In order to solve these problems brought by urbanization. Diversified concepts and technologies of sustainable rainwater management came into being. Among them, the most representative include the best management measures (BMPs:
No, the low-impact development (LID) implemented by the United States on the basis of1BMPs in 1990s; Sustainable Urban Drainage System (SUDS) was launched in the UK at the same time to maintain a benign water cycle;
Based on the idea that rainwater management should be suitable for the regional ecological background, Melbourne, Australia, as a demonstration city, has carried out "Research on Water-sensitive Urban Design": Low Impact Urban Design and Development (LIUDD) integrating the concepts of LID and WSUD in New Zealand;
These ideas are the product of urbanization. They are all committed to finding rainwater management solutions suitable for specific locations or regions.
At the beginning of this century, China began to pay more attention to rainwater management. Recognize that rainwater is a recyclable resource. Some attempts and efforts have been made in this regard. For example, the combination of rainwater utilization and landscape system has achieved certain results. This paper will summarize the advanced concepts and technical methods of rainwater utilization. This paper aims to strengthen the understanding of storm flood management, establish confidence in solving storm flood problems with advanced concepts, and prove that storm flood management can not only realize ecological benefits. At the same time, it can also produce economic and aesthetic value.
Development and application of rainwater management system abroad. 1 American Best Management Practices (BMPs) and Low Impact Development (LID) System The United States has attached importance to rainwater management for a long time. The best management measures were first put forward in 1972, and now after nearly 40 years of development, a complete theoretical and technical system has been formed, which has been implemented and verified all over the world. On this basis, a wave of low-impact development rose in the United States in the 1990s, and the American Society of Civil Engineers (ASCE) held international low-impact development conferences regularly. 20lO International Low Impact Development Conference was held in San Francisco in April, with the theme of redefining urban water.
Compared with the traditional rainwater treatment system, it adopts a different perspective.
The traditional way is to discharge rainwater into the rainwater pipe network as soon as possible, and then enter the nearby water body. BMPs is a rainwater facility that collects, stores or guides rainwater to penetrate into the soil and downstream according to the design flow. Treat rainwater nearby. In order to reduce runoff and pollutants, control the flow.
Usually divided into two forms. Structural BMP and unstructured BMP. Sometimes there is no clear boundary between structural bone morphogenetic protein and non-structural bone morphogenetic protein. The most significant difference between them is the emphasis on unstructured BMP. Prevention. The structural bone morphogenetic protein focuses on. Relieve runoff caused by rainstorm and its influence on water quality. Unstructured BMP It involves a broader level of planning and design. It can even be promoted to policy. It is a collection of practices that can improve environmental and economic benefits. Structural bone morphogenetic protein is relatively easy to understand. It is a series of concrete technical means of rainwater management. Table 2 summarizes the main types of unstructured and structured BMP.
Low Impact Development (LID) is a relatively new concept in rainwater management. As early as1990s, Prince George County, Maryland, as a pioneer, proposed and applied LID technology for the first time. LID is an innovative and sustainable integrated rainwater management strategy. It simulates natural hydrological process by means of planning and design, and creates functional water landscape. Its purpose is to control the source. Make rainwater naturally seep down and reduce runoff. LID usually uses the landscape elements in the site to replace the expensive rainwater collection facilities at the end of the basin to solve the rainwater problem. "LID can not only be applied to new projects. It is also effective in dealing with urban renewal and completed projects.
The goal of the design is to meet the urban development and ensure the vitality of the site. Reduce the negative impact of urban development on natural hydrological processes. And maintain or restore the ecological function of the site. The LID design process is continuous and repeatable, which mainly includes the following five concepts: (1) In the design, the hydrological process should be considered as a whole; Rainwater management system should simulate natural hydrological process to meet the needs of water quantity, water quality and natural resources protection.
Decentralized control through micro-management: simulating natural processes.
The whole site should be regarded as a series of interrelated and interactive small-scale designs. This structure helps to provide flexibility for management and control. And form a bottom-up management chain.
Source control: control runoff where it occurs, so as to eliminate the risk of pollutant accumulation downstream.
Integrate unstructured systems. Deal with this problem in the simplest way:
The design recognizes the potential of natural systems to remove pollutants and advocates making full use of biological and chemical processes in soil. Natural systems are easier to design and maintain than artificial facilities. Incorporating the natural elements in the site into the storm flood management system can not only save costs, but also bring additional benefits. Therefore, the maintenance and restoration of natural elements (such as vegetation and soil restoration) is particularly important.
Utilize multifunctional landscape, architecture and infrastructure: There are many specific LID technical means to choose from in planning and design. One of the first selection criteria is to meet the design needs and achieve the purpose of rain and flood control.
Technology is usually multifunctional. Can meet all kinds of needs. The roof garden is a good example. It can not only realize the regulation of rain and flood, but also provide a pleasant environment.
Based on the above ideas. The ideal LID website design will make full use of the natural landscape. Minimize runoff. The existing natural water flow channel is protected. So as to reduce the dependence on drainage facilities and reduce the engineering quantity. On the contrary. Traditional rainwater site design usually increases runoff. As a result, we have to rely on large-scale rainwater facilities. The main strategy. LID planning and design includes the following aspects:
Extend the passage time of runoff; Maintain natural flood discharge channels and disperse runoff as much as possible; Separate impervious areas (such as impervious pavement and roof) from the drainage system. On the contrary, rainwater permeates through permeable areas; Protect natural vegetation and soil that can slow down runoff, filter pollutants and easily penetrate downward; Guide runoff through vegetation-covered areas to filter runoff and replenish groundwater; Provide small-scale distributed components and devices to achieve control objectives; Treat pollutants on the spot or prevent them from being produced.
From 65438 to the early 1970s, the United States began to develop a new rainwater management model to eliminate the weakness of the traditional rainwater pipe network system in dealing with heavy rain. After years of research and practice, from the government to the public. Everyone is aware of the importance of rainwater management. A relatively complete rain and flood management system has been formed. Seattle, San Francisco and Portland can all be regarded as models of rainwater management in the United States. At present, the experience of the United States has been recognized by other countries in the world, and its ideas and technical methods are constantly expanding.
.2 With the continuous expansion of cities, the rainwater management system in Europe. Europe has gradually deepened its emphasis on rainwater control. Constantly explore effective storm management measures and take them as an important part of the sustainable development strategy. In order to meet the ever-changing demand of rainwater management, BMPs technology from the United States is also widely used in most parts of Europe. BMPs integrates a series of planning, design and management methods related to rain and flood, and considers hydrological process, environment and people's aesthetic and entertainment needs.
The first few years of European development. The main goal of most structural BMPs is to control runoff and reduce peak flow. In the following five or six years, Europe began to pay attention to the maintenance of water quality while controlling water quantity. The most commonly used in Germany are shallow grass pits and seepage canals. Due to frequent floods.
In 1990s, BMP was widely accepted in France. , such as retention ponds and permeable pavement. In countries located in cold regions, such as Sweden and Denmark, reservoirs are most used: shallow grass ditches and infiltration ponds are used to control the melting of rain and snow in cold weather. Some countries in southern Europe such as Greece, Italy, Spain and Portugal. The use of BMP is relatively small, but they have begun to try to use technology to deal with precipitation in some sites. BMPs technology is widely used in Britain. Table 3 describes the application of BMPs in the UK.
On the basis of structural BMPs, Britain has developed a sustainable urban drainage system (SUDS), which has become the mainstream of rainwater management in British urban planning. The National Working Group on Sustainable Urban Drainage System was established on 200 1. In 2004, the Working Group issued the Interim Guidelines for Practice Reports, which put forward the strategic methods for implementing sustainable drainage systems in England and Wales and provided detailed technical guidance.
The so-called sustainable urban drainage system refers to the adoption of a series of management measures and control means. The surface water discharge field J is treated by a more sustainable method than the traditional technology. SUDS includes different levels of technical methods:
Prevention: use site design and family and community management to prevent runoff and pollutant discharge; Source control: control the runoff at or near the source; Site control: unified management of runoff from different sources; Area control: manage runoff at several different locations. Wetlands and retention ponds are usually used.
After nearly 20 years of exploration. Europe, especially Britain, has formed a relatively mature system in the concept, technology and norms of storm water management.
.3 Storm Water Management in Oceania Early Morning Urban Design (WSUD) and Low Impact Urban Design and Development in New Zealand Water Sensitive Urban Design (WSUD) have been problems in traditional drainage systems in Australia since the end of 1990. Develop rainwater management and treatment methods. The core view of this method is that water is a valuable resource, and a series of water-related technologies should be integrated into the urban landscape, thus reducing the need for structural measures. " The goal of WSUD is to effectively solve the problem of runoff, protect the surrounding environment, save water and maximize the natural circulation of water in urban areas, and enhance the value of the city in environment, recreation, culture and aesthetics. In order to achieve this goal, we must weigh the relationship between various water processes. The concept of WSUD mainly includes the following five points:
Protecting the natural system: protecting and upgrading the natural water system in the process of urban development.
Integrating rainwater treatment means into the landscape: take the collected rainwater as a landscape element to maximize the visual quality and recreational value.
Ensure water quality: ensure the water quality in the process of urban development.
Reduce runoff and peak flow: reduce runoff by seepage pool and reducing impervious pavement.
Increase income while reducing the cost of urban development: minimize the cost of drainage facilities and improve the landscape, thus enhancing regional value.
The characteristic of WSUD in Australia is that it regards the whole water cycle as a whole and emphasizes the smoothness of the water cycle. As a subsystem, rainwater management supports the normal operation of the whole cycle (Figure 2). In addition, it also emphasizes the integration of rainwater management into the urban landscape system, which can not only save costs, but also improve the value of the landscape.
Low Impact Urban Design and Development (LIUDD) is a national scientific research aimed at promoting low impact design in New Zealand.
The development of LID draws on the experience of LID in North America and Australia to some extent. It attempts to improve the sustainability of the built environment through a set of comprehensive methods, avoid a series of negative social, economic and natural impacts brought by the development of traditional cities, and protect the integrity of aquatic and terrestrial ecosystems. Through proper planning, investment and management means, cities can advance along the new development model on the premise of meeting environmental needs and ensuring economic development. The main principles in LIUDD system are divided into three levels. The principles of the previous level are integrated into the next level. And exquisite.
The first principle in the system, that is, the highest principle, is that people should reach the understanding that human activities should respect the natural material circulation and energy flow, minimize the negative effects, and realize the optimization of river basin management. This principle runs through the whole system. LIUDD regards watershed as the basic spatial unit of urban design and management. The study of watershed ecological carrying capacity is the core content of watershed ecological carrying capacity research.
Similar to WSUD, rainwater management is regarded as part of maintaining normal water circulation. The difference is that LIUDD covers a wider range.
As a branch of the whole urban development design system, water cycle focuses on urban development with water as the core.
The development of storm flood management in China started slightly later than that in developed countries, and the storm flood management technology and measures have not been widely promoted. However, China is facing a more serious water crisis, and the water problems are more complicated and diverse because of its vast territory. The construction of rainwater management system needs a lot of research support and a free data sharing platform. At the same time, stormwater management is an interdisciplinary field. It requires the joint efforts of researchers and planners with different professional backgrounds. In addition, the construction of the whole system also requires extensive public participation. From the above aspects, compared with developed countries. Our country is still slightly lacking.
In recent years, China has realized the importance and necessity of storm water management, and governments and departments at all levels attach great importance to policy research in related fields. For example, China Academy of Engineering's major consulting project "Strategic Research on Sustainable Development of Water Resources in China" published a research report collection "Sustainable Development and Utilization of Urban Water Resources in China". Among them, the utilization potential of urban rainwater in China is estimated to realize the utilization of rainwater resources. Save water. Repair the water environment and ecological environment. Reduce urban floods. In order to achieve the goal of advanced technology, economic rationality, safety and reliability of rainwater utilization projects in buildings and residential areas, in September 2006, People's Republic of China (PRC) and the Ministry of Construction promulgated the Technical Specification for Rainwater Utilization Projects in Buildings and Residential Areas, which was implemented as a national standard. Many areas have also begun to attach importance to storm water management, and carried out related research, such as "Shenzhen Storm Water Resources Utilization Planning Research" and so on.
In terms of theoretical research. More and more scholars began to pay attention to the rainwater management model based on China's national conditions, including: urban rainwater pollutant control, urban rainwater storage, building rainwater utilization model and so on. 13L32 1。 An innovation in the theoretical research of rain and flood management in China is to construct rain and flood safety patterns of different scales and levels. The theory of rain and flood security pattern is put forward to solve the problems of flood disaster and water shortage faced by cities in China. According to the theory of rain and flood security pattern, solving urban rain and flood problems should be holistic and multi-objective. Rather than a single engineering measure. The key to the construction of rain and flood safety pattern is to determine the spatial position of water control process, and realize the storage of rain and flood through the protection and reasonable planning of these key positions. Rainwater can be reused by interception and infiltration.
In practice. Beijing is the first city in China to use rainwater.
It started in 2008. Beijing urban rainwater control and utilization demonstration project is one of the earlier urban rainwater utilization projects in China. The project pays attention to the integration of rainwater utilization into landscape construction to realize the unity of ecological value and leisure value. In addition, representative projects such as Houtan Park of Shanghai World Expo, Tianjin Bridge Garden Park and Oriental Sun City in Shunyi District of Beijing have inspired the development of rainwater utilization concepts and technologies abroad. As well as China's emphasis on rainwater utilization in recent years, it can be seen that under the background of global climate change, dealing with urban rainwater and flood problems is not only related to human interests, but also related to the maintenance of ecosystems. How to solve this problem. From the experience at home and abroad, we should pay attention to the following points; It is necessary to change the traditional concept that rain is a disaster and advocate prevention first.
The new sustainable rainwater management needs to treat rainwater as a friend. Guide it. So as to take advantage of it. On the premise that conditions permit, we should give priority to prevention. For example, pay attention to the protection of local natural resources, adopt intensive development and attach importance to the management of toxic and harmful substances. The implementation of these aspects is inseparable from public participation.
Strengthen the research and policy support of rain and flood management. Understand various ecological processes through scientific and systematic research. Actively develop new theories and technologies for rainwater utilization. Establish a sound policy system on the basis of scientific research. Formulate laws, regulations and rules on urban rainwater management, and standardize and legalize rainwater utilization.
The urban water system is considered as a part of the master plan. This is beneficial to the overall sustainable development of the region and the effect of rainwater management.
Popularize rainwater management technology so that it can be implemented in planning and design of different scales. At present, various specific storm and flood management technologies are quite mature.
And it has been widely used and popularized abroad. Its effect has also been verified.
However, the specific application should be combined with the characteristics of the site itself and fully consider the needs of planning and design. Because the rainwater problem is extremely regional, it is closely related to specific hydrogeology and built water conservancy facilities, so these factors should be considered when popularizing specific technologies.
Conclusion Under the background of global climate change and urbanization, how to make full and rational use of water resources is a problem that every country must face. Rainwater is an important source of water. If it is still treated in the traditional way, it will not solve a series of environmental problems such as waterlogging caused by the change of urban underlying surface. Therefore, many countries in the world are trying to find ways of rainwater recycling and effective management. Developed countries have made achievements in the theory, method and application of rainwater utilization. Modern storm water management in China started a little later than that in developed countries, so we should learn from the experience and lessons of foreign cases. Build a storm flood management system suitable for China's national conditions, and realize the new sustainable development of storm flood utilization.