Sponge City Construction Research Articles

Environmental and economic cost-benefit comparison of sponge city construction in different urban functional regions

This study conducts a life cycle environmental and economic quantification comparison of urban runoff source control facilities (URSCFs) through construction and operation stages in two urban functional regions (i.e., residential area and campus). From the environmental perspective, URSCFs construction in residential area has both higher environmental impacts and benefits than that in campus. The operation stage of URSCFs can observe significant benefit for both residential area and campus. We then develop a set of monetized method to make a comprehensive benefit evaluation (i.e., environmental, economic, and social benefit) of URSCFs. Overall, the two areas have payback time less than thirteen years for their investment which is acceptable when compared with the assumed total service period (30 years). Specifically, the payback time of campus is 5.62 years and residential area is 12.44 years. This implies that the campus has great potential to achieve high cost-benefit ratio and thus the Sponge City construction in campus can implement URSCFs with less engineering and material consumption due to its more spacious site than residential area with high building density. For both residential area and campus, permeable pavement has the highest environmental impact and economic cost because of the concrete consumption. Thus, we recommend that it should be cautious of the construction of concrete permeable pavement and find environmentally and economically alternatives in future URSCFs projects.

Spatiotemporal variation of essential ecosystem services and their trade-off/synergy along with rapid urbanization in the Lower Pearl River Basin, China

The Lower Pearl River Basin (LPRB) of China has witnessed the rapidest urbanization in the world, along with which there has been significant spatiotemporal heterogeneity of essential ecosystem services and their trade-off/synergy within this rapid urbanization region. This study firstly explored the spatiotemporal heterogeneity of three essential ecosystem services (i.e., the carbon sequestration service, habitat quality and water yield) in the LPRB with the Integrated Valuation of Ecosystem Services and Trade-offs model based on time-series data during 1990–2015. This study then categorized the study area into different urbanization areas according to the urbanization level, and thereafter separately revealed the trade-off/synergy between these ecosystem services with correlation analysis on the sub-watershed scale. Results suggested the carbon sequestration service and habitat quality in the whole study area showed a slightly decreasing trend, while the water yield in the whole study area showed significant inter-annual fluctuation. Besides, there were obvious differences in the trade-off/synergy between three essential ecosystem services in different urbanization areas, indicating urbanization had important impacts on these ecosystem services and their trade-off/synergy. Specifically, there was always a significant synergy between the carbon sequestration service and habitat quality, which tended to decline and then keep stable as urbanization proceeds. While there was a trade-off between the carbon sequestration service and water yield, which tended to be firstly stronger and significant but then weaker and insignificant as urbanization proceeds. By contrast, there tended to be a decreasing but still significant trade-off between the habitat quality and water yield as urbanization proceeds. Moreover, there was an unusual trade-off/synergy between the water yield and the other two ecosystem services in 1990 and 2015, which was primarily due to the significant spatial variation of some relatively unstable factors (e.g., precipitation). It is necessary to take proper measures (e.g., sponge city construction, water transfer projects) to cope with the effects of these relatively unstable factors on the essential ecosystem services as urbanization proceeds. The results of this study can provide valuable supporting information for land use management to guarantee sustainable provision of essential ecosystem services in these rapid urbanization areas.

Determining the fracture properties of pervious concrete specimens with various micro-structures and geometries

Pervious concrete is one of essential components in construction of sponge city, and the current study mainly focuses on the fracture performance of such promising material. Combined with three-point-bending (3-p-b) tests, a new method is proposed to determine the fracture properties of pervious concrete on the basis of Boundary Effect Model (BEM). The effects of material micro-structures (pore structure, aggregate structure) and specimen geometries on the fracture of pervious concrete are incorporated into the proposed formula in the form of fictitious crack. Then four groups of 3-p-b test results are collected to verify the proposed methods. The results show that the fracture properties obtained are independent of the specimen geometries, but are significantly influenced by the micro-structure of pervious concrete. The pervious concrete is strengthened with the increase of aggregate sizes, but is weakened with the increase of voids contents. Taking into account all the conclusions offered above, the fracture properties are strongly suggested to be carefully considered during the design of pervious concrete structures.

Retraction Note: Plant planning and urban construction of sponge city based on GIS system

Retraction Note: Plant planning and urban construction of sponge city based on GIS system

The scenario simulations and several problems of the Sponge City construction in semi-arid loess region, Northwest China

The scenario simulations and several problems of the Sponge City construction in semi-arid loess region, Northwest China

A chemical-mechanics model for the mechanics deterioration of pervious concrete subjected to sulfate attack

Strength deterioration is one of the primary indicators to reduce the durability of pervious concrete under sulfate attack. This study aimed to establish a chemical–mechanical model to predict the strength evolution. The compressive strength and splitting tensile strength of pervious concrete in three different concentrations of sodium sulfate solution were obtained by experiments. A corrosion coefficient was adopted to evaluate the deterioration of compressive strength. The corrosion coefficient model was developed by considering the pore filling effect of expansion products and the corrosion damage induced by expansion stress. Compared with the experimental results, the developed model could better characterize the deterioration process of pervious concrete. Therefore, the model proposed in this paper provides a more reliable solution for the design and durability life assessment of pervious pavement engineering in sponge city construction projects.

Comparison of runoff from low-impact development measures in arid and humid cities

A study was undertaken to identify differences in the performance of low-impact development (LID) measures in arid and humid cities. Yinchuan and Guangzhou in China were selected as a representative of each type. A stormwater management model was constructed with the aid of a geographic information system and LID measures of permeable pavements (PP), rain gardens (RG), green roofs (GR) and combinations of these were then designed. The results showed that a combination of PP, RG and GR provided the largest reduction in total runoff, peak runoff and runoff coefficient in both cities. Paired measures also delivered a significantly higher performance than single measures, with PP plus GR better than other paired combinations. The results of this work could guide the construction of sponge cities in both arid and humid areas.

Laboratory Evaluation on the Road Performance of Diatomite Modified Porous Asphalt Mixture

Porous asphalt mixture (PAM) is an indispensable pavement material for the construction of sponge city with low-cost and environment friendly characteristics, which conducive to replenishing urban groundwater and alleviating the heat island effect. The main purpose of this article is to explore the change of road performance and water permeability of PAM under different diatomite dosage, and determine the optimal amount of diatomite content. First, the volume characteristics of diatomite permeable asphalt mixture (D-PAM) were measured by Darcy’s law, the void of D-PAM decreased slightly according to the test results. Furthermore, based on the water damage Marshall test and freeze-thaw splitting test, the water stability of D-PAM increases significantly with the increase of diatomite content. At last, the low-temperature anti-cracking performance and ductility of D-PAM were carried out based on the acoustic emission (AE) detector and the Low temperature universal mechanics testing machine. According to the experimental results, it is recommended that the content of diatomite is 10%.

Effect of highly efficient substrate modifier, super-absorbent polymer, on the performance of the green roof

Green roofs are commonly used in sponge city construction. However, the limitations of substrate thickness and strong sunlight have caused water retention to become the primary problem in the promotion of this technology. Super-absorbent polymer (SAP) is a material with excellent water absorption capacity that is expected to improve the substrate to solve the problem of the insufficient water storage capacity of green roofs. In this study, the basic performances of two types of SAPs, namely polyacrylate sylvite and acrylic acid-attapulgite hybrid (P-SAP and A-SAP, respectively), were evaluated on a bench-scale. The results showed that both SAPs had good water absorption, reusability, and fertilizer protection ability. These SAPs could maintain high water absorption within a certain range of salinity, pH, and temperature. Although water absorption of P-SAP was higher than that of A-SAP, the latter showed a significant advantage in substrate modification. After adding A-SAP (application rate: 0.6%, particle size: 12 mesh), the water storage capacity of the substrate was significantly improved, with an increase in the saturation moisture content of 23.8% and a decrease in the infiltration rate of 48.5%. A simulator of green roof was constructed with A-SAP under optimal conditions. The enhancement of the water retention capacity increased the drought resistance of the plants, which improved their growth; in particular, the fresh weight was 98% higher than that of the control group. A-SAP increased the rate of building up the lawn by 25%. The average soil moisture of the A-SAP group was 63.3%, which was 10.0% higher than that of the control group. An increase of more than 26% in the runoff control capacity was found in the green roof with A-SAP. Overall, our study indicates that A-SAP is a practical and efficient modifier for green roofs.

Classification of sponge city construction modes based on regional features.

In order to make the sponge city construction model more consistent with the inherent characteristics of the city, this paper constructs classification of the sponge city construction index system. We carry out multivariate statistical and cluster analysis based on geographic information system (GIS) and classify the different regions of mainland China, putting forward key points of construction for different types of regions. The results show that climatic factor, hydrological factor and soil factor are the main factors affecting sponge city construction, followed by city scale and level of urban economic development; the third is underlying surface type and geomorphological type. The cities are classified into ten clusters, and they present a continuously zonal or flaky distribution from northeast to southwest on the whole; more than 80% of cities obviously present a continuously zonal or flaky distribution. Each of the nine clusters has at least one pilot city, which can be used as a reference for construction.

Research on the efficient water-absorbing ceramsite generated by dredged sediments in Dian Lake-China and coal fly ash.

In order to transform the dredged sediment (DS) into an efficient water-absorbing ceramsite (EWAC), the coal fly ash (CFA) and expansion agent were used to blend, expand, and sinter with the DS in the Dian Lake-China. A new type of high EWAC was prepared with the absorption ratio of 66.71%, which was much higher than similar products. The heavy metals leaching (HML) of EWAC showed that the concentration of As was 0.90 mg/L and the Hg, Pb, Cd, and Cr were too low to be detected. The characterization analysis showed that the EWAC cross section contained a lot of hydroxyl, ether, and P-Cl hydrophilic group by Fourier transform infrared (FT-IR), scanning electron microscope (SEM), and Brunauer-Emmett-Teller (BET) specific surface area (SSA) test method. The above groups and structures could greatly improve the water absorption (WA) performance of the EWAC. What's more, the SSA of the EWAC could reach 4.468 m2 /g. The results of Comsol Multiphysics indicated that the SSA and average pore size (APS) of the EWACs were 10 and 6 times higher than the commercial ceramsites, respectively. The research provided the utilization of the DS with technical and theoretical basis for the construction of sponge city. PRACTITIONER POINTS: The article was focus on the utilization of dredged sediment (DS) and coal fly ash (CFA) for the basic material preparation technology and its toxicity test as the sponge city. First, the raw materials were the DS in Dian Lake (Kunming, Yunnan, China) and CFA (thermal power plants), which were all belonged to the hazardous solid waste and was made to the efficient water-absorbing ceramsite (EWAC). Second, the water absorption (WA) performance of the EWAC was improved greatly whose absorption ratio was much higher than similar products reached 66.71%. The specific surface area (SSA) and average pore size (APS) of the EWACs were 10 and 6 times higher than the commercial ceramsites (CCs), respectively. Finally, the heavy metals leaching (HML) of As was 0.90 mg/L, and the HML of Hg, Pb, Cd, and Cr was all lower than 0.05 mg/L, which could not only not cause secondary pollution but provide the new ideas for the resource utilization of large amount of DS. So, we thought this article was suitable for the journal.

Effects of low impact development on the stormwater runoff and pollution control

The frequent urbanization and extreme rainfall events have posed the threat to the urban environment. The implementation of low impact development (LID) practices with great potential for control urban flood and overflow pollution is not comprehensively understood yet due to the influence of complex factors (i.e., hydrological pattern, installation location, and vertical parameter setting). In this study, the hydraulic and water quality model were used to analyze the hydrological and pollution reduction of outfall and storage under different hydrological patterns, vertical parameter setting, and green infrastructure installation locations, which can determine the best implementation of the scheme for overflow pollution control. The results showed that nine parameters of the vertical layer regarding the four parameters impacted the peak value and load of suspended solids (SS). The combination scheme of the LID practices was further proposed based on the selection and analysis of the single LID practice. Besides, considering the installation location, the downstream installed location was a better choice. The horizontal connection of overflow runoff and pollution could be reduced by up to 9.75% and 36.46%, respectively. In addition, the horizontal connection can effectively reduce the peak value of inflow and pollutants at the time of assessing storage tank impact, which reach the maximum of 14.08% and 29.25%, respectively. The pollutants distribution became uniform and showed better resilience against rainfall intensity, which is beneficial to the management of stormwater. Our findings can provide guidance for Sponge City construction and effectively alleviate the combined sewer overflow.

The Effectiveness of the Rainwater Garden under Different Rainfall and Different Soil Conditions in Hangzhou, Zhejiang

At present, there are still problems in applicability and lack of basic research in the construction of sponge cities in Zhejiang Province. In this paper, a generalized model of the rainwater garden box is established. The planting soil, park soil and soil mixed with fine sand and coarse sand in Hangzhou area are selected as the rainwater garden medium layer. The artificial rainfall test method is used to simulate seepage and storage efficiency of rain garden under the once every two years rainfall and once every five years rainfall of Hangzhou city. The test results show that under the same soil conditions, the maximum infiltration flow rate under the once every two years rainfall is 0.2 cm3/s more than that under the once every five years, and the maximum infiltration rate of planting soil has exceeded the maximum infiltration rate under the once every five years. Under the once every two years rainfall, the maximum infiltration flow of the planting soil, planting soil and fine sand are each composed of half, and planting soil and coarse sand are each composed of half are 2.1, 4.8 and 5.6 cm3/s, respectively; the maximum infiltration flow of the the park soil, park soil and fine sand are each composed of half, and the park soil and coarse sand are each composed of half, are 0.7, 7.7and 9.2 cm3/s, respectively. At the same time, after adding fine sand, the infiltration amount increases by about 1/4 compared to before mixing; after adding coarse sand, the infiltration amount increases by about 1/3 compared to before mixing. It can be seen that the infiltration capacity of the park soil is much better than that of the planting soil after the sand-grain mixing ratio. The results of this research can provide theoretical basis and technical reference for the construction of Hangzhou sponge city.

RETRACTED ARTICLE: Environmental change of rainfall erosivity based on GIS system and architectural design of sponge city

With the continuous development of society and the continuous improvement of scientific and technological level, it has greatly promoted the development of many fields. Especially civil engineering, civil engineering plays an important role in the development of China. Civil engineering survey is an indispensable part of civil engineering work. The application of GIS system technology in engineering survey helps to improve the accuracy and efficiency of survey, ensure the orderly development of the project, and improve the construction quality. However, rainfall erosivity reflects the potential ability of rainfall to cause soil erosion. Many scientists use R value of rainfall erosion rate to calculate soil erosion coefficient and draw curve equation. Therefore, it is an important guideline to study the spatial and temporal distribution characteristics of R value, establish simple regression function, quantitative prediction of soil and water loss, and soil and water conservation plan. With the continuous changes of economy and society, the global environment is also changing, which inevitably affects human beings. With the accelerating process of new urbanization, urban planning and architectural design are also deepening. On the one hand, it is necessary to improve the urban living environment and seriously implement the construction of sponge city. On the other hand, the green roof design of urban rainwater drainage and storage must be coordinated with it. The sustainable development of economy and society promotes the strong rise of construction industry. Architectural design is an important part of construction engineering, which can represent the construction standard of construction engineering. Based on the research of GIS system and rainfall erosivity environment change, this paper applies it to the architectural design of sponge City, and then promotes the vigorous development of urban construction.

A study on the actual situation of sponge city construction policy in various provinces and cities in China

A study on the actual situation of sponge city construction policy in various provinces and cities in China

Research of Sponge City Landscape Planning Based on Landscape Security Pattern

With the rapid urbanization and increasing urban impervious areas in China, the construction of the sponge city has gradually turned to the urban ecological space planning. Based on the theory of landscape safety pattern, the construction of sponge city should improve the rainwater management system from multiple scales and enhance the functional of urban landscape space. Firstly, the paper describes the ecological basement elements of the sponge urban landscape safety pattern, as well as the steps and technical methods of sponge urban landscape planning. Secondly, taking Shenfu New City as an example to elaborate the method of sponge urban landscape planning from multiple scales, the landscape ecological planning. The approach is introduced into the theoretical method of sponge city construction, and the feasibility of the study is illustrated by verificationof model, which provides new ideas and methods for sponge urban landscape planning.

Preparation method of epoxy resin sand based permeable material

The sand was pretreated in different ways, and the epoxy resin was selected as the cementing material to prepare the epoxy resin sand based permeable material. This kind of modification and treatment of permeable materials can obtain more superior performance and more widely used permeable materials, which provides a material basis for the construction of sponge city.

WITHDRAWN: Urban ecological analysis and health risk assessment under the concept of the sponge city.

Ahead of Print article withdrawn by publisher.

Cellular automata based framework for evaluating mitigation strategies of sponge city

Urban surface water flooding is increasing because of climate change and urbanization, and brings great challenges to urban sustainable development. It is, therefore, most important to develop urban flood management approaches to alleviate the consequences of floods. China is implementing a “sponge city” initiative to tackle urban surface water flooding and improve urban water management. There is, however, limited cost-effectiveness evaluation to support the choice of economically efficient mitigation strategies. To address this gap, this study developed an evaluation framework based on cellular automata and cost–benefit analysis to assess the performance of mitigation strategies in sponge city construction. This approach is demonstrated with a case study of Siergou (Dalian, China), which has a total area of 10.1 km2. The mitigation measures of green roofs, permeable pavements and bio-retention were used to generate mitigation scenarios. A two-dimensional cellular automata-based model was used to simulate urban surface water flooding. The results obtained from the case study indicate that the framework can achieve cost-effective mitigation strategies for sponge city construction, which can support robust decision making. The distribution of mitigation strategies has great impacts on the effectiveness of alleviating urban flood risk. This study provides new insight into the development of cost-effective mitigation strategies for sponge city construction.

Prioritizing sponge city sites in rapidly urbanizing watersheds using multi-criteria decision model.

Spatial planning is crucial for sponge city (SC) construction; however, prioritizing SC sites at the watershed scale has not been fully explored. In this study, a multi-criteria decision model, considering demand and suitability of SC construction, was established by monitoring, model simulation, and index calculation. This new model was then tested in a rapidly urbanizing watershed, Beijing, China, and the priority of SC construction at both grid scale (1km×1km) and subwatershed scale was ranked. The results showed that the highest priority was found in emerging regions where urbanization is ongoing and followed by urban core areas. In addition, six indexes were identified by clustering heatmaps as key factors affecting the priority of SC planning, including topographic index, water pollution index, pollution rate based on the state standard of surface water environment quality, urbanization planning, urban levels, and vegetation index, which could guide SC planning in data-lacking regions. The approach and findings in this study cannot only provide helpful references for watershed managers and urban planners but also can be easily used in other regions.