scholarly journals Using urban morphology for flood risk in residential areas in Ho Chi Minh city

2016 ◽  
Vol 19 (2) ◽  
pp. 146-153
Author(s):  
Hoa Thanh Le ◽  
Chau Thi Phuong Nguyen
Keyword(s):  
Land Use ◽  
Fractal Geometry ◽  
Urban Areas ◽  
Large Scale ◽  
Urban Morphology ◽  
Ho Chi Minh City ◽  
Residential Density ◽  
Urban Center ◽  
Rapid Urbanization ◽  
The City

Urban morphology in urban studies is used to classify and manage the distribution of urban densities. In urban planning, it helps to identify the emerging problems and solve the disorder of urban functions as in the megacity of Ho Chi Minh City. Rapid urbanization has increased the development footprint with disordered densities of building footprint, incomplete infrastructure and urban - peripheral instability. And it, then, caused more flood problems to the city. This study was based on applying fractal geometry, GIS on large-scale maps for identifying residential density based on urban morphology. The land-use map and the building footprints map of 2010 were integrated in fractal geometry to analyze the distribution of urban areas by the large scale of GIS data. This study showed HCMC had problems on irrational development in residential densities areas; and uneven development of population and residential density between the urban areas. At block scale of land-use block, in urban center had highest densities of building footprints and population, then, the medium densities in developing districts and rural-sub-districts. With these densities, there was more flood in high density areas, as in urban center, and less flood in lower density areas, as in sub-urban areas. These problems may cause some limitations to development of social, commercial, industrial, and infrastructure in HCMC. City needs to have flood control and management for development of the city.

Barriers and levers for implementing sustainable Nature-Based Solutions in cities

2021 ◽  
Author(s):  
Chloé Duffaut ◽  
Nathalie Frascaria-Lacoste ◽  
Pierre-Antoine Versini
Keyword(s):  
Urban Areas ◽  
Large Scale ◽  
Project Managers ◽  
Global Changes ◽  
Human Beings ◽  
Urban Context ◽  
Urban Plan ◽  
Education And Awareness ◽  
Awareness Raising ◽  
The City

<p>Hydro-meteorological risks are increasing and this could be due to global changes. These risks are particularly important in the urban context where most human beings live. Indeed, the impervious surfaces present in cities increase the risk of flooding, for example. Nature-Based Solutions can help to reduce these risks by creating permeable soils or storing water while promoting biodiversity. In this context, it is essential to understand what hinders the development and sustainability of these Nature-based Solutions in the city and what could help to deploy them on a large scale. For this purpose, various professionals working on Nature-Based Solutions in the city in France, were interviewed between 2020 and 2021, both in the academic and operational sectors, or even at the interface between the two: researchers in ecology or hydrology, IUCN (International Union for Conservation of Nature) project manager, project managers at the Regional Biodiversity Agency, director and natural environment manager of a watershed union, agro-economists engineer among others. They were asked what are the barriers and potential opportunities for Nature-Based Solutions implementation and sustainability in city. By analysing their answers, it emerges that the obstacles are more often cultural, political or financial than technical. The potential levers often mentioned are education and awareness-raising at all levels, especially for elected officials and the general public. Regulations such as the PLU (Local Urban Plan) and new funding for more natural spaces in the city also seem to be means of promoting Nature-based Solutions in urban areas. These interviews with diverse professionals directly involved in Nature-Based Solutions in cities allow to give real courses of action to be taken to democratize these Solutions throughout the French territory, or even internationally, and therefore ultimately reduce the risks of hydro-meteorology. This is one of the objectives of the French ANR project EVNATURB (Assessment of ecosystem performance of a renaturation of the urban environment), in which this study has been carried out.</p>

scholarly journals Quantifying Horizontal and Vertical Movements in Ho Chi Minh City by Sentinel-1 Radar Interferometry

2020 ◽  
Author(s):  
Dinh Ho Tong Minh ◽  
Yen-Nhi NGO ◽  
Thu Trang Lê ◽  
Trung Chon Le ◽  
Hong Son Bui ◽  
...  
Keyword(s):  
Time Series ◽  
Large Scale ◽  
European Space Agency ◽  
Ground Subsidence ◽  
Ho Chi Minh City ◽  
Vertical Movements ◽  
Space Agency ◽  
Permanent Scatterers ◽  
The City ◽  
East West

Ho Chi Minh City (HCMC), the most populous city and the economic center of Viet Nam, has faced ground subsidence in recent decades. This work aims at providing an unprecedented spatial extent coverage of the subsidence in HCMC in both horizontal and vertical components using Interferometric Synthetic Aperture Radar (InSAR) time series. For this purpose, an advanced InSAR technique PSDS (Permanent Scatterers and Distributed Scatterers) was applied to two big European Space Agency (ESA) Sentinel-1 datasets composed of 96 ascending and 202 descending images, acquired from 2014 to 2020 over HCMC area. A time series of 33 Cosmos SkyMED images was also used for comparison purpose. The combination of ascending and descending satellite passes allows the decomposition of the light of sight velocities into horizontal East-west and vertical components. By taking into account the presence of the horizontal East-west movement, our finding indicates that the precision of the decomposed vertical velocity can be improved up to 3 mm/year for Sentinel-1 data. The obtained results revealed that subsidence is most severe in areas along the Sai Gon river in the northwest-southeast axis and the southwest of the city with the maximum value up to 80 mm/year, consistent with findings in the literature. The magnitude of horizontal East-West velocities is relatively small and a large-scale westward motion can be observed in the northwest of the city at a rate of 2-5 mm/year. Together, these results reinforced the remarkable suitability of ESA's Sentinel-1 SAR for subsidence applications even for non-Europe countries such as Vietnam and Southeast Asia.

scholarly journals Thermal Comfort Simulation on Cik Ditiro Corridor

2019 ◽  
Vol 46 (1) ◽  
pp. 67-78
Author(s):  
Septian Eka Prayoga ◽  
Arif Kusumawanto
Keyword(s):  
Land Use ◽  
Thermal Comfort ◽  
Urban Areas ◽  
Rapid Development ◽  
Thermal Conditions ◽  
Simulation Method ◽  
Surface Material ◽  
Climate Variable ◽  
The City ◽  
Research Show

Surface materials that turn into hard surface material and lack of vegetations are some of the effects of rapid development that can affect the micro climate in urban areas. This happened on Cik Ditiro corridor in the city of Yogyakarta which had quite dense activities, this was marked by various functions of land use and human activities throughout the day. The method is simulation method that uses the EnviMET 4.0 software and the empirical measurements. This method is to simulate the value of each climate variable in existing conditions and ideal conditions. The results of this research show that the condition of the Cik Ditiro corridor still belongs to the heat which is uncomfortable thermal conditions. Recommendations result of this research is to make better thermal comfort on corridor. The result of this research to give recommendations in terms of improving better for thermal comfort.

scholarly journals Analyzing the Issue of On-street Parking in Commercial Areas: A Case Study of the City of Hyderabad, Pakistan

2018 ◽  
Vol 01 (02) ◽  
pp. 01-09
Author(s):  
Baig Farrukh ◽  
Sahito Noman ◽  
Bano Arsla ◽  
Keyword(s):  
Traffic Congestion ◽  
Urban Areas ◽  
Survey Methodology ◽  
Greenhouse Gas Emission ◽  
Central Business District ◽  
Rapid Urbanization ◽  
Analysis Technique ◽  
Business District ◽  
Public Views ◽  
The City

In developing countries, rapid urbanization has created an enormous pressure on land use, infrastructure and transportation. The fast growing ratio of motorized vehicles in urban areas is the main cause of environmental degradation. Almost 80% of the greenhouse gas emission is from vehicles in cities. In the city centers, on-street parking is considered the major cause of traffic congestion. The aim of this study was to evaluate the problems of on-street parking and disorderly parking at Central Business District (CBD) of Hyderabad city. The field survey methodology was adopted to perceive the current traffic problems in the city center and traffic count survey was carried out in both peak and off hours. The data was analyzed using descriptive statistics frequency analysis technique with the help of Statistical Package for the Social Sciences (SPSS). The findings revealed that increasing number of vehicles, on-street parking, improper parking, encroachment, inadequate parking space and poor condition of roads are the main causes of traffic congestion. The study bridges up the research gap of determining public views about on-street parking challenges in the context of Hyderabad, Pakistan and provides statistical results which may equally be adapted by policy makers and transportation planners in order to improve the traffic situation.

Villages in the City: Patterns of Urbanization in the Pearl River Delta, Dakar, and Zanzibar

2020 ◽  
pp. 49-76
Author(s):  
Garth Myers
Keyword(s):  
Land Use ◽  
Pearl River ◽  
Land Use Patterns ◽  
Rapid Urbanization ◽  
Use Patterns ◽  
The Pearl River Delta ◽  
Urban Transformations ◽  
Global North ◽  
The Pearl River ◽  
The City

The second chapter centers on patterns, specifically the geographic land-use and housing patterns common to rapid urbanization that overtakes the surrounding countryside. The chapter uses the Chinese concept of chengzhongcun, or urbanized village, along with the related concepts of chengbiancun and chengwaicun, villages on the city-edge and in the suburbs, and Chinese scholarship analyzing what happens to them in the PRD. The chapter applies these ideas to other similarly rapid urban transformations in Dakar and Zanzibar, with references to the comparability in other cities of the book. The purpose is to work toward conceptualizing from outside global North frameworks when looking at land-use patterns in urbanization. If one seeks to understand the patterns of 21st century planetary urbanization, one ought to look at the places where those patterns are most rapidly transforming the landscape and find the language there that is used to describe and analyze them. This chapter is a small experiment in doing so.

scholarly journals Incidence of Photovoltaics in Cities Based on Indicators of Occupancy and Urban Sustainability

Energies ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 810 ◽  
Author(s):  
Antonio Barragán-Escandón ◽  
Esteban Zalamea-León ◽  
Julio Terrados-Cepeda
Keyword(s):  
Urban Areas ◽  
Large Scale ◽  
Local Context ◽  
Social Dimensions ◽  
Country Level ◽  
Urban Energy ◽  
Urban Level ◽  
Energy Emissions ◽  
The Impact ◽  
The City

Previous research has assessed the potential of solar energy against possible demand; however, the sustainability issues associated with the use of large-scale photovoltaic deployment in urban areas have not been jointly established. In this paper, the impact of photovoltaic energy in the total urban energy mix is estimated using a series of indicators that consider the economic, environmental and social dimensions. These indicators have been previously applied at the country level; the main contribution of this research is applying them at the urban level to the city of Cuenca, Ecuador. Cuenca is close to the equatorial line and at a high altitude, enabling this area to reach the maximum self-supply index because of the high irradiation levels and reduced demand. The solar potential was estimated using a simple methodology that applies several indexes that were proven reliable in a local context considering this particular sun path. The results demonstrate that the solar potential can meet the electric power demand of this city, and only the indicator related to employment is positive and substantially affected. The indicators related to the price of energy, emissions and fossil fuel dependency do not change significantly, unless a fuel-to-electricity transport system conversions take place.

scholarly journals Spatio-Temporal Variation Analysis of Landscape Pattern Response to Land Use Change from 1985 to 2015 in Xuzhou City, China

2018 ◽  
Vol 10 (11) ◽  
pp. 4287 ◽  
Author(s):  
Yantao Xi ◽  
Nguyen Thinh ◽  
Cheng Li
Keyword(s):  
Land Use ◽  
Landscape Pattern ◽  
Urban Areas ◽  
Vegetation Index ◽  
Agricultural Land ◽  
Local Level ◽  
Land Use Changes ◽  
Landscape Patterns ◽  
Rapid Urbanization ◽  
Barren Land

Rapid urbanization has dramatically spurred economic development since the 1980s, especially in China, but has had negative impacts on natural resources since it is an irreversible process. Thus, timely monitoring and quantitative analysis of the changes in land use over time and identification of landscape pattern variation related to growth modes in different periods are essential. This study aimed to inspect spatiotemporal characteristics of landscape pattern responses to land use changes in Xuzhou, China durfing the period of 1985–2015. In this context, we propose a new spectral index, called the Normalized Difference Enhanced Urban Index (NDEUI), which combines Nighttime light from the Defense Meteorological Satellite Program/Operational Linescan System with annual maximum Enhanced Vegetation Index to reduce the detection confusion between urban areas and barren land. The NDEUI-assisted random forests algorithm was implemented to obtain the land use/land cover maps of Xuzhou in 1985, 1995, 2005, and 2015, respectively. Four different periods (1985–1995, 1995–2005, 2005–2015, and 1985–2015) were chosen for the change analysis of land use and landscape patterns. The results indicate that the urban area has increased by about 30.65%, 10.54%, 68.77%, and 143.75% during the four periods at the main expense of agricultural land, respectively. The spatial trend maps revealed that continuous transition from other land use types into urban land has occurred in a dual-core development mode throughout the urbanization process. We quantified the patch complexity, aggregation, connectivity, and diversity of the landscape, employing a number of landscape metrics to represent the changes in landscape patterns at both the class and landscape levels. The results show that with respect to the four aspects of landscape patterns, there were considerable differences among the four years, mainly owing to the increasing dominance of urbanized land. Spatiotemporal variation in landscape patterns was examined based on 900 × 900 m sub-grids. Combined with the land use changes and spatiotemporal variations in landscape patterns, urban growth mainly occurred in a leapfrog mode along both sides of the roads during the period of 1985 to 1995, and then shifted into edge-expansion mode during the period of 1995 to 2005, and the edge-expansion and leapfrog modes coexisted in the period from 2005 to 2015. The high value spatiotemporal information generated using remote sensing and geographic information system in this study could assist urban planners and policymakers to better understand urban dynamics and evaluate their spatiotemporal and environmental impacts at the local level to enable sustainable urban planning in the future.

scholarly journals Abandoned Farmland Location in Areas Affected by Rapid Urbanization Using Textural Characterization of High Resolution Aerial Imagery

2020 ◽  
Vol 9 (4) ◽  
pp. 191 ◽  
Author(s):  
Juan José Ruiz-Lendínez
Keyword(s):  
Urban Areas ◽  
Spatial Information ◽  
Arable Land ◽  
Aerial Imagery ◽  
Rapid Urbanization ◽  
Abandoned Farmland ◽  
Textural Characterization ◽  
Study Results ◽  
Abandoned Land ◽  
The City

Several studies have demonstrated that farmland abandonment occurs not only in rural areas, but is also closely interlinked with urbanization processes. Therefore, the location of abandoned land and the registration of the spatial information referring to it play important roles in urban land management. However, mapping abandoned land or land in the process of abandonment is not an easy task because the limits between the different land uses are not clear and precise. It is therefore necessary to develop methods that allow estimating and mapping this type of land as accurately as possible. As an alternative to other geomatics methods such as satellite remote sensing, our approach proposes a framework for automatically locating abandoned farmland in urban landscapes using the textural characterization and segmentation of aerial imagery. Using the city of Poznań (Poland) as a case study, results demonstrated the feasibility of applying our approach, reducing processing time and workforce resources. Specifically and by comparing the results obtained with the data provided by CORINE Land Cover, 2275 ha (40.3%) of arable land within the city limits were abandoned, and the area of abandoned arable land was almost 9.2% of the city’s area. Finally, the reliability of the proposed methodology was assessed from two different focuses: (i) the accuracy of the segmentation results (from a positional point of view) and (ii) the efficiency of locating abandoned land (as a specific type of land use) in urban areas particularly affected by rapid urbanization.

scholarly journals Coastal Landscape Vulnerability Analysis in Eastern China—Based on Land-Use Change in Jiangsu Province

2020 ◽  
Vol 17 (5) ◽  
pp. 1702
Author(s):  
Yangfan Zhou ◽  
Lijie Pu ◽  
Ming Zhu
Keyword(s):  
Land Use ◽  
Human Activities ◽  
Large Scale ◽  
Positive Impact ◽  
Eastern China ◽  
Landscape Management ◽  
Vulnerability Index ◽  
Jiangsu Province ◽  
Assessment Model ◽  
Rapid Urbanization

The unreasonable land use in rapid urbanization areas induced by large-scale urban construction activities have caused massive ecological issues. In this study, landscape vulnerability index (LVI) and landscape human interference index (LHAI) were originally addressed and calculated using multi-temporal land-use data from 2000 to 2015. Then, the spatial-temporal relationship assessment model of landscape fragility caused by human activities were constructed for each county of Jiangsu Province, China, so as to analyze the spatial distribution of landscape vulnerability and determine the impacts of artificial disturbance on landscape vulnerability. The results showed: (1) The number of counties with middle and high landscape vulnerability increased from 20 in 2000 to 27 in 2015 with a peak value (33) in 2010. (2) Counties with high-intensity human activities showed an upward trend. (3) Land use generally has a significant and diverse impact on landscape vulnerability. At the county level, the LVI was positively correlated with the LHAI before 2010 and was followed by a negative correlation of them. As concluded from this study, a total of four sub-regions (continuous benefit zones, variable benefit zones, continuous harmful zones, and variable harmful zones) have been identified for sustainable landscape management in the future. (4) The LVI suggests that the landscape vulnerability in Jiangsu did not continue to deteriorate in the study period. Further, accelerated land exploitation has produced a positive impact on regional economic development and ecological protection. This study provided an effective method set for analyzing the environmental impacts caused by human activities and promoting future ecosystem management in coastal areas.

scholarly journals Estimation of Ecological Connectivity in a City Based on Land Cover and Urban Habitat Maps

2020 ◽  
Vol 12 (22) ◽  
pp. 9529
Author(s):  
Dohee Kim ◽  
Wonhyeop Shin ◽  
Heejoon Choi ◽  
Jihwan Kim ◽  
Youngkeun Song
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Green Infrastructure ◽  
Urban Areas ◽  
Landscape Connectivity ◽  
Urban Habitat ◽  
Ecological Data ◽  
Ecological Connectivity ◽  
Future Work ◽  
The City

Anthropogenic land use has led to the loss and fragmentation of native habitats and disruption to ecosystem processes, resulting in a decline in landscape connectivity and biodiversity. Here, in order to find the potentials of improvements in ecological connectivity, we provide a spatial analysis to present differences in ecological connectivity based on land cover maps and urban habitat maps in Suwon city, Republic of Korea. We generated two permeability maps for use in a network analysis, one being land cover and the other urban habitat, including a 5-km buffer area from the city boundary. We then determined the current-flow betweenness centrality (CFBC) for each map. Our results indicate that forests are typically the most highly connected areas in both maps. However, in the land cover map results, nearly all high-priority areas were in the mountainous region (CFBC value: 0.0100 ± 0.0028), but the urban habitat indicated that grasslands and rivers within the city also significantly contribute to connectivity (CFBC value: 0.0071 ± 0.0022). The CFBC maps developed here could be used as a reference when introducing green infrastructure in cities. Before establishing ecological networks for urban areas, future work should integrate the land use and ecological data of different administrative districts with continuous ecological connection.

Sign in / Sign up

Export Citation Format

Share Document