A New Approach to Urban Rainwater Management

Based on an analysis of our research results and the main problems relating to urban rainwater treatment, we propose a new approach to urban rainwater management in China. The necessity and feasibility of such a new approach are discussed. From an ecological point of view all components of the global system, including residents living in cities, have the same right to enjoy rainwater. Therefore, urban rainwater should neither be simply drained as waste water, nor be completely harvested as a kind of resource. The objective of this new approach is to maintain the natural hydrological cycle in urban areas during urbanization. When necessary, it could also be used to regulate the amount of runoff, evaporation and infiltration in a city in order to rehabilitate the hydrological cycle given the local conditions. Three basic principles should be adopted in rainwater management, i.e., separation of rainfall from sewage, limited utilization and small and decentralized facilities. Four methods can be used for urban rainwater management: rainwater harvest, rainwater infiltration, rainwater storage and rainwater pipes. The natural hydrological cycle in urban areas could be rehabilitated through rainwater management, which is of great importance for sustainable development of our cities.

Introduction to rainwater management in Australia and suggestions for China's water problems

Australia is one of the world leaders in water management. The country meets the challenge of water shortage with established integrated water management in which rainwater is taken as a too precious resource to be just drained off. In Australia, rainwater is extensively harvested and polished to provide cheaper supply for potable and non-potable domestic uses, irrigation, landscaping, refilling aquifers and other uses. Implementing dual management over the quantity and quality of storm water and practicing water sensitive urban design (WSUD) in urban areas effectively control non-point-source pollution of waterways by pollutants carried with runoffs, reduce the discharge of rainwater and thus protect properties and lives from damage by floods. These achievements are attributed to constant reinforcement by govenments from federal to local levels in policy, financial, legal and educational aspects, and also to the lasting efforts of professional communities and water industry in developing requisite techniques, demonstrating the benefits and fostering public credence of rainwater reuse. The successful rainwater management practices in Australia suggest rainwater harvesting can be a complimentary means for the South-to-North Water Transfer Scheme to solve the water shortage in China's northern regions, and thus release to a degree the pressure on the Yangtze water resources. Best management practices of rainwater can be an effective controlling strategy for flooding and non-point-source water pollution of waterways. Such in-site source control initiatives have particular significance to protecting slow waterways of weak self-purification ability, like the Three Gorges Reservior.

Construction Approaches of Urban Spongy Park Based on Low Impact Development

Rapid urbanization has brought various water-concerning problems to cities, such as water source scarcity, water pollution, fl ood disaster, and habitat loss of aquatic life, Low Impact Development(LID) is a signifi cant approach of solving these problems. Through sorting out causes and connotations of LID and urban spongy park, this proposed that fl exible design is the core content of spongy park construction, and on this basis analyzed objectives, contents and approaches of urban spongy park construction, put forward strategies suitable for the construction of urban spongy parks in China, in order to instruct future construction of domestic urban spongy parks and promote the development of ecological civilization.

Ecological Function of Urban Green Roof and Analysis of Its Influencing Factors

Based on the analysis of the multiple ecological functions of green roofs, the main factors affecting the ecological functions of green roofs are expounded and the numerical simulation methods for quantitative calculation of ecological functions of green roofs are summarized in order to provide theoretical and method support for the construction of urban green roofs.

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

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