacted on the utilization of land which is not in accordance with its allocation. The modification of riparian area on the right and left sides of the river for settlements has reduced the function of the river, because in addition to river conservation, river has a double role as the securer of water source and as the protector of its surrounding area. Therefore, riparian area becomes more important to be considered. The riparian area in settlement area is assumed to be adequate for a 10-15 meters inspection road to be built on. The real condition of the rivers in North Jayapura District of Jayapura City, compared to the criteria of riparian area for settlement area, has not been inappropriate. The river’s function as the protector of its surrounding area has gone astray. If there is someday a flood, the impact may cause material damage or even life victims.