scholarly journals Effects of Urban Forms on Separate Drainage Systems: A Virtual City Perspective

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 758 ◽  
Author(s):  
Jia ◽  
Sitzenfrei ◽  
Rauch ◽  
Liang ◽  
Liu
Keyword(s):  
Urban Form ◽  
Domestic Wastewater ◽  
Cost Effective ◽  
Three Dimensions ◽  
Rapid Urbanization ◽  
Drainage Systems ◽  
Urban Forms ◽  
Storm Water Management Model ◽  
Wastewater Systems ◽  
Performance Dimensions

The development of urban drainage systems is challenged by rapid urbanization; however, little attention is paid to the urban form and its effects on these systems. This study develops an integrated city-drainage model that configures typical urban forms and their associated drainage infrastructures, specifically domestic wastewater and rainwater systems, to analyze the relationship between them. Three typical types of urban forms were investigated: the square, the star, and the strip. Virtual cities were designed first, with the corresponding drainage systems generated automatically and then linked to a model herein called the Storm Water Management Model (SWMM). Evaluation was based on 200 random configurations of wastewater/rainwater systems with different structures or attributes. The results show that urban forms play more important roles on three dimensions of performance, namely economic efficiency, effectiveness, and adaptability, of the rainwater systems than of the wastewater systems. Cost is positively correlated to the effectiveness of rainwater systems among the different urban forms, while adaptability is negatively correlated to the other two performance dimensions. Regardless of the form, it is difficult for a city to make its drainage systems simultaneously cost-effective, efficient, and adaptable based on the virtual cities we investigated. This study could inspire the urban planning of both built-up and to-be-built areas to become more sustainable with their drainage infrastructure by recognizing the pros and cons of different macroscale urban forms.

Urban drainage system planning and design – challenges with climate change and urbanization: a review

2015 ◽  
Vol 72 (2) ◽  
pp. 165-179 ◽  
Author(s):  
Zeinab Yazdanfar ◽  
Ashok Sharma
Keyword(s):  
Climate Change ◽  
Drainage System ◽  
Cost Effective ◽  
Local Area ◽  
Urban Drainage ◽  
Rapid Urbanization ◽  
Drainage Systems ◽  
Planning And Design ◽  
Urban Drainage Systems ◽  
Fit For Purpose

Urban drainage systems are in general failing in their functions mainly due to non-stationary climate and rapid urbanization. As these systems are becoming less efficient, issues such as sewer overflows and increase in urban flooding leading to surge in pollutant loads to receiving water bodies are becoming pervasive rapidly. A comprehensive investigation is required to understand these factors impacting the functioning of urban drainage, which vary spatially and temporally and are more complex when weaving together. It is necessary to establish a cost-effective, integrated planning and design framework for every local area by incorporating fit for purpose alternatives. Carefully selected adaptive measures are required for the provision of sustainable drainage systems to meet combined challenges of climate change and urbanization. This paper reviews challenges associated with urban drainage systems and explores limitations and potentials of different adaptation alternatives. It is hoped that the paper would provide drainage engineers, water planners, and decision makers with the state of the art information and technologies regarding adaptation options to increase drainage systems efficiency under changing climate and urbanization.

scholarly journals Inclusion of Hydraulic Controls in Rehabilitation Models of Drainage Networks to Control Floods

Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 514
Author(s):  
Leonardo Bayas-Jiménez ◽  
F. Javier Martínez-Solano ◽  
Pedro L. Iglesias-Rey ◽  
Daniel Mora-Melia ◽  
Vicente S. Fuertes-Miquel
Keyword(s):  
Genetic Algorithm ◽  
Drainage System ◽  
Optimal Solution ◽  
Hydraulic Control ◽  
Drainage Systems ◽  
Storm Water Management Model ◽  
Drainage Networks ◽  
Extreme Rain ◽  
Rain Events ◽  
The Cost

A problem for drainage systems managers is the increase in extreme rain events that are increasing in various parts of the world. Their occurrence produces hydraulic overload in the drainage system and consequently floods. Adapting the existing infrastructure to be able to receive extreme rains without generating consequences for cities’ inhabitants has become a necessity. This research shows a new way to improve drainage systems with minimal investment costs, using for this purpose a novel methodology that considers the inclusion of hydraulic control elements in the network, the installation of storm tanks and the replacement of pipes. The presented methodology uses the Storm Water Management Model for the hydraulic analysis of the network and a modified Genetic Algorithm to optimize the network. In this algorithm, called the Pseudo-Genetic Algorithm, the coding of the chromosomes is integral and has been used in previous studies of hydraulic optimization. This work evaluates the cost of the required infrastructure and the damage caused by floods to find the optimal solution. The main conclusion of this study is that the inclusion of hydraulic controls can reduce the cost of network rehabilitation and decrease flood levels.

scholarly journals Evaluation of the Main Function of Low Impact Development Based on Rainfall Events

Water ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2231
Author(s):  
Meiyan Feng ◽  
Kwansue Jung ◽  
Fengping Li ◽  
Hongyan Li ◽  
Joo-Cheol Kim
Keyword(s):  
Low Impact Development ◽  
Hydrological Process ◽  
Main Function ◽  
Storm Events ◽  
Rapid Urbanization ◽  
Rainfall Events ◽  
Hydrological Balance ◽  
Storm Water Management Model ◽  
Cycle System ◽  
Positive Effect

Low Impact Development (LID) is one of the sustainable approaches to urban stormwater management in areas with rapid urbanization. Although LID has been shown to have a positive effect in flood reduction, the hydrological balance regulation effect of LID under a variety of rainfall events is not fully understood. In this study, we assessed the hydrological efficiency of LID at two residential–commercial mixed sites in Korea to investigate the main function of LID in terms of diverse rainfall characteristics. Storm Water Management Model (SWMM) was constructed to simulate the hydrological process numerical simulations in the pre-development, post-development and LID design scenarios, respectively. The model was calibrated and validated by using five observed rainfall–runoff events. Then, four single and four multiple LID practices (LIDs) were used to estimate their effectiveness under seven different designed rainfall events. The results indicate that LIDs substantially influence the hydrology cycle system, while the regulating effect varies with rainfall amounts. The efficiency of LIDs in flood reduction is proved to be more effective during lower storm events. However, LIDs should be designed to primarily prioritize the restoration of hydrological balance when the rainfall return period is longer.

scholarly journals Effectiveness of low-impact development for urban inundation risk mitigation under different scenarios: a case study in Shenzhen, China

2018 ◽  
Vol 18 (9) ◽  
pp. 2525-2536 ◽  
Author(s):  
Jiansheng Wu ◽  
Rui Yang ◽  
Jing Song
Keyword(s):  
Local Governments ◽  
Risk Mitigation ◽  
Low Impact Development ◽  
Green Roofs ◽  
Rapid Urbanization ◽  
Storm Water Management Model ◽  
Inundation Depth ◽  
High Hazard ◽  
Hazard Level ◽  
Hazard Levels

Abstract. The increase in impervious surfaces associated with rapid urbanization is one of the main causes of urban inundation. Low-impact development (LID) practices have been studied for mitigation of urban inundation. This study used a hydrodynamic inundation model, coupling SWMM (Storm Water Management Model) and IFMS-Urban (Integrated Flood Modelling System–Urban), to assess the effectiveness of LID under different scenarios and at different hazard levels. The results showed that LID practices can effectively reduce urban inundation. The maximum inundation depth was reduced by 3 %–29 %, average inundation areas were reduced by 7 %–55 %, and average inundation time was reduced by 0 %–43 % under the eight scenarios. The effectiveness of LID practices differed for the three hazard levels, with better mitigation of urban inundation at a low hazard level than at a high hazard level. Permeable pavement (PP) mitigated urban inundation better than green roofs (GRs) under the different scenarios and at different hazard levels. We found that more implementation area with LID was not necessarily more efficient, and the scenario of 10 % PP+10 % GR was more efficient for the study area than other scenarios. The results of this study can be used by local governments to provide suggestions for urban inundation control, disaster reduction, and urban renewal.

scholarly journals Computing climate-smart urban land use with the Integrated Urban Complexity model (IUCm 1.0)

2019 ◽  
Vol 12 (1) ◽  
pp. 525-539 ◽  
Author(s):  
Roger Cremades ◽  
Philipp S. Sommer
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Energy Consumption ◽  
Urban Form ◽  
Urban Land ◽  
Urban Land Use ◽  
Urban Mobility ◽  
Urban Forms ◽  
Complex Features ◽  
Combat Climate Change

Abstract. Cities are fundamental to climate change mitigation, and although there is increasing understanding about the relationship between emissions and urban form, this relationship has not been used to provide planning advice for urban land use so far. Here we present the Integrated Urban Complexity model (IUCm 1.0) that computes “climate-smart urban forms”, which are able to cut emissions related to energy consumption from urban mobility in half. Furthermore, we show the complex features that go beyond the normal debates about urban sprawl vs. compactness. Our results show how to reinforce fractal hierarchies and population density clusters within climate risk constraints to significantly decrease the energy consumption of urban mobility. The new model that we present aims to produce new advice about how cities can combat climate change.

scholarly journals WetSpa-Urban: An Adapted Version of WetSpa-Python, A Suitable Tool for Detailed Runoff Calculation in Urban Areas

Water ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2460 ◽  
Author(s):  
Nahad Rezazadeh Helmi ◽  
Boud Verbeiren ◽  
Charlotte Wirion ◽  
Ann van Griensven ◽  
Imeshi Weerasinghe ◽  
...  
Keyword(s):  
Open Source ◽  
Surface Runoff ◽  
Urban Areas ◽  
Statistical Investigation ◽  
Hydrological Processes ◽  
Rapid Urbanization ◽  
Storm Water Management Model ◽  
Distributed Process ◽  
Model Efficiency ◽  
Event Based

A tool called WetSpa-Urban was developed to respond to the need for precise runoff estimations in an increasingly urbanized world. WetSpa-Urban links the catchment model WetSpa-Python to the urban drainage model Storm Water Management Model (SWMM). WetSpa-Python is an open-source, fully distributed, process-based model that accurately represents surface hydrological processes but does not simulate hydraulic structures. SWMM is a well-known open-source hydrodynamic tool that calculates pipe flow processes in an accurate manner while runoff is calculated conceptually. Merging these tools along with certain modifications, such as improving the efficiency of surface runoff calculation and simulating flow at the sub-catchment level, makes WetSpa-Urban suitable for event-based and continuous rainfall–runoff modeling for urban areas. WetSpa-Urban was applied to the Watermaelbeek catchment in Brussels, Belgium, which recently experienced rapid urbanization. The model efficiency was evaluated using different statistical methods, such as Nash–Sutcliffe efficiency and model bias. In addition, a statistical investigation, independent of time, was performed by applying the box-cox transformation to the observed and simulated values of the flow peaks. By speeding up the simulation of the hydrological processes, the performance of the surface runoff calculation increased by almost 130%. The evaluation of the simulated 10 minute flow versus the observed flow at the outlet of the catchment for 2015 reached a Nash–Sutcliffe efficiency of 0.86 and a bias equal to 0.06.

scholarly journals Expert-level Automated Biomarker Identification in Optical Coherence Tomography Scans

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Thomas Kurmann ◽  
Siqing Yu ◽  
Pablo Márquez-Neila ◽  
Andreas Ebneter ◽  
Martin Zinkernagel ◽  
...  
Keyword(s):  
Machine Learning ◽  
Optical Coherence Tomography ◽  
Critical Role ◽  
Cost Effective ◽  
Automated Analysis ◽  
Machine Learning Algorithms ◽  
Three Dimensions ◽  
Optical Coherence ◽  
Clinical Routine ◽  
Wide Range

Abstract In ophthalmology, retinal biological markers, or biomarkers, play a critical role in the management of chronic eye conditions and in the development of new therapeutics. While many imaging technologies used today can visualize these, Optical Coherence Tomography (OCT) is often the tool of choice due to its ability to image retinal structures in three dimensions at micrometer resolution. But with widespread use in clinical routine, and growing prevalence in chronic retinal conditions, the quantity of scans acquired worldwide is surpassing the capacity of retinal specialists to inspect these in meaningful ways. Instead, automated analysis of scans using machine learning algorithms provide a cost effective and reliable alternative to assist ophthalmologists in clinical routine and research. We present a machine learning method capable of consistently identifying a wide range of common retinal biomarkers from OCT scans. Our approach avoids the need for costly segmentation annotations and allows scans to be characterized by biomarker distributions. These can then be used to classify scans based on their underlying pathology in a device-independent way.

scholarly journals Construction of Cooling Corridors with Multiscenarios on Urban Scale: A Case Study of Shenzhen

2020 ◽  
Vol 12 (15) ◽  
pp. 5903
Author(s):  
Jiansheng Wu ◽  
Si Li ◽  
Nan Shen ◽  
Yuhao Zhao ◽  
Hongyi Cui
Keyword(s):  
Urban Heat Island ◽  
Three Dimensions ◽  
Cooling Effect ◽  
Control Line ◽  
Heat Island ◽  
Rapid Urbanization ◽  
Administrative Region ◽  
Total Length ◽  
Urban Heat ◽  
Pass Through

Under the background of rapid urbanization, the urban heat island (UHI) effect is becoming increasingly significant. It is very important for the sustainable development of cities to carry out quantitative research on the mitigation of the UHI effect at an urban scale. Taking Shenzhen as an example, this paper puts forward a method for building a cooling corridor for the city with multiscenarios based on the theory of ecological security pattern (ESP), which can realize quantitative planning of the spatial layout of urban green infrastructure (UGI) to alleviate the UHI effect. In this study, cooling sources are identified from the three dimensions of habitat quality, landscape connectivity, and the capacity to provide cooling ecosystem services. The cooling corridors that are superior at cooling, isolation, and ventilation are selected and optimized. The results show that the identified ecological cooling source area accounts for 33.18% of the total area of Shenzhen, and more than 85% of the area falls within the scope of the basic ecological control line of Shenzhen. There are 48 cooling corridors with a total length of 289.17 km in the cooling priority scenario, which mostly pass through the high-temperature and subhigh-temperature areas of each administrative region and city, providing a good cooling effect but poor feasibility. There are 48 corridors with a total length of 326.66 km in the isolation priority scenario, which mostly pass through the administrative region boundary and have a weak connection with the urban heat island, avoiding the built-up areas with strong human activities. As consequence, cooling is relatively achievable, but its effect is not ideal. There are 47 corridors with a total length of 368.06 km in the ventilation priority scenario, including many urban main roads and river systems that fully utilize the area’s strong natural wind conditions and realize various functions; however, the cooling effect is suboptimal. Corridors with great potential in cooling, isolation, ventilation, and noise reduction were determined after comprehensive optimization.

scholarly journals Study on Riparian Shading Envelope for Wetlands to Create Desirable Urban Bioclimates

Atmosphere ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1348
Author(s):  
Abu Taib Mohammed Shahjahan ◽  
Khandaker Shabbir Ahmed ◽  
Ismail Bin Said
Keyword(s):  
Urban Heat Island ◽  
Urban Form ◽  
Water Surface ◽  
Inversion Layer ◽  
Urban Heat Island Effect ◽  
Heat Island ◽  
Rapid Urbanization ◽  
Island Effect ◽  
Urban Heat ◽  
Riparian Shading

Climate change and rapid urbanization are adversely affecting the urban environment by exacerbating the widely reported urban heat island effect in Dhaka, Bangladesh. Two wetland areas with variable riparian shadings in the warm-humid conditions of urban Dhaka were investigated through field campaigns on microclimatic parameters for their cooling potential on the surrounding urban fabric. It was observed that an inversion layer of fully saturated air develops over the water surface of wetland, suppressing evaporation from the wetland water surface layer, which was effectively reducing the heat exchange between the water surface and the air layer above it through its action as an insulating vapor blanket. Due to this effect, the wetland was unable to render as a source of coolth for the surrounding overheated urban area. This effect of the inversion layer was more pronounced in the urban wetland without riparian shading either by the urban form or tree canopy. A multiphysics simulation study conducted on the selected urban wetlands indicates the effect of differential shading pattern on the relation between fetch and inversion layer thickness. This research hypothesizes that the wetland can act as an urban adaption measure against the urban heat island effect by potentially transforming them into an urban cooling island (UCI) towards a favorable urban bioclimate.

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