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Construction and Application of “the Sponge City” in Different Precipitation Regions: Case Studies in Pingxiang and Ji’nan, China
Available online at www.sciencedirect.com
ScienceDirect Availableonline onlineatatwww.sciencedirect.com www.sciencedirect.com Available Energy Procedia 00 (2018) 000–000
ScienceDirect ScienceDirect
www.elsevier.com/locate/procedia
Energy (2019) 000–000 207–212 EnergyProcedia Procedia159 00 (2017) www.elsevier.com/locate/procedia
Applied Energy Symposium and Forum, Renewable Energy Integration with Mini/Microgrids, REM 2018, 29–30 September 2018, Rhodes, Greece The 15th International Symposium on District Heating and Cooling Construction and Application of “the Sponge City” in Different Precipitation Regions: Case Studies in Pingxiang and Ji’nan, China Assessing the feasibility of using the heat demand-outdoor a, Han a, Yan Wu * temperature function forXu a long-term district heat demand forecast a
China Aerospace Academy of Architectural Design & Research Co., Ltd, Beijing 102627, China
I. Andrića,b,c*, A. Pinaa, P. Ferrãoa, J. Fournierb., B. Lacarrièrec, O. Le Correc a IN+ Center for Innovation, Technology and Policy Research - Instituto Superior Técnico, Av. Rovisco Pais 1, 1049-001 Lisbon, Portugal Abstract
b Veolia Recherche & Innovation, 291 Avenue Dreyfous Daniel, 78520 Limay, France Département Systèmes Énergétiquesand et Environnement Atlantique, 4 rue Kastler, 44300 Nantes, city France This article briefly introduces the conception connotation of- IMT the sponge city, andAlfred 30 pilot cities of sponge are discussed c
according to the different rainfall belt in China. On the basic of this point, we take Pingxiang, Jiangxi Province in the humid area and Ji’nan, Shandong Province in semi humid area as the examples, summarizing their climatic characteristics, the construction demand, the construction idea and route, as well as the related guarantee. Authors believe that the sponge city construction ideas Abstract need to rely closely to the local climate characteristics, geographical characteristics, special conditions and other practical situations. In addition, this paper also provides a reference for other cities to build sponge cities in the same rainfall belt. District heating networks are commonly addressed in the literature as one of the most effective solutions for decreasing the greenhouse gas emissions from theElsevier building sector. These systems require high investments which are returned through the heat © 2019 The Published Ltd. Copyright ©Authors. 2018 Elsevier Ltd. by All rights reserved. sales. Due to access the changed conditions and building policies, heat demand in the future could decrease, This is an open article climate under the CC-BY-NC-ND licenserenovation (https://creativecommons.org/licenses/by-nc-nd/4.0/) Selection and peer-review under responsibility of the scientific committee of the Applied Energy Symposium and Forum, Selection and under period. responsibility of the scientific committee of the Applied Energy Symposium and Forum, prolonging thepeer-review investment return Renewable Energy Integration with Mini/Microgrids, REM 2018. Renewable Energy Mini/Microgrids, 2018. The main scope of Integration this paper iswith to assess the feasibilityREM of using the heat demand – outdoor temperature function for heat demand forecast. The district of Alvalade, located in Lisbon (Portugal), was used as a case study. The district is consisted of 665 Keywords: Sponge city; Precipitation characteristics; Climatic region; Construction and application; Urban planning and design buildings that vary in both construction period and typology. Three weather scenarios (low, medium, high) and three district renovation scenarios were developed (shallow, intermediate, deep). To estimate the error, obtained heat demand values were compared with results from a dynamic heat demand model, previously developed and validated by the authors. 1.The Conception of sponge city and the evaluating indicators results showed that when only weather change is considered, the margin of error could be acceptable for some applications (the error in annual demand was lower than 20% for all weather scenarios considered). However, after introducing renovation With thethe occurrence extremeup weather events in the world recentand years, the surface watercombination environment of cities scenarios, error valueofincreased to 59.5% (depending on thein weather renovation scenarios considered). inThe various countries has been threatened. In response to this problem, the United States first proposed the "Low Impact value of slope coefficient increased on average within the range of 3.8% up to 8% per decade, that corresponds to the Development" (LID) concept [1] in the 1990s. The significance is to enhance urban rainstorm management, improve decrease in the number of heating hours of 22-139h during the heating season (depending on the combination of weather and renovation considered). On thethrough other hand, function increased for 7.8-12.7% per decade on the and protect scenarios urban water environment rational use intercept of low-impact development facilities, and(depending promote water coupled scenarios). The values suggested couldconservation be used to modify function for this, the scenarios and security, resource conservation and energy at thethe same time.parameters Inspired by China's considered, 2013 Central improve the accuracy of heat demand estimations. Urbanization Work Conference clearly put forward the concept of “Sponge City”, and successively released the © 2017 The Authors. Published by Elsevier Ltd. Peer-review under responsibility of the Scientific Committee of The 15th International Symposium on District Heating and Cooling. * Corresponding author. Tel.: +86 10 89060515; fax: +86 10 89060999 * Corresponding author. Tel.: +86 10 89060515; fax: +86 10 89060999 E-mail address: [email protected] Keywords: Heat demand; Forecast; Climate change
1876-6102 Copyright © 2018 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the Applied Energy Symposium and Forum, Renewable Energy Integration with Mini/Microgrids, REM 2018. 1876-6102 © 2017 The Authors. Published by Elsevier Ltd. 1876-6102 © 2019 The Authors. Published by Elsevier Ltd. Peer-review under responsibility of the Scientific Committee of The 15th International Symposium on District Heating and Cooling. This is an open access article under the CC-BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/) Selection and peer-review under responsibility of the scientific committee of the Applied Energy Symposium and Forum, Renewable Energy Integration with Mini/Microgrids, REM 2018. 10.1016/j.egypro.2018.12.052
Xu Han et al. / Energy Procedia 159 (2019) 207–212 Xu Han, Yan Wu/ Energy Procedia 00 (2018) 000–000
208 2
“Sponge City Construction Technical Guide (Trial)” and “Sponge City Construction Performance Evaluation and Assessment Method (Trial)” [2-4]. They clarified the six categories of first-level assessment indicators for sponge city construction (i.e. water ecology, water environment, water resources, water security, system construction and implementation, display) and 18 subdivisions Secondary indicators. Among them, “control rate of total annual runoff” is designated as the core evaluation index. The meaning is the proportion of the total controlled annual rainfall (including natural infiltration, artificial infiltration, accumulation, evapotranspiration, reuse, etc.) to the total annual rainfall. 2. Precipitation characteristic zones and pilot sponge cities distribution in China 2.1. Precipitation characteristic in China China has a vast territory, and its geographical and climatic characteristics vary greatly. The overall distribution of precipitation shows a gradual decrease from southeast to northwest. The 800mm annual precipitation is the boundary between humid and sub-humid areas, and is located on the Qinling-Huaihe line. The average annual precipitation in most areas of China is between 173.0~494.9 mm and the rainy season and dry season are distinct: from May to September, the annual precipitation in most parts of China exceeds 90% of the whole year, of which from June to August. 70% of the annual precipitation. Figure 1 is an overview of the classification of annual precipitation in China.
Fig. 1. Distribution of precipitation characteristic zones in China.
2.2. Pilot sponge cities distribution in different rainfall characteristic zones in China Table 1 shows the results of the thirty experimental sponge cities in China according to different precipitation characteristics. It can be seen that most of the pilot cities are concentrated in humid and semi-humid areas, 15 and 11 respectively. Moreover, there are three in rainy areas and only one in semi-arid areas. This paper selects one pilot sponge city in two different precipitation feature zones (humid and semi-humid) to outline its construction plan, characteristics, overall progress and preliminary results. The goal is to provide reference and reference for the construction of sponge urban areas for the same rainfall feature belt. Table 1. The pilot sponge cities in different precipitation characteristics. Precipitation characteristics Rainy area Humid Semi-humid
Pilot cities Zhuhai, Shenzhen, Sanya Zhenjiang, Jiaxing, Chizhou, Xiamen, Pingxiang, Wuhan, Changde, Nanning, Chongqing, Suining, Gui'an, Shanghai, Ningbo, Fuzhou, Yuxi Qian'an, Baicheng, Ji’nan, Hebi, Xixian, Beijing, Tianjin, Dalian,
Total 3 15 11
Xu Han et al. / Energy Procedia 159 (2019) 207–212 Xu Han, Yan Wu / Energy Procedia 00 (2018) 000–000 Qingdao, Qingyang, Guyuan Xining (None)
Semi-arid Arid
209 3 1 0
3. Construction and application situation of sponge city in humid area: the case in Pingxiang Pingxiang City, Jiangxi Province, as the first pilot sponge city established in China, has ranked first in the annual performance appraisal for two consecutive years [5]. This section takes Pingxiang City in a humid area as an example to discuss its construction mode and characteristics. 3.1. General situation of Pingxiang City Pingxiang is a prefecture-level city in Jiangxi Province. It is located in the western part of Jiangxi Province. And it is located between 113°35′~114°17′ east longitude and 27°20′~28°0′ north latitude. The total area is 3831 km2. In 2015, the population was about 1.93 million. Pingxiang is a typical subtropical humid monsoon climate with an annual average temperature of 17.3 °C. The annual precipitation is abundant, and the annual average precipitation reaches 1596.7mm, which is between the wet and rainy belts. The average monthly precipitation and monthly average temperature distribution in Pingxiang are shown in Figure 2. It can be seen from the figure that the annual precipitation distribution in Pingxiang is uneven, mainly concentrated in April to June. 250
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Fig. 2. Monthly precipitation and temperature distribution in Pingxiang.
3.2. Construction demand Water shortage Pingxiang is a typical mountainous and hilly city. It shows the characteristics of high surrounding terrain, low intermediate terrain and poor water storage capacity. The central city of Pingxiang has concentrated most of the population, industrial and mining enterprises and high-water consumption industries. It has typical water quality, resource and engineering water shortage characteristics. Water pollution In recent years, urban expansion, road construction, coal mining, industrial wastewater and domestic sewage discharge in Pingxiang City have led to the narrowing, turbidity and odor of water in many rivers. Uneven precipitation and water use time The precipitation and water use time in Pingxiang are uneven. The rainfall from April to June accounts for 44.5% of the total, while the urban water consumption only accounts for 20% of the whole year. From July to September, the city's rainfall accounts for 20% of the year, while urban water consumption accounts for 70% of the year. Urban internal waterlogging The special terrain of Pingxiang is easy to cause mountain runoff to flow into the urban area along the Pingshui River during heavy rains, which often leads to a serious increase in the short-term internal diameter flow in the urban area. Taking Wanlong Bay, the most serious waterlogging, as an example, an internal waterlogging of about 30km2 has been formed over the years. The average submergence depth during rainstorms is 50~120cm [6].
Xu Han et al. / Energy Procedia 159 (2019) 207–212 Xu Han, Yan Wu/ Energy Procedia 00 (2018) 000–000
210 4
3.3. Construction target Based on the actual situation, Pingxiang drafted 4 aspects of construction targets including water ecology, water environment, water resources and water safety, as shows in Figure 5.
Fig. 3. Construction target of sponge city in Pingxiang.
3.4. Mainly engineering measurements The process of sponge city construction in Pingxiang was mainly included the source controlling, process controlling and terminal controlling, the detailed engineering measures as shows in Figure 4. Source control
Process control
Terminal control
Permeable paving Ecological revetment Sinking green space construction Vegetation buffer zone Construction of biological Grass planting ditch pavement Ecological wetland and rainwater retention measures Seepage well, seepage pipe and ecological pond Shallow ditch construction of deep ditch construction sedimentation tank vegetation Dust measure construction Water quality purification Laying of initial rainwater disposal facilities Other ecological measures Green roof paving Fig. 4. The mainly engineering measurements of sponge city construction of Pingxiang.
3.5. Preliminary construction results (1) Water ecology: total annual runoff control rate increased from 30% to over 75% in pilot zones, and the diversity of aquatic vegetation was increased significantly. (2) Water environment: removal rate of suspended solids was over 50% in rivers, and the water quality of main rivers and lakes have basically reached the IV water standard. (3) Water sources: rainwater utilization achieved 8%, and it were widely used in municipal cleaning, landscaping, green plant watering and river replenishment. Annual water saving was about 2 million and 560 thousand tons. (4) Water safety: 49 water accumulation points have been eliminated or obviously relieved; 43 residential blocks never suffer the city floods. 4. Construction and application situation of sponge city in semi-humid area: the case in Ji’nan 4.1. General situation of Ji’nan City Ji’nan is the provincial capital of Shandong Province. It is located in the central of Shandong. And it is located in 117°00′ east longitude and 36°40′ north latitude. The total area is 8177 km2. In 2016, the population was about 7.23
Xu Han et al. / Energy Procedia 159 (2019) 207–212 Xu Han, Yan Wu / Energy Procedia 00 (2018) 000–000
211 5
million. Ji’nan is a typical monsoon climate of medium latitudes climate with an annual average temperature of 13.8 °C. The annual precipitation is about 685 mm and the average monthly precipitation and monthly average temperature distribution in are shown in Figure 5. It can be seen that the annual precipitation distribution mainly concentrated in July and August. 200
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-5
Fig. 5. Monthly precipitation and temperature distribution in Pingxiang.
4.2. Construction demand Water shortage The annual average water sources in Ji’nan is 1 billion 748 million m3, among them, the available part take account of 66%, therefore, the water resources per capita only 290 m³/year, which equal to 1/7 of national average level in China. Urban internal waterlogging Ji’nan's topography is high in the South and low in the north, and the highest difference is over 130 m. During heavy rains, the old city areas often leads to a serious urban waterlogging due to the irrational urban planning and designing in before. Water pollution In Ji’nan, the phonemes of sewage directly discharged into rivers; besides, a number of animal carcasses, feces, pesticide residue are produced in farming areas, which affects water quality in each river seriously. Pilot point distribution and construction target The district of Xinglong, Daminghu area in Ji’nan was designated as the first sponge city construction pilot area (Figure 6). The total area of the pilot area is 39 km2, with a population of 0.32 million.
(a) Location of the pilot area in Ji’nan (b) Detailed area of Xionglong district Fig. 6. Location of the pilot area of sponge city in Ji’nan
On the basis of “Urban master plan of Ji’nan (2011~2020)”, the total annual runoff control rate was designed of 70%, and the area of built sponge city was about 410 km2, as well as the controlled rainfall was drafted as 9 million 510 thousand m³. Table 2 is the construction target of Ji’nan.
6212
Xu Han,Xu YanHan Wu/etEnergy Procedia 00 (2018) 000–000 al. / Energy Procedia 159 (2019) 207–212 Table 2 Sponge city construction target of Ji’nan Controlling items Before Rainwater discharge 66.2% Green and permeable pavement 33.8% Underlying surface Natural water and constructed wetlands Cistern -
Target 30.0% 26.7% 30.8% 7.0% 5.5%
4.3. Preliminary construction results After more than two years construction, the total investment of the city's planning project has reached 85%, and the number of green plants, the living environment increased significantly. According to statistics, the water level of Baotu Spring rose by 3cm only rely on recirculation irrigation water from Liyang Lake. The new green space increased 30 thousand m2 in Qianfo Hill scenic. 4 new reservoirs were built, and the water storage capacity reached 1000 m3. 5. Conclusion In this article, 30 pilot cities of sponge city are listed according to the different rainfall belt in China. On the basic of this point, we take Pingxiang, Jiangxi Province in the humid area and Ji’nan, Shandong Province in semi humid area as the examples, summarizing their climatic characteristics, the construction demand, the construction idea and route, as well as the related guarantee. According to the mentioned work above, authors believe that the sponge city construction ideas need to rely closely to the local climate characteristics, geographical characteristics, special conditions and other practical situations. Besides, this paper aim to provide reference for other cities to build sponge cities in the same rainfall belt. Acknowledgements This work was supported by the National Key R&D Program of China-Source identification, monitoring and integrated control of indoor microbial contamination (No. 2017YFC0702800). References: [1] [2] [3] [4] [5] [6]
Guillette Anne. Low Impact Development Technologies[EB/OL]. http://www.wbdg.org/resources/low-impact-development-technologies. Yingxia Xie. China's "Sponge City" Development: The Overall Idea and Policy Proposal [J]. People’s Tribune, 2016, 11(21):26-30. Jun Xia, Yongyong Zhang, Yin Zhang, et al. Research and prospects of water problems in construction of sponge cities in China [J]. Yangtze River, 2017, 48(20):1-5. Zaijian Yuan, Chen Liang, Dingqiang Li. Progress and Prospect of the Study on Sponge City in China [J]. Ecology and Environmental Sciences, 2017, 26(05):896-901. Jinfeng Zeng. Preliminary analysis of development demands and construction thoughts of sponge city of Pingxiang City [J] Yangtze River, 2015, 46(22): 17-20. Haidong Xu, Chenchen Zhao, Mei Lv, et al. Practice of the Comprehensive Improvement in Waterlogged Areas Based on Sponge City: A Case Study of Wanlongwan in Pingxiang [J]. CHINA WATER ＆ WASTE WATER, 2017, 33(18):9-13.
ScienceDirect Availableonline onlineatatwww.sciencedirect.com www.sciencedirect.com Available Energy Procedia 00 (2018) 000–000
ScienceDirect ScienceDirect
www.elsevier.com/locate/procedia
Energy (2019) 000–000 207–212 EnergyProcedia Procedia159 00 (2017) www.elsevier.com/locate/procedia
Applied Energy Symposium and Forum, Renewable Energy Integration with Mini/Microgrids, REM 2018, 29–30 September 2018, Rhodes, Greece The 15th International Symposium on District Heating and Cooling Construction and Application of “the Sponge City” in Different Precipitation Regions: Case Studies in Pingxiang and Ji’nan, China Assessing the feasibility of using the heat demand-outdoor a, Han a, Yan Wu * temperature function forXu a long-term district heat demand forecast a
China Aerospace Academy of Architectural Design & Research Co., Ltd, Beijing 102627, China
I. Andrića,b,c*, A. Pinaa, P. Ferrãoa, J. Fournierb., B. Lacarrièrec, O. Le Correc a IN+ Center for Innovation, Technology and Policy Research - Instituto Superior Técnico, Av. Rovisco Pais 1, 1049-001 Lisbon, Portugal Abstract
b Veolia Recherche & Innovation, 291 Avenue Dreyfous Daniel, 78520 Limay, France Département Systèmes Énergétiquesand et Environnement Atlantique, 4 rue Kastler, 44300 Nantes, city France This article briefly introduces the conception connotation of- IMT the sponge city, andAlfred 30 pilot cities of sponge are discussed c
according to the different rainfall belt in China. On the basic of this point, we take Pingxiang, Jiangxi Province in the humid area and Ji’nan, Shandong Province in semi humid area as the examples, summarizing their climatic characteristics, the construction demand, the construction idea and route, as well as the related guarantee. Authors believe that the sponge city construction ideas Abstract need to rely closely to the local climate characteristics, geographical characteristics, special conditions and other practical situations. In addition, this paper also provides a reference for other cities to build sponge cities in the same rainfall belt. District heating networks are commonly addressed in the literature as one of the most effective solutions for decreasing the greenhouse gas emissions from theElsevier building sector. These systems require high investments which are returned through the heat © 2019 The Published Ltd. Copyright ©Authors. 2018 Elsevier Ltd. by All rights reserved. sales. Due to access the changed conditions and building policies, heat demand in the future could decrease, This is an open article climate under the CC-BY-NC-ND licenserenovation (https://creativecommons.org/licenses/by-nc-nd/4.0/) Selection and peer-review under responsibility of the scientific committee of the Applied Energy Symposium and Forum, Selection and under period. responsibility of the scientific committee of the Applied Energy Symposium and Forum, prolonging thepeer-review investment return Renewable Energy Integration with Mini/Microgrids, REM 2018. Renewable Energy Mini/Microgrids, 2018. The main scope of Integration this paper iswith to assess the feasibilityREM of using the heat demand – outdoor temperature function for heat demand forecast. The district of Alvalade, located in Lisbon (Portugal), was used as a case study. The district is consisted of 665 Keywords: Sponge city; Precipitation characteristics; Climatic region; Construction and application; Urban planning and design buildings that vary in both construction period and typology. Three weather scenarios (low, medium, high) and three district renovation scenarios were developed (shallow, intermediate, deep). To estimate the error, obtained heat demand values were compared with results from a dynamic heat demand model, previously developed and validated by the authors. 1.The Conception of sponge city and the evaluating indicators results showed that when only weather change is considered, the margin of error could be acceptable for some applications (the error in annual demand was lower than 20% for all weather scenarios considered). However, after introducing renovation With thethe occurrence extremeup weather events in the world recentand years, the surface watercombination environment of cities scenarios, error valueofincreased to 59.5% (depending on thein weather renovation scenarios considered). inThe various countries has been threatened. In response to this problem, the United States first proposed the "Low Impact value of slope coefficient increased on average within the range of 3.8% up to 8% per decade, that corresponds to the Development" (LID) concept [1] in the 1990s. The significance is to enhance urban rainstorm management, improve decrease in the number of heating hours of 22-139h during the heating season (depending on the combination of weather and renovation considered). On thethrough other hand, function increased for 7.8-12.7% per decade on the and protect scenarios urban water environment rational use intercept of low-impact development facilities, and(depending promote water coupled scenarios). The values suggested couldconservation be used to modify function for this, the scenarios and security, resource conservation and energy at thethe same time.parameters Inspired by China's considered, 2013 Central improve the accuracy of heat demand estimations. Urbanization Work Conference clearly put forward the concept of “Sponge City”, and successively released the © 2017 The Authors. Published by Elsevier Ltd. Peer-review under responsibility of the Scientific Committee of The 15th International Symposium on District Heating and Cooling. * Corresponding author. Tel.: +86 10 89060515; fax: +86 10 89060999 * Corresponding author. Tel.: +86 10 89060515; fax: +86 10 89060999 E-mail address: [email protected] Keywords: Heat demand; Forecast; Climate change
1876-6102 Copyright © 2018 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the Applied Energy Symposium and Forum, Renewable Energy Integration with Mini/Microgrids, REM 2018. 1876-6102 © 2017 The Authors. Published by Elsevier Ltd. 1876-6102 © 2019 The Authors. Published by Elsevier Ltd. Peer-review under responsibility of the Scientific Committee of The 15th International Symposium on District Heating and Cooling. This is an open access article under the CC-BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/) Selection and peer-review under responsibility of the scientific committee of the Applied Energy Symposium and Forum, Renewable Energy Integration with Mini/Microgrids, REM 2018. 10.1016/j.egypro.2018.12.052
Xu Han et al. / Energy Procedia 159 (2019) 207–212 Xu Han, Yan Wu/ Energy Procedia 00 (2018) 000–000
208 2
“Sponge City Construction Technical Guide (Trial)” and “Sponge City Construction Performance Evaluation and Assessment Method (Trial)” [2-4]. They clarified the six categories of first-level assessment indicators for sponge city construction (i.e. water ecology, water environment, water resources, water security, system construction and implementation, display) and 18 subdivisions Secondary indicators. Among them, “control rate of total annual runoff” is designated as the core evaluation index. The meaning is the proportion of the total controlled annual rainfall (including natural infiltration, artificial infiltration, accumulation, evapotranspiration, reuse, etc.) to the total annual rainfall. 2. Precipitation characteristic zones and pilot sponge cities distribution in China 2.1. Precipitation characteristic in China China has a vast territory, and its geographical and climatic characteristics vary greatly. The overall distribution of precipitation shows a gradual decrease from southeast to northwest. The 800mm annual precipitation is the boundary between humid and sub-humid areas, and is located on the Qinling-Huaihe line. The average annual precipitation in most areas of China is between 173.0~494.9 mm and the rainy season and dry season are distinct: from May to September, the annual precipitation in most parts of China exceeds 90% of the whole year, of which from June to August. 70% of the annual precipitation. Figure 1 is an overview of the classification of annual precipitation in China.
Fig. 1. Distribution of precipitation characteristic zones in China.
2.2. Pilot sponge cities distribution in different rainfall characteristic zones in China Table 1 shows the results of the thirty experimental sponge cities in China according to different precipitation characteristics. It can be seen that most of the pilot cities are concentrated in humid and semi-humid areas, 15 and 11 respectively. Moreover, there are three in rainy areas and only one in semi-arid areas. This paper selects one pilot sponge city in two different precipitation feature zones (humid and semi-humid) to outline its construction plan, characteristics, overall progress and preliminary results. The goal is to provide reference and reference for the construction of sponge urban areas for the same rainfall feature belt. Table 1. The pilot sponge cities in different precipitation characteristics. Precipitation characteristics Rainy area Humid Semi-humid
Pilot cities Zhuhai, Shenzhen, Sanya Zhenjiang, Jiaxing, Chizhou, Xiamen, Pingxiang, Wuhan, Changde, Nanning, Chongqing, Suining, Gui'an, Shanghai, Ningbo, Fuzhou, Yuxi Qian'an, Baicheng, Ji’nan, Hebi, Xixian, Beijing, Tianjin, Dalian,
Total 3 15 11
Xu Han et al. / Energy Procedia 159 (2019) 207–212 Xu Han, Yan Wu / Energy Procedia 00 (2018) 000–000 Qingdao, Qingyang, Guyuan Xining (None)
Semi-arid Arid
209 3 1 0
3. Construction and application situation of sponge city in humid area: the case in Pingxiang Pingxiang City, Jiangxi Province, as the first pilot sponge city established in China, has ranked first in the annual performance appraisal for two consecutive years [5]. This section takes Pingxiang City in a humid area as an example to discuss its construction mode and characteristics. 3.1. General situation of Pingxiang City Pingxiang is a prefecture-level city in Jiangxi Province. It is located in the western part of Jiangxi Province. And it is located between 113°35′~114°17′ east longitude and 27°20′~28°0′ north latitude. The total area is 3831 km2. In 2015, the population was about 1.93 million. Pingxiang is a typical subtropical humid monsoon climate with an annual average temperature of 17.3 °C. The annual precipitation is abundant, and the annual average precipitation reaches 1596.7mm, which is between the wet and rainy belts. The average monthly precipitation and monthly average temperature distribution in Pingxiang are shown in Figure 2. It can be seen from the figure that the annual precipitation distribution in Pingxiang is uneven, mainly concentrated in April to June. 250
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25
200
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0
Fig. 2. Monthly precipitation and temperature distribution in Pingxiang.
3.2. Construction demand Water shortage Pingxiang is a typical mountainous and hilly city. It shows the characteristics of high surrounding terrain, low intermediate terrain and poor water storage capacity. The central city of Pingxiang has concentrated most of the population, industrial and mining enterprises and high-water consumption industries. It has typical water quality, resource and engineering water shortage characteristics. Water pollution In recent years, urban expansion, road construction, coal mining, industrial wastewater and domestic sewage discharge in Pingxiang City have led to the narrowing, turbidity and odor of water in many rivers. Uneven precipitation and water use time The precipitation and water use time in Pingxiang are uneven. The rainfall from April to June accounts for 44.5% of the total, while the urban water consumption only accounts for 20% of the whole year. From July to September, the city's rainfall accounts for 20% of the year, while urban water consumption accounts for 70% of the year. Urban internal waterlogging The special terrain of Pingxiang is easy to cause mountain runoff to flow into the urban area along the Pingshui River during heavy rains, which often leads to a serious increase in the short-term internal diameter flow in the urban area. Taking Wanlong Bay, the most serious waterlogging, as an example, an internal waterlogging of about 30km2 has been formed over the years. The average submergence depth during rainstorms is 50~120cm [6].
Xu Han et al. / Energy Procedia 159 (2019) 207–212 Xu Han, Yan Wu/ Energy Procedia 00 (2018) 000–000
210 4
3.3. Construction target Based on the actual situation, Pingxiang drafted 4 aspects of construction targets including water ecology, water environment, water resources and water safety, as shows in Figure 5.
Fig. 3. Construction target of sponge city in Pingxiang.
3.4. Mainly engineering measurements The process of sponge city construction in Pingxiang was mainly included the source controlling, process controlling and terminal controlling, the detailed engineering measures as shows in Figure 4. Source control
Process control
Terminal control
Permeable paving Ecological revetment Sinking green space construction Vegetation buffer zone Construction of biological Grass planting ditch pavement Ecological wetland and rainwater retention measures Seepage well, seepage pipe and ecological pond Shallow ditch construction of deep ditch construction sedimentation tank vegetation Dust measure construction Water quality purification Laying of initial rainwater disposal facilities Other ecological measures Green roof paving Fig. 4. The mainly engineering measurements of sponge city construction of Pingxiang.
3.5. Preliminary construction results (1) Water ecology: total annual runoff control rate increased from 30% to over 75% in pilot zones, and the diversity of aquatic vegetation was increased significantly. (2) Water environment: removal rate of suspended solids was over 50% in rivers, and the water quality of main rivers and lakes have basically reached the IV water standard. (3) Water sources: rainwater utilization achieved 8%, and it were widely used in municipal cleaning, landscaping, green plant watering and river replenishment. Annual water saving was about 2 million and 560 thousand tons. (4) Water safety: 49 water accumulation points have been eliminated or obviously relieved; 43 residential blocks never suffer the city floods. 4. Construction and application situation of sponge city in semi-humid area: the case in Ji’nan 4.1. General situation of Ji’nan City Ji’nan is the provincial capital of Shandong Province. It is located in the central of Shandong. And it is located in 117°00′ east longitude and 36°40′ north latitude. The total area is 8177 km2. In 2016, the population was about 7.23
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million. Ji’nan is a typical monsoon climate of medium latitudes climate with an annual average temperature of 13.8 °C. The annual precipitation is about 685 mm and the average monthly precipitation and monthly average temperature distribution in are shown in Figure 5. It can be seen that the annual precipitation distribution mainly concentrated in July and August. 200
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-5
Fig. 5. Monthly precipitation and temperature distribution in Pingxiang.
4.2. Construction demand Water shortage The annual average water sources in Ji’nan is 1 billion 748 million m3, among them, the available part take account of 66%, therefore, the water resources per capita only 290 m³/year, which equal to 1/7 of national average level in China. Urban internal waterlogging Ji’nan's topography is high in the South and low in the north, and the highest difference is over 130 m. During heavy rains, the old city areas often leads to a serious urban waterlogging due to the irrational urban planning and designing in before. Water pollution In Ji’nan, the phonemes of sewage directly discharged into rivers; besides, a number of animal carcasses, feces, pesticide residue are produced in farming areas, which affects water quality in each river seriously. Pilot point distribution and construction target The district of Xinglong, Daminghu area in Ji’nan was designated as the first sponge city construction pilot area (Figure 6). The total area of the pilot area is 39 km2, with a population of 0.32 million.
(a) Location of the pilot area in Ji’nan (b) Detailed area of Xionglong district Fig. 6. Location of the pilot area of sponge city in Ji’nan
On the basis of “Urban master plan of Ji’nan (2011~2020)”, the total annual runoff control rate was designed of 70%, and the area of built sponge city was about 410 km2, as well as the controlled rainfall was drafted as 9 million 510 thousand m³. Table 2 is the construction target of Ji’nan.
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Xu Han,Xu YanHan Wu/etEnergy Procedia 00 (2018) 000–000 al. / Energy Procedia 159 (2019) 207–212 Table 2 Sponge city construction target of Ji’nan Controlling items Before Rainwater discharge 66.2% Green and permeable pavement 33.8% Underlying surface Natural water and constructed wetlands Cistern -
Target 30.0% 26.7% 30.8% 7.0% 5.5%
4.3. Preliminary construction results After more than two years construction, the total investment of the city's planning project has reached 85%, and the number of green plants, the living environment increased significantly. According to statistics, the water level of Baotu Spring rose by 3cm only rely on recirculation irrigation water from Liyang Lake. The new green space increased 30 thousand m2 in Qianfo Hill scenic. 4 new reservoirs were built, and the water storage capacity reached 1000 m3. 5. Conclusion In this article, 30 pilot cities of sponge city are listed according to the different rainfall belt in China. On the basic of this point, we take Pingxiang, Jiangxi Province in the humid area and Ji’nan, Shandong Province in semi humid area as the examples, summarizing their climatic characteristics, the construction demand, the construction idea and route, as well as the related guarantee. According to the mentioned work above, authors believe that the sponge city construction ideas need to rely closely to the local climate characteristics, geographical characteristics, special conditions and other practical situations. Besides, this paper aim to provide reference for other cities to build sponge cities in the same rainfall belt. Acknowledgements This work was supported by the National Key R&D Program of China-Source identification, monitoring and integrated control of indoor microbial contamination (No. 2017YFC0702800). References: [1] [2] [3] [4] [5] [6]
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