Impact Of Urban Expansion Research Articles

An Assessment of the Environmental and Social Impacts of Urban Expansion: Case of Arab Countries

Problem statement: Most Arab countries currently experience urban population growth at high rates, whereby over half the population lives in towns and cities, a trend which, in some cases, reaches more than 90%. Urbanization in the Arab world has been fuelled by high fertility rates, substantial rural-urban migration, international labor migration and the concentration of economic activity in urban areas. Moreover, urbanization mixed with the high fertility rates and the large percentage of youth in the Arab world will continue to put pressure on federal governments to address the socio-economic problems. This paper assesses the direct effects of urban expansion on environment and society in Arab World. Approach: This paper uses information about demographic changes and hydrologic data in the Arab World for the last years. The goal is to understand the connection between urbanization, water quality pollution and biodiversity in this Region. Official reports from governments, United Nations, World Bank and Economic and Social Commission for Western Asia (UN-ESCWA) are used. Results: Results indicate that there has been notable urban growth, lack of access to improved water sources, pollution and a loss of biodiversity as new urban developments have appeared in these areas. The population increase in a volcanically active area is particularly troubling since it poses a potential human health risk. Conclusion/Recommendations: The review also shows a direct correlation between urbanization with the reduction of water quality, air pollution and loss in biological diversity regarding species and ecosystems.

The impact of urban expansion and agricultural legacies on trace metal accumulation in fluvial and lacustrine sediments of the lower Chesapeake Bay basin, USA

The progressively declining ecological condition of the Chesapeake Bay is attributed to the influx of contaminants associated with sediment loads supplied by its largest tributaries. The continued urban expansion in the suburbs of Virginia cities, modern agricultural activities in the Shenandoah Valley, the anthropogenic and climate driven changes in fluvial system hydrodynamics and their potential associated impacts on trace metals enrichment in the bay's tributaries necessitate constant environmental monitoring of these important water bodies. Eight 210Pb and 137Cs dated sediment cores and seventy two sediment grab samples were used to analyze the spatial and temporal distributions of Al, Ca, Mg, Cr, Cd, As, Se, Pb, Cu, Zn, Mn, and Fe in the waterways of the Virginia portion of the Chesapeake Bay basin. The sediment cores for trace metal historical fluctuation analysis were obtained in lower fluvial-estuarine environments and reservoirs in the upper reaches of the basin. The trace metal profiles revealed high basal enrichment factors (EF) of between 0.05 and 40.24, which are interpreted to represent early nineteenth century agricultural activity and primary resource extraction. Surficial enrichment factors on both cores and surface grab samples ranged from 0.01 (Cu) to 1421 (Cd), with Pb, Cu, Zn, and Cd enrichments a plausible consequence of modern urban expansion and industrial development along major transportation corridors. Contemporary surficial enrichments of As, Se, and Cr also ranged between 0 and 137, with the higher values likely influenced by lithological and atmospheric sources. Pearson correlation analyses suggest mining and agricultural legacies, coupled with aerosol deposition, are responsible for high metal concentrations in western lakes and headwater reaches of fluvial systems, while metal accumulation in estuarine reaches of the major rivers can be attributed to urban effluence and the remobilization of legacy sediments.

Loss of a lake system in a megacity: The impact of urban expansion on seasonal meteorology in Mexico City

AbstractThe Mexico City Metropolitan Area (MCMA) has undergone significant urban expansion in a closed basin that once supported a large lacustrine system. While urbanization has been mentioned as a factor in observed meteorological trends, a systematic study of the effects of land use‐land cover change (LULCC) on seasonal meteorology is lacking. In this study, we utilize the Weather Research and Forecasting (WRF) system to determine the spatiotemporal changes in near‐surface air temperature, precipitation, and boundary layer conditions induced by the modern‐day urban landscape relative to presettlement conditions. We capture the MCMA extent through an improved Landsat‐based multicategory urban classification and therefore account for intraurban spatial heterogeneity and further conduct additional experiments to examine the sensitivity to anthropogenic heating within WRF. We find that accounting for these factors produced the best simulations of thermal conditions, with RMSE values less than 1.5°C at all measurement stations, and an improved diurnal cycle of air temperature and precipitation. We then assessed the impacts of LULCC in the MCMA, finding that thermal changes were largest during daytime hours, with temperature increasing, on average, by more than 4°C. Furthermore, we utilize these simulations to mechanistically link the built environment‐induced increase in air temperature to simulated increases in rainfall during the evening hours. To our knowledge, this study provides the first dynamical and thermodynamical evidence to support the rainfall enhancements documented through observations in the MCMA and link it quantitatively to the warming effects associated with urbanization. These results have important implications for understanding the meteorological conditions leading to widespread urban flooding in the MCMA.

The Impact of Past and Future Urban Expansion on Soil Resources in Central Arkansas, 1994–2030

As cities expand, activities associated with urban growth disturb and seal soil resources. Urban processes compact, move, deposit, and contaminate soils, affecting local soil ecosystems and environmental quality at increasing scales. This article offers a spatially explicit account of the impact of urban expansion on soil resources in central Arkansas from 1994 to 2030 and proposes a conceptual framework that situates the impacts of urbanization on soil resources at multiple scales. We analyzed three soil characteristics (available water storage, agricultural productivity, and soil organic carbon) in the context of urban growth patterns over a 10,000 km2 study area centered on the capital of Little Rock. From 1994 to 2011, urbanization occurred near primary transportation networks and existing urban centers. From 2011 to 2030, urban growth will likely expand along the transportation corridors into the Ouachita Mountains and Arkansas Valley. By 2030, we estimate that urbanization will affect 10 percent of the region's soil resources with varying impacts on soil quality and quantity. Our results provide place-specific knowledge of soil disturbance, which is useful for creating policies and initiatives to mitigate degradation of soil resources with increasing urbanization.

Evaluation of urban water resource security under urban expansion using a system dynamics model

Because of rapid economic development and urbanization, water shortage has become a serious problem in the arid region of China. To investigate urban water resource security, the supply demand pressure of water resources and the urban expansion index were analyzed under different developing scenarios in this paper. Based on the economic data of Urumqi, a typical inland city in the arid area, under the present development scenario from 2011 to 2030, a system dynamics model was constructed to simulate the water resource security. The results show that there will be great influence of urban expansion on water resource security in Urumqi in the future. Water resources are projected to become increasingly scarce if the urban expansion is left unchanged in terms of population, economic growth and water-use efficiency. To find a sustainable method for water resource use, four scenarios of urban expansion were set up based on the sensitive variables. Based on comparison of water consumption under the different scenarios, the harmonize scheme for urban water resource security is the best choice for the development of Urumqi. If the impact of urban expansion on urban water resource security alleviates in the future, the main parameters would have to reach a new standard of water use. Reducing the sewage and increasing the reuse proportion of wastewater are also very important for relieving the stress of water shortage. This research can serve as a reference for water resource allocation and urban planning in arid areas.

Assessment of Socio-economic Impacts of Urban Expansion: A Study of Dilla Town Administration in Gedeo Zone

This study was conducted in Dilla Town Administration at Gedeo Zone, SNNPRS, Ethiopia. The objectives of this study were to assess the socio-economic impacts of urban expansion. The study is based on both primary and secondary data. The primary data has been collected by questionnaires and interviews with 99 respondents of Dilla Town Administration in Gedeo Zone. Even though the Federal Democratic Republic of Ethiopia (FDRE) constitution ensures provision of adequate amenities to the people. This study showed that the Dilla town has been facing lack of various basic amenities, which include insufficient public facilities, acute shortage of houses, poor sanitation, and employment, etc.; all these, in fact are manifested in deprived poverty of the metropolis. To challenge these problems, an enormous effort has so far been exercised by the Town Administration, even though these are not adequate. Based on the data analysis and interpretation, particularly the major findings, the conclusion drawn is that waste management system of the town was poor, there was lack of awareness of education, the level of primary education was low. Most of the households do not have their ownership right of housing and do not have their own water pipe. The expansion of town is making a positive impact on residents with job opportunity. Due to these reasons, the researcher concluded that most of the households were dissatisfied by waste management system, lack of primary education, and ownership right of housing as well as their own water pipe. Most of the respondents were satisfied by access of roads in the town. Based on the identified findings, the researcher recommends that the administration should provide basic amenities and facilities like building of new primary schools, arrangements of waste collection trucks and maintain residential areas for the societies.

Impacts of urban expansion on nitrogen and phosphorus flows in the food system of Beijing from 1978 to 2008

Rapid growth of metropolitan areas is associated with increased flows of nitrogen (N) and phosphorus (P) in the food production–consumption system. However, quantitative analyses of these flows during urban expansion and information about their controlling factors are scarce.Here, we report on N and P flows in the food system of Beijing, which experienced a remarkable growth in population number between especially 1978–2008, using a combination of statistical data bases, surveys and the NUFER model (nutrient flow in the food system, environment and resource). The N (or P) cost of food is defined as the amount of ‘new’ N (or P) used in food production for the delivery of 1kg N (or P) in the food entering household. ‘New’ N (P) includes fertilizer N (P), biological N fixation, atmospheric N deposition, and imports of N (P) via feed and food. Recycled N (P) includes N (P) in crop residues, manures and wastes.We found that the rapid increase in temporary migrants greatly increased food imports to Beijing metropolitan areas and thereby led to an apparent decrease of the N and P cost of food. The input of ‘new’ N to the food system of Beijing metropolitan areas increased from 180 to 281Gg, and for P from 33.5 to 50.4Gg during 1978–2008, as a result of increases in population and changes in food consumption patterns per capita. The food and feed imports in per cent of total ‘new’ N and P inputs increased from 31 to 63% for N and from 18 to 46% for P during 1978–2008. The N and P cost of the food was relatively low compared to the mean of China, and decreased over time. About 52% of the new N input and 85% of the new P input was not recycled in 2008, it accumulated as wastes (in crop residues, animal excreta, and human excreta and household wastes). The N and P use efficiencies in crop and animal production were low, i.e., only 17% for N and 11% for P in 2008. Total losses of ammonia (NH3) and nitrous oxide (N2O) to air and of N to groundwater and surface waters increased by a factor of about 3, and losses of P to groundwater and surface waters increased by a factor of 37 in the period 1978–2008.Key measures for decreasing N and P accumulation and losses are (1) developing satellite towns, (2) expelling animal production to rural areas, and (3) effective collection of the wastes and animal manure, and the utilization of these in rural areas outside Beijing. These findings may also portend changes in other metropolitan areas in China and elsewhere in the rapidly developing world.

Urban expansion dynamics and natural habitat loss in China: a multiscale landscape perspective

China's extensive urbanization has resulted in a massive loss of natural habitat, which is threatening the nation's biodiversity and socioeconomic sustainability. A timely and accurate understanding of natural habitat loss caused by urban expansion will allow more informed and effective measures to be taken for the conservation of biodiversity. However, the impact of urban expansion on natural habitats is not well-understood, primarily due to the lack of accurate spatial information regarding urban expansion across China. In this study, we proposed an approach that can be used to accurately summarize the dynamics of urban expansion in China over two recent decades (1992-2012), by integrating data on nighttime light levels, a vegetation index, and land surface temperature. The natural habitat loss during the time period was evaluated at the national, ecoregional, and local scales. The results revealed that China had experienced extremely rapid urban growth from 1992 to 2012 with an average annual growth rate of 8.74%, in contrast with the global average of 3.20%. The massive urban expansion has resulted in significant natural habitat loss in some areas in China. Special attention needs to be paid to the Pearl River Delta, where 25.79% or 1518 km(2) of the natural habitat and 41.99% or 760 km(2) of the local wetlands were lost during 1992-2012. This raises serious concerns about species viability and biodiversity. Effective policies and regulations must be implemented and enforced to sustain regional and national development in the context of rapid urbanization.

城市森林调控空气颗粒物功能的研究现状与展望

By the impact of urban expansion,industrial development and increased car ownership,air particulate matters have been becoming the primary pollutant in many cities. As the largest and unique ecological system with a self-cleaning function in urban ecological construction,the urban forest not only provides a relatively clean recreation space for residents in the city under the polluted environment,but also plays an important role in purifying the pollution of air particulate matter. In this paper,the regulating function of urban forests was explicated from several aspects including regulation mechanism,analysis method,and functional variation and spatial-temporal variation pattern of different individuals and urban forest types in regulating the air particulate matter. Results indicated that: there have been relative more studies on regulation mechanism involving in physical dustfull while the study on chemical cleaning of dust is lack; Application of the weight method for determining of vegetation dust retention draws more attention while study on the concentration method application for purifying air particulate matter of the environment in urban forest is relatively less. In the near future,the processes and mechanism of chemical dust-removal by forests,and all-around regulating effects of urban forests should be systematically studied,and transformation and practical application of the research findings will be an important direction.

The impact of urban expansion on agricultural land use intensity in China

China's urbanization has resulted in significant changes in both agricultural land and agricultural land use. However, there is limited understanding about the relationship between the two primary changes occurring to China's agricultural land – the urban expansion on agricultural land and agricultural land use intensity. The goal of this paper is to understand this relationship in China using panel econometric methods. Our results show that urban expansion is associated with a decline in agricultural land use intensity. The area of cultivated land per capita, a measurement about land scarcity, is negatively correlated with agricultural land use intensity. We also find that GDP in the industrial sector negatively affects agricultural land use intensity. GDP per capita and agricultural investments both positively contribute to the intensification of agricultural land use. Our results, together with the links between urbanization, agricultural land, and agricultural production imply that agricultural land expansion is highly likely with continued urban expansion and that pressures on the country's natural land resources will remain high in the future.

Impact of urban expansion on meteorological observation data and overestimation to regional air temperature in China

Since the implementation of the reform and opening up policy in China in the late 1970s, some meteorological stations 'entered' cities passively due to urban expansion. Changes in the surface and built environment around the stations have influenced observations of air temperature. When the observational data from urban stations are applied in the interpolation of national or regional scale air temperature dataset, they could lead to overestimation of regional air temperature and inaccurate assessment of warming. In this study, the underlying surface surrounding 756 meteorological stations across China was identified based on remote sensing images over a number of time intervals to distinguish the rural stations that 'entered' into cities. Then, after removing the observational data from these stations which have been influenced by urban expansion, a dataset of background air temperatures was generated by interpolating the observational data from the remaining rural stations. The mean urban heat island effect intensity since 1970 was estimated by comparing the original observational records from urban stations with the background air temperature interpolated. The result shows that urban heat island effect does occur due to urban expansion, with a higher intensity in winter than in other seasons. Then the overestimation of regional air temperature is evaluated by comparing the two kinds of grid datasets of air temperature which are respectively interpolated by all stations' and rural stations' observational data. Spatially, the overestimation is relatively higher in eastern China than in the central part of China; however, both areas exhibit a much higher effect than is observed in western China. We concluded that in the last 40 years the mean temperature in China increased by about 1.58A degrees C, of which about 0.01A degrees C was attributed to urban expansion, with a contribution of up to 0.09A degrees C in the core areas from the overestimation of air temperature.

Impacts of urban expansion and future green planting on summer precipitation in the Beijing metropolitan area

In this study, an analysis of long‐term rainfall data reveals that the rapid urban expansion in Beijing since 1981 is statistically correlated to summer rainfall reduction in the northeast areas of Beijing from 1981 to 2005. This coincides with the period in which the shortage of water in the Beijing area has become a serious factor for sustainable economic development. Meanwhile, an analysis of the aerosol optical depth (AOD) from the Total Ozone Mapping Spectrometer spanning the years from 1980 to 2001 shows that there is no clear secular trend in summer AOD in Beijing. With the particular purpose of further understanding the effects of urban expansion on summer rainfall and the potential measures to mitigate such effects, a mesoscale weather/land‐surface/urban–coupled model along with different urban land‐use change scenarios are used to conduct numerical simulations for two selected heavy summer rainfall events with different, but representative, summer weather patterns in Beijing. Results show that urban expansion can produce less evaporation, higher surface temperatures, larger sensible heat fluxes, and a deeper boundary layer. This leads to less water vapor, more mixing of water vapor in the boundary layer, and hence less (more) convective available potential energy (convective inhibition energy). The combination of these factors induced by expanding urban surfaces is helpful in reducing precipitation for the Beijing area in general and, in particular, for the Miyun reservoir area (the major source for the local water supply). Increasing green vegetation coverage in the Beijing area would produce more rainfall, and model results show that planting grass seems more effective than planting trees. For the same vegetation, the rainfall difference from simulations using two green‐planting layouts (annular and cuneiform) is small.

Impact of urban expansion on regional temperature change in the Yangtze River Delta

Based on non-radiance-calibrated DMSP/OLS nighttime light imagery from 1992 to 2003, urban land area statistical data, meteorological data and land surface temperature data retrieved by MODIS and NOAA/AVHRR data, the influence of urbanization on regional climatic trend of temperature in the Yangtze River Delta (YRD) was analyzed. Conclusions are as follows: 1) There is a significant urbanization process from 1992 to 2003 in the YRD. Four city clusters of Nanjing-Zhenjiang-Yangzhou, Suzhou-Wuxi-Changzhou, Shanghai and Hangzhou Bay form a zigzag city belt. The increase rate of annual mean air temperature in city-belt is 0.28–0.44°C/10a from 1991 to 2005, which is far larger than that of non-city-belt. 2) The urban heat island (UHI) effect on regional mean air temperature in different seasons is summer>autumn>spring>winter. 3) The UHI intensity and the urban total population logarithm are creditably correlated. 4) The UHI effect made the regional annual mean air temperature increased 0.072°C from 1961 to 2005, of which 0.047°C from 1991 to 2005, and the annual maximum air temperature increased 0.162°C, of which 0.083°C from 1991 to 2005. All these indicating that the urban expansion in the YRD from 1991 to 2005 may be regarded as a serious climate signal.

Changing rural–urban linkages in Mali, Nigeria and Tanzania

This paper compares and contrasts changing rural–urban linkages drawing on research in six case study areas in Mali, Nigeria and Tanzania. The aim of the research was to gain a better understanding of the ways in which the livelihoods of rural and urban households rely on both rural-based and urban-based resources, and on exchanges between urban and rural areas. The paper describes changes in farming systems under the impact of urban expansion, with special attention to access to land and other natural resources such as water, and also access to markets and the role of traders, especially small-scale operators. It also examines how changing rural and urban contexts, as well as wider national and regional contexts, affect patterns of income diversification and mobility, especially the differential impacts with regard to women and men and to young and older people. Finally, it analyzes the role of the case studies’ urban centres in the economic and social development of their surrounding regions.

Science and ecosystem management in the national parks

Our national parks are more than mere recreational destinations. They are repositories of the nation's biological diversity and contain some of the last ecosystem remnants needed as standards to set reasonable goals for sustainable development throughout the land. Nevertheless, public pressure for recreation has largely precluded adequate research and resource monitoring in national and ignorance of ecosystem structure and function in parks has led to costly mistakes--such as predator control and fire suppression--that continue to threaten parks today. This volume demonstrates the value of ecological knowledge in protecting parks and shows how modest investments in knowledge of park ecosystems can pay handsome dividends. Science and Ecosystem Management in the National Parks presents twelve case studies of long-term research conducted in and around national parks that address major natural resource issues. These cases demonstrate how the use of longer time scales strongly influence our understanding of ecosystems and how interpretations of short-term patterns in nature often change when viewed in the context of long-term data sets. Most importantly, they show conclusively that scientific research significantly reduces uncertainty and improves resource management decisions. Chosen by scientists and senior park managers, the cases offer a broad range of topics, including: air quality at Grand Canyon; interaction between moose and wolf populations on Isle Royale; control of exotic species in Hawaiian parks; simulation of natural fire in the parks of the Sierra Nevada; and the impact of urban expansion on Saguaro National Monument. Because national parks are increasingly beset with conflicting views of their management, the need for knowledge of park ecosystems becomes even more critical--not only for the parks themselves, but for what they can tell us about survival in the rest of our This book demonstrates to policymakers and managers that decisions based on knowledge of ecosystems are more enduring and cost effective than decisions derived from uninformed consensus. It also provides scientists with models for designing research to meet threats to our most precious natural resources. If we can learn to save the parks, observe Halvorson and Davis, perhaps we can learn to save the world. Contents- I. Introduction-1. Natural Resources Management in U.S. National Parks: Evolving from Belief to Science-2. Management in National Parks: from Scenery to Science- II. Long-term Versus Short-term Views-3. Fire Research and Management in the Sierra Nevada National Parks-4. Yellowstone Lake and Its Cutthroat Trout-5. Moose and Wolf Populations on Isle Royale National Park-6. Saguaro Cactus Dynamics-7. Alien Species in Hawaiian National Parks- III. No Park Is an Island-8. Water Rights and Devil's Hole Pupfish at Death Valley National Monument-9. Urban Encroachment at Saguaro National Monument-10. Karst Hydrological Research at Mammoth Cave National Park-11. Air Quality in Grand Canyon- IV. Protection Versus Use-12. Rare Plant Monitoring at Indiana Dunes National Lakeshore-13. Wilderness Research and Management in the Sierra Nevada National Parks-14. River Management at Ozark National Scenic Riverways- V. Summary and Analysis-15. Summary of Long-term Research Applied to Major Resource Issues in U.S. National Parks-16. Lessons Learned from a Century of Applying Research Results to Management of National Parks-