Path Exploration and Practice of Sponge City Construction in the Pearl River Delta:A Case Study of Dalang Town,Dongguan City

In order to deal with global climate warming and practice the construction of national ecological civilization,a sponge city has become an important national plan for regional comprehensive management and development because it can systematically solve the issues of regional water resources,water security,water environment and water ecology,and provide a comprehensive plan of sustainable development for regional water control,storage and use.Sponge city construction has been carried out across the country.In this paper,taking Dalang Town as an example,and combining its local climate,geological geomorphology,hydrological conditions,current situation and future planning of urban space,management system and other characteristics,the connotation,construction strategy and objectives,index decomposition and other key contents of sponge city were discussed,and the methods of sponge city construction in the builtup area with high rainfall,abundant groundwater and high density were studied to provide reference for formulating solutions and schemes for Dalang Town and developing sponge city construction in the Pearl River Delta.

Waterfront Spatial Design from the Perspective of Sponge City

Due to environmental awareness, demand for watercourse landscape eco- function is growing domestically. However, flood control and drainage are the only focuses, and the rest functions of water course are slighted. Besides, cross-section biodiversity is falling and wetland self-cleaning capacity is impairing, resulting from river limitation on riverbed, making a straight river bend and revetment. So, water course has to be managed from ecology, economy, culture and social effect, to re- store natural river function and meet human demands. And to return to nature and people first would be the general principles.

Sustainable city development challenged by extreme weather in a warming world

The year of 2021 has witnessed many extreme weather events across the world that have shocked and challenged human society,in particular for the populous cities,challenging progress on sustainable city development.In the comment we highlighted the record-breaking rainstorm that is considered to happen only“once-in-a-thousand-years”on 20 July 2021 in Zhengzhou,China;and a series of short and long-term resilience enhancement and risk reducing measures to climate change and natural hazard risks.We found that increasing frequency and intensity of extreme weather events caused by human-induced climate change challenges progress on sustainable city development,but could also accelerate activities to enable cities to become more resilient.This comment is essential to advance towards the sustainable city development goal(SDG 11)in China’s mega cities,as well as informing progress for other global cities.

Design and achievement of cloud geodatabase for a sponge city

Building a cloud geodatabase for a sponge city is crucial to integrate the geospatial information dispersed in various departments for multi-user high concurrent access and retrieval,high scalability and availability,efficient storage and management.In this study,Hadoop distributed computing framework,including Hadoop distributed file system and MapReduce(mapper and reducer),is firstly designed with a parallel computing framework to process massive spatial data.Then,access control with a series of standard application programming interfaces for different functions is designed,including spatial data storage layer,cloud geodatabase access layer,spatial data access layer and spatial data analysis layer.Subsequently,a retrieval model is designed,including direct addressing via file name,three-level concurrent retrieval and block data retrieval strategies.Main functions are realised,including real-time concurrent access,high-performance computing,communication,massive data storage,efficient retrieval and scheduling decisions on the multi-scale,multi-source and massive spatial data.Finally,the performance of Hadoop cloud geodatabases is validated and compared with that of the Oracle database.The cloud geodatabase for the sponge city can avoid redundant configuration of personnel,hardware and software,support the data transfer,model debugging and application development,and provide accurate,real-time,virtual,intelligent,reliable,elastically scalable,dynamic and on-demand cloud services of the basic and thematic geographic information for the construction and management of the sponge city.

The Enlightenment on Urban Ecological Construction by Research Progress of Sponge City in China Based on Literature Analysis

To quantitatively analyze main figure,field,agency and level of sponge city research in China,and clear research focus and hot spot in each year,by using the Full Text Database of Chinese Sci-tech Periodicals and other retrieval tools,the statistics and analysis of 3152 research literatures on sponge city published in domestic academic journals of 2004-2016 are conducted based on bibliometrics. It is found that since the concept of " sponge city" was firstly proposed in 2012,development research of sponge city involves 40 subject fields and is mainly published in 32 kinds of journals,which is dominated by natural science research( 1427 literatures). Researchers are mainly from each college and university,some design institutes and Chinese Academy of Sciences. The research could play certain guidance significance for further research and construction of ecological city construction in China.

Developmental Application of Roof Greening against the Background of “Sponge City”: A Case Study of Ningbo City

In view of the problems of architectural eco-civilization in Ningbo City against the background of "sponge city", this paper proposed that development of roof greening in the city met the development concepts of sponge city, summarized six basic countermeasures and four cooperation mechanisms for the developmental application of roof greening in Ningbo City by analyzing practical experience of roof greening construction in foreign countries.

Urban Design Strategy Research Based on the Concept of Sponge City: A Case Study of Renbei District in Chengdu

Cities are currently confronted with many urban problems, such as water shortages, water quality pollution, floods, and the loss of habitats of aquatic organisms, and badly in need of a more comprehensive solution. In this context, the concept of "sponge city" is proposed. This paper, based on the theory of sponge city and low impact development, elaborated the origin, development, connotation, and construction method of "sponge city" concept. In this paper, the urban design scheme of Renbei District in Chengdu was taken for example to analyze the geographical environment and climate characteristics of Chengdu and explain the formation and verification of the scheme. It is considered that the "sponge city" is different from the traditional urban infrastructure. It is essentially an ecological approach. Its core is to build a cross-scale urban water ecological infrastructure to comprehensively solve the prominent water-related problems of urban and rural areas in China.

Construction Strategy of Sponge City in the Old Urban Area of Kunming Based on LID Concept

Sponge city construction,as an important measure of ecological construction in China,can effectively solve a series of problems such as large annual runoff,serious non-point source pollution,regional water shortage,low utilization rate of rain and flood resources,unsustainable ecological benefits of water landscape and poor landscape functions in urbanization construction. This paper uses LID concept to construct sponge city in the old urban area of Kunming,to reduce the total runoff and promote the utilization of rainfall and flood resources so as to rebuild,upgrade and optimize the regional environment and provide some reference for the regional construction of small-scale sponge city.

Operation and Maintenance Challenges in China“Sponge City”Program

China started a Sponge City program to offset the adverse impacts of urban developments and to tackle many water-related problems.By emphasizing stormwater management practices with“natural solutions”,many positive results have been achieved.The operation and maintenance(O&M)of Sponge City to support long-term success gained considerable focus.China is facing challenges many developed countries have encountered,as well as unique ones due to specific social,economic,and environmental conditions.This study identified and discussed Sponge City O&M challenges:(1)scheduling challenges,(2)technical challenges,(3)in short of local regulation/ordnance,(4)inadequate O&M assessment standard,(5)underprovided training,(6)PPP related concerns,(7)inter-agency coordination needs,(8)ownership and responsible party issues,(9)substandard documentation,and(10)funding and financial concerns.Selected cases and progress in pilot cities are introduced in the discussions.

Discussion on the Technological Path of Promoting the Sponge City Construction by Systematic Scheme in Small Catchment

Construction of the sponge city by small catchment is going to be the fundamental approach to contiguously promote the development of sponge city during the next phase in China.An effective guiding scheme to guarantee the contiguous promotion of sponge city is the systematic scheme of sponge city.An area in Shenzhen is taken as an example,and the compiling method and challenges of systematic scheme of sponge city are explored,principally including the targets setting under small catchment,the structure of overall thinking,compiling the scheme of runoff emission reduction from the source,perfecting aquatic environment,promoting water safety by the orientation of objective and issue,as well as the integration of each scheme and arrangement of construction mission.

A study on evaluation index system of the sponge city construction of Gui-An New District

The construction of sponge city, should effectively alleviate our country city water, strengthen the rainwater collection and utilization and transform urban development mode to the low impact development mode. In 2015, the pilot city of sponge city's construction has begun to take shape with the push of the Ministry of Housing and Urban-Rural Development of the Peoples' Republic of China, the Ministry of Finance and the Ministry of Water Resources. For the pilot cities, they should strengthen the performance evaluation process and play the leading role of the nation demonstration. Taking the aspects of sponge city project's management, runoff volume control into consideration, sponge city initially formed a set of scientific and objective evaluation index which is in order to reflect the effectiveness of Gui-An New Area's construction.What's more, through analyzing the sponge city's deficiency of the performance evaluation, I also carry out the work that need to put forward suggestions.

Analysis of Several Problems in the Construction of Sponge City

Sponge city refers to a new urban construction concept used to solve urban flood disasters and water ecological problems.It is important for the construction of ecological civilization.It plays an important role in the green development and livability of the city.In the construction of a sponge city,it is necessary to make special urban planning and improve the top-level design.In recent years,China has developed a number of sponge city pilot projects.The numerous experiments act as important references for the urban construction in China.This paper mainly analyzes the requirements for the construction of sponge city and discusses several problems as well as solutions in the construction.

Exploration of Sponge System Design in Wetland Parks Based on Rainwater and Flood Control: A Case Study of Southern Anhui Province

Based on the background that wetland resources in China are under threat and urgently need to be protected,a series of rainwater and flood problems caused by urban construction is analyzed comprehensively,and the design and planning methods of wetland parks in response to rainwater and flood disasters caused by floods and heavy rainfall are explored.Southern Anhui with complex and variable terrain and frequent rainfall and flood disasters is selected as the research area,with Xuanzhou District of Xuancheng City as the main research object.The relationship between municipal drainage of urban park and water conservancy drainage is investigated from different sample selection,design samples,and design flow rates.Based on literature review and model building methods,an urban storm flood model suitable for typical wetland parks in southern Anhui is constructed after processing the survey data using Arc GIS,SWMM(storm water management model).On this basis,a methodology and principles for designing a sponge system of wetland park based on rainwater and flood control are proposed,including technical measures such as rainwater collection,retention,and purification.This paper provides certain research results in design schemes,effect evaluations,ecological and social benefits,and useful suggestions and solutions for urban stormwater management and resilience development.

Reflection on Popular Concepts of Landscape Design

Guided by the values of harmonious coexistence between humans and nature,methods and concepts such as“biodiversity”,“sponge cities”,and“urban agriculture”have become popular.These methods and concepts are indisputable as a value orientation.But if conditional truth is promoted nationwide as unconditional truth,it will inevitably move from one extreme to the other.Starting from specific issues and practical experience,combined with the regional differences in the natural conditions,social customs and climate environment,the four popular viewpoints of“urban agriculture”,“biodiversity”,“local characteristics”,and“sponge cities”are reflected,and their“exclusion”reactions in certain regions are revealed,in order to awaken people’s rational thinking about popular concepts.

Laboratory Study on Stormwater Runoff Treatment via Sand-Based Micron-scale Pore Pervious Paver

Stormwater runoff samples from a road in China were collected and analyzed for pH,TSS(total suspended solid),TDS(total dissolved solid),COD(chemical oxygen demand),TP(total phosphorus),TN(total nitrogen),Pb,Al,Zn,Fe,Cd,and Mn.Results showed that the pollutant concentrations from road runoff were relatively high.TSS and COD concentrations exceeded the Class B effluent requirement of the Chinese Standards of Pollutant Discharge from municipal WWTPs(wastewater treatment plants).COD,TP,and TN concentrations exceeded Class V of the Chinese Environmental Quality Standard for Surface Water.TSS,Zn,Fe,and Al concentrations exceeded the USEPA(U.S.Environmental Protection Agency)benchmark values.All these indicated proper runoff treatment to avoid negative impacts on the environment is needed.Metal partitioning analysis was conducted and it showed that Pb,Al,Zn,Fe,and Mn exist mostly in particulate forms in the runoff.Thus,gravitational settlement and filtration can still be cost-effective methods for removing most of these metals.Runoff samples were treated through two bench-scale laboratory set-ups,composed of micron-scale pore pervious paver systems and subsoil.The average removal rates of TSS,TP,and TN were 95.2%,81.8%,64.1%,and 64.4%,respectively.The removal rates of Pb,Al,Zn,Fe,and Cd also reached 50%-99.2%.The tested sand-based pervious paver has micron-scale pores with good filtration potential.The system can effectively reduce stormwater runoff pollution,thereby reducing the potential for groundwater pollution.In addition,residues and sediments collected from the surfaces of the pervious pavers were also tested.The metallic constituents in the residues and sediments were correlated to these in the runoff.Pb and Cr were low in the residues,but Zn exceeded the Class A limit of the Chinese Control Standard of Pollutants in Sludge for Agricultural Applications.Thus,proper disposal of the solid wastes generated from the pavers is also to be further investigated.

Urban and river flooding:Comparison of flood risk management approaches in the UK and China and an assessment of future knowledge needs

Increased urbanisation,economic growth,and long-term climate variability have made both the UK and China more susceptible to urban and river flooding,putting people and property at increased risk.This paper presents a review of the current flooding challenges that are affecting the UK and China and the actions that each country is undertaking to tackle these problems.Particular emphases in this paper are laid on(1)learning from previous flooding events in the UK and China,and(2)which management methodologies are commonly used to reduce flood risk.The paper concludes with a strategic research plan suggested by the authors,together with proposed ways to overcome identified knowledge gaps in flood management.Recommendations briefly comprise the engagement of all stakeholders to ensure a proactive approach to land use planning,early warning systems,and water-sensitive urban design or redesign through more effective policy,multi-level flood models,and data driven models of water quantity and quality.

Component Optimization and Seepage Simulation Method of Resin Based Permeable Brick

In order to solve the problem of urban surface runoff,it is necessary to study permeable brick deeply.Tensile test and DMA test were used to study the binder material of permeable brick,and a material with the best mechanical properties was selected as the binder of resin based permeable brick;The permeable brick with single gradation and continuous gradation and porosity of 0.1–0.5 gradient is constructed by 3D modeling method.The particle composition and the seepage simulation results of permeable brick under different design parameters were analyzed;A resin-based permeable brick with micro-pores was prepared using the selected binder and desert sand with high roundness as aggregate,and compared with the simulation,its water permeability coefficient is 3.25×10-2 cm/s and the compressive strength is 36.19 MPa.In the seepage simulation of permeable brick,it is known that with the increase of gradation width“value i”,the water permeability coefficient increases.Therefore,in order to control the number of aggregate particles and obtain better seepage performance,the wide gradation of i≥4 and the design porosity of 0.3–0.4 should be considered.This study provides a research basis and a simulation method for the component optimization of resin based permeable brick.

Urban ecological sustainability assessment of the human-made system and natural system based on emergy and GIS approach

Due to the complexity of sustainable urban research,the environmental sustainability was assessed.Taking the sponge city as an example,the case study was conducted based on the integrated geographic information system(GIS)and emergy methods.The results demonstrate that the emergy of agricultural crops,major industrial products,comprehensive energy products,imports and exports,waste products and increased natural system emergy are the decisive factors for the sustainability assessment.Agricultural crops are the primary contributor,which accounts for 48.9%of the total emergy amount.Urban solid waste has a self-evident superiority in the waste products emergy proportion.Surface water and vegetal biomass emergy possess the pivotal consequences,far higher than soil organic matter.The sewage treatment stations(0.11%)play a small role in the sustainability assessment of the sponge city.The emergy sustainability index is 0.02181,which indicates poor environmental sustainability.According to the study results,increasing renewable energy input proportion and adopting the vegetal biomass of high unit emergy values(UEVs)can improve the sustainability level.

Study on Migration Law of Runoff Pollutants in Bio-retention Tank

The migration law of runoff pollutants in bio-retention tank was studied through the experimental research, containing calculation formula of pollutants reduction coefficient. After that, the technology of reducing and controlling runoff pollution by bio-retention tank was demonstrated. The result showed that bio-retention tank can reduce runoff by 15%-85%, and the pollutant emissions can be cut by 35%-95%. At the same time, it had good ecological landscape effect. The study can provide a reference for the design method of road bio-retention tank in sponge city construction, and basic technical methods and parameters for the subsequent construction of comprehensive control platform for urban rainwater runoff and the layout optimization of comprehensive measures of water quality and quantity.

Application of Urban Green Stormwater Infrastructure in Wetland Park Construction

The positive role of urban green stormwater infrastructure(GIS)and wetland park construction in the process of“sponge city”construction is analyzed by expounding the connotation and problems of“sponge city”construction.Through the analysis of relevant cases,the realization approaches of combing different types of GIS with wetland park landscape design are interpreted,and it is pointed out that different types of GIS can guide the further practice of“sponge city”construction.