可持续城市水环境系统规划设计方法与工具研究

在明确可持续城市水环境系统概念特征的基础上,以最大化系统的可持续性为根本目标提出了系统规划设计原则,建立了以系统模式选择、空间布局优化与工程设计为核心步骤的三阶段规划方法,自主研发了规划新工具——基于多属性不确定性决策的系统模式筛选模型与基于空间多目标优化的系统布局优化模型。将所建立的方法与工具应用于某新城地区的水系统规划,为当地确定了系统建设模式与空间布局最优方案,并验证了研究成果从理念原则、方法工具、与现有规划体系衔接等多个层面满足当前城市水环境系统规划的需求。

基于功能湿地的生态社区水环境建设

水景住宅是我国近年来房地产开发的热点,然而开发过程中水环境的后期治理和运行过程中问题频现,因此,国内外学者和开发商开始针对生态水景进行规划设计和开发研究,以实现社区水环境可持续发展的目的。文章基于功能湿地的生态特性和功能特性,提出当今生态水景住宅社区的水环境与功能湿地相结合,同时将湿地系统与雨水收集、中水回用进行整合设计,以国内外社区生态水环境的实践为例证进行开放性的研究。

A discussion of the risks and benefits of using rock terracing to limit soil erosion in Guizhou Province

The construction of stone terraces to minimise soil erosion is common throughout Guizhou. This technique, however, has high inherent risk. Stone terraces are usually much higher than those with earth risers. While they trap a greater thickness of soil on the slope they increase the risk of slope failures, reduce moisture and nutrient availability to plants, and thin more soil up slope. The stone risers also threaten long-term productivity. When a riser collapses debris is deposited over the terrace below making farming difficult. These breaches in the terrace focus surface runoff leading to gully formation and increased sediment transport down slope. Artificial drainage systems, often used in conjunction with terracing, compound the risk. These channels prevent precipitation from soaking into the soil. This limits groundwater and soil moisture recharge which reduces the availability of water for crops and the length of the growing season. The rapid drainage of water from the slope reduces the time of concentration of the catchment resulting in an increase in flood activity. Floods are caused by smaller rainstorm events. They arrive faster and peak quicker and higher than before the channels were constructed. Engineering solutions to soil erosion must therefore be used in conjunction with, and are not as a substitute for, good land management strategies. Furthermore, despite changes in land use practices, and the application of new technologies, there is a maximum amount of production that can be obtained from this land on a sustainable basis.

Sustainable Application of a Novel Water Cycle Using Seawater for Toilet Flushing

Global water security is a severe issue that threatens human health and well-being. Finding sustainable alternative water resources has become a matter of great urgency. For coastal urban areas, desalinated seawater could serve as a freshwater supply. However, since 20%-30% of the water supply is used for flushing waste from the city, seawater with simple treatment could also partly replace the use of freshwater. In this work, the freshwater saving potential and environmental impacts of the urban water system （water-wastewater closed loop） adopting seawater desalination, seawater for toilet flushing （SWTF）, or reclaimed water for toilet flushing （RWTF） are compared with those of a conventional freshwater system, through a life-cycle assessment and sensitivity analysis. The potential applications of these processes are also assessed. The results support the environmental sustainability of the SWTF approach, but its potential application depends on the coastal distance and effective population density of a city. Developed coastal cities with an effective population density exceeding 3000 persons.km-2 and located less than 30 km from the seashore （for the main pipe supplying seawater to the city） would benefit from applying SWTF, regardless of other impact parameters. By further applying the sulfate reduction, autotrophic denitrification, and nitrification integrated （SANI） process for wastewater treatment, the maximum distance from the seashore can be extended to 60 km. Considering that most modern urbanized cities fulfill these criteria, the next generation of water supply systems could consist of a freshwater supply coupled with a seawater supply for sustainable urban development.

Social Responsibility and Environmental Sustainability： The Case of Caixa Geral de Dep6sitos （Portugal） and Vale （Brazil）

Social responsibility requires a set of duties and obligations, whether individuals or firms in relation to society and to the communities in which the organization is operating. The tradition of social intervention in Portugal dates from the fifteenth century and the founding of Mercy. However, environmental issues have never been felt in a sensitive position in responsible business, given the weakness of industrial development which lasted until the 60＇s. In Brazil, the corporate social responsibility is still particularly a big challenge, since the actions of social responsibility have not contributed effectively to improve the living conditions of society and the transformation of existing social reality. The purpose of this study is to emphasize the perspective of environmental sustainability that underpins the more general concept of social responsibility and, through the case study Caixa Geral de Dep6sitos, assess the strengths and weaknesses of the development of measures of social responsibility in this area in Portugal, and present the case of the company Vale, carrying out business in Brazil

China’s Food Security Status:Assessment and Strategic Reflections

Based on an internationally recognized concept of food security, this paper has created a system of eight indicators to analyze China＇s food security. For the proper control and analysis of this study, the authors of this paper have chosen these indicators： supply, distribution, consumption, utilization efficiency, food security results, stability, sustainability and controllability. Results indicate that China＇s food security is currently at a high level and has been increasing in recent years. China＇s food security has multiple advantages with various indicators that include a self-sufficiency ratio, per capita calorie intake and protein supply that are above world average levels, even exceeding the average level of some developed countries. Major challenges facing China＇s food security include an unreasonable nutrition structure and poor environmental sustainability. In order to increase China＇s food security level, efforts must be made to adjust output structure, adopt an environmentally friendly pattern of production, attach importance to demand management, reduce unreasonable consumption and loss and moderately lower China＇s food reserve ratio.

Maize-rice cropping systems in Bangladesh： Status and research needs

Maize-rice cropping systems are expanding in Bangladesh. Hybrid maize has increasing demand and value, particularly for poultry feed, while rice remains the traditional dominant starch staple food. Bangladesh maize yields （with average farm yields around 5.7 t·ha^-1） are among the highest found in Asia. Cool winter （Rabi） season maize followed by T. Aman （monsoon） rice is the major cropping system; however it is now becoming diversified with many other crops including potato. Financially, hybrid maize is far more profitable than boro （irrigated） rice, wheat, or most other competing winter season Rabi crops. Although maize is relatively problem-free in Bangladesh, some constraints are intensifying with increased concern over input supply and soil-related environmental sustainability. An array of new technologies for sustainable intensive maize production systems is emerging in Bangladesh and some are being promoted and adopted. Continued sustainability of hybrid maize production in Bangladesh depends on optimization of planting time, quality seed of appropriate hybrids, balanced use of nutrient inputs along with soil fertility conservation and other management, for which further research would be high priority.

Resilient Development of Urban Waterfront in Fast-Changing Cities--A Case Study of Wuhan, China

Urban waterfronts, where the land of city meets a body of water, are unique and finite resources representing the best opportunities for community enhancement and enrichment. On the other hand, waterfronts are also high-risk areas, where the water-related disasters could seriously affect the long-term sustainability of urban environment. This paper focuses on the relationship of the cities with their waterfronts. It presents a case study of Wuhan--a Chinese metropolis, where waterfronts play an important role in its urban planning policy. It attempts to investigate the mechanism of waterfront transformation, and to find out which strategies to adapt and what resilience means in terms of urban waterfronts in a rapidly transforming city. This article examines some representative urban projects on the waterfront and summarizes spatial models applied on the waterfront with distinct policies. Finally, it demonstrates that an urban waterfront is an ＂osmotic interface＂ which should be more correctly envisaged as a network of places, functions, additions and hinges between the city and its water environment. It clarifies that waterfront areas represent a multidisciplinary and multitasking issue in perspective of urban resilient development.

Infilled Reinforced Concrete Beams for Sustainable Construction

This paper presents a study carried out on infilled reinforced concrete beams for sustainable construction. In reinforced concrete beams, less stressed concrete below neutral axis can be replaced by some light weight material to reduce the weight of the structure and also achieve the economy. The used infilled material is brick. Sustainability can be achieved by replacing the partially used concrete. By saving concrete, the authors save cement, which reduces the green house gases emissions. So it is considered as environment friendly. Since infilled beam acts like a layered member, there needs a theory to analyze it. Method of initial functions is used for the analysis of the infilled RC （reinforced concrete） beams. This method is successfully applied on infilled beam. Results show that physical conditions are verified for infilled beam.