Zhu Zhihong, female, professor-level senior engineer. Member of the Expert Committee for Technical Guidance of Sponge City Construction of the Ministry of Housing and Urban-Rural Development, director of China Landscape Architecture Society, executive director of Beijing Landscape Architecture Society and director of Beijing Engineering Survey and Design Association. He is currently the president and chief engineer of Beijing Garden Ancient Architecture Design and Research Institute Co., Ltd.
The standards and specifications involved in the compilation mainly include: national standard Code for Park Design, Beijing local standard Standard for Garden Green Space Construction, Code for Design of Rainwater-harvesting Green Space Construction Project, industry standard Provisions for the Depth of Design Documents of Municipal Public Works (2013 Edition), and Technical Guide for the Construction of Sponge City by the Ministry of Housing and Urban-Rural Development.
The main monographs and papers are: rockery project, analysis of the regeneration of local landscape of historical gardens from the perspective of planning and design, and the ideal of living in a garden.
The main award-winning works include: the reconstruction of the Summer Palace Farming and Weaving Map Scenic Area and environmental engineering won the first prize of the Ministry of Construction’s excellent urban and rural survey and design in 2005, the second prize of land management in the 6th Asia-Pacific Landscape Architecture Award of the International Federation of Landscape Architects in 2009, the People’s Square in Shijiazhuang won the third prize of the Ministry of Construction’s excellent urban and rural survey and design in 2005, and the Legu Park in the south gate of Pinggu New Town won the third prize of Beijing’s excellent landscape design in 2013. In 2013, the project of the cultural exhibition area of ancient dwellings in the 9th China International Garden Expo won the second prize of the 2015 China Survey and Design Association, the landscape improvement plan and the first-phase construction project of Kenli Minfeng Lake won the first prize of the 2015 National Excellent Engineering Survey and Design Industry Award, and the park project of Yanqi Lake Ecological Demonstration Zone won the first prize of the 2017 National Excellent Engineering Survey and Design Industry Award.
1. Liu Hongwei: When did you first come into contact with the concept of "sponge city"? When will this concept be put into practice from the project level, and how many pilots and projects will be involved in the construction?
● Zhu Zhihong: In 2012, the Beijing Municipal Bureau of Landscaping and Greening issued the Notice on Further Strengthening the Construction of Rainwater-utilizing Urban Green Space, requiring that all newly-built and renovated urban parks, unit courtyards and residential green spaces should be equipped with rainwater utilization facilities to improve their rainwater utilization capacity. I presided over the compilation of "Design Guide for Rainwater Control and Utilization Project in Beijing Garden Green Space" and studied the technical problems of rainwater control and utilization in green space.
As a landscape planning and design worker, I have always adhered to the method of organizing surface rainwater collection and discharge by using topography from professional study to design practice, and combined with appropriate engineering measures to solve related rainwater problems. However, the new problems in the new period can not be completely solved by traditional methods. After the "July 21" torrential rain in Beijing, we actively studied the role of green space in urban rain and flood management, and compiled the Beijing local standard "Code for Design of Rain-harvesting Green Space Engineering". In 2013, in the green space construction project of Yanqi Lake Ecological Demonstration Zone, we actively practiced, combining landscape and municipal specialty, and comprehensively coordinated the regional rainwater problem, mainly coordinating the relationship between regional flood discharge and green space, using topographic organization to control rainwater runoff, laying seepage wells to intercept rainwater, designing landscape-transferring grass ditches on municipal roadsides, connecting municipal drainage culverts, arranging rainwater ponds in low-lying areas, and gathering regional runoff rainwater to form a water landscape and become a habitat for aquatic animals and birds. After the completion and operation of the project, the effect is very outstanding in both landscape and function.
Since 2014, the construction of sponge city has become a national action. The Ministry of Housing and Urban-Rural Development has compiled and issued the Technical Guide for the Construction of Sponge City (Trial). I have the honor to participate in some work, and since then I have begun to learn and think about the concept of "sponge city" and understand its concept and connotation from fields outside the garden.
Up to now, although I have not participated in many projects in pilot cities, we are actively practicing the concept of "sponge city" in green space design and implementing it in various projects according to local conditions, such as Beijing 2019 World Horticultural Exposition, Beijing New Airport Landscape Project, Beijing Tongzhou Administrative Sub-center Green Heart Project and other important construction projects in Beijing. Especially the urban green heart project, the content of sponge city construction is relatively comprehensive, and the green space not only plays the role of source control, but also plays an important role in reducing urban waterlogging.
2. Liu Hongwei: As a member of the Technical Steering Expert Committee of the Ministry of Housing and Urban-Rural Development, how many pilots and projects have you visited in recent years? What do you think of the pilot work of sponge city construction?
● Zhu Zhihong: I am very fortunate to be a member of the Technical Steering Expert Committee for Sponge City Construction of the Ministry of Housing and Urban-Rural Development. Sponge city construction involves multi-disciplinary comprehensive contents. For me, I have gradually deepened my understanding of the concept of "Sponge City" in my personal practice and the practice of pilot cities. As a member of the expert committee, I participated in the inspection, supervision and assessment of pilot cities from time to time, and visited 9 pilot cities in the first batch and 5 pilot cities in the second batch successively.
During my visit to the pilot cities, I found that everyone’s understanding of the concept of sponge city has a very obvious development process, and the construction of sponge city is groping. Whether planning or design, there is a process from unclear understanding to gradually finding the right direction, from the beginning of "concave green space and permeable pavement are sponge cities" to reorganizing the city’s wading system and drainage zoning, strengthening the systematicness between projects, comprehensively coordinating and solving problems, and realizing the planning objectives. In view of the natural characteristics of cities and regions, it is more and more clear to attach importance to the protection of natural ecological background and coordinate the relationship between construction and protection. The pilot cities have made great efforts. An urban pilot area, generally 20 ~ 30 square kilometers, involves the comprehensive coordination of water conservancy, municipal administration, architecture, gardens and other disciplines, and the coordination and unity of multi-sector management. Almost every city is learning while doing, facing great difficulties and challenges.
The pilot project of sponge city construction will enable city managers, citizens and industries to gradually understand and accept the concept of sponge city, and deepen their understanding and explore amendments in practice. In just four years, some pilot cities have achieved essential transformation, really improved the urban environment, and achieved remarkable results in solving urban waterlogging, black and smelly water bodies and so on. With the construction of the Sponge City pilot project, gardens and green spaces around a group of citizens have also been completed, providing new places for citizens to relax, bringing obvious improvement to citizens’ lives, allowing people to personally experience the government’s determination and substantial changes in their living environment, and actually improving their sense of acquisition, happiness and security.
With the continuous advancement of pilot construction, various academic forums and exchange activities held all over the country have also provided opportunities for professionals and managers to communicate and discuss, spread the concept and technology of sponge city construction, guide the whole society to understand sponge city, pay attention to the concept of sponge city in urban construction, and spread the ideas of sponge city.
The real scene of Chongqing Yuelai New Town Guobo Center after sponge transformation.
The pilot cities have also explored the way to build a local sponge city, gradually established systematic thinking, embodied the concept, quality, measures and achievements of the sponge city, carried out various practices such as government management, urban planning, engineering design, construction and operation, and promoted the construction of the national sponge city construction policy system, technical system, management system and industrial system, and reconstructed the harmonious relationship between urban people and water.
What is important is the construction of systems and standards. The practice of pilot cities provides a research basis for the formulation of technical standards and norms for sponge city construction. At present, the technical standards of sponge city have been embedded in the provisions of various professional standards and norms, such as planning, municipal administration, architecture, gardens, etc. For example, when I wrote the national standard "Code for Park Design", it was at the beginning of the pilot project of sponge city construction, so I timely added the content of sponge city to this set of standards, which is very important to the garden industry, and gave the solutions to the technical problems in the practice of sponge city. The connection between professional norms and sponge city makes planning and design practitioners implement the concept of sponge city from the beginning of urban planning, which provides technical and regulatory protection for the all-round and sustainable implementation of sponge city.
3. Liu Hongwei: How to achieve the integration of function and landscape in sponge city construction project is a big test, and it is also a key factor to determine the effectiveness of the project. As an authoritative expert in domestic landscape, how do you evaluate the progress of domestic pilot cities in this regard, and what are the experiences and lessons worthy of attention and consideration by the industry?
● Zhu Zhihong: The function and landscape of the sponge city construction project are not a pair of irreconcilable contradictions. From the practice of pilot cities, many projects have good landscape effects, and some projects have added smart water landscape due to the construction of sponge cities, and even contain profound water culture, which has become a new business card of the city. Apart from the unprofessional factors of design, most of the disharmony between function and landscape lies in the treatment of special space. For example, in the selection of plant varieties for natural revetment, the influence of water level change on plants should generally be considered. Often in the north, few plants can survive in the environment where the water level changes greatly, especially in the saline-alkali areas in the north, which is more difficult. Comparatively speaking, southern cities are richer in plant resources than northern cities, and often have better landscape effects. In the construction project of sponge city, the integration of function and landscape is indeed an important aspect to reflect the skill of planners. For example, it is difficult to ensure the landscape of seepage ponds in Beijing. Generally, there is water for half a year, and the water depth varies from 0.5 to 2 meters, so the landscape effect is good, but there are still half a year when it is a dry pit and desolate. If we can comprehensively coordinate the utilization of water resources, combine rainwater utilization with reclaimed water utilization, and make reclaimed water as supplementary water for landscape ecology, we can not only ensure good landscape effect, but also generate enough storage space. Landscape design has always paid attention to "water depends on the garden, and the garden is alive because of water". Water is the most active element in landscape design, and landscape architects have accumulated rich experience in long-term practice. However, faced with the requirements of the new concept of sponge city, the traditional design methods are challenged.The vertical organization of the site, the choice of facilities and plants, and the ecological landscape solutions are all facing innovative needs. The landscape designers have provided multi-angle solutions and innovative ideas for the sponge city from the perspective of landscape, and made outstanding contributions to the integration of functions and landscapes.
Nanning Shimen Forest Park Comprehensive Sponge Real Scene after Heavy Rain Yang Menghan/photo
The construction of sponge city has been carried out for more than four years. From the perspective of function and landscape integration, the combination of road greening and sponge city construction is particularly worth discussing. It is undoubtedly a very important measure to use road attached green space as the control space for road rainwater runoff and reduce runoff pollution. At present, there are not many projects with good landscape. The main problems are the traditional road section form, road planning and height difference, which are not applicable to the new rainwater control and utilization methods in the new period. When the height difference between the rain mouth and the road surface and green space is well coordinated, it is often difficult to solve the broken ridge, which is not conducive to the protection of the shoulder and the landscape. Therefore, at present, China still needs in-depth practice, summary, and explore appropriate ways in many aspects such as the control mode of road rainwater runoff pollution, the role of green space, and the more optimized road section form.
From the construction of pilot cities, the top-level design is the most important. The wrong functional orientation or unclear functional orientation restricts the effectiveness of the sponge city construction project to some extent, and even hinders the further comprehensive promotion of the sponge city construction. I have met some plans that require the indicators of green space projects to "absorb the rainwater of green space and surrounding construction land, and the rainwater will not be discharged once every 50 years" in order to relieve waterlogging. As a green space with recreational function, there is no way to achieve the comprehensive functional requirements of recreation, safety, landscape and waterlogging storage under such indicators. Reasonable planning, positioning and design of solutions are the necessary prerequisites to achieve both landscape and function.
The choice of plants and practical research are still on the road. Traditional garden design has formed the experience of plant selection in long-term design, construction and maintenance, which is the best choice based on different soil, climate, environment and other conditions, and has a scientific basis based on local conditions. In the construction of sponge city, a lot of plant growth space contrary to the traditional model has been practiced, some of which really belong to the designer’s blind imagination, while others need plant observation and selection through project field practice rather than laboratory practice. Only through a lot of practical work, can we choose suitable plants, so that the garden landscape can show its due vitality while exerting its functions.
4. Liu Hongwei: Since the implementation of the pilot project of sponge city construction, what impressed you about the pilot cities and construction projects that you participated in or guided?
● Zhu Zhihong: When you walk through several pilot cities, you will find that each city has some different natural and geographical features, and combined with plant and architectural features, it shows strong differences in style and features. In the convergent development of urbanization, although they all face the challenges of old city reconstruction and new city construction guidelines, all localities have combined their own characteristics and resource advantages, kept upright and innovated, and formed a systematic method of sponge city construction with their own characteristics. Although they all carry out the concept of sponge city, adhere to the idea of "source emission reduction-process control-system governance" and comprehensively apply various measures of "infiltration, stagnation, storage, purification, use and discharge", many urban innovations have explored different models that can be popularized and replicated.
For example, Chongqing is a mountainous city with large natural height difference, steep rain slopes and serious runoff erosion. In terms of technical measures, we use technical means such as "high slope storage and low slow discharge, infiltration and reuse to promote circulation" to develop strengths and avoid weaknesses, and to discharge quickly and slow down the flow, so as to deal with the unique problems in the construction of mountain sponge cities. Another example is Baicheng, which needs to deal with the technical problems of freezing and thawing in the cold and water-deficient areas in the north. When I visited Baicheng for the first time, the freezing and thawing phenomenon in the cold area in the north was beyond my imagination. Conventional permeable pavement could not adapt to the high latitude and cold environment, so it became a difficult problem to solve the problem of snow melting agent invasion and frost heaving damage of permeable pavement. There are also comprehensive sponges in Shimen Forest Park in Nanning.
In addition to the pilot cities mentioned above, there are many other pilot cities that have left a deep impression on me. As a brand-new concept and way of urban development, it is far from enough to put the first principle of sponge city into practice according to local conditions, staying at the conceptual level and copying it. Therefore, in the promotion of the concept of sponge city, all localities should deeply discover their own problems and characteristics, innovate mechanisms, innovative technologies and innovative models, and establish their own development ideas of sponge city according to local conditions.
5. Liu Hongwei: In addition to the pilot project of sponge city construction supported by the central government, pilot projects at provincial and municipal levels are also being carried out one after another throughout the country. What do you think of the progress of the pilot projects at provincial and municipal levels? Any specific suggestions?
● Zhu Zhihong: First, actively carry out study and research on pilot cities. The detours in the pilot and the lessons of failure in practice are very valuable experiences. If the pilot cities can contribute these, the sponge cities will be built more smoothly in the future.
Second, improving the mechanism plays a key role in promoting the progress of provincial and municipal pilot work, infiltrating the concept of sponge city construction into all walks of life and unconscious conscious actions, and becoming a part of the routine work of all industries and departments. In a sense, when the concept of sponge city construction is truly implemented in all aspects of urban development, it is not even necessary to set up a special sponge office or special planning for sponge city construction, so that the sponge city can truly become the ideological concept guiding our work and become the "new normal" of urban construction and development.
6. Liu Hongwei: What do you think of the development trend of sponge city construction and its specific role in exploring a development path of a city with China characteristics?
● Zhu Zhihong: Sponge City is a solution to a series of wading problems in the rapid development of urbanization with China characteristics under the background of contemporary ecological civilization construction in China. China city builders and managers have given great affirmation to the theory of sponge city, which has also caused a lot of thoughts and debates on the concept, technical approaches and existing problems of sponge city construction at different levels. Undoubtedly, sponge city is an urban development mode to improve the quality of new urbanization and promote the harmonious development between man and nature. However, the practice and exploration of sponge city is still in the initial stage, from clarifying the concepts of various indicators and facilities, to exploring technology and correcting direction, etc., all need to be further studied. At the same time, the spread of the concept and technology of sponge city requires a lot of in-depth training for urban builders at all levels. Personally, I think that as far as landscape architects are concerned, many people just memorize the term "sponge city", but they still have a little knowledge of specific professional knowledge and need to study in depth.
The United Nations World Water Development Report 2018 pointed out: "The concept of China sponge city is an excellent sample of nature-based solutions." China Municipal Government adheres to the development concept of innovation, coordination, green, openness and sharing, actively explores ways to ensure water safety, improve water environment and restore water ecology, and has accumulated some experience. Although the construction of sponge city is accompanied by many disputes, the effect of the pilot project is gradually emerging, and the concept and connotation of sponge city are being further enriched. "If you don’t accumulate steps, there will be no miles; If you don’t accumulate small streams, you can’t become rivers and seas. " The construction of sponge city can not be achieved overnight, nor can it be achieved by centralized construction once and for all. It is a systematic and long-term work. In the process of pilot construction, pilot cities have worked hard to explore and formulate a number of long-term mechanisms. The policy system, technical system, management system and industrial system of sponge city construction are gradually being formed and improved, which has accumulated inexhaustible power for the long-term development of sponge city construction. The demonstration and incentive function of the excellent model benchmark will gradually emerge.
China’s characteristic city development road must be an innovative road. The integration of city and nature takes time, and the construction of sponge city has a long way to go and needs constant practice and exploration. However, the bright spot of the pilot construction makes us full of hope and confidence in the "sponge city".
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