Effects of Urbanization on Storm Water Run-off : A Case Study of Kathmandu Metropolitan City, Nepal

In urban and suburban areas, much of the land surface is covered by buildings and pavements, which do not allow precipitation and snowmelt to soak into the ground. Instead, most developed areas rely on storm drains to carry large amounts of runoff from roofs and paved areas to nearby waterways. Hard surfaces such as streets, parking lots and built-up areas are impervious surfaces through which, water cannot pass through. As more and more landscapes are covered with hard impervious surfaces, the amount of water that infltrates, decreases and the amount that runs off, increases. This research is focused on studying run-off conditions in context of urban areas. The study area is Kathmandu Metropolitan City (KMC). The City is in the stage of rapid urbanization and with it, a rapid increase in built-up spaces. As a result, the city is losing a balance between impervious and pervious cover. Loss of greeneries and unpaved open spaces are causing rapid drain of rain-water. This is creating a disturbance in the hydrological cycle of the area. For assessing the extent of runoff, total runoff was estimated of KMC, as per the surface characteristics and using rational method for calculation. Parameters for determining run-off coeffcients were mainly land cover and land use data, soil type and slope of surface. Results show that current runoff is alarmingly high, indicated by the difference between the run-off values of pre and post-development scenarios. Urban development pattern has caused a major impact, in the prevailing run-off and it is very crucial that these issues are addressed in urban planning to promote effective solutions for maintaining water cycle and water resources in urban areas. Journal of the Institute of Engineering, 2015, 11(1): 36-49

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Seasonal Variations of Daytime Land Surface Temperature and Their Underlying Drivers over Wuhan, China

Remote Sensing ◽

10.3390/rs13020323 ◽

2021 ◽

Vol 13 (2) ◽

pp. 323

Author(s):

Liang Chen ◽

Xuelei Wang ◽

Xiaobin Cai ◽

Chao Yang ◽

Xiaorong Lu

Keyword(s):

Surface Temperature ◽

Land Surface Temperature ◽

Land Surface ◽

Vegetation Index ◽

Normalized Difference Vegetation Index ◽

Maximum Temperature ◽

Maximum Temperature Difference ◽

Rapid Urbanization ◽

The Impact ◽

The City

Rapid urbanization greatly alters land surface vegetation cover and heat distribution, leading to the development of the urban heat island (UHI) effect and seriously affecting the healthy development of cities and the comfort of living. As an indicator of urban health and livability, monitoring the distribution of land surface temperature (LST) and discovering its main impacting factors are receiving increasing attention in the effort to develop cities more sustainably. In this study, we analyzed the spatial distribution patterns of LST of the city of Wuhan, China, from 2013 to 2019. We detected hot and cold poles in four seasons through clustering and outlier analysis (based on Anselin local Moran’s I) of LST. Furthermore, we introduced the geographical detector model to quantify the impact of six physical and socio-economic factors, including the digital elevation model (DEM), index-based built-up index (IBI), modified normalized difference water index (MNDWI), normalized difference vegetation index (NDVI), population, and Gross Domestic Product (GDP) on the LST distribution of Wuhan. Finally, to identify the influence of land cover on temperature, the LST of croplands, woodlands, grasslands, and built-up areas was analyzed. The results showed that low temperatures are mainly distributed over water and woodland areas, followed by grasslands; high temperatures are mainly concentrated over built-up areas. The maximum temperature difference between land covers occurs in spring and summer, while this difference can be ignored in winter. MNDWI, IBI, and NDVI are the key driving factors of the thermal values change in Wuhan, especially of their interaction. We found that the temperature of water area and urban green space (woodlands and grasslands) tends to be 5.4 °C and 2.6 °C lower than that of built-up areas. Our research results can contribute to the urban planning and urban greening of Wuhan and promote the healthy and sustainable development of the city.

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PARAMETERS OF INTEREST FOR THE DESIGN OF GREEN INFRASTRUCTURE

Journal of Urban and Environmental Engineering ◽

10.4090/juee.2019.v13n1.092101 ◽

2019 ◽

pp. 92-101

Author(s):

Marija Šperac ◽

Dino Obradović

Keyword(s):

Air Quality ◽

Urban Environment ◽

Air Temperature ◽

Green Infrastructure ◽

Land Surface ◽

Urban Areas ◽

Hydrological Cycle ◽

Urban Environments ◽

Land Surfaces ◽

Selection Of

The urbanization process significantly reduced the permeability of land surfaces, which affected the changes of runoff characteristics and the relations in the hydrological cycle. In urban environments, the relationships within the hydrological cycle have changed in quantity, in particular: precipitation, air temperature, evaporation, and infiltration. By applying the green infrastructure (GI) to urban environments is beneficial for the water resources and the social community. GI has an effect on the improvement of ecological, economic, and social conditions. Using GI into urban areas increases the permeability of land surfaces, whereby decreasing surface runoff, and thus the frequency of urban floods. It also has a significant influence on the regulation of air quality, water purification, climate change impact, and the changes in the appearance of the urban environment. When planning and designing the GI, it is necessary to identify the type of GI and determine the size and location of the selected GI. Since each urban environment has its own characteristics, it is necessary to analyze them before deciding on the GI. The paper analyzed meteorological parameters (precipitation, air temperature, insolation, air humidity) affecting the selection of GI types, using the specific example of an urban environment – the City of Osijek, Croatia. Significant parameters when designing GI are operation and maintenance These parameters directly affect the efficiency of GI. The proper selection of GI and its location results in maximum gains: the reduction of land surface drainage - drainage of the sewage system, purification and retention of precipitation at the place of production, the improvement of air quality, and the improvement of living conditions in urban environments

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

Journal of Art Architecture and Built Environment ◽

10.32350/jaabe.12.01 ◽

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.

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

ISPRS International Journal of Geo-Information ◽

10.3390/ijgi9040191 ◽

2020 ◽

Vol 9 (4) ◽

pp. 191 ◽

Cited By ~ 2

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.

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Mapping Urban Areas Using a Combination of Remote Sensing and Geolocation Data

Remote Sensing ◽

10.3390/rs11121470 ◽

2019 ◽

Vol 11 (12) ◽

pp. 1470 ◽

Cited By ~ 7

Author(s):

Nan Xia ◽

Liang Cheng ◽

ManChun Li

Keyword(s):

Remote Sensing ◽

Land Surface ◽

Urban Areas ◽

Large Scale ◽

High Spatial Resolution ◽

Human Life ◽

Human Movement ◽

Night Time ◽

Urban Mapping ◽

The City

Urban areas are essential to daily human life; however, the urbanization process also brings about problems, especially in China. Urban mapping at large scales relies heavily on remote sensing (RS) data, which cannot capture socioeconomic features well. Geolocation datasets contain patterns of human movement, which are closely related to the extent of urbanization. However, the integration of RS and geolocation data for urban mapping is performed mostly at the city level or finer scales due to the limitations of geolocation datasets. Tencent provides a large-scale location request density (LRD) dataset with a finer temporal resolution, and makes large-scale urban mapping possible. The objective of this study is to combine multi-source features from RS and geolocation datasets to extract information on urban areas at large scales, including night-time lights, vegetation cover, land surface temperature, population density, LRD, accessibility, and road networks. The random forest (RF) classifier is introduced to deal with these high-dimension features on a 0.01 degree grid. High spatial resolution land cover (LC) products and the normalized difference built-up index from Landsat are used to label all of the samples. The RF prediction results are evaluated using validation samples and compared with LC products for four typical cities. The results show that night-time lights and LRD features contributed the most to the urban prediction results. A total of 176,266 km2 of urban areas in China were extracted using the RF classifier, with an overall accuracy of 90.79% and a kappa coefficient of 0.790. Compared with existing LC products, our results are more consistent with the manually interpreted urban boundaries in the four selected cities. Our results reveal the potential of Tencent LRD data for the extraction of large-scale urban areas, and the reliability of the RF classifier based on a combination of RS and geolocation data.

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Impacts of Snow Darkening by Light-absorbing aerosols on the Water Cycle over the Western Eurasia and East Asia

10.5194/egusphere-egu2020-6556 ◽

2020 ◽

Author(s):

Jeong Sang ◽

Maeng-Ki Kim ◽

William K. M. Lau ◽

Kyu-Myong Kim

Keyword(s):

Land Surface ◽

Moisture Transport ◽

Hydrological Cycle ◽

Water Cycle ◽

Initial Conditions ◽

East Asian ◽

Development Program ◽

Eurasian Continent ◽

Absorbing Aerosols ◽

Western Eurasia

In this paper, we have investigated the snow darkening effects by light-absorbing aerosols on the regional changes of the water cycle over the Eurasian continent using the NASA GEOS-5 Model with aerosol tracers and a state-of-the-art snow darkening module, the Goddard SnoW Impurity Module (GOSWIM) for the land surface. Two sets of ten-member ensemble experiments for 10-years were carried out forced by prescribed sea surface temperature (2002-2011) with different atmospheric initial conditions, with and without SDE, respectively. Results show that SDE can exert a significant regional influence in partitioning the contributions of evaporative and advective processes on the hydrological cycle, during spring and summer season. Over western Eurasia, SDE-induced rainfall increase during early spring can be largely explained by the increased evaporation from snowmelt. Rainfall, however, decreases in early summer due to the reduced evaporation as well as moisture divergence and atmospheric subsidence associated with the development of an anomalous mid- to upper tropospheric anticyclonic circulation. On the other hand, in the East Asian monsoon region, moisture advection from adjacent ocean is a main contributor to rainfall increase in the melting season. Warmer land-surface caused by earlier snowmelt and subsequent drying further increases moisture transport and convergence significantly enhancing rainfall over the region. This findings suggest that the SDE may play an important role in leading to hotter and drier summer over western Eurasia, through coupled land-atmosphere interaction, while enhancing East Asian summer monsoonal precipitation via enhanced land-ocean thermal contrast and moisture transport due to SDE-induced warmer Eurasian continent.&#160;This work was supported by the Korea Meteorological Administration Research and Development Program under grant KMI2018-03410.

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Preliminary results of the Analysis of Precipitation Processes in the Eastern Ebro Subbasin (WISE-PreP) Field Campaign within HILIAISE

10.5194/ems2021-269 ◽

2021 ◽

Author(s):

Joan Bech ◽

Mireia Udina ◽

Bernat Codina ◽

Sergi Gonzalez ◽

Albert Garcia ◽

...

Keyword(s):

Land Surface ◽

Water Cycle ◽

Weather Prediction ◽

Surface Characteristics ◽

Ensemble Prediction ◽

Field Campaign ◽

Preliminary Results ◽

The World ◽

Precipitation Processes ◽

Semi Arid

Understanding future changes of the terrestrial water cycle and their interaction with human activity, with emphasis on agricultural areas, was selected as one of the World Climate Research Programme (WCRP) Grand Challenges, entitled &#8220;Water for the Food Baskets of the World&#8221;. Within this framework, the scientific objectives of the &#8220;Human Imprint on Land surface Interactions with the Atmosphere over the Iberian Semi-arid Environment&#8221; (HILIAISE) are the characterization of evapotranspiration and other key processes of water cycle in semi-arid environments. For this purpose, an international field campaign, scheduled for 2021, has been planned focused on a region with highly contrast surface characteristics (irrigated vs non-irrigated areas), particularly during summer.An overview and preliminary results of a specific project (WISE-PreP) within HILIAISE is given here. WISE-PreP was designed to study precipitation processes aiming to characterize possible differences in precipitation induced by surface characteristics. For this purpose, planned instrumentation for the campaign includes the deployment of three sites equipped each with a vertical radar Doppler Micro Rain Radar (MRR) and a laser disdrometer (PARSIVEL), covering both irrigated and non-irrigated sites, with three disdrometers (model PARSIVEL-2) and three MRRs (one model MRR-2 and two MRR-PROs). Time series of vertical precipitation profiles will be recorded to study microphysical processes trough the evolution of raindrop size distributions and related variables including precipitation intensity or convective vs stratiform rainfall regimes. Additional observations include raingauge data, C-band Doppler weather radar observations, and satellite products, as well as high resolution deterministic numerical weather prediction model data plus Ensemble Prediction Systems (EPS) model output. Funding for this research was provided by &#8220;Analysis of Precipitation Processes in the Eastern Ebro Subbasin&#8221; (WISE-PreP, RTI2018-098693-B-C32) and the Water Research Institute (IdRA) of the University of Barcelona.

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UniFHy v0.1: A community framework for the terrestrial water cycle in Python

10.5194/gmd-2021-419 ◽

2021 ◽

Author(s):

Thibault Hallouin ◽

Richard J. Ellis ◽

Douglas B. Clark ◽

Simon J. Dadson ◽

Andrew G. Hughes ◽

...

Keyword(s):

Land Surface ◽

Hydrological Cycle ◽

Water Cycle ◽

System Model ◽

Unified Framework ◽

Future Developments ◽

Land System ◽

Road Map ◽

Terrestrial Water ◽

Floods And Droughts

Abstract. Land surface, hydrological, and groundwater modelling communities all have expertise in simulating the hydrological processes at play in the land system, but these communities have largely remained distinct with limited collaboration between disciplines. In order to address key societal questions regarding the future availability of water resources and the intensity of extreme events such as floods and droughts in a changing climate, these communities must build on the strengths of one another. The development of a common modelling infrastructure, a framework, can contribute to stimulating cross-fertilisation between them. By allowing (parts of) their existing models to be coupled together, improved land system models can be built to better understand and simulate the terrestrial hydrological cycle. This paper presents a Python implementation of such a framework named the Unified Framework for Hydrology (unifhy). The framework aims to provide the technical infrastructure required to couple models, taking into account the specific needs of a land system model. Its conceptual design and technical capabilities are outlined first, before its usage and useful characteristics are demonstrated through case studies. The limitations of the current framework and necessary future developments are finally presented as a road map for later versions and/or other implementations of the framework.

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Changes in Urbanization and Urban Heat Island Effect in Dhaka City

10.21203/rs.3.rs-442136/v1 ◽

2021 ◽

Author(s):

A S M Shanawaz Uddin ◽

Najeebullah Khan ◽

Abu Reza Md. Towfiqul I ◽

Mohammad Kamruzzaman ◽

Shamsuddin Shahid

Keyword(s):

Urban Heat Island ◽

Land Surface ◽

Urban Areas ◽

Clustering Algorithm ◽

Planning Process ◽

Urban Expansion ◽

Heat Island ◽

Dhaka City ◽

Urban Heat ◽

The City

Abstract Urbanization changes the local environment, resulting in urban heat island (UHI) effect and deteriorating human life quality. Knowledge of urban environments and temperature changes is important to outline the urban planning process for mitigation of UHI effect. The study aimed to assess the changes in urban areas and UHI effects in Dhaka city, Bangladesh from 2001to 2017, using Moderate Resolution Imaging Spectroradiometer (MODIS) daily day- and nighttime land surface temperature (LST) data from 2001to 2017. The expansion of the city was calculated using the city clustering algorithm (CCA). The temperature of the identified urbanized area was analyzed and compared with the adjacent regions. The changes in urban temperature were estimated using non-parametric statistical methods. The results showed that the Dhaka city area has grown by 19.12% and its inhabitants by 76.65% during 2001–2017. Urban expansion and dense settlements caused an increase in average temperature in some areas of Dhaka city nearly 3°C compared to that at its boundary. The day and night temperatures at Dhaka city's warmest location were nearly 7 and 5ºC, respectively, more than the coolest point outside the city. The city's annual average day- and nighttime temperature was increasing at a rate of 0.03° and 0.023°C/year over the period 2001–2017. The rising temperature would increase the UHI effect in the future, which combined with high humidity, may cause a significant increase in public health risk in the city if mitigation practices are not followed.

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Future scenarios of thermal bioclimatic conditions in a humid tropical city under urban development

Ambiente e Agua - An Interdisciplinary Journal of Applied Science ◽

10.4136/ambi-agua.2092 ◽

2018 ◽

Vol 13 (5) ◽

pp. 1

Author(s):

Vicente De Paulo Rodrigues da Silva ◽

Joel Silva Santos ◽

Eduardo Rodrigues Viana de Lima ◽

Romildo Morant de Holanda ◽

Enio Pereira de Sousa ◽

...

Keyword(s):

Wind Speed ◽

Relative Humidity ◽

Air Temperature ◽

Urban Areas ◽

Kendall Test ◽

Future Scenarios ◽

Rapid Urbanization ◽

Mann Kendall Test ◽

Bioclimatic Conditions ◽

The City

Urbanization modifies the heat balance in urban areas and has negative effects on landscape, aesthetics, energy efficiency, human health and the inhabitants’ quality of life. This work evaluated future scenarios of bioclimatic conditions for João Pessoa, a humid tropical city in Northeast Brazil. The scenarios were determined based on trends in air temperature, relative humidity and wind speed for the time period from 1968 to 2015. The study was performed for two distinct periods of three months each (dry and wet seasons) using data from weather stations equipped with thermo-hygrometers and cup anemometers located in nine representative areas of the city. Trends in air temperature, relative humidity, wind speed, and effective temperature index (ET index) time series were evaluated using the Mann-Kendall test. Results indicated that the air temperature showed an increasing trend of 0.34°C/decade, whereas the relative humidity showed a decreasing trend of 0.49%/decade and the wind speed values ranged from 1.3 ms-1 to 3.80 ms-1. These trends are statistically significant according to the Mann-Kendall test (p<0.05). The air temperature increased between the 1980s and 2010s, which corresponds to a period of rapid urbanization of the city. Future environmental conditions in João Pessoa will be determined in accordance with the urbanization processes.

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