scholarly journals Addressing Challenges of Urban Water Management in Chinese Sponge Cities via Nature-Based Solutions

Water ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2788
Author(s):  
Yunfei Qi ◽  
Faith Ka Shun Chan ◽  
Colin Thorne ◽  
Emily O’Donnell ◽  
Carlotta Quagliolo ◽  
...  
Keyword(s):  
Flood Risk ◽  
Urban Water ◽  
Operating Life ◽  
Rapid Urbanization ◽  
Urban Flood ◽  
Natural Processes ◽  
Trade Offs ◽  
Wide Range ◽  
Fit For Purpose ◽  
Competing Priorities

Urban flooding has become a serious issue in most Chinese cities due to rapid urbanization and extreme weather, as evidenced by severe events in Beijing (2012), Ningbo (2013), Guangzhou (2015), Wuhan (2016), Shenzhen (2019), and Chongqing (2020). The Chinese “Sponge City Program” (SCP), initiated in 2013 and adopted by 30 pilot cities, is developing solutions to manage urban flood risk, purify stormwater, and provide water storage opportunities for future usage. Emerging challenges to the continued implementation of Sponge Cities include (1) uncertainty regarding future hydrological conditions related to climate change projections, which complicates urban planning and designing infrastructure that will be fit for purpose over its intended operating life, and (2) the competing priorities of stakeholders and their reluctance to make trade-offs, which obstruct future investment in the SCP. Nature-Based Solutions (NBS) is an umbrella concept that emerged from Europe, which encourages the holistic idea of considering wider options that combine “Blue–Green” practices with traditional engineering to deliver “integrated systems of Blue–Green–Grey infrastructure”. NBS includes interventions making use of natural processes and ecosystem services for functional purposes, and this could help to improve current pilot SCP practices. This manuscript reviews the development of the SCP, focusing on its construction and design aspects, and discusses how approaches using NBS could be included in the SCP to tackle not only urban water challenges but also a wide range of social and environmental challenges, including human health, pollution (via nutrients, metals, sediments, plastics, etc.), flood risk, and biodiversity.

scholarly journals Risk Assessment of Urban Floods Based on a SWMM-MIKE21-Coupled Model Using GF-2 Data

2021 ◽  
Vol 13 (21) ◽  
pp. 4381
Author(s):  
Lidong Zhao ◽  
Ting Zhang ◽  
Jun Fu ◽  
Jianzhu Li ◽  
Zhengxiong Cao ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Return Period ◽  
Flood Risk ◽  
Global Climate ◽  
Total Loss ◽  
Return Periods ◽  
Rapid Urbanization ◽  
Urban Floods ◽  
Urban Flood ◽  
Inundation Depth

Global climate change and rapid urbanization have caused increases in urban floods. Urban flood risk assessment is a vital method for preventing and controlling such disasters. This paper takes the central region of Cangzhou city in Hebei Province as an example. Detailed topographical information, such as the buildings and roads in the study area, was extracted from GF-2 data. By coupling the two models, the SWMM and MIKE21, the spatial distribution of the inundation region, and the water depth in the study area under different return periods, were simulated in detail. The results showed that, for the different return periods, the inundation region was generally consistent. However, there was a large increase in the mean inundation depth within a 10-to-30-year return period, and the increase in the maximum inundation depth and inundation area remained steady. The comprehensive runoff coefficient in all of the scenarios exceeded 0.8, indicating that the drainage system in the study area is insufficient and has a higher flood risk. The flood risk of the study area was evaluated based on the damage curve, which was obtained from field investigations. The results demonstrate that the loss per unit area was less than CNY 250/m2 in each return period in the majority of the damaged areas. Additionally, the total loss was mainly influenced by the damaged area, but, in commercial areas, the total loss was highly sensitive to the inundation depth.

Assessing Permeability Controls and Flood Risks Related to Urban Impervious Surface Expansion: A Case Study of the Southern Part of Kunming City, China

2021 ◽  
Author(s):  
Tong Xu ◽  
Zhiqiang Xie ◽  
Fei Zhao ◽  
Yimin Li ◽  
Shouquan Yang ◽  
...  
Keyword(s):  
Flood Risk ◽  
Underlying Surface ◽  
Rapid Urbanization ◽  
Urban Flood ◽  
Flood Risks ◽  
Flood Disasters ◽  
Surface Permeability ◽  
Flooding Risk ◽  
The Impact ◽  
Urban Flood Risk

Abstract Because of climate change and rapid urbanization, urban impervious underlying surfaces have expanded, causing Chinese cities to become strongly affected by flood disasters. Therefore, research on urban flood risks has greatly increased in the past decade, with studies focusing on reducing the risk of flood disaster. From 2012 to 2020, the impervious underlying surface has increased, and the permeable underlying surface has decreased annually in Kunming City. This study was conducted to investigate the impact of continuous changes in the urban underlying surface on flood disasters in the Runcheng area south of Kunming City from 2012 to 2020. We constructed a two-dimensional flood model to conduct flood simulations and flood risk analysis for this area. The relationship between the permeability of the underlying surface and urban flood risk was simulated and analyzed by varying the urban underlying surface permeability (30%, 35%, 40%, 45%, 50%, 55%, and 60%). The simulation results indicate that the urban flood risk increased with increases in the impervious underlying surface, with a threshold permeability of 35%. Once the permeability of the urban underlying surface decreased to below 35%, the flood risk increased rapidly. We demonstrated the impact of the urban underlying surface permeability on the risk of urban flood disasters, which is useful for urban planning decisions and urban flooding risk controls.

scholarly journals Urban Flood Risk and Economic Viability Analyses of a Smart Sustainable Drainage System

2021 ◽  
Vol 13 (24) ◽  
pp. 13889
Author(s):  
Helena M. Ramos ◽  
Mohsen Besharat
Keyword(s):  
Flood Risk ◽  
Computational Modelling ◽  
Economic Viability ◽  
Urban Drainage ◽  
Accurate Analysis ◽  
Rapid Urbanization ◽  
Protection Measures ◽  
Urban Flood ◽  
Drainage Systems ◽  
Urban Drainage Systems

Urban drainage systems are in transition from functioning simply as a transport system to becoming an important element of urban flood protection measures providing considerable influence on urban infrastructure sustainability. Rapid urbanization combined with the implications of climate change is one of the major emerging challenges. The increased concerns with water security and the ageing of existing drainage infrastructure are new challenges in improving urban water management. This study carried out in the Seixal area in Portugal examines flood risk analyses and mitigation techniques performed by computational modelling using MIKE SHE from the Danish Hydraulic Institute (DHI). Several scenarios were compared regarding flood risk and sustainable urban drainage systems (SuDS) efficiency. To obtain a more accurate analysis, the economic viability of each technique was analyzed as well through (i) life cost analysis and (ii) taking into account the damages caused by a certain type of flood. The results present that the best scenario is the one that will minimize the effects of great urbanization and consequently the flood risk, which combines two different measures: permeable pavement and detention basin. This alternative allows us to fully explore the mitigation capacity of each viable technique, demonstrating a very important improvement in the flood mitigation system in Seixal.

Urban flood risk assessment using sewer flooding databases

2011 ◽  
Vol 64 (4) ◽  
pp. 832-840 ◽  
Author(s):  
Nicolas Caradot ◽  
Damien Granger ◽  
Jean Chapgier ◽  
Frédéric Cherqui ◽  
Bernard Chocat
Keyword(s):  
Flood Risk ◽  
Drainage System ◽  
Decision Makers ◽  
Level Of Service ◽  
Urban Water ◽  
Urban Flooding ◽  
Urban Flood ◽  
Global Challenge ◽  
Effective Strategies ◽  
Definition Of

Sustainable water management is a global challenge for the 21st century. One key aspect remains protection against urban flooding. The main objective is to ensure or maintain an adequate level of service for all inhabitants. However, level of service is still difficult to assess and the high-risk locations difficult to identify. In this article, we propose a methodology, which (i) allows water managers to measure the service provided by the urban drainage system with regard to protection against urban flooding; and (ii) helps stakeholders to determine effective strategies for improving the service provided. One key aspect of this work is to use a database of sewer flood event records to assess flood risk. Our methodology helps urban water managers to assess the risk of sewer flooding; this approach does not seek to predict flooding but rather to inform decision makers on the current level of risk and on actions which need to be taken to reduce the risk. This work is based on a comprehensive definition of risk, including territorial vulnerability and perceptions of urban water stakeholders. This paper presents the results and the methodological contributions from implementing the methodology on two case studies: the cities of Lyon and Mulhouse.

scholarly journals Hydrodynamics of long-duration urban floods: experiments and numerical modelling

2016 ◽  
Vol 16 (6) ◽  
pp. 1413-1429 ◽  
Author(s):  
Anaïs Arrault ◽  
Pascal Finaud-Guyot ◽  
Pierre Archambeau ◽  
Martin Bruwier ◽  
Sébastien Erpicum ◽  
...  
Keyword(s):  
Numerical Model ◽  
Shallow Water ◽  
Flood Risk ◽  
Hydraulic Modelling ◽  
Complex Flow ◽  
Urban District ◽  
Validation Data ◽  
Urban Flood ◽  
Wide Range ◽  
Flow Features

Abstract. Flood risk in urbanized areas raises increasing concerns as a result of demographic and climate changes. Hydraulic modelling is a key component of urban flood risk analysis; yet, detailed validation data are still lacking for comprehensively validating hydraulic modelling of inundation flow in urbanized floodplains. In this study, we present an experimental model of inundation flow in a typical European urban district and we compare the experimental observations with predictions by a 2-D shallow-water numerical model. The experimental set-up is 5 m  ×  5 m and involves seven streets in each direction, leading to 49 intersections. For a wide range of inflow discharges, the partition of the measured outflow discharges at the different street outlets was found to remain virtually constant. The observations also suggest that the street widths have a significant influence on the discharge partition between the different streets' outlets. The profiles of water depths along the streets are mainly influenced by the complex flow processes at the intersections, while bottom roughness plays a small part. The numerical model reproduces most of the observed flow features satisfactorily. Using a turbulence model was shown to modify the length of the recirculations in the streets, but not to alter significantly the discharge partition. The main limitation of the numerical model results from the Cartesian grid used, which can be overcome by using a porosity-based formulation of the shallow-water equations. The upscaling of the experimental observations to the field is also discussed.

scholarly journals Assessing the Impact Index of Urbanization Index on Urban Flood Risk

2019 ◽  
Vol 8 (2) ◽  
pp. 509-516
Keyword(s):  
Land Use ◽  
Flood Risk ◽  
Flood Hazard ◽  
Risk Index ◽  
Flood Management ◽  
Management Approach ◽  
Rapid Urbanization ◽  
Urban Flood ◽  
Tapi Basin ◽  
The Impact

The process of urbanization has changed overall Land use/Land cover patterns which are being attributed to flooding and resulting in the economic damages from flooding events. This current study aims to evaluate the implication of spatiotemporal changes of LULC Pattern on the flood risk of Surat city (Gujarat, India), Lower Tapi Basin. The Topographical maps and satellite imagery of Resources-1 of the year 1968 and the year 2006 respectively are used for analyses the urbanization index. As the flood risk is a combination of flood hazard, and vulnerability of the urbanized area, flood losses are expected to rise due to change in each of these aspects. The remote sensing and spatial analysis tools of Geographic Information System (GIS) have been used to statistically examine the flood risk index along with their different land-use scenarios. It has been observed that other than natural processes, rapid urbanization obstructions are being considered as one of the main drivers of flood risk aggravation, and if so, it has made essential for the implementation of flood management approach at the top priority for reducing the risk of flood.

Urban flood risk warning under rapid urbanization

2015 ◽  
Vol 139 ◽  
pp. 3-10 ◽  
Author(s):  
Yangbo Chen ◽  
Haolan Zhou ◽  
Hui Zhang ◽  
Guoming Du ◽  
Jinhui Zhou
Keyword(s):  
Flood Risk ◽  
Rapid Urbanization ◽  
Urban Flood ◽  
Risk Warning ◽  
Urban Flood Risk

Water supply and sanitation planning model: a management tool for large Brazilian cities

2003 ◽  
Vol 3 (1-2) ◽  
pp. 469-476
Author(s):  
S.R.A. Soares ◽  
R.S. Bernardes
Keyword(s):  
Water Supply ◽  
Low Income ◽  
Management Tool ◽  
Urban Water ◽  
Rapid Urbanization ◽  
Modeling Approach ◽  
Developing Cities ◽  
Starting Point ◽  
Water And Wastewater ◽  
Water Supply And Sanitation

The sanitary problems promoted by the rapid urbanization process in developing cities are usually resulted from the absence of planning, high population concentration and inadequate water and wastewater infrastructure for low income people. Because the provision and planning of water supply and is a complex task, a modeling approach was used to enhance the understanding of the process and the aspects involved. In the development of a model, not only the technical aspects were taken into account, but other aspects related to the provision of drinking water and the water resources protection were also analyzed, such as institutional, financial, socioeconomic, environmental and public health. In the modeling process two different methods of conceptualization were used to describe the urban water flow through the water and wastewater systems linked to various aspects related to their implementation in large developing cities. The urban water systems of five large metropolitan areas in Brazil were also evaluated for the complete model. It is expected that the modeling approach developed in this paper consists of a valuable methodology for water supply and sanitation planning in Brazilian cities, and other developing cities with the same characteristics. The suggested conceptual model could, at least, provide more than a starting point for a useful urban water management tool.

scholarly journals Fundamental limits of electron and nuclear spin qubit lifetimes in an isolated self-assembled quantum dot

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
George Gillard ◽  
Ian M. Griffiths ◽  
Gautham Ragunathan ◽  
Ata Ulhaq ◽  
Callum McEwan ◽  
...  
Keyword(s):  
Quantum Dot ◽  
Spin Relaxation ◽  
Nuclear Spin ◽  
Operating Conditions ◽  
External Control ◽  
Spin Qubits ◽  
Fundamental Limits ◽  
Trade Offs ◽  
Wide Range ◽  
Spin Qubit

AbstractCombining external control with long spin lifetime and coherence is a key challenge for solid state spin qubits. Tunnel coupling with electron Fermi reservoir provides robust charge state control in semiconductor quantum dots, but results in undesired relaxation of electron and nuclear spins through mechanisms that lack complete understanding. Here, we unravel the contributions of tunnelling-assisted and phonon-assisted spin relaxation mechanisms by systematically adjusting the tunnelling coupling in a wide range, including the limit of an isolated quantum dot. These experiments reveal fundamental limits and trade-offs of quantum dot spin dynamics: while reduced tunnelling can be used to achieve electron spin qubit lifetimes exceeding 1 s, the optical spin initialisation fidelity is reduced below 80%, limited by Auger recombination. Comprehensive understanding of electron-nuclear spin relaxation attained here provides a roadmap for design of the optimal operating conditions in quantum dot spin qubits.

scholarly journals Gene Expression Space Shapes the Bioprocess Trade-Offs among Titer, Yield and Productivity

2021 ◽  
Vol 11 (13) ◽  
pp. 5859
Author(s):  
Fernando N. Santos-Navarro ◽  
Yadira Boada ◽  
Alejandro Vignoni ◽  
Jesús Picó
Keyword(s):  
Gene Expression ◽  
Gene Transcription ◽  
Performance Metrics ◽  
Cell Mass ◽  
Gene Copy ◽  
Substrate Uptake ◽  
Promoter Strength ◽  
Expression Levels ◽  
Trade Offs ◽  
Wide Range

Optimal gene expression is central for the development of both bacterial expression systems for heterologous protein production, and microbial cell factories for industrial metabolite production. Our goal is to fulfill industry-level overproduction demands optimally, as measured by the following key performance metrics: titer, productivity rate, and yield (TRY). Here we use a multiscale model incorporating the dynamics of (i) the cell population in the bioreactor, (ii) the substrate uptake and (iii) the interaction between the cell host and expression of the protein of interest. Our model predicts cell growth rate and cell mass distribution between enzymes of interest and host enzymes as a function of substrate uptake and the following main lab-accessible gene expression-related characteristics: promoter strength, gene copy number and ribosome binding site strength. We evaluated the differential roles of gene transcription and translation in shaping TRY trade-offs for a wide range of expression levels and the sensitivity of the TRY space to variations in substrate availability. Our results show that, at low expression levels, gene transcription mainly defined TRY, and gene translation had a limited effect; whereas, at high expression levels, TRY depended on the product of both, in agreement with experiments in the literature.

Sign in / Sign up

Export Citation Format

Share Document