scholarly journals Urbanization impacts on flood risks based on urban growth data and coupled flood models

2021 ◽  
Vol 106 (1) ◽  
pp. 613-627
Author(s):  
Boyu Feng ◽  
Ying Zhang ◽  
Robin Bourke
Keyword(s):  
Land Use ◽  
Surface Area ◽  
Flood Risk ◽  
Flash Flood ◽  
Impervious Surface ◽  
Urban Land ◽  
Growth Data ◽  
Impervious Surface Area ◽  
Urban Flood ◽  
Area Percentage

AbstractUrbanization increases regional impervious surface area, which generally reduces hydrologic response time and therefore increases flood risk. The objective of this work is to investigate the sensitivities of urban flooding to urban land growth through simulation of flood flows under different urbanization conditions and during different flooding stages. A sub-watershed in Toronto, Canada, with urban land conversion was selected as a test site for this study. In order to investigate the effects of urbanization on changes in urban flood risk, land use maps from six different years (1966, 1971, 1976, 1981, 1986, and 2000) and of six simulated land use scenarios (0%, 20%, 40%, 60, 80%, and 100% impervious surface area percentages) were input into coupled hydrologic and hydraulic models. The results show that urbanization creates higher surface runoff and river discharge rates and shortened times to achieve the peak runoff and discharge. Areas influenced by flash flood and floodplain increases due to urbanization are related not only to overall impervious surface area percentage but also to the spatial distribution of impervious surface coverage. With similar average impervious surface area percentage, land use with spatial variation may aggravate flash flood conditions more intensely compared to spatially uniform land use distribution.

scholarly journals A 30-meter resolution dataset of China's urban impervious surface area and green space fractions, 2000–2018

2020 ◽  
Author(s):  
Wenhui Kuang ◽  
Shu Zhang ◽  
Xiaoyong Li ◽  
Dengsheng Lu
Keyword(s):  
Land Use ◽  
Surface Area ◽  
Urban Areas ◽  
Green Space ◽  
Impervious Surface ◽  
Urban Land ◽  
Google Earth ◽  
Urban Land Use ◽  
Impervious Surface Area ◽  
Urban Impervious Surface

Abstract. Urban impervious surface area (UISA) and urban green space (UGS) are two core components of cities for characterizing urban environments. Although several global or national urban land use/cover products such as Globeland30 and FROM-GLC are available, they cannot effectively delineate the complex intra-urban land cover components. Here we proposed a new approach to map fractional UISA and UGS in China using Google Earth Engine (GEE) based on multiple data sources. The first step is to extract the vector boundaries of urban areas from China's Land Use/cover Dataset (CLUD). The UISA was retrieved using the logistic regression from the Landsat-derived annual maximum Normalized Difference Vegetation Index (NDVI). The UGS was developed through linear calibration between reference UGS from high spatial resolution image and the normalized NDVI. Thus, the China's UISA and UGS fraction datasets (CLUD-Urban) at 30-meter resolution are generated from 2000 to 2018. The overall accuracy of national urban areas is over 92 %. The root mean square errors of UISA and UGS fractions are 0.10 and 0.14, respectively. The datasets indicate that total urban area of China was 7.10 ×104 km2 in 2018, with average fractions of 70.70 % for UISA and 26.54 % for UGS. The UISA and UGS increased with unprecedented annual rates of 1,492.63 km2/yr and 400.43 km2/yr during 2000–2018. CLUD-Urban can enhance our understanding of urbanization impacts on ecological and urban dwellers’ environments, and can be used in such applications as urban planning, urban environmental studies and practices. The datasets can be downloaded from https://doi.org/10.5281/zenodo.3778424 (Kuang et al., 2020).

scholarly journals Evaluating the Dynamic Changes of Urban Land and Its Fractional Covers in Africa from 2000–2020 Using Time Series of Remotely Sensed Images on the Big Data Platform

2021 ◽  
Vol 13 (21) ◽  
pp. 4288
Author(s):  
Zherui Yin ◽  
Wenhui Kuang ◽  
Yuhai Bao ◽  
Yinyin Dou ◽  
Wenfeng Chi ◽  
...  
Keyword(s):  
Time Series ◽  
Surface Area ◽  
Urban Area ◽  
Impervious Surface ◽  
Remotely Sensed ◽  
Urban Land ◽  
Living Environment ◽  
Impervious Surface Area ◽  
Continental Scale ◽  
Remotely Sensed Images

Dramatic urban land expansion and its internal sub-fraction change during 2000–2020 have taken place in Africa; however, the investigation of their spatial heterogeneity and dynamic change monitoring at the continental scale are rarely reported. Taking the whole of Africa as a study area, the synergic approach of normalized settlement density index and random forest was applied to assess urban land and its sub-land fractions (i.e., impervious surface area and vegetation space) in Africa, through time series of remotely sensed images on a cloud computing platform. The generated 30-m resolution urban land/sub-land products displayed good accuracy, with comprehensive accuracy of over 90%. During 2000–2020, the evaluated urban land throughout Africa increased from 1.93 × 104 km2 to 4.18 × 104 km2, with a total expansion rate of 116.49%, and the expanded urban area of the top six countries accounted for more than half of the total increments, meaning that the urban expansion was concentrated in several major countries. A turning green Africa was observed, with a continuously increasing ratio of vegetation space to built-up area and a faster increment of vegetation space than impervious surface area (i.e., 134.43% vs., 108.88%) within urban regions. A better living environment was also found in different urbanized regions, as the newly expanded urban area was characterized by lower impervious surface area fraction and higher vegetation fraction compared with the original urban area. Similarly, the humid/semi-humid regions also displayed a better living environment than arid/semi-arid regions. The relationship between socioeconomic development factors (i.e., gross domestic product and urban population) and impervious surface area was investigated and both passed the significance test (p < 0.05), with a higher fit value in the former than the latter. Overall, urban land and its fractional land cover change in Africa during 2000–2020 promoted the well-being of human settlements, indicating the positive effect on environments.

scholarly journals Stormwater Utility Fee Estimation Method for Individual Land Use Areas

2021 ◽  
Author(s):  
jaehyun Yoo ◽  
Jae-Hyun Yoo ◽  
Kye-Hyun Kim ◽  
Ji-Yong Choi ◽  
Chol-Young Lee
Keyword(s):  
Land Use ◽  
Surface Area ◽  
Spatial Data ◽  
Phase 1 ◽  
Estimation Method ◽  
Impervious Surface ◽  
Industrial Area ◽  
Rate System ◽  
Impervious Surface Area ◽  
Apartment Complexes

Abstract In South Korea, a reasonable rate system that can be domestically applied to calculate the sewage and stormwater separately from the domestic sewage fee system is needed. This study proposes a phased pricing scenario to separate sewage and stormwater in Bupyeong-gu, Incheon, and the rate changes are compared based on a simulated calculation of the stormwater utility fee. In this investigation, stormwater runoff cases from other countries and the current domestic system are analyzed. A stormwater utility fee introduction scenario is presented that considers the impervious surface area. Water and sewage usage statistics and hydrant spatial data were collected from the Incheon Metropolitan City Waterworks Authority, and the total amount of water and sewage fees from the land use area were calculated. The stormwater utility fee was calculated, and the rates of each step were compared. The total sewage fee of Bupyeong-gu during 2014 was 21,685,446,578 won and the phased stormwater utility fee was calculated, assuming that 40% represents the stormwater cost. The sewage fee for the residential area in phase 3 decreased by 0.77% compared to phase 1. For the commercial areas, the sewage fee decreased by 36.87%. Because the impervious surface ratio was high, the overall area contributing to the impervious surface area was small. In the industrial area, the sewage fee increased by 8.35%. In the green area, the sewage fee increased by 37.46%. The sewage fee for the apartment complexes decreased by 10.6%. Finally, the possibility of estimating the actual stormwater utility fee is confirmed.

scholarly journals Land Use Vulnerability towards the Flood Risk in Surakarta City

2019 ◽  
Vol 280 ◽  
pp. 01011 ◽  
Author(s):  
Nur Miladan ◽  
Feira Ariani ◽  
Shifa Nurul Indah Pertiwi ◽  
Raafi Setiawan ◽  
Kusumaningdyah Nurul Handayani
Keyword(s):  
Land Use ◽  
Flood Risk ◽  
Urban Areas ◽  
Land Use Changes ◽  
Urban Land ◽  
Urban Land Use ◽  
Economic Losses ◽  
Risk Level ◽  
Urban Flood ◽  
Economic Assets

Urban flood risk is one of the frequent disasters in Indonesiancities. It causes the urban vulnerabilities including urban land use, community socio-economic assets, urban infrastructures and buildings. The massive urban land use changes will lead to the increase of flood riskif those changes do not manage properly. In other side, the increase offlood risk is also caused by the land use vulnerability. The assessment ofland use vulnerability on flood risk is an important element to identify theurban socio economic losses. Furthermore, the understanding of land usevulnerability could be an essential aspect for the urban land use plansrelating to the process of urban planning. This study has purpose to assessthe vulnerability of land use on flood risk in Surakarta City. This city hasseveral rivers flowing inside urban areas, and often, the flood occurrencestook place due to overflows of those rivers. This research used thedeductive approach. The data and information provided by the institutionaldocuments, and field observation. The result of the research indicated thatthe hazard level has more influence than the land use vulnerability level inthe calculation of flood risk. Furthermore, it demonstrated that the land usevulnerability level is not certainly linier correlated to the risk level.

Impervious Surface Area: Effects

2020 ◽  
pp. 93-99
Author(s):  
Carl L. Zimmerman ◽  
Daniel L. Civco
Keyword(s):  
Surface Area ◽  
Impervious Surface ◽  
Impervious Surface Area ◽  
Area Effects
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